ASN RSS https://amnat.org/ Latest press releases and announcements from the ASN en-us Sat, 20 Apr 2019 05:00:00 GMT 60 “Bimodal pollination systems in Andean Melastomataceae involving birds, bats, and rodents” https://amnat.org/an/newpapers/JulyDellinger.html The DOI will be https://dx.doi.org/10.1086/703517 Biomodal pollination systems in the Andes: nectar adaptations to birds, South African scent compounds in rodent flowers A&nbsp;flower pollinated only by a single animal species is the most extreme case of specialization in plant-pollinator interactions and this flower will show specific adaptations to its pollinator to maximize reproductive output. On the other extreme, generalized pollination systems involve many different animal species (often of different groups, e.g. beetles, flies, butterflies) and generalist flowers are adapted to make use of all of these different pollinators simultaneously. Flowers visited by two pollinator groups (e.g. hummingbirds and bats), such as documented in a new paper in The&nbsp;American Naturalist by Dellinger et al., lie between these extremes and may help understand when and how specialized or generalized pollination systems evolve. In her PhD project, Dellinger investigated floral adaptations to variable combinations of two different pollinator groups in four closely related South American plant species. She conducted pollinator observations and experiments in three different cloud forest sites in Ecuador. Dellinger et al. found that all investigated species were effectively pollinated by one diurnally active pollinator group and a nocturnally active one (hummingbirds/bats, hummingbirds/rodents, flowerpiercers/rodents). All species have widely open flowers, which allow access to the nectar reward to both pollinator groups at all times. Nectar sugar composition shows typical adaptations to diurnal bird pollinators while scent profiles indicate adaptation to nocturnal bat/rodent pollinators. Dellinger et al. conclude that these pollination systems are specialized rather than generalized and exhibit ‘bimodal’ adaptations to exploit two different pollinator groups. Apparently, being specialized on these pollinator combinations is advantageous and outweighs costs (trade-offs) reported for other pollination systems involving more than one pollinator group. Abstract Floral adaptation to a single most effective functional pollinator group leads to specialized pollination syndromes. However, adaptations allowing for pollination by two functional groups (bimodal pollination systems) remain a conundrum rarely investigated. We tested if floral scent and nectar traits of species visited by two functional pollinator groups indicate specialization on either one of the two or (intermediate) bimodal systems. We studied pollination biology in four species of Meriania (Melastomataceae) in the Ecuadorian Andes. Pollinator observations and exclusion experiments showed that each species was effectively pollinated by two functional groups (hummingbirds/bats; hummingbirds/rodents; flowerpiercers/rodents), nectar composition followed known bird preferences and scent profiles gave mixed support for specialization on bats and rodents. Our results suggest that nectar rewarding Meriania species have evolved stable bimodal pollination strategies with parallel adaptations to two functional pollinator groups. The discovery of rodent pollination is particularly important given its rarity outside of South Africa. Síndromes florales bimodales en Melastomataceae Andinas incluyendo aves, murcielagos y ratones La adaptación a solo un grupo funcional de polinizadores lleva a síndromes florales especializados, pero todavía no se entiende bien cómo las flores pueden adaptarse a la polinización por dos grupos de polinizadores (síndromes bimodales). Analizamos el olor floral y características del néctar de cuatro especies de Meriania (Melastomataceae) visitadas por dos grupos distintos de polinizadores, para evaluar si hay síndromes de polinización a un solo grupo funcional de polinizadores o muestra síndromes bimodales. Nuestros experimentos mostraron que en cada especie de Meriania dos grupos de polinizadores (colibríes/murciélagos; colibríes/ratones; pinchaflores/ratones) son eficientes en el transporte de polen. La composición del néctar indicó especialización a los polinizadores diurnos (colibríes, pinchaflores), mientras que el olor de las flores mostró más especialización por los polinizadores nocturnos (murciélagos y ratones). Nuestros resultados sugieren que especies nectaríferas de Meriania evolucionaron síndromes bimodales estables con adaptaciones paralelas a dos grupos funcionales de polinizadores. El descubrimiento de polinización por ratones es especialmente importante por la rareza con que ocurre fuera de Sudáfrica. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703517 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703517">Read the Article</a></i> </p> --> <p><b>Biomodal pollination systems in the Andes: nectar adaptations to birds, South African scent compounds in rodent flowers </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">A</span>&nbsp;flower pollinated only by a single animal species is the most extreme case of specialization in plant-pollinator interactions and this flower will show specific adaptations to its pollinator to maximize reproductive output. On the other extreme, generalized pollination systems involve many different animal species (often of different groups, e.g. beetles, flies, butterflies) and generalist flowers are adapted to make use of all of these different pollinators simultaneously. Flowers visited by two pollinator groups (e.g. hummingbirds and bats), such as documented in a new paper in <i>The&nbsp;American Naturalist</i> by Dellinger et al., lie between these extremes and may help understand when and how specialized or generalized pollination systems evolve. </p><p>In her PhD project, Dellinger investigated floral adaptations to variable combinations of two different pollinator groups in four closely related South American plant species. She conducted pollinator observations and experiments in three different cloud forest sites in Ecuador. Dellinger et al. found that all investigated species were effectively pollinated by one diurnally active pollinator group and a nocturnally active one (hummingbirds/bats, hummingbirds/rodents, flowerpiercers/rodents). All species have widely open flowers, which allow access to the nectar reward to both pollinator groups at all times. Nectar sugar composition shows typical adaptations to diurnal bird pollinators while scent profiles indicate adaptation to nocturnal bat/rodent pollinators. Dellinger et al. conclude that these pollination systems are specialized rather than generalized and exhibit ‘bimodal’ adaptations to exploit two different pollinator groups. Apparently, being specialized on these pollinator combinations is advantageous and outweighs costs (trade-offs) reported for other pollination systems involving more than one pollinator group. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">F</span>loral adaptation to a single most effective functional pollinator group leads to specialized pollination syndromes. However, adaptations allowing for pollination by two functional groups (bimodal pollination systems) remain a conundrum rarely investigated. We tested if floral scent and nectar traits of species visited by two functional pollinator groups indicate specialization on either one of the two or (intermediate) bimodal systems. We studied pollination biology in four species of <i>Meriania</i> (Melastomataceae) in the Ecuadorian Andes. Pollinator observations and exclusion experiments showed that each species was effectively pollinated by two functional groups (hummingbirds/bats; hummingbirds/rodents; flowerpiercers/rodents), nectar composition followed known bird preferences and scent profiles gave mixed support for specialization on bats and rodents. Our results suggest that nectar rewarding <i>Meriania</i> species have evolved stable bimodal pollination strategies with parallel adaptations to two functional pollinator groups. The discovery of rodent pollination is particularly important given its rarity outside of South Africa. </p> <h4>Síndromes florales bimodales en Melastomataceae Andinas incluyendo aves, murcielagos y ratones</h4> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">L</span>a adaptación a solo un grupo funcional de polinizadores lleva a síndromes florales especializados, pero todavía no se entiende bien cómo las flores pueden adaptarse a la polinización por dos grupos de polinizadores (síndromes bimodales). Analizamos el olor floral y características del néctar de cuatro especies de <i>Meriania</i> (Melastomataceae) visitadas por dos grupos distintos de polinizadores, para evaluar si hay síndromes de polinización a un solo grupo funcional de polinizadores o muestra síndromes bimodales. Nuestros experimentos mostraron que en cada especie de <i>Meriania</i> dos grupos de polinizadores (colibríes/murciélagos; colibríes/ratones; pinchaflores/ratones) son eficientes en el transporte de polen. La composición del néctar indicó especialización a los polinizadores diurnos (colibríes, pinchaflores), mientras que el olor de las flores mostró más especialización por los polinizadores nocturnos (murciélagos y ratones). Nuestros resultados sugieren que especies nectaríferas de <i>Meriania</i> evolucionaron síndromes bimodales estables con adaptaciones paralelas a dos grupos funcionales de polinizadores. El descubrimiento de polinización por ratones es especialmente importante por la rareza con que ocurre fuera de Sudáfrica. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 17 Apr 2019 05:00:00 GMT “Phytoplankton species richness along coastal and estuarine salinity continua” https://amnat.org/an/newpapers/AugOlli.html The DOI will be https://dx.doi.org/10.1086/703657 Phytoplankton diversity-salinity relation follows Remane curve: High richness at fresh and saline ends, low at brackish Throughout the evolutionary time scales, the boundary between freshwater and ocean salinity has been a tough one for aquatic organisms to cross. Compared to freshwater and the ocean, a lower number of species thrive at brackish salinity. This textbook knowledge stems from the classical work by Adolf Remane with benthic macro-invertebrate diversity in the Baltic Sea, and has shaped our understanding of species richness along the salinity gradient for 85 years. When it comes to phytoplankton, the base of the aquatic food chain, it is surprising how little scrutiny the matter has received. This is partly due to the rareness of high-quality phytoplankton data sets covering the full salinity range from fresh water to the ocean. Recently some researchers have proposed a reversal of Remane’s concept for protists and phytoplankton, with a richness maximum at brackish salinities. Analysis of sizeable phytoplankton data sets from two large coastal ecosystems, the Chesapeake Bay and the Baltic Sea, unambiguously corroborated the validity of the Remane concept in terms of both alpha and gamma species richness. These analyses, based on >15,000 phytoplankton samples, revealed in both data sets minima in species richness at salinities around 7-9, and increasing diversity towards both limbs of the salinity gradient. Why does this matter? Biodiversity is the basis of ecosystem functioning and services; hence, understanding the drivers of biodiversity become mandatory for human wellbeing. Our results support the idea that ecological scaling rules apply to microbial diversity in ways similar to what is known from the macrobial realm. The results enable us to predict changes in diversity, and the associated ecosystem functions, in the era of global change, where coastal and estuarine salinity gradients are shifting due to changes in precipitation and hydrology. Abstract High number of freshwater species at low salinity, and a corresponding high number of marine species at high salinity, enveloping a conspicuous richness minimum at intermediate salinities, has shaped our basic understanding of biodiversity along a coastal salinity gradient for almost 80 years. Visualized as the ‘Remane curve’, this iconic concept was originally based on sedentary macroinvertebrates in the Baltic Sea. To what extent the concept can be generalized, particularly to free-drifting organisms, is currently debated. Here we use ca 16,000 phytoplankton samples from 2 large coastal ecosystems, the Baltic Sea and the Chesapeake Bay, to analyze the relationship between salinity and phytoplankton species richness. Alpha diversity showed a consistent variation along the salinity gradient, with a minimum at mesohaline salinities at around 7 – 9. Rarefied species pools at narrow salinity intervals also showed reduced diversity at intermediate salinities, surrounded by high richness towards both ends of the gradient. The cumulative likelihood of species presence validated the minimum at intermediate salinities. Community composition changed abruptly at the α diversity minimum in the Baltic Sea, while it changed gradually along the salinity gradient in the Chesapeake Bay. We conclude that the Remane concept is in every respect valid for phytoplankton. Fütoplaktoni liigirikkus rannikumere ja estuaari soolsusgradientidel Ligi 80 aastat on meie arusaama vee organismide liigirikkusest soolsusgradiendil kujundanud paradigmaks muutunud Remane kõver. Selle järgi on magevee liigirikkus suur, suur on liigirikkus ka ookeanis, kuid vahepealses riimveelises osas on tuntav liigirikkuse madalseis. Adolf Remane sedastas oma seaduspära uurides põhjaeluliste suurselgrootute liigirikkust Läänemeres. Kas ja millisel määral on seaduspära kehtiv teiste organismirühmade puhul, eriti vabalt hõljuvate plankterite puhul, ei ole teada. Me analüüsisime ligi 16,000 fütoplanktoni proovi liigirikkust kahe suure ökosüsteemi, Läänemere ja Chesapeake Lahe soolsusgradientidel. Proovide liigirikkus oli madalaim gradiendi mesohaliinses piirkonnas, soolsusel 7 – 9. Ka harvenduskõverad kitsastes soolsusvahemikes näitasid madalat liigirikkust mesohaliinses piirkonnas ja fütoplanktoni liigirikkus suurenemist nii magevee, kui ookeani soolsuse suunal. Liikide kumulatiivne esinemise tõenäosus soolsuse gradiendil näitas samuti liigirikkuse miinimumi riimveelises osas. Chesapeake Lahes muutub fütoplanktoni kooslus mageveelisest mereliseks sujuvalt kogu soolsusgradiendil. Kontrastina, Läänemere eripäraks on fütoplanktoni koosluse järsk muutus liigirikkuse miinimumi piirkonnas. Analüüsi tulemused näitavad, et Remane printsiip on täiel määral kehtiv ka fütoplanktoni puhul. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703657 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703657">Read the Article</a></i> </p> --> <p><b>Phytoplankton diversity-salinity relation follows Remane curve: High richness at fresh and saline ends, low at brackish </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">T</span>hroughout the evolutionary time scales, the boundary between freshwater and ocean salinity has been a tough one for aquatic organisms to cross. Compared to freshwater and the ocean, a lower number of species thrive at brackish salinity. This textbook knowledge stems from the classical work by Adolf Remane with benthic macro-invertebrate diversity in the Baltic Sea, and has shaped our understanding of species richness along the salinity gradient for 85 years. </p><p>When it comes to phytoplankton, the base of the aquatic food chain, it is surprising how little scrutiny the matter has received. This is partly due to the rareness of high-quality phytoplankton data sets covering the full salinity range from fresh water to the ocean. Recently some researchers have proposed a reversal of Remane’s concept for protists and phytoplankton, with a richness maximum at brackish salinities. </p><p>Analysis of sizeable phytoplankton data sets from two large coastal ecosystems, the Chesapeake Bay and the Baltic Sea, unambiguously corroborated the validity of the Remane concept in terms of both alpha and gamma species richness. These analyses, based on &gt;15,000 phytoplankton samples, revealed in both data sets minima in species richness at salinities around 7-9, and increasing diversity towards both limbs of the salinity gradient. </p><p>Why does this matter? Biodiversity is the basis of ecosystem functioning and services; hence, understanding the drivers of biodiversity become mandatory for human wellbeing. Our results support the idea that ecological scaling rules apply to microbial diversity in ways similar to what is known from the macrobial realm. The results enable us to predict changes in diversity, and the associated ecosystem functions, in the era of global change, where coastal and estuarine salinity gradients are shifting due to changes in precipitation and hydrology. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">H</span>igh number of freshwater species at low salinity, and a corresponding high number of marine species at high salinity, enveloping a conspicuous richness minimum at intermediate salinities, has shaped our basic understanding of biodiversity along a coastal salinity gradient for almost 80 years. Visualized as the ‘Remane curve’, this iconic concept was originally based on sedentary macroinvertebrates in the Baltic Sea. To what extent the concept can be generalized, particularly to free-drifting organisms, is currently debated. Here we use ca 16,000 phytoplankton samples from 2 large coastal ecosystems, the Baltic Sea and the Chesapeake Bay, to analyze the relationship between salinity and phytoplankton species richness. Alpha diversity showed a consistent variation along the salinity gradient, with a minimum at mesohaline salinities at around 7 – 9. Rarefied species pools at narrow salinity intervals also showed reduced diversity at intermediate salinities, surrounded by high richness towards both ends of the gradient. The cumulative likelihood of species presence validated the minimum at intermediate salinities. Community composition changed abruptly at the α diversity minimum in the Baltic Sea, while it changed gradually along the salinity gradient in the Chesapeake Bay. We conclude that the Remane concept is in every respect valid for phytoplankton. </p> <h4>Fütoplaktoni liigirikkus rannikumere ja estuaari soolsusgradientidel</h4> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">L</span>igi 80 aastat on meie arusaama vee organismide liigirikkusest soolsusgradiendil kujundanud paradigmaks muutunud Remane kõver. Selle järgi on magevee liigirikkus suur, suur on liigirikkus ka ookeanis, kuid vahepealses riimveelises osas on tuntav liigirikkuse madalseis. Adolf Remane sedastas oma seaduspära uurides põhjaeluliste suurselgrootute liigirikkust Läänemeres. Kas ja millisel määral on seaduspära kehtiv teiste organismirühmade puhul, eriti vabalt hõljuvate plankterite puhul, ei ole teada. Me analüüsisime ligi 16,000 fütoplanktoni proovi liigirikkust kahe suure ökosüsteemi, Läänemere ja Chesapeake Lahe soolsusgradientidel. Proovide liigirikkus oli madalaim gradiendi mesohaliinses piirkonnas, soolsusel 7 – 9. Ka harvenduskõverad kitsastes soolsusvahemikes näitasid madalat liigirikkust mesohaliinses piirkonnas ja fütoplanktoni liigirikkus suurenemist nii magevee, kui ookeani soolsuse suunal. Liikide kumulatiivne esinemise tõenäosus soolsuse gradiendil näitas samuti liigirikkuse miinimumi riimveelises osas. Chesapeake Lahes muutub fütoplanktoni kooslus mageveelisest mereliseks sujuvalt kogu soolsusgradiendil. Kontrastina, Läänemere eripäraks on fütoplanktoni koosluse järsk muutus liigirikkuse miinimumi piirkonnas. Analüüsi tulemused näitavad, et Remane printsiip on täiel määral kehtiv ka fütoplanktoni puhul. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 17 Apr 2019 05:00:00 GMT “Consistent associations between body size and hidden contrasting color signals across a range of insect taxa” https://amnat.org/an/newpapers/JulyLoefflerHenry.html The DOI will be https://dx.doi.org/10.1086/703535 The evolution of hidden contrasting coloration is associated with body size in insects Coloration frequently serves to protect insects from visual predators through crypsis, warning signals, and mimicry. While these color patterns are often permanently displayed, some insect species use their anti-predatory color signals more dynamically: they normally remain camouflaged, but reveal conspicuous colors transiently upon approach by predators. Recent studies have demonstrated that such flash (in moving prey) and deimatic (in stationary prey) conspicuous displays are more effective in deterring predators when exhibited by larger prey than smaller prey. Thus, one might expect that hidden conspicuous color signals would be more likely to be found in large than small prey species. The collaborative research team between Carleton University and Mokpo National University tested this hypothesis in five different insect groups that are known to utilize hidden conspicuous color signals: Orthoptera, Mantidae, Phasmatidae, Saturniidae, and Sphingidae. Our findings suggest that after controlling for the effect of shared ancestry, the presence of hidden conspicuous color signals is indeed associated with large size in most of the studied insect taxa. These results therefore provide further evidence that anti-predator traits in insects is at least in part mediated by body size. Abstract While there have been a number of recent advances in our understanding of the evolution of animal color patterns, much of this work has focused on color patterns that are constantly displayed. However, some animals hide functional color signals and only display them transiently through behavioral displays. These displays are widely employed as a secondary defense following detection when fleeing (flash display) or when stationary (deimatic display). Yet if displays of hidden colors are so effective in deterring predation, why have not all species evolved them? An earlier study suggested that the hidden anti-predatory color signals in insects are more likely to have evolved in species with large size because either (or both): i) large cryptic prey are more frequently detected and pursued and ii) hidden color signals in large prey are more effective in deterring predation than small prey. These arguments should apply universally to any prey that use hidden signals so the association between large size and hidden contrasting color signals should be evident across diverse groups of prey. In this study, we tested this prediction in five different groups of insects. Using phylogenetically controlled analysis to elucidate the relationship between body size and color contrast between forewings and hindwings, we found evidence for the predicted size-color contrast associations in four different groups of insects, namely Orthoptera, Phasmatidae, Mantidae, Saturniidae, but not in Sphingidae. Collectively, our study indicates that body size plays an important role in explaining variation in the evolution of hidden contrasting color signals in insects. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703535 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703535">Read the Article</a></i> </p> --> <p><b>The evolution of hidden contrasting coloration is associated with body size in insects </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">C</span>oloration frequently serves to protect insects from visual predators through crypsis, warning signals, and mimicry. While these color patterns are often permanently displayed, some insect species use their anti-predatory color signals more dynamically: they normally remain camouflaged, but reveal conspicuous colors transiently upon approach by predators. Recent studies have demonstrated that such flash (in moving prey) and deimatic (in stationary prey) conspicuous displays are more effective in deterring predators when exhibited by larger prey than smaller prey. Thus, one might expect that hidden conspicuous color signals would be more likely to be found in large than small prey species. The collaborative research team between Carleton University and Mokpo National University tested this hypothesis in five different insect groups that are known to utilize hidden conspicuous color signals: Orthoptera, Mantidae, Phasmatidae, Saturniidae, and Sphingidae. Our findings suggest that after controlling for the effect of shared ancestry, the presence of hidden conspicuous color signals is indeed associated with large size in most of the studied insect taxa. These results therefore provide further evidence that anti-predator traits in insects is at least in part mediated by body size. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">W</span>hile there have been a number of recent advances in our understanding of the evolution of animal color patterns, much of this work has focused on color patterns that are constantly displayed. However, some animals hide functional color signals and only display them transiently through behavioral displays. These displays are widely employed as a secondary defense following detection when fleeing (flash display) or when stationary (deimatic display). Yet if displays of hidden colors are so effective in deterring predation, why have not all species evolved them? An earlier study suggested that the hidden anti-predatory color signals in insects are more likely to have evolved in species with large size because either (or both): i) large cryptic prey are more frequently detected and pursued and ii) hidden color signals in large prey are more effective in deterring predation than small prey. These arguments should apply universally to any prey that use hidden signals so the association between large size and hidden contrasting color signals should be evident across diverse groups of prey. In this study, we tested this prediction in five different groups of insects. Using phylogenetically controlled analysis to elucidate the relationship between body size and color contrast between forewings and hindwings, we found evidence for the predicted size-color contrast associations in four different groups of insects, namely Orthoptera, Phasmatidae, Mantidae, Saturniidae, but not in Sphingidae. Collectively, our study indicates that body size plays an important role in explaining variation in the evolution of hidden contrasting color signals in insects. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 17 Apr 2019 05:00:00 GMT “Eco-evolutionary dynamics in the wild: clonal turnover and stability in Daphnia populations” https://amnat.org/an/newpapers/JulySteiner-A.html The DOI will be https://dx.doi.org/10.1086/703484 Abstract There is increasing recognition of the importance of rapid adaptation in the dynamics of populations and communities. While the effects of rapid adaptation on the stability of populations have been shown in experimental systems, demonstration of their impacts in natural populations are rare. We examined the relationship between clonal dynamics and population stability of natural Daphnia pulex populations experiencing seasonal environmental variation. We show that the degree of asynchrony in a population&#39;s clonal dynamics is tightly linked to its population-level stability. Populations whose clonal abundances were more asynchronous were more stable temporally. Variation in asynchrony was related to variability in primary productivity, and experiments using clones from the study populations revealed significant genotype by environment interactions in response to food level. This suggests that clonal turnover was not due to neutral dynamics alone but may be linked to variation in functional traits associated with resource acquisition and conversion. More forthcoming papers &raquo; <p><em>The DOI will be https://dx.doi.org/10.1086/703484 </em></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703484">Read the Article</a></i> </p> --> <h3>Abstract</h3> <p><strong>T</strong>here is increasing recognition of the importance of rapid adaptation in the dynamics of populations and communities. While the effects of rapid adaptation on the stability of populations have been shown in experimental systems, demonstration of their impacts in natural populations are rare. We examined the relationship between clonal dynamics and population stability of natural <em>Daphnia pulex</em> populations experiencing seasonal environmental variation. We show that the degree of asynchrony in a population&#39;s clonal dynamics is tightly linked to its population-level stability. Populations whose clonal abundances were more asynchronous were more stable temporally. Variation in asynchrony was related to variability in primary productivity, and experiments using clones from the study populations revealed significant genotype by environment interactions in response to food level. This suggests that clonal turnover was not due to neutral dynamics alone but may be linked to variation in functional traits associated with resource acquisition and conversion.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family:georgia; font-size:large"><em>More forthcoming papers</em> &raquo;</span></a></div> Wed, 17 Apr 2019 05:00:00 GMT “Evolutionary hysteresis and ratchets in the evolution of periodical cicadas” https://amnat.org/an/newpapers/JulyToivonen.html The DOI will be https://dx.doi.org/10.1086/703563 Evolutionary hysteresis and ratchets promote the evolution of long synchronous life cycles in periodical cicadas The authors show how two interesting evolutionary mechanisms, hysteresis and ratchets, promote the evolution of long and synchronous life-cycles in the periodical cicadas. Evolutionary hysteresis is a phenomenon wherein evolution not only depends on the current environmental conditions but also on the history of environmental change. Evolutionary ratchets are mechanisms that cause evolution to become “locked” such that it can only proceed in one direction. The authors show that the evolution of perfectly synchronous life-cycles in the periodical cicadas is unlikely in contemporary climates. However, the harsh environmental conditions encountered during past ice ages may have been instrumental in the evolution of synchronicity. Further, once a synchronous life-cycle is attained it cannot be lost even when the environmental conditions become favorable again (evolutionary hysteresis). The authors show that once periodical cicadas evolved synchronous life cycles they would only have been able to develop ever longer life cycles and it became impossible for them to return to non-synchronous or shorter life cycles (evolutionary ratchet). While this paper concentrates on a specific case study, the authors hope to inspire others to look for evolutionary ratchets and hysteresis in other contexts as well. Abstract It has been previously hypothesized that the perfectly synchronized mass emergence of periodical cicadas (Magicicada spp.) evolved as a result of a switch from size-based to age-based emergence. In the former case cicada nymphs emerge immediately (at the first opportunity) upon reaching maturity whereas in the latter case nymphs wait in order to emerge at a specific age. Here we use an individual-based model to simulate the cicada life cycle and to study the evolution of periodicity. We find that if age-based emergence evolves in a constant abiotic environment, it typically results in a population that is proto-periodic and synchronous emergence of the whole population is not achieved. However, perfect periodicity and synchronous emergence can be attained, if the abiotic environment changes back-and-forth between favorable and unfavorable conditions (hysteresis). Furthermore, once age-based emergence evolves, generally it can only be invaded by other age-based emergence strategies with longer cycle lengths (evolutionary ratchet). Together, these mechanisms promote the evolution of long periodic life cycles and synchronous emergence in the \textit{Magicicada}. We discuss how our results connect to previous theories and recent phylogenetic studies on Magicicada evolution. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703563 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703563">Read the Article</a></i> </p> --> <p><b>Evolutionary hysteresis and ratchets promote the evolution of long synchronous life cycles in periodical cicadas </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">T</span>he authors show how two interesting evolutionary mechanisms, hysteresis and ratchets, promote the evolution of long and synchronous life-cycles in the periodical cicadas. Evolutionary hysteresis is a phenomenon wherein evolution not only depends on the current environmental conditions but also on the history of environmental change. Evolutionary ratchets are mechanisms that cause evolution to become “locked” such that it can only proceed in one direction. </p> <p>The authors show that the evolution of perfectly synchronous life-cycles in the periodical cicadas is unlikely in contemporary climates. However, the harsh environmental conditions encountered during past ice ages may have been instrumental in the evolution of synchronicity. Further, once a synchronous life-cycle is attained it cannot be lost even when the environmental conditions become favorable again (evolutionary hysteresis). The authors show that once periodical cicadas evolved synchronous life cycles they would only have been able to develop ever longer life cycles and it became impossible for them to return to non-synchronous or shorter life cycles (evolutionary ratchet). </p> <p>While this paper concentrates on a specific case study, the authors hope to inspire others to look for evolutionary ratchets and hysteresis in other contexts as well.</p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">I</span>t has been previously hypothesized that the perfectly synchronized mass emergence of periodical cicadas (<i>Magicicada</i> spp.) evolved as a result of a switch from size-based to age-based emergence. In the former case cicada nymphs emerge immediately (at the first opportunity) upon reaching maturity whereas in the latter case nymphs wait in order to emerge at a specific age. Here we use an individual-based model to simulate the cicada life cycle and to study the evolution of periodicity. We find that if age-based emergence evolves in a constant abiotic environment, it typically results in a population that is proto-periodic and synchronous emergence of the whole population is not achieved. However, perfect periodicity and synchronous emergence can be attained, if the abiotic environment changes back-and-forth between favorable and unfavorable conditions (hysteresis). Furthermore, once age-based emergence evolves, generally it can only be invaded by other age-based emergence strategies with longer cycle lengths (evolutionary ratchet). Together, these mechanisms promote the evolution of long periodic life cycles and synchronous emergence in the \textit{Magicicada}. We discuss how our results connect to previous theories and recent phylogenetic studies on Magicicada evolution. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 17 Apr 2019 05:00:00 GMT “Dense dwarfs versus gelatinous giants: The trade-offs and physiological limits determining the body plan of planktonic filter feeders” https://amnat.org/an/newpapers/AugDoelger.html The DOI will be https://dx.doi.org/10.1086/703656 Gelatinous plankton form a special group of marine organisms due to their distinctly watery bodies with low carbon content. We find the gelatinous body plan mainly in large, centimeter-sized plankton who feed by filtering their micron-sized prey out of the water instead of perceiving it at a distance. Why do such planktonic giants tend to be gelatinous while microbes (dwarfs) that filter feed on the same prey stay dense? A marine biologist and two physicists in the Centre for Ocean Life at the Technical University of Denmark have resolved this question by developing a new theoretical model. By modeling the energy budget of filter feeders, the authors show that the interplay between gain and cost of energy has the key implication that a minimum filter area is necessary to collect enough food to sustain a living. Through comparison of their model predictions and existing data on filter feeders, the authors conclude that filter feeders need to be either small or if they are large to increase the filter area by being gelatinous in order to survive in dilute oceanic environments. Large plankton that are non-gelatinous also exist, but they either live in prey-rich environments or compensate by sensing their prey at a distance. Such understanding of planktonic survival strategies is essential to model and predict the global distributions of plankton. It directly connects to the main goal of the Centre for Ocean Life where marine ecologists, physicists, chemists, and mathematicians are working jointly to build a trait-based description of life in the ocean. Abstract Most marine plankton have a high energy (carbon) density, but some are gelatinous with approximately hundred times more watery bodies. How do those distinctly different body plans emerge and what are the trade-offs? We address this question by modeling the energy budget of planktonic filter feeders across life forms from micron-sized unicellular microbes like choanoflagellates to centimeter-sized gelatinous tunicates such as salps. We find two equally successful strategies, one being small with high energy density (dense dwarf), and the other being large with low energy density (gelatinous giant). The constraint that forces large – but not small – filter feeders to be gelatinous is identified as a lower limit to the size-specific filter area, below which the energy costs lead to starvation. A further limit is found from the maximum size-specific motor force that restricts the access to optimum strategies. The quantified constraints are discussed in the context of other resource acquisition strategies. We argue that interception feeding strategies can only be accessed by large organisms if they are gelatinous. On the other hand, organisms that use remote prey sensing do not need to be gelatinous, even if they are large. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703656 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703656">Read the Article</a></i> </p> --><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">G</span>elatinous plankton form a special group of marine organisms due to their distinctly watery bodies with low carbon content. We find the gelatinous body plan mainly in large, centimeter-sized plankton who feed by filtering their micron-sized prey out of the water instead of perceiving it at a distance. Why do such planktonic giants tend to be gelatinous while microbes (dwarfs) that filter feed on the same prey stay dense? A marine biologist and two physicists in the Centre for Ocean Life at the Technical University of Denmark have resolved this question by developing a new theoretical model. </p><p>By modeling the energy budget of filter feeders, the authors show that the interplay between gain and cost of energy has the key implication that a minimum filter area is necessary to collect enough food to sustain a living. Through comparison of their model predictions and existing data on filter feeders, the authors conclude that filter feeders need to be either small or if they are large to increase the filter area by being gelatinous in order to survive in dilute oceanic environments. Large plankton that are non-gelatinous also exist, but they either live in prey-rich environments or compensate by sensing their prey at a distance. </p><p>Such understanding of planktonic survival strategies is essential to model and predict the global distributions of plankton. It directly connects to the main goal of the Centre for Ocean Life where marine ecologists, physicists, chemists, and mathematicians are working jointly to build a trait-based description of life in the ocean. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">M</span>ost marine plankton have a high energy (carbon) density, but some are gelatinous with approximately hundred times more watery bodies. How do those distinctly different body plans emerge and what are the trade-offs? We address this question by modeling the energy budget of planktonic filter feeders across life forms from micron-sized unicellular microbes like choanoflagellates to centimeter-sized gelatinous tunicates such as salps. We find two equally successful strategies, one being small with high energy density (dense dwarf), and the other being large with low energy density (gelatinous giant). The constraint that forces large – but not small – filter feeders to be gelatinous is identified as a lower limit to the size-specific filter area, below which the energy costs lead to starvation. A further limit is found from the maximum size-specific motor force that restricts the access to optimum strategies. The quantified constraints are discussed in the context of other resource acquisition strategies. We argue that interception feeding strategies can only be accessed by large organisms if they are gelatinous. On the other hand, organisms that use remote prey sensing do not need to be gelatinous, even if they are large. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 17 Apr 2019 05:00:00 GMT “Host responses to foreign eggs across the avian visual color space” https://amnat.org/an/newpapers/JulyHanley.html The DOI will be https://dx.doi.org/10.1086/703534 Scientists detect color biases in the rejection behavior of the blackbird Painting eggs using vibrant colors may conjure pleasant springtime childhood memories for many people. A team of scientists led by Dr. Daniel Hanley of Long Island University–Post do this every season for science. Dr. Hanley and his lab are interested in natural colors: how they are used and how they evolve. Birds’ eggs range from blue-green to brown and can be variably speckled, and birds examine their own eggs for many reasons. One such reason is that some birds will lay their eggs in other birds’ nests. No bird wants to come back to their nest and find an additional mouth to feed, especially when that foster child may evict and kill its foster siblings. The appearance of an imposter egg is one way that birds evaluate whether an egg belongs to them or another bird. Traditional theory assumes that if the egg appears quite similar to their own a bird will likely accept it, but if it differs considerably the bird will reject it. In a paper appearing in The&nbsp;American Naturalist, Dr. Hanley and his colleagues Dr. Mark Hauber (University of Illinois Urbana-Champaign), Tom&aacute;&scaron; Grim, and Karel Gern used an experimental approach to study how the common blackbird, an European species, responds to an unprecedented range of colors. Since birds can see a far greater range of colors than humans can, Dr. Hanley and co-author Karel Gern (shown above) made a bird-specific color wheel to paint eggs, manipulating the three main components of color: hue (e.g., blue, aquamarine, magenta, etc.), saturation (i.e. intensity), and brightness. They found that birds responded strongly to a far greater array of colors than had been previously tested. In addition, they found that the components of color interacted, such that birds may respond to one hue but only if it were an intense color. This group has also shown that hosts in North America, Europe, and South America all remove brown eggs at a much higher rate than blue-green eggs, despite how different they appear from their own eggs. These findings illustrate that we have a lot to learn about how wild birds use color information in their decision making; however, studies such as these are slowly closing that gap. Abstract Despite extensive research on the sensory and cognitive processes of host rejection of avian brood parasites’ eggs, the underlying perceptual and cognitive mechanisms are not sufficiently understood. Historically, most studies of host egg discrimination assumed that hosts rejected a parasite’s egg from their nest based on the perceived color and pattern differences between the parasite’s egg and their own. A recent study used a continuous range of parasitic egg colors and discovered that hosts were more likely to reject browner foreign eggs than foreign eggs that were more blue-green, even when their absolute perceived color differences from the hosts’ own egg colors were similar. However, the extent of these color biases across the avian perceivable color space remains unclear. Therefore, we built upon this previous study by testing European blackbirds’ (Turdus merula) responses to model eggs spanning an unprecedented volume of the avian color space. We found that host decisions depended on avian perceived hue, saturation, and luminance of the parasite’s egg; hosts generally accepted eggs that were bluer or more blue-green, and more often rejected eggs that were less saturated or darker. We suggest that future studies investigate the underlying mechanisms of foreign egg discrimination in other host lineages to determine the prevalence and phylogenetic conservation of such perceptual biases among birds. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703534 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703534">Read the Article</a></i> </p> --> <p><b>Scientists detect color biases in the rejection behavior of the blackbird </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">P</span>ainting eggs using vibrant colors may conjure pleasant springtime childhood memories for many people. A team of scientists led by Dr. Daniel Hanley of Long Island University&ndash;Post do this every season for science. Dr. Hanley and his lab are interested in natural colors: how they are used and how they evolve. Birds&rsquo; eggs range from blue-green to brown and can be variably speckled, and birds examine their own eggs for many reasons. One such reason is that some birds will lay their eggs in other birds&rsquo; nests. No bird wants to come back to their nest and find an additional mouth to feed, especially when that foster child may evict and kill its foster siblings. The appearance of an imposter egg is one way that birds evaluate whether an egg belongs to them or another bird. Traditional theory assumes that if the egg appears quite similar to their own a bird will likely accept it, but if it differs considerably the bird will reject it.</p> <p>In a paper appearing in <em>The&nbsp;American Naturalist</em>, Dr. Hanley and his colleagues Dr. Mark Hauber (University of Illinois Urbana-Champaign), Tom&aacute;&scaron; Grim, and Karel Gern used an experimental approach to study how the common blackbird, an European species, responds to an unprecedented range of colors. Since birds can see a far greater range of colors than humans can, Dr. Hanley and co-author Karel Gern (shown above) made a bird-specific color wheel to paint eggs, manipulating the three main components of color: hue (e.g., blue, aquamarine, magenta, etc.), saturation (i.e. intensity), and brightness. They found that birds responded strongly to a far greater array of colors than had been previously tested. In addition, they found that the components of color interacted, such that birds may respond to one hue but only if it were an intense color. This group has also shown that hosts in North America, Europe, and South America all remove brown eggs at a much higher rate than blue-green eggs, despite how different they appear from their own eggs. These findings illustrate that we have a lot to learn about how wild birds use color information in their decision making; however, studies such as these are slowly closing that gap.</p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">D</span>espite extensive research on the sensory and cognitive processes of host rejection of avian brood parasites&rsquo; eggs, the underlying perceptual and cognitive mechanisms are not sufficiently understood. Historically, most studies of host egg discrimination assumed that hosts rejected a parasite&rsquo;s egg from their nest based on the perceived color and pattern differences between the parasite&rsquo;s egg and their own. A recent study used a continuous range of parasitic egg colors and discovered that hosts were more likely to reject browner foreign eggs than foreign eggs that were more blue-green, even when their absolute perceived color differences from the hosts&rsquo; own egg colors were similar. However, the extent of these color biases across the avian perceivable color space remains unclear. Therefore, we built upon this previous study by testing European blackbirds&rsquo; (<em>Turdus merula</em>) responses to model eggs spanning an unprecedented volume of the avian color space. We found that host decisions depended on avian perceived hue, saturation, and luminance of the parasite&rsquo;s egg; hosts generally accepted eggs that were bluer or more blue-green, and more often rejected eggs that were less saturated or darker. We suggest that future studies investigate the underlying mechanisms of foreign egg discrimination in other host lineages to determine the prevalence and phylogenetic conservation of such perceptual biases among birds.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family:georgia; font-size:large"><em>More forthcoming papers</em> &raquo;</span></a></div> Wed, 17 Apr 2019 05:00:00 GMT “Evolution of stress-induced mutagenesis in the presence of horizontal gene transfer” https://amnat.org/an/newpapers/JulyRam.html The DOI will be https://dx.doi.org/10.1086/703457 Stress-induced mutagenesis can evolve and increase the adaptation rate even in the presence of horizontal gene transfer Mutations are usually considered random events. However, over the last 20 years it has become apparent that some microbes generate more mutations under stress conditions such as starvation, DNA damage, and antibiotics. In 2012, Ram and Hadany used mathematical models and computer simulations to show that stress-induced mutation is likely to evolve. Their models focused on microbes that do not exchange genes – that is, asexual microbes, as far as we can think of sex as the exchange of genetic material between unrelated individuals. However, several molecular mechanisms in microbes can lead to a primitive kind of sex called horizontal gene transfer, in which small pieces of DNA are transmitted between cells. For example, some microbes will take up DNA molecules from their environment and incorporate it to their genome in a process called transformation. Theory suggests that horizontal gene transfer will decrease the evolutionary advantage of generating new mutations: why should a cell risk mutating, when most mutations are harmful, if instead it can just pick up an advantageous mutation from another cell? In new research published in The&nbsp;American Naturalist, Ram and Hadany test if stress-induced mutation can evolve even in the presence of horizontal gene transfer. They find that although horizontal gene transfer reduces the evolutionary advantage of stress-induced mutation, the latter can still be evolutionary advantageous, especially if horizontal gene transfer is also induced by stress. Moreover, they show that stress-induced mutation accelerates adaptation to new environments. Therefore, the authors suggest that mutation and horizontal gene transfer can complement rather than exclude each other, and that mutation is likely to be correlated with stressful conditions even in microbes that undergo horizontal gene transfer. Abstract Stress-induced mutagenesis has been observed in multiple species of bacteria and yeast. It has been suggested that in asexual populations, a mutator allele that increases the mutation rate during stress can sweep to fixation with the beneficial mutations it generates. However, even asexual microbes can undergo horizontal gene transfer and rare recombination, which typically interfere with the spread of mutator alleles. Here we examine the effect of horizontal gene transfer on the evolutionary advantage of stress-induced mutator alleles. Our results demonstrate that stress-induced mutator alleles are favored by selection even in the presence of horizontal gene transfer, and more so when the mutator alleles also increase the rate of horizontal gene transfer. We suggest that when regulated by stress, mutation and horizontal gene transfer can be complementary, rather than competing, adaptive strategies, and that stress-induced mutagenesis has important implications for evolutionary biology, ecology, and epidemiology, even in the presence of horizontal gene transfer and rare recombination. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703457 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703457">Read the Article</a></i> </p> --> <p><b>Stress-induced mutagenesis can evolve and increase the adaptation rate even in the presence of horizontal gene transfer </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">M</span>utations are usually considered random events. However, over the last 20 years it has become apparent that some microbes generate more mutations under stress conditions such as starvation, DNA damage, and antibiotics. In 2012, Ram and Hadany used mathematical models and computer simulations to show that stress-induced mutation is likely to evolve. Their models focused on microbes that do not exchange genes – that is, asexual microbes, as far as we can think of sex as the exchange of genetic material between unrelated individuals. However, several molecular mechanisms in microbes can lead to a primitive kind of sex called <i>horizontal gene transfer</i>, in which small pieces of DNA are transmitted between cells. For example, some microbes will take up DNA molecules from their environment and incorporate it to their genome in a process called <i>transformation</i>. Theory suggests that horizontal gene transfer will decrease the evolutionary advantage of generating new mutations: why should a cell risk mutating, when most mutations are harmful, if instead it can just pick up an advantageous mutation from another cell?</p> <p>In new research published in <i>The&nbsp;American Naturalist</i>, Ram and Hadany test if stress-induced mutation can evolve even in the presence of horizontal gene transfer. They find that although horizontal gene transfer reduces the evolutionary advantage of stress-induced mutation, the latter can still be evolutionary advantageous, especially if horizontal gene transfer is also induced by stress. Moreover, they show that stress-induced mutation accelerates adaptation to new environments. Therefore, the authors suggest that mutation and horizontal gene transfer can complement rather than exclude each other, and that mutation is likely to be correlated with stressful conditions even in microbes that undergo horizontal gene transfer. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">S</span>tress-induced mutagenesis has been observed in multiple species of bacteria and yeast. It has been suggested that in asexual populations, a mutator allele that increases the mutation rate during stress can sweep to fixation with the beneficial mutations it generates. However, even asexual microbes can undergo horizontal gene transfer and rare recombination, which typically interfere with the spread of mutator alleles. Here we examine the effect of horizontal gene transfer on the evolutionary advantage of stress-induced mutator alleles. Our results demonstrate that stress-induced mutator alleles are favored by selection even in the presence of horizontal gene transfer, and more so when the mutator alleles also increase the rate of horizontal gene transfer. We suggest that when regulated by stress, mutation and horizontal gene transfer can be complementary, rather than competing, adaptive strategies, and that stress-induced mutagenesis has important implications for evolutionary biology, ecology, and epidemiology, even in the presence of horizontal gene transfer and rare recombination.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “Lagging adaptation to climate change supersedes local adaptation to herbivory in an annual monkeyflower” https://amnat.org/an/newpapers/AugKooyers.html Read the Article Adaptation lag! Elevation-matched California monkeyflowers populations have higher fitness in Oregon sites than Oregon monkeyflowers In the western US, climate change is causing the timing of growing seasons to shift. Spring is starting earlier on average, and consequently populations are experiencing seasonal conditions more characteristic of habitats to their south. In addition, precipitation is falling more often as rain rather than as snow, which deprives plant populations in mountainous areas of the snowmelt that serves as a dependable water source into summer. A team led by Nicholas Kooyers and Benjamin Blackman examined how well annual populations of the common monkeyflower, a widespread species in the western US, are adapting to cope with these environmental shifts. At both low and high elevation field sites, they find that local Oregon populations are less well adapted to their current environment than populations sampled from >500 miles south in California at equivalent elevations. Thus, their results are consistent with what is known as an adaptation lag, a pattern where local populations fare worse in current climates than populations whose historical climates better match current climates. What gave the California populations the advantage? The team found that they possessed several trait differences that fostered success in earlier growing seasons through timing reproduction to occur at more favorable times at each site. Oregon plants did have at least one home court advantage though. They sustained less damage from herbivores than the more heavily chewed on California plants, suggesting future years at these sites may also feature mismatches between Oregon herbivore communities and California-like growing seasons. Although they did not thrive as well as the California populations, the Oregon populations are not yet facing a truly dire threat from the changing climate. They still produced sufficient seed to sustain positive population growth rates even in the drastically early year when the team completed their study. Nonetheless, that the team observed patterns consistent with an adaptation lag even in this species, which has all the qualities like a short generation time and vast reservoirs of genetic variation that should favor rapid adaptation to changing climates, is dismaying for the many species that lack such evolutionary advantages. Abstract While native populations are often adapted to historical biotic and abiotic conditions at their home site, populations from other locations in the range may be better adapted to current conditions due to changing climates or extreme conditions in a single year. We examine whether local populations of a widespread species maintain a relative advantage over distant populations that have evolved at sites better matching the current climate. Specifically, we grew lines derived from low and high elevation annual populations in California and Oregon of the common monkeyflower (Erythranthe guttata), and conducted phenotypic selection analyses in low and high elevation common gardens in Oregon to examine relative fitness and the traits mediating relative fitness. Californian low elevation populations have the highest relative fitness in the low elevation site and Californian high elevation populations have the highest relative fitness in the high elevation site. Relative fitness differences are mediated by selection for properly timed transitions to flowering with selection favoring more rapid growth rates at the low elevation site and greater vegetative biomass prior to flowering at the high elevation site. Fitness advantages for Californian plants occur despite incurring higher herbivory at both sites than the native Oregonian plants. Our findings suggest a lag in adaptation causes maladaptation in extreme years that may be more prevalent in future climates, but local populations still have high growth rates and thus are not yet threatened. More forthcoming papers &raquo; <!-- <p><i>The DOI will be https://dx.doi.org/10.1086/702312 </i></p> --> <p><i><a href="https://dx.doi.org/10.1086/702312">Read the Article</a></i> </p> <p><b>Adaptation lag! Elevation-matched California monkeyflowers populations have higher fitness in Oregon sites than Oregon monkeyflowers </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">I</span>n the western US, climate change is causing the timing of growing seasons to shift. Spring is starting earlier on average, and consequently populations are experiencing seasonal conditions more characteristic of habitats to their south. In addition, precipitation is falling more often as rain rather than as snow, which deprives plant populations in mountainous areas of the snowmelt that serves as a dependable water source into summer. </p><p>A team led by Nicholas Kooyers and Benjamin Blackman examined how well annual populations of the common monkeyflower, a widespread species in the western US, are adapting to cope with these environmental shifts. At both low and high elevation field sites, they find that local Oregon populations are less well adapted to their current environment than populations sampled from >500 miles south in California at equivalent elevations. Thus, their results are consistent with what is known as an adaptation lag, a pattern where local populations fare worse in current climates than populations whose historical climates better match current climates. </p><p>What gave the California populations the advantage? The team found that they possessed several trait differences that fostered success in earlier growing seasons through timing reproduction to occur at more favorable times at each site. Oregon plants did have at least one home court advantage though. They sustained less damage from herbivores than the more heavily chewed on California plants, suggesting future years at these sites may also feature mismatches between Oregon herbivore communities and California-like growing seasons. </p><p>Although they did not thrive as well as the California populations, the Oregon populations are not yet facing a truly dire threat from the changing climate. They still produced sufficient seed to sustain positive population growth rates even in the drastically early year when the team completed their study. Nonetheless, that the team observed patterns consistent with an adaptation lag even in this species, which has all the qualities like a short generation time and vast reservoirs of genetic variation that should favor rapid adaptation to changing climates, is dismaying for the many species that lack such evolutionary advantages. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">W</span>hile native populations are often adapted to historical biotic and abiotic conditions at their home site, populations from other locations in the range may be better adapted to current conditions due to changing climates or extreme conditions in a single year. We examine whether local populations of a widespread species maintain a relative advantage over distant populations that have evolved at sites better matching the current climate. Specifically, we grew lines derived from low and high elevation annual populations in California and Oregon of the common monkeyflower (<i>Erythranthe guttata</i>), and conducted phenotypic selection analyses in low and high elevation common gardens in Oregon to examine relative fitness and the traits mediating relative fitness. Californian low elevation populations have the highest relative fitness in the low elevation site and Californian high elevation populations have the highest relative fitness in the high elevation site. Relative fitness differences are mediated by selection for properly timed transitions to flowering with selection favoring more rapid growth rates at the low elevation site and greater vegetative biomass prior to flowering at the high elevation site. Fitness advantages for Californian plants occur despite incurring higher herbivory at both sites than the native Oregonian plants. Our findings suggest a lag in adaptation causes maladaptation in extreme years that may be more prevalent in future climates, but local populations still have high growth rates and thus are not yet threatened. </p> <div style="float: right;"><za href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “The critical role of infectious disease in compensatory population growth in response to culling” https://amnat.org/an/newpapers/JulyTanner-A.html The DOI will be https://dx.doi.org/10.1086/703437 Using mathematical models we show how culling populations harboring endemic disease can lead to compensatory growth Abstract Despite the ubiquity of disease in nature, the role that disease dynamics play in the compensatory growth response to harvesting has been ignored. We use a mathematical approach to show that harvesting can lead to compensatory growth due to a release from disease-induced mortality. Our findings imply that culling in systems that harbor virulent parasites can reduce disease prevalence and increase population density. Our models predict that this compensation occurs for a broad range of infectious disease characteristics unless disease induces long-lasting immunity in hosts. Our key insight is that a population can be regulated at a similar density by disease or at reduced prevalence by a combination of culling and disease. We illustrate our predictions with a system-specific model representing wild boar tuberculosis infection, parameterized for central Spain, and find significant compensation to culling. Given that few wildlife diseases are likely to induce long-lived immunity, populations with virulent diseases may often be resilient to harvesting. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703437 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703437">Read the Article</a></i> </p> --> <p><b>Using mathematical models we show how culling populations harboring endemic disease can lead to compensatory growth </b></p><h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">D</span>espite the ubiquity of disease in nature, the role that disease dynamics play in the compensatory growth response to harvesting has been ignored. We use a mathematical approach to show that harvesting can lead to compensatory growth due to a release from disease-induced mortality. Our findings imply that culling in systems that harbor virulent parasites can reduce disease prevalence and increase population density. Our models predict that this compensation occurs for a broad range of infectious disease characteristics unless disease induces long-lasting immunity in hosts. Our key insight is that a population can be regulated at a similar density by disease or at reduced prevalence by a combination of culling and disease. We illustrate our predictions with a system-specific model representing wild boar tuberculosis infection, parameterized for central Spain, and find significant compensation to culling. Given that few wildlife diseases are likely to induce long-lived immunity, populations with virulent diseases may often be resilient to harvesting. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “Seed masting causes fluctuations in optimum litter size and lag load in a seed predator” https://amnat.org/an/newpapers/AugMcAdam.html The DOI will be https://dx.doi.org/10.1086/703743 Boom-bust cycles in seed production increase seed escape by inducing maladaptation in seed predators Instead of producing similar amounts of seeds each year, some plant species produce very few seeds for several years followed by a bumper seed crop. This boom-bust pattern of seed production is called ‘masting’ and is thought to increase tree fitness by alternately swamping and starving seed predators. In this study, the authors proposed a new idea – perhaps masting causes natural selection on seed predators to differ between these feast and famine conditions. If this changeable selection reduces the abundance of seed predators, this could further increase the benefits of masting. The authors tested this hypothesis using 28 years of data on North American red squirrels in the Yukon Territory of Canada. In many organisms, it is best to produce an intermediate number of offspring. Produce too many and each will be too small to survive. Produce too few and each will survive well, but there won’t be many of them. An intermediate number of offspring optimally balances these two processes. In this study, the authors found that optimum litter size in red squirrels depends on whether it is a mast year for white spruce cones, their main source of food. In bust years for cones, litter sizes of red squirrels closely match optimum litter sizes. But during mast years, when food is plentiful, the optimum litter size is much larger. Red squirrels somehow know when a mast year is coming and produce larger litters in the spring of mast years, but this increase is small compared to the large increase in optimum litter size during mast years. As a result, squirrels don’t recruit as many offspring during mast years as they would have if they had produced larger litters, which is good for tree fitness. So, in addition to swamping and starving seed predators, boom-bust patterns of seed production can also cause seed predators to evolve more frugal life histories that are well suited to common years of low food abundance, but are poorly adapted to less common, resource-rich mast years. Abstract The episodic production of large seed crops by some perennial plants (masting) is known to increase seed escape by alternately starving and swamping seed predators. These pulses of resources might also act as an agent of selection on the life histories of seed predators, which could indirectly enhance seed escape by inducing an evolutionary load on seed predator populations. We measured natural selection on litter size of female North American red squirrels (Tamiasciurus hudsonicus) across 28 years and five white spruce (Picea glauca) masting events. Observed litter sizes were similar to optimum litter sizes during non-mast years but were well below optimum litter sizes during mast years. Mast events, therefore, caused selection for larger litters (β′ = 0.25) and a lag load (L = 0.25) on red squirrels during mast years. Reduced juvenile recruitment associated with this lag load increased the number of spruce cones escaping squirrel predation. Although, offspring and parents often experienced opposite environments with respect to the mast, we found no effect of environmental mismatches across generations on either offspring survival or population growth. Instead, squirrels plastically increased litter sizes in anticipation of mast events, which partially, although not completely, reduced the lag load resulting from this change in food availability. These results, therefore, suggest that in addition to ecological and behavioral effects on seed predators, mast seed production can further enhance seed escape by inducing maladaptation in seed predators through fluctuations in optimal trait values. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703743 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703743">Read the Article</a></i> </p> --> <p><b>Boom-bust cycles in seed production increase seed escape by inducing maladaptation in seed predators </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">I</span>nstead of producing similar amounts of seeds each year, some plant species produce very few seeds for several years followed by a bumper seed crop. This boom-bust pattern of seed production is called ‘masting’ and is thought to increase tree fitness by alternately swamping and starving seed predators. In this study, the authors proposed a new idea – perhaps masting causes natural selection on seed predators to differ between these feast and famine conditions. If this changeable selection reduces the abundance of seed predators, this could further increase the benefits of masting. </p> <p>The authors tested this hypothesis using 28 years of data on North American red squirrels in the Yukon Territory of Canada. In many organisms, it is best to produce an intermediate number of offspring. Produce too many and each will be too small to survive. Produce too few and each will survive well, but there won’t be many of them. An intermediate number of offspring optimally balances these two processes. In this study, the authors found that optimum litter size in red squirrels depends on whether it is a mast year for white spruce cones, their main source of food. In bust years for cones, litter sizes of red squirrels closely match optimum litter sizes. But during mast years, when food is plentiful, the optimum litter size is much larger. Red squirrels somehow know when a mast year is coming and produce larger litters in the spring of mast years, but this increase is small compared to the large increase in optimum litter size during mast years. As a result, squirrels don’t recruit as many offspring during mast years as they would have if they had produced larger litters, which is good for tree fitness. </p><p>So, in addition to swamping and starving seed predators, boom-bust patterns of seed production can also cause seed predators to evolve more frugal life histories that are well suited to common years of low food abundance, but are poorly adapted to less common, resource-rich mast years. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">T</span>he episodic production of large seed crops by some perennial plants (masting) is known to increase seed escape by alternately starving and swamping seed predators. These pulses of resources might also act as an agent of selection on the life histories of seed predators, which could indirectly enhance seed escape by inducing an evolutionary load on seed predator populations. We measured natural selection on litter size of female North American red squirrels (<i>Tamiasciurus hudsonicus</i>) across 28 years and five white spruce (<i>Picea glauca</i>) masting events. Observed litter sizes were similar to optimum litter sizes during non-mast years but were well below optimum litter sizes during mast years. Mast events, therefore, caused selection for larger litters (<i>β′</i> = 0.25) and a lag load (<i>L</i> = 0.25) on red squirrels during mast years. Reduced juvenile recruitment associated with this lag load increased the number of spruce cones escaping squirrel predation. Although, offspring and parents often experienced opposite environments with respect to the mast, we found no effect of environmental mismatches across generations on either offspring survival or population growth. Instead, squirrels plastically increased litter sizes in anticipation of mast events, which partially, although not completely, reduced the lag load resulting from this change in food availability. These results, therefore, suggest that in addition to ecological and behavioral effects on seed predators, mast seed production can further enhance seed escape by inducing maladaptation in seed predators through fluctuations in optimal trait values. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “Maladaptive shifts in life history in a changing environment” https://amnat.org/an/newpapers/AugCotto.html Read the Article Maladaptation can induce false-adaptive shifts in life history if different trait values maximize different vital rates As climate warms, the performance of many organisms is affected, with negative effects on some aspects of their life cycle, but also of positive effects on others. Should we interpret such cases of improved performance as evidence for climate change facilitating the persistence of those populations? A model by researchers from CNRS, the University of Montpellier (France) and the University of British Columbia (Canada) suggests caution in doing so. In some birds, breeding earlier in the season increases the number of chicks raised in that year, but compromises the parent prospects of survival. Similarly, in some plants, flowering early is associated with the production of a higher number of fruits, but increases the risk of being grazed. The seasonal timing of key events in the life cycle of many organisms has already been modified by the warming of temperatures. Further genetic evolution of populations will be necessary to adapt this timing to future climates. How will the conflicting consequences of altered timing on different aspects of the life cycle affect this adaptive race? The model predicts that even adapting populations will lag behind the climate. Such lags in adaptation however have unforeseen consequences for the life cycle of these organisms, with negative effects on some aspects of performance (e.g. on fecundity) and, more surprisingly, positive effects on others (e.g. on survival). Increased performance in some aspects of the life cycle under a changing climate may reflect the population inability to evolve fast enough and may be observed in populations on the verge of extinction. Lags in adaptation may also trigger drastic changes in the life cycle, with some populations evolving to reproduce only once during an individual’s lifetime. This study therefore suggests that consequences of climate change should be integrated over the whole life cycle to conclude about the persistence prospects of populations. Abstract Many species facing climate change have complex life cycles, with individuals in different stages differing in their sensitivity to a changing climate and their contribution to population growth. We use a quantitative genetics model to predict the dynamics of adaptation in a stage-structured population confronted with a steadily changing environment. Our model assumes that different optimal phenotypic values maximize different fitness components, consistent with many empirical observations. In a constant environment, the population evolves towards an equilibrium phenotype, which represents the best compromise given the trade-off between vital rates. In a changing environment however, the mean phenotype in the population will lag behind this optimal compromise. We show that this lag may result in a shift along the trade-off between vital rates, with negative consequences for some fitness components, but, less intuitively, improvements in some others. Complex eco-evolutionary dynamics can emerge in our model due to feedbacks between population demography and adaptation. Because of such feedbacks loops, selection may favor further shifts in life history in the same direction as caused by maladaptive lags. These shifts in life history could be wrongly interpreted as adaptations to the new environment, while they only reflect the inability of the population to adapt fast enough. More forthcoming papers &raquo; <!-- <p><i>The DOI will be https://dx.doi.org/10.1086/702716 </i></p> --> <p><i><a href="https://dx.doi.org/10.1086/702716">Read the Article</a></i> </p> <p><b>Maladaptation can induce false-adaptive shifts in life history if different trait values maximize different vital rates </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">A</span>s climate warms, the performance of many organisms is affected, with negative effects on some aspects of their life cycle, but also of positive effects on others. Should we interpret such cases of improved performance as evidence for climate change facilitating the persistence of those populations? A model by researchers from CNRS, the University of Montpellier (France) and the University of British Columbia (Canada) suggests caution in doing so. </p><p>In some birds, breeding earlier in the season increases the number of chicks raised in that year, but compromises the parent prospects of survival. Similarly, in some plants, flowering early is associated with the production of a higher number of fruits, but increases the risk of being grazed. The seasonal timing of key events in the life cycle of many organisms has already been modified by the warming of temperatures. Further genetic evolution of populations will be necessary to adapt this timing to future climates. How will the conflicting consequences of altered timing on different aspects of the life cycle affect this adaptive race? The model predicts that even adapting populations will lag behind the climate. Such lags in adaptation however have unforeseen consequences for the life cycle of these organisms, with negative effects on some aspects of performance (e.g. on fecundity) and, more surprisingly, positive effects on others (e.g. on survival). Increased performance in some aspects of the life cycle under a changing climate may reflect the population inability to evolve fast enough and may be observed in populations on the verge of extinction. Lags in adaptation may also trigger drastic changes in the life cycle, with some populations evolving to reproduce only once during an individual’s lifetime. This study therefore suggests that consequences of climate change should be integrated over the whole life cycle to conclude about the persistence prospects of populations.</p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">M</span>any species facing climate change have complex life cycles, with individuals in different stages differing in their sensitivity to a changing climate and their contribution to population growth. We use a quantitative genetics model to predict the dynamics of adaptation in a stage-structured population confronted with a steadily changing environment. Our model assumes that different optimal phenotypic values maximize different fitness components, consistent with many empirical observations. In a constant environment, the population evolves towards an equilibrium phenotype, which represents the best compromise given the trade-off between vital rates. In a changing environment however, the mean phenotype in the population will lag behind this optimal compromise. We show that this lag may result in a shift along the trade-off between vital rates, with negative consequences for some fitness components, but, less intuitively, improvements in some others. Complex eco-evolutionary dynamics can emerge in our model due to feedbacks between population demography and adaptation. Because of such feedbacks loops, selection may favor further shifts in life history in the same direction as caused by maladaptive lags. These shifts in life history could be wrongly interpreted as adaptations to the new environment, while they only reflect the inability of the population to adapt fast enough. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “Phenotypic plasticity and local adaptation in a wild hibernator evaluated through reciprocal translocation” https://amnat.org/an/newpapers/AugLane-A.html Read the Article Abstract Phenological shifts are the most commonly reported ecological responses to climate change, and can be produced rapidly by phenotypic plasticity. However, both the limits of plasticity, and whether it will be sufficient to maintain local adaptation (or even lead to maladaptation) are less clear. Increased winter precipitation has been shown to lead to phenological delays and corresponding annual decreases in fitness in Columbian ground squirrels (Urocitellus columbianus). We took advantage of natural phenological variation (across elevations) in this species to better assess the extent of phenotypic plasticity in emergence dates and the relationships between emergence dates and individual annual fitness. We coupled a reciprocal translocation experiment with natural monitoring across two populations separated by approximately 500 m in elevation. Individuals in both populations responded plastically to both spring temperature and winter precipitation. Translocated individuals adjusted their emergence dates to approach those of individuals in their adoptive populations, but did differ significantly in their emergence dates from residents. There were no differences in annual fitness among treatment groups, nor selection on emergent date within a year. Phenotypic plasticity is thus sufficient to allow individuals to respond to broad environmental gradients, but the influence of variation in emergence dates on annual fitness requires further investigation. More forthcoming papers &raquo; <!-- <p><i>The DOI will be https://dx.doi.org/10.1086/702313</i></p> --> <p><i><a href="https://dx.doi.org/10.1086/702313">Read the Article</a></i> </p><h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">P</span>henological shifts are the most commonly reported ecological responses to climate change, and can be produced rapidly by phenotypic plasticity. However, both the limits of plasticity, and whether it will be sufficient to maintain local adaptation (or even lead to maladaptation) are less clear. Increased winter precipitation has been shown to lead to phenological delays and corresponding annual decreases in fitness in Columbian ground squirrels (<i>Urocitellus columbianus</i>). We took advantage of natural phenological variation (across elevations) in this species to better assess the extent of phenotypic plasticity in emergence dates and the relationships between emergence dates and individual annual fitness. We coupled a reciprocal translocation experiment with natural monitoring across two populations separated by approximately 500 m in elevation. Individuals in both populations responded plastically to both spring temperature and winter precipitation. Translocated individuals adjusted their emergence dates to approach those of individuals in their adoptive populations, but did differ significantly in their emergence dates from residents. There were no differences in annual fitness among treatment groups, nor selection on emergent date within a year. Phenotypic plasticity is thus sufficient to allow individuals to respond to broad environmental gradients, but the influence of variation in emergence dates on annual fitness requires further investigation. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “Why so variable: can genetic variance in flowering thresholds be maintained by fluctuating selection?” https://amnat.org/an/newpapers/JulyRees.html The DOI will be https://dx.doi.org/10.1086/703436 Why populations are genetically variable is a puzzle: Here is why fluctuating selection might hold the key Many processes are thought to allow the maintenance of genetic variation in natural populations. However, determining which ones operate in the wild is difficult. The authors’ previous work exploring the evolution of flowering thresholds (the critical size a plant must achieve before it can flower) suggested that even in a variable environment, where the conditions for growth, survival, and reproduction vary from year to year, a single strategy was best and so the maintenance of genetic variation was not possible. Here the researchers extend their models to include quantitative genetic variation and ask whether a gene which increases the mutation rate would be adaptive. For one species where they assume a constant environment, selection does not favor an increase in mutation rate, and genetic variation in the threshold size for flowering is maladaptive. In contrast, for the other species where they assume a variable environment, an increase in mutation rate is adaptive. The authors suggest this is a consequence of disruptive selection which favors genotypes in the tails of the flowering threshold distribution. They suspect this mechanism may operate in many natural systems. Abstract We use integral projection models (IPM) and individual-based simulations to study the evolution of genetic variance in two monocarpic plant systems. Previous approaches combining IPMs with an Adaptive Dynamics-style invasion analysis predicted that genetic variability in the size threshold for flowering will not be maintained, which conflicts with empirical evidence. We ask if this discrepancy can be resolved by making more realistic assumptions about the underlying genetic architecture: assuming a multilocus quantitative trait in an outcrossing diploid species. To do this, we embed the infinitesimal model of quantitative genetics into an IPM for a sizestructured cosexual plant species. The resulting IPM describes the joint dynamics of individual size and breeding value of the evolving trait. We apply this general framework to the monocarpic perennials Oenothera glazioviana and Carlina vulgaris. The evolution of heritable variation in threshold size is explored, in both individual-based models (IBMs) and IPMs, using a mutation rate modifier approach. In the Oenothera model, where the environment is constant, there is selection against producing genetically variable offspring. In the Carlina model, where the environment varies between years, genetically variable offspring provide a selective advantage, allowing the maintenance of genetic variability. The contrasting predictions of Adaptive Dynamics and Quantitative Genetics models for the same system suggest that fluctuating selection may be more effective at maintaining genetic variation than previously thought. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703436 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703436">Read the Article</a></i> </p> --> <p><b>Why populations are genetically variable is a puzzle: Here is why fluctuating selection might hold the key </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">M</span>any processes are thought to allow the maintenance of genetic variation in natural populations. However, determining which ones operate in the wild is difficult. The authors’ previous work exploring the evolution of flowering thresholds (the critical size a plant must achieve before it can flower) suggested that even in a variable environment, where the conditions for growth, survival, and reproduction vary from year to year, a single strategy was best and so the maintenance of genetic variation was not possible. </p><p>Here the researchers extend their models to include quantitative genetic variation and ask whether a gene which increases the mutation rate would be adaptive. For one species where they assume a constant environment, selection does not favor an increase in mutation rate, and genetic variation in the threshold size for flowering is maladaptive. In contrast, for the other species where they assume a variable environment, an increase in mutation rate is adaptive. The authors suggest this is a consequence of disruptive selection which favors genotypes in the tails of the flowering threshold distribution. They suspect this mechanism may operate in many natural systems.</p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">W</span>e use integral projection models (IPM) and individual-based simulations to study the evolution of genetic variance in two monocarpic plant systems. Previous approaches combining IPMs with an Adaptive Dynamics-style invasion analysis predicted that genetic variability in the size threshold for flowering will not be maintained, which conflicts with empirical evidence. We ask if this discrepancy can be resolved by making more realistic assumptions about the underlying genetic architecture: assuming a multilocus quantitative trait in an outcrossing diploid species. To do this, we embed the infinitesimal model of quantitative genetics into an IPM for a sizestructured cosexual plant species. The resulting IPM describes the joint dynamics of individual size and breeding value of the evolving trait. We apply this general framework to the monocarpic perennials <i>Oenothera glazioviana</i> and <i>Carlina vulgaris</i>. The evolution of heritable variation in threshold size is explored, in both individual-based models (IBMs) and IPMs, using a mutation rate modifier approach. In the <i>Oenothera</i> model, where the environment is constant, there is selection against producing genetically variable offspring. In the <i>Carlina</i> model, where the environment varies between years, genetically variable offspring provide a selective advantage, allowing the maintenance of genetic variability. The contrasting predictions of Adaptive Dynamics and Quantitative Genetics models for the same system suggest that fluctuating selection may be more effective at maintaining genetic variation than previously thought. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “Ecological and evolutionary stabilities of biotrophism, necrotrophism, and saprotrophism” https://amnat.org/an/newpapers/JulySuzuki.html The DOI will be https://dx.doi.org/10.1086/703485 Diverse trophic strategies of fungi are studied theoretically, revealing novel insight into their control and evolution Fungi have diverse strategies for utilizing plants as their nutrient resources. For example, obligate biotrophs like wheat leaf rust reproduce in living hosts, obligate necrotrophs like take-all fungi kill infected hosts and reproduce in dead material, while obligate saprotrophs like fairy ring mushrooms reproduce only in dead plant residues in the environment. What is the most efficient trophic strategy for fungi to utilize a given plant population while ecologically sustaining it? How have such diverse trophic strategies evolved in fungi? To tackle these questions, Sayaki U. Suzuki at CARC/NARO and Akira Sasaki at SOKENDAI attempted to construct an epidemiological model that explores three trophic modes (biotrophic, necrotrophic and saprotrophic transmissions) for fungi to utilize plants. Although their model is simple, consisting only of four states of host plants (susceptible living plant, infected living plant, uninfected dead plant, and infected dead plant), it adequately describes the ecological behavior of plant pathogenic fungi. Using this model, they obtained the threshold condition for the spread of the disease epidemic and reorganized the conventional physiological classification of fungi from the ecological perspective. They then proposed four types of ecological groups corresponding to the patterns of dependence on nutrient resources, either living or dead plants. It is also possible to draw guidelines from this model for controlling crop diseases suitable for each fungal type of nutrient dependency. By analyzing the evolution of virulence in their plant-fungi model, they found that a milder fungal virulence in living plants is always selected for if plant-fungi populations are in a stable (endemic) state. However, with a sufficiently strong necrotrophic transmission rate, the host population densities show sustained cycles, which promotes the evolution towards higher virulence. They refer to this self-reinforcement towards highly virulent necrotrophs as “necrotrophic spiral”. Abstract Fungi have multiple trophic behaviors including biotrophism (parasitism on living hosts), necrotrophism (parasitism through killing host tissues), and saprotrophism (feeding on decaying organic matter). Historical classifications of plant pathogens are based on many different axes, including their trophic dependence on living and dead plants, their pathogenicity and mutualistic relationship to host plants, and their transmission pathways and infection mechanisms. Such diverse classifications are sometimes conflicting with each other. Clarifying the delineations among these groups would promote synthesis of fungal biology with current ecological and evolutionary concepts. To ask when biotrophic, necrotrophic, or saprotrophic fungi are maintained and are favored by selection, we constructed an epidemiological model that describes the transitions between four states of host plants: susceptible living plant (S), infected living plant (I), uninfected dead plant (D), and infected dead plant, or plant residue (R). S and D represent two kinds of resource—living and dead plant tissues—for fungal inocula (I and R). We obtained values for the basic reproductive number (R0), which defines the persistence criteria of fungi. Based on our results, we propose four types of ecological groups corresponding to the patterns of dependence on nutrient resources: (i) parasitism-dependent fungi, characterized by their critical dependence on living plants; (ii) saprotrophism-dependent fungi, characterized by their critical dependence on dead plants; (iii) facultatively dependent fungi, which are neither parasitism nor saprotrophism dependent; and (iv) doubly dependent fungi, which are neither wholly parasitism dependent nor wholly saprotrophism dependent. This grouping can be used to suggest principles for effective pest control. Our model also reveals simple conditions for the evolution of fungal trophic behaviors. We found that, in the absence of a trade-off between virulence and other life history parameters, milder fungal virulence in living plants is always selected for if plant–fungus population dynamics are stable. However, with sufficiently strong necrotrophic transmission, the host population densities show sustained cycles, which promotes the evolution of higher virulence. Epidemiological synthesis of diverse trophism in plant-fungi relationship in our model thus opens the way to discuss the evolution of fungal lifestyles as a function of ecological conditions. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703485 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703485">Read the Article</a></i> </p> --> <p><b>Diverse trophic strategies of fungi are studied theoretically, revealing novel insight into their control and evolution </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">F</span>ungi have diverse strategies for utilizing plants as their nutrient resources. For example, <i>obligate biotrophs</i> like wheat leaf rust reproduce in living hosts, <i>obligate necrotrophs</i> like take-all fungi kill infected hosts and reproduce in dead material, while <i>obligate saprotrophs</i> like fairy ring mushrooms reproduce only in dead plant residues in the environment. What is the most efficient trophic strategy for fungi to utilize a given plant population while ecologically sustaining it? How have such diverse trophic strategies evolved in fungi? To tackle these questions, Sayaki U. Suzuki at CARC/NARO and Akira Sasaki at SOKENDAI attempted to construct an epidemiological model that explores three trophic modes (biotrophic, necrotrophic and saprotrophic transmissions) for fungi to utilize plants. Although their model is simple, consisting only of four states of host plants (susceptible living plant, infected living plant, uninfected dead plant, and infected dead plant), it adequately describes the ecological behavior of plant pathogenic fungi. </p><p>Using this model, they obtained the threshold condition for the spread of the disease epidemic and reorganized the conventional physiological classification of fungi from the ecological perspective. They then proposed four types of ecological groups corresponding to the patterns of dependence on nutrient resources, either living or dead plants. It is also possible to draw guidelines from this model for controlling crop diseases suitable for each fungal type of nutrient dependency. </p><p>By analyzing the evolution of virulence in their plant-fungi model, they found that a milder fungal virulence in living plants is always selected for if plant-fungi populations are in a stable (endemic) state. However, with a sufficiently strong necrotrophic transmission rate, the host population densities show sustained cycles, which promotes the evolution towards higher virulence. They refer to this self-reinforcement towards highly virulent necrotrophs as “necrotrophic spiral”.</p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">F</span>ungi have multiple trophic behaviors including biotrophism (parasitism on living hosts), necrotrophism (parasitism through killing host tissues), and saprotrophism (feeding on decaying organic matter). Historical classifications of plant pathogens are based on many different axes, including their trophic dependence on living and dead plants, their pathogenicity and mutualistic relationship to host plants, and their transmission pathways and infection mechanisms. Such diverse classifications are sometimes conflicting with each other. Clarifying the delineations among these groups would promote synthesis of fungal biology with current ecological and evolutionary concepts. To ask when biotrophic, necrotrophic, or saprotrophic fungi are maintained and are favored by selection, we constructed an epidemiological model that describes the transitions between four states of host plants: susceptible living plant (S), infected living plant (I), uninfected dead plant (D), and infected dead plant, or plant residue (R). S and D represent two kinds of resource—living and dead plant tissues—for fungal inocula (I and R). We obtained values for the basic reproductive number (R0), which defines the persistence criteria of fungi. Based on our results, we propose four types of ecological groups corresponding to the patterns of dependence on nutrient resources: (i) <i>parasitism-dependent fungi</i>, characterized by their critical dependence on living plants; (ii) <i>saprotrophism-dependent fungi</i>, characterized by their critical dependence on dead plants; (iii) <i>facultatively dependent fungi</i>, which are neither parasitism nor saprotrophism dependent; and (iv) <i>doubly dependent fungi</i>, which are neither wholly parasitism dependent nor wholly saprotrophism dependent. This grouping can be used to suggest principles for effective pest control. Our model also reveals simple conditions for the evolution of fungal trophic behaviors. We found that, in the absence of a trade-off between virulence and other life history parameters, milder fungal virulence in living plants is always selected for if plant–fungus population dynamics are stable. However, with sufficiently strong necrotrophic transmission, the host population densities show sustained cycles, which promotes the evolution of higher virulence. Epidemiological synthesis of diverse trophism in plant-fungi relationship in our model thus opens the way to discuss the evolution of fungal lifestyles as a function of ecological conditions. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “Unpacking conditional neutrality: genomic signatures of selection on conditionally beneficial and conditionally deleterious mutations” https://amnat.org/an/newpapers/AugMee-A.html Abstract It is common to look for signatures of local adaptation in genomes by identifying loci with extreme levels of allele frequency divergence among populations. This approach to finding genes associated with local adaptation often assumes antagonistic pleiotropy, wherein alternative alleles are strongly favored in alternative environments. Conditional neutrality has been proposed as an alternative to antagonistic pleiotropy, but conditionally neutral polymorphisms are transient and it is unclear how much outlier signal would be maintained under different forms of conditional neutrality. Here, we use individual-based simulations and a simple analytical heuristic to show that a pattern that mimics local adaptation at the phenotypic level, where each genotype has the highest fitness in its home environment, can be produced by the accumulation of mutations that are neutral in their home environment and deleterious in non-local environments. Because conditionally deleterious mutations likely arise at a rate many times higher than conditionally beneficial mutations, they can have a significant cumulative effect on fitness even when individual effect sizes are small. We show that conditionally deleterious mutations driving non-local maladaptation may be undetectable by even the most powerful genome scans, as differences in allele frequency between populations are typically small. We also explore the evolutionary effects of conditionally-beneficial mutations and find that they can maintain significant signals of local adaptation, and they would be more readily detectable than conditionally deleterious mutations using conventional genome scan approaches. We discuss implications for interpreting outcomes of transplant experiments and genome scans that are used to study the genetic basis of local adaptation. More forthcoming papers &raquo; <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">I</span>t is common to look for signatures of local adaptation in genomes by identifying loci with extreme levels of allele frequency divergence among populations. This approach to finding genes associated with local adaptation often assumes antagonistic pleiotropy, wherein alternative alleles are strongly favored in alternative environments. Conditional neutrality has been proposed as an alternative to antagonistic pleiotropy, but conditionally neutral polymorphisms are transient and it is unclear how much outlier signal would be maintained under different forms of conditional neutrality. Here, we use individual-based simulations and a simple analytical heuristic to show that a pattern that mimics local adaptation at the phenotypic level, where each genotype has the highest fitness in its home environment, can be produced by the accumulation of mutations that are neutral in their home environment and deleterious in non-local environments. Because conditionally deleterious mutations likely arise at a rate many times higher than conditionally beneficial mutations, they can have a significant cumulative effect on fitness even when individual effect sizes are small. We show that conditionally deleterious mutations driving non-local maladaptation may be undetectable by even the most powerful genome scans, as differences in allele frequency between populations are typically small. We also explore the evolutionary effects of conditionally-beneficial mutations and find that they can maintain significant signals of local adaptation, and they would be more readily detectable than conditionally deleterious mutations using conventional genome scan approaches. We discuss implications for interpreting outcomes of transplant experiments and genome scans that are used to study the genetic basis of local adaptation. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT 2019 American Naturalist Student Paper Award https://amnat.org/announcements/ANNStuPaperAwa.html The American Naturalist Student Paper Award is for work that was published in 2018 and that was performed primarily by the first author and primarily while she or he was an undergraduate or graduate student. There were over seventy eligible papers. The recipient of the 2019 Student Paper Award is Marta Strecker Shocket, for her paper "Temperature drives epidemics in a zooplankton-fungus disease system: a trait-driven approach points to transmission via host foraging” (April 2018, 191(4):435-451), co-authored with Alexander Strauss, Jessica Hite, Maja Ijivar, ZDavid Civitello, Meghan Duffy, Carla C&atilde;ceres, and Spencer Hall. This is a remarkable combination of experimental work, modeling, and observational natural history rolled into one. Dr. Shocket and collaborators asked how climate warming will affect the dynamics of disease outbreaks. They emphasize the need for a mechanistic understanding of host-parasite interactions and the role of temperature to generate effective predictions. They develop a trait-based model that considers how temperature affects host foraging rates in a Daphnia-fungus interaction, and parameterized the model with laboratory experiments. They found that warming increased Daphnia foraging rates, which in turn increased fungal transmission success and epidemic size. The Editors appreciated the well-integrated mix of field data, lab experiments, mesocosm experiments, and theory, in service of a mechanistic understanding of species interactions. This paper has the potential to set a new standard for studies of the role of temperature-dependence in disease dynamics. Nicolas Schnedler-Meyer, for his paper “Evolution of complex asexual reproductive strategies in jellyfish”, coauthored with Simone Pigolotti and Patizio Mariani (July 2018, 192(1):72-80). This paper stood out to us because it presents a simple but elegant model of life history evolution that was solidly grounded in natural history (jellyfish life cycles). The study considers the diversity of asexual modes of reproduction in scyphozoan jellyfish, to describe tradeoffs among dispersal, dormancy, and local spread. Which life history strategy dominates depends on the nature of environmental variation, as the authors demonstrate with an Evolutionary Stable Strategy analysis. Not only do they effectively model which life histories should evolve in which environmental settings for jellyfish, but they do an excellent job of linking their findings to similar kinds of variance discounting adaptations in plants and other animals. They very effectively relate their model results back to published empirical literature, in ways that both provide compelling support for their approach and raise new testable hypotheses. Amanda Gibson, for her paper “Periodic, parasite-mediated selection for and against sex”, co-authored with Lynda Delph, Daniela Vergara, and Curt Lively (November 2018, 192(5):537-551). This is an impressive exploration of the maintenance of polymorphic reproductive strategies (sexual or asexual) via frequency-dependent co-evolution between host and pathogen. The authors fuse long-term field data and mescocosm experiments to demonstrate that a parasite Microphallus evolves to specialize on whichever host snail type (sexual or asexual) is most common, thereby maintaining host polymorphism. The fusion of experimental and field data is impressive, and yields a major contribution to a fundamental and long-standing subject in evolutionary biology, the maintenance of sexual reproduction. Daniel I. Bolnick, Editor-in-Chief Russell Bonduriansky, Editor Alice Winn, Editor with the 2017 editors who handled many of the 2018 papers, Judith Bronstein, former Editor-in-Chief Yannis Michilakis, former Editor <p><em>The American Naturalist</em> Student Paper Award is for work that was published in 2018 and that was performed primarily by the first author and primarily while she or he was an undergraduate or graduate student. There were over seventy eligible papers.</p> <p>The recipient of the 2019 Student Paper Award is Marta Strecker Shocket, for her paper <a href="https://www.journals.uchicago.edu/doi/full/10.1086/696096">&quot;Temperature drives epidemics in a zooplankton-fungus disease system: a trait-driven approach points to transmission via host foraging&rdquo;</a> (April 2018, 191(4):435-451), co-authored with Alexander Strauss, Jessica Hite, Maja Ijivar, ZDavid Civitello, Meghan Duffy, Carla C&atilde;ceres, and Spencer Hall. This is a remarkable combination of experimental work, modeling, and observational natural history rolled into one. Dr. Shocket and collaborators asked how climate warming will affect the dynamics of disease outbreaks. They emphasize the need for a mechanistic understanding of host-parasite interactions and the role of temperature to generate effective predictions. They develop a trait-based model that considers how temperature affects host foraging rates in a Daphnia-fungus interaction, and parameterized the model with laboratory experiments. They found that warming increased Daphnia foraging rates, which in turn increased fungal transmission success and epidemic size. The Editors appreciated the well-integrated mix of field data, lab experiments, mesocosm experiments, and theory, in service of a mechanistic understanding of species interactions. This paper has the potential to set a new standard for studies of the role of temperature-dependence in disease dynamics.</p><ul> <li><strong>Nicolas Schnedler-Meyer</strong>, for his paper <a href="https://www.journals.uchicago.edu/doi/full/10.1086/697538">&ldquo;Evolution of complex asexual reproductive strategies in jellyfish&rdquo;</a>, coauthored with Simone Pigolotti and Patizio Mariani (July 2018, 192(1):72-80). This paper stood out to us because it presents a simple but elegant model of life history evolution that was solidly grounded in natural history (jellyfish life cycles). The study considers the diversity of asexual modes of reproduction in scyphozoan jellyfish, to describe tradeoffs among dispersal, dormancy, and local spread. Which life history strategy dominates depends on the nature of environmental variation, as the authors demonstrate with an Evolutionary Stable Strategy analysis. Not only do they effectively model which life histories should evolve in which environmental settings for jellyfish, but they do an excellent job of linking their findings to similar kinds of variance discounting adaptations in plants and other animals. They very effectively relate their model results back to published empirical literature, in ways that both provide compelling support for their approach and raise new testable hypotheses.</li> <li><strong>Amanda Gibson,</strong> for her paper <a href="https://www.journals.uchicago.edu/doi/full/10.1086/699829">&ldquo;Periodic, parasite-mediated selection for and against sex&rdquo;</a>, co-authored with Lynda Delph, Daniela Vergara, and Curt Lively (November 2018, 192(5):537-551). This is an impressive exploration of the maintenance of polymorphic reproductive strategies (sexual or asexual) via frequency-dependent co-evolution between host and pathogen. The authors fuse long-term field data and mescocosm experiments to demonstrate that a parasite Microphallus evolves to specialize on whichever host snail type (sexual or asexual) is most common, thereby maintaining host polymorphism. The fusion of experimental and field data is impressive, and yields a major contribution to a fundamental and long-standing subject in evolutionary biology, the maintenance of sexual reproduction.</li> </ul> <p><br /> Daniel I. Bolnick, Editor-in-Chief<br /> Russell Bonduriansky, Editor<br /> Alice Winn, Editor</p> <p>with the 2017 editors who handled many of the 2018 papers,<br /> Judith Bronstein, former Editor-in-Chief<br /> Yannis Michilakis, former Editor</p> Mon, 15 Apr 2019 05:00:00 GMT “A residence time theory for biodiversity” https://amnat.org/an/newpapers/JulyLocey-A.html The DOI will be https://dx.doi.org/10.1086/703456 Abstract From microorganisms to the largest macroorganisms, much of Earth’s biodiversity is subject to forces of physical turnover. Residence time is the ratio of an ecosystem’s size to its rate of flow and provides a means for understanding the influence of physical turnover on biological systems. Despite its use across scientific disciplines, residence time has not been integrated into the broader understanding of biodiversity, life history, and the assembly of ecological communities. Here, we propose a residence time theory for the growth, activity, abundance, and diversity of traits and taxa in complex ecological systems. Using thousands of stochastic individual-based models to simulate energetically constrained life history processes, we show that our predictions are conceptually sound, mutually compatible, and support ecological relationships that underpin much of biodiversity theory. We discuss the importance of residence time across the ecological hierarchy and propose how residence time can be integrated into theories ranging from population genetics to macroecology. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703456 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703456">Read the Article</a></i> </p> --><h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">F</span>rom microorganisms to the largest macroorganisms, much of Earth’s biodiversity is subject to forces of physical turnover. Residence time is the ratio of an ecosystem’s size to its rate of flow and provides a means for understanding the influence of physical turnover on biological systems. Despite its use across scientific disciplines, residence time has not been integrated into the broader understanding of biodiversity, life history, and the assembly of ecological communities. Here, we propose a residence time theory for the growth, activity, abundance, and diversity of traits and taxa in complex ecological systems. Using thousands of stochastic individual-based models to simulate energetically constrained life history processes, we show that our predictions are conceptually sound, mutually compatible, and support ecological relationships that underpin much of biodiversity theory. We discuss the importance of residence time across the ecological hierarchy and propose how residence time can be integrated into theories ranging from population genetics to macroecology. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT Call for ASN Graduate Student Representatives https://amnat.org/announcements/NomGCtoECRep.html The American Society of Naturalists Graduate Student Council invites applications for two to three new graduate student representatives to join us! As a member of the Graduate Student Council you have the chance to participate in the workings of the society and interact with many of the great researchers who are members of the ASN. The ASN is committed to developing a variety of initiatives to provide more valuable services to its student members. Representatives take part in several committees that include choosing ASN-sponsored workshops, helping choose winners of the annual student research grant, organizing student events at conferences, participating in various committees, and running the website for grad student ASN members at http://asngrads.com/. Each year we seek new members to join for a 3-year term. We are also open to new roles or ideas for things you think the Grad Council could do to encourage student involvement and interaction among researchers. If you are interested in joining, please email Shengpei Wang (swang74@syr.edu) by June 30th with the subject line “ASN GC application” and attach a single pdf document containing your CV and a short paragraph (less than 1 page) about what you hope to contribute and why you want to join the grad council.Kim Gilbert&nbsp;(GC rep 2014-2015): "Serving on the ASN grad council is a fantastic opportunity to not only meet faculty, post-docs, and students from a wide range of universities, but to become more involved in a great community of researchers in ecology and evolution. You learn about how journal societies run, as well as the ins and outs of organizing conference events. You also serve as an important representative for all graduate student members of the ASN to ensure the society is doing its best to meet student&#39;s needs at conferences or through other opportunities." Emily Weiss (GC rep 2013-2014): Serving on the Grad Council really was an incredibly enriching experience for me, and I hope that many other students will apply and get to have that experience too. Rafael Maia&nbsp;(GC rep 2013-2014): "I served the council for a couple years and strongly recommend it. Great society, exciting possibilities!" Courtney Fitzpatrick&nbsp;(founding GC rep): "Grad students: excellent opportunity to get involved, meet collaborators/mentors, and learn about your scientific society!" <p>The American Society of Naturalists Graduate Student Council invites applications for two to three new graduate student representatives to join us!</p> <p>As a member of the Graduate Student Council you have the chance to participate in the workings of the society and interact with many of the great researchers who are members of the ASN. The ASN is committed to developing a variety of initiatives to provide more valuable services to its student members.</p> <p>Representatives take part in several committees that include choosing ASN-sponsored workshops, helping choose winners of the annual student research grant, organizing student events at conferences, participating in various committees, and running the website for grad student ASN members at <a href="http://asngrads.com/">http://asngrads.com/</a>.</p> <p>Each year we seek new members to join for a 3-year term. We are also open to new roles or ideas for things you think the Grad Council could do to encourage student involvement and interaction among researchers.</p> <p>If you are interested in joining, please email Shengpei Wang (<a href="mailto:swang74@syr.edu?subject=ASN%20GC%20application&amp;body=%20">swang74@syr.edu</a>) by June 30<sup>th</sup> with the subject line &ldquo;ASN GC application&rdquo; and attach a single pdf document containing your CV and a short paragraph (less than 1 page) about what you hope to contribute and why you want to join the grad council.</p><p><strong>Kim Gilbert&nbsp;</strong>(GC rep 2014-2015):<br /> &quot;Serving on the ASN grad council is a fantastic opportunity to not only meet faculty, post-docs, and students from a wide range of universities, but to become more involved in a great community of researchers in ecology and evolution. You learn about how journal societies run, as well as the ins and outs of organizing conference events. You also serve as an important representative for all graduate student members of the ASN to ensure the society is doing its best to meet student&#39;s needs at conferences or through other opportunities.&quot;</p> <p><strong>Emily Weiss (</strong>GC rep 2013-2014):<br /> Serving on the Grad Council really was an incredibly enriching experience for me, and I hope that many other students will apply and get to have that experience too.</p> <p><strong>Rafael Maia&nbsp;</strong>(GC rep 2013-2014):<br /> &quot;I served the council for a couple years and strongly recommend it. Great society, exciting possibilities!&quot;</p> <p><strong>Courtney Fitzpatrick</strong>&nbsp;(founding GC rep):<br /> &quot;Grad students: excellent opportunity to get involved, meet collaborators/mentors, and learn about your scientific society!&quot;</p> Mon, 15 Apr 2019 05:00:00 GMT “Hidden Markov models reveal tactical adjustment of temporally-clustered courtship displays in response to the behaviors of a robotic female” https://amnat.org/an/newpapers/JulyPerry.html The DOI will be https://dx.doi.org/10.1086/703518 To convince females to mate, males in many species spend a great deal of energy producing vocal and dance displays during courtship. In order to put on a good show for females that are likely to mate with them, males may have to be tactical in how they spend that energy. One way they may do this is by responding to female behaviors that indicate interest (or lack of interest) in mating. Investigators at the University of California, Davis studied whether male greater sage-grouse (Centrocercus urophasianus) adjust their display effort in response to female behaviors. To do so, they tested males on their display grounds in Wyoming with a robotic female, which either imitated the behaviors of real females uninterested in mating (pecking at the ground) or females becoming interested in mating (standing upright and looking toward the male). To determine whether males adjusted their display effort in response to these female behaviors, they analyzed the timing of males’ displays using a hidden Markov model (or HMM). HMMs are a versatile statistical tool that can be adapted to accommodate different types of time series data. Like many species of birds, frogs, and insects, male sage-grouse display in bouts separated by intervals of inactivity. The HMM enabled the researchers to determine that male sage-grouse primarily respond to female behaviors by adjusting their display persistence (rather than their display rate). They also found that these adjustments were directly related to males’ success in convincing real females to mate. Males with more matings were more persistent regardless of robot behavior, while males with fewer matings tended to reserve their display effort for when the robotic female already looked interested. Two simpler statistical techniques that are commonly used to quantify animals’ display effort were much less effective at analyzing the same data set. This study demonstrates that HMMs can be very useful for quantifying changes in animals’ display bout behavior, which will benefit researchers interested in broad questions about the evolution of animal sexual displays. Abstract We present a statistical approach—a custom-built hidden Markov model (HMM)—that is broadly applicable to the analysis of temporally-clustered display events, as found in many animals, including birds, orthopterans, and anurans. This HMM can simultaneously estimate both the expected lengths of each animal’s display bouts and also their within-bout display rates. We highlight the HMM’s ability to estimate changes in animals’ display effort over time and across different social contexts, using data from male greater sage-grouse (Centrocercus urophasianus). Male display effort was modeled across three sites in two experimental treatments (robotic female simulating interested or uninterested behavior) and in the presence or absence of live females. Across contexts, we show that sage-grouse males primarily adjust their bout lengths, rather than their within-bout display rates. Males’ responses to female behavior were correlated with male mating success: males with more matings showed high display persistence regardless of female behavior, while males with fewer matings tended to invest selectively in females that were already showing interest in mating. Additionally, males with higher mating success responded more to female presence versus absence. We conclude with suggestions for adapting our HMM approach for use in other animal systems. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703518 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703518">Read the Article</a></i> </p> --><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">T</span>o convince females to mate, males in many species spend a great deal of energy producing vocal and dance displays during courtship. In order to put on a good show for females that are likely to mate with them, males may have to be tactical in how they spend that energy. One way they may do this is by responding to female behaviors that indicate interest (or lack of interest) in mating. Investigators at the University of California, Davis studied whether male greater sage-grouse (<i>Centrocercus urophasianus</i>) adjust their display effort in response to female behaviors. To do so, they tested males on their display grounds in Wyoming with a robotic female, which either imitated the behaviors of real females uninterested in mating (pecking at the ground) or females becoming interested in mating (standing upright and looking toward the male). To determine whether males adjusted their display effort in response to these female behaviors, they analyzed the timing of males’ displays using a hidden Markov model (or HMM). HMMs are a versatile statistical tool that can be adapted to accommodate different types of time series data. </p><p>Like many species of birds, frogs, and insects, male sage-grouse display in bouts separated by intervals of inactivity. The HMM enabled the researchers to determine that male sage-grouse primarily respond to female behaviors by adjusting their display persistence (rather than their display rate). They also found that these adjustments were directly related to males’ success in convincing real females to mate. Males with more matings were more persistent regardless of robot behavior, while males with fewer matings tended to reserve their display effort for when the robotic female already looked interested. Two simpler statistical techniques that are commonly used to quantify animals’ display effort were much less effective at analyzing the same data set. This study demonstrates that HMMs can be very useful for quantifying changes in animals’ display bout behavior, which will benefit researchers interested in broad questions about the evolution of animal sexual displays. </p><hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">W</span>e present a statistical approach—a custom-built hidden Markov model (HMM)—that is broadly applicable to the analysis of temporally-clustered display events, as found in many animals, including birds, orthopterans, and anurans. This HMM can simultaneously estimate both the expected lengths of each animal’s display bouts and also their within-bout display rates. We highlight the HMM’s ability to estimate changes in animals’ display effort over time and across different social contexts, using data from male greater sage-grouse (<i>Centrocercus urophasianus</i>). Male display effort was modeled across three sites in two experimental treatments (robotic female simulating interested or uninterested behavior) and in the presence or absence of live females. Across contexts, we show that sage-grouse males primarily adjust their bout lengths, rather than their within-bout display rates. Males’ responses to female behavior were correlated with male mating success: males with more matings showed high display persistence regardless of female behavior, while males with fewer matings tended to invest selectively in females that were already showing interest in mating. Additionally, males with higher mating success responded more to female presence versus absence. We conclude with suggestions for adapting our HMM approach for use in other animal systems. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT “Phenotype-environment matching predicts both positive and negative effects of intraspecific variation” https://amnat.org/an/newpapers/JulyDibble-A.html The DOI will be https://dx.doi.org/10.1086/703483 Phenotype matching predicts effects of intraspecific variation on population dynamics and disease epidemics Abstract Natural populations can vary considerably in their genotypic and/or phenotypic diversity. Differences in this intraspecific diversity can have important consequences for contemporary ecological dynamics, but the direction and magnitude of these effects appear inconsistent across studies and systems. Here we proposed and tested the hypothesis that context-dependent ecological effects of altering phenotypic variance are predictable and arise from the relationship between a population’s mean phenotype and the local environmental optimum. By factorially manipulating the mean and variance of a key host trait in environments with and without a lethal parasite, we demonstrate that increasing phenotypic variance can have beneficial effects for host populations (e.g. smaller disease epidemics), but only when the population’s initial phenotype was poorly-matched to the local environment. When phenotypes were initially well-suited to environmental conditions, in contrast, greater phenotypic variance led to larger disease epidemics. Significant reductions in individual susceptibility occurred in both contexts over time, but the mechanisms leading to those reductions differed; strong selection was caused by either a ‘suboptimal’ trait mean and insufficient trait variance, or a ‘near-optimal’ trait mean and too much trait variance. Increasing intraspecific variation is clearly not always beneficial for populations, instead producing predictable ecological and evolutionary effects that depend on environmental context and biological interactions. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703483 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703483">Read the Article</a></i> </p> --> <p><b>Phenotype matching predicts effects of intraspecific variation on population dynamics and disease epidemics </b></p><h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">N</span>atural populations can vary considerably in their genotypic and/or phenotypic diversity. Differences in this intraspecific diversity can have important consequences for contemporary ecological dynamics, but the direction and magnitude of these effects appear inconsistent across studies and systems. Here we proposed and tested the hypothesis that context-dependent ecological effects of altering phenotypic variance are predictable and arise from the relationship between a population’s mean phenotype and the local environmental optimum. By factorially manipulating the mean and variance of a key host trait in environments with and without a lethal parasite, we demonstrate that increasing phenotypic variance can have beneficial effects for host populations (e.g. smaller disease epidemics), but only when the population’s initial phenotype was poorly-matched to the local environment. When phenotypes were initially well-suited to environmental conditions, in contrast, greater phenotypic variance led to larger disease epidemics. Significant reductions in individual susceptibility occurred in both contexts over time, but the mechanisms leading to those reductions differed; strong selection was caused by either a ‘suboptimal’ trait mean and insufficient trait variance, or a ‘near-optimal’ trait mean and too much trait variance. Increasing intraspecific variation is clearly not always beneficial for populations, instead producing predictable ecological and evolutionary effects that depend on environmental context and biological interactions. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 15 Apr 2019 05:00:00 GMT 2019 Presidential Award https://amnat.org/announcements/ANNPresAwa.html The recipients of the Presidential Award for 2018 are Meike J. Wittmann and Tadashi Fukami, for their paper Eco-Evolutionary Buffering: Rapid Evolution Facilitates Regional Species Coexistence despite Local Priority Effects in the June 2018 issue. The Presidential Award is chosen by the President of the American Society of Naturalists from all of the papers published in The American Naturalist&nbsp;during the preceding calendar year. This paper is a fine example of the synthetic tradition of The American Naturalist, wedding ecology and evolution. Weitmann and Fukami propose an evolutionary hypothesis to solve an ecological conundrum: how can species diversity persist with strong priority effects? They develop a metacommunity model that includes evolution of a costly resistance to interference competition from other species. With the possibility of such evolution, a species which becomes common may evolve to become more invadable by other species, thereby retaining the diversity of the system. With evolution, the regional coexistence of species is possible even with local priority effects. &nbsp; Michael C. Whitlock President, American Society of Naturalists <p>The recipients of the Presidential Award for 2018 are Meike J. Wittmann and Tadashi Fukami, for their paper<a href="https://www.journals.uchicago.edu/doi/full/10.1086/697187"> Eco-Evolutionary Buffering: Rapid Evolution Facilitates Regional Species Coexistence despite Local Priority Effects</a> in the June 2018 issue. The Presidential Award is chosen by the President of the American Society of Naturalists from all of the papers published in <em>The American Naturalist</em>&nbsp;during the preceding calendar year.</p> <p>This paper is a fine example of the synthetic tradition of <em>The American Naturalist, </em>wedding ecology and evolution. Weitmann and Fukami propose an evolutionary hypothesis to solve an ecological conundrum: how can species diversity persist with strong priority effects? They develop a metacommunity model that includes evolution of a costly resistance to interference competition from other species. With the possibility of such evolution, a species which becomes common may evolve to become more invadable by other species, thereby retaining the diversity of the system. With evolution, the regional coexistence of species is possible even with local priority effects.</p> <p>&nbsp;</p> <p>Michael C. Whitlock<br /> President, American Society of Naturalists</p> Mon, 15 Apr 2019 05:00:00 GMT The ASN Student Research Award Recipients for 2019 https://amnat.org/announcements/ANNStuResearchAWA.html First Last &nbsp;Research Gaurav Kandlikar Quantifying the effects of soil microbes on California annual plant community dynamics Ken Thompson Biomechanical incompatibilities and mutation-order speciation Katherine Holmes How do community context and plasticity contribute to local adaptation in plants? Kara Million MHC diversity and patterns of parasite infection in Darters (Etheostoma) of Indiana Jessie Mutz The evolvability of density: effects of multiple traits and their evolutionary potential on the density phenotype Andre Moncrieff Multiple hybrid zones in a widespread Amazonian bird reveal different evolutionary processes Sheela Turbek Explaining mismatches between genetic and phenotypic divergence in a rapid radiation of finch-like birds Linyi Zhang Testing the repeatability of ecological speciation under divergent host use across a community of gall -forming insects Suad Yoon Novel immunological interactions as an overlooked aspect of global change: insights from the host range expansion of Lycaeides melissa William Booker The Evolutionary Dynamics of Gene Duplications in Structured Populations The ASN Student Research Awards support research by student members that advances the goals of the society: the conceptual unification of ecology, evolution, or behavior. Each award consists of a $2,000 check to the candidate. An applicant must be a member of the ASN (membership is international), must hold a bachelor’s degree or equivalent, must have passed to candidacy in a Ph.D. program or equivalent, and must be at least one year from completing the PhD. Projects in all types of research (i.e., laboratory, field, theory) are encouraged. Proposals are judged on originality, strength, and significance of the questions being addressed, prospects for significant results, and the match between the proposed research and the ASN mission. <table border="1" cellpadding="1" cellspacing="1" style="width:100%"> <tbody> <tr> <td>First</td> <td>Last</td> <td>&nbsp;Research</td> </tr> <tr> <td>Gaurav</td> <td>Kandlikar</td> <td>Quantifying the effects of soil microbes on California annual plant community dynamics</td> </tr> <tr> <td>Ken</td> <td>Thompson</td> <td>Biomechanical incompatibilities and mutation-order speciation</td> </tr> <tr> <td>Katherine</td> <td>Holmes</td> <td>How do community context and plasticity contribute to local adaptation in plants?</td> </tr> <tr> <td>Kara</td> <td>Million</td> <td>MHC diversity and patterns of parasite infection in Darters (Etheostoma) of Indiana</td> </tr> <tr> <td>Jessie</td> <td>Mutz</td> <td>The evolvability of density: effects of multiple traits and their evolutionary potential on the density phenotype</td> </tr> <tr> <td>Andre</td> <td>Moncrieff</td> <td>Multiple hybrid zones in a widespread Amazonian bird reveal different evolutionary processes</td> </tr> <tr> <td>Sheela</td> <td>Turbek</td> <td>Explaining mismatches between genetic and phenotypic divergence in a rapid radiation of finch-like birds</td> </tr> <tr> <td>Linyi</td> <td>Zhang</td> <td>Testing the repeatability of ecological speciation under divergent host use across a community of gall -forming insects</td> </tr> <tr> <td>Suad</td> <td>Yoon</td> <td>Novel immunological interactions as an overlooked aspect of global change: insights from the host range expansion of <em>Lycaeides melissa</em></td> </tr> <tr> <td>William</td> <td>Booker</td> <td>The Evolutionary Dynamics of Gene Duplications in Structured Populations</td> </tr> </tbody> </table> <p>The ASN Student Research Awards support research by student members that advances the goals of the society: the conceptual unification of ecology, evolution, or behavior. Each award consists of a $2,000 check to the candidate. An applicant must be a member of the ASN (membership is international), must hold a bachelor&rsquo;s degree or equivalent, must have passed to candidacy in a Ph.D. program or equivalent, and must be at least one year from completing the PhD.</p> <p>Projects in all types of research (i.e., laboratory, field, theory) are encouraged. Proposals are judged on originality, strength, and significance of the questions being addressed, prospects for significant results, and the match between the proposed research and the ASN mission.</p> Wed, 10 Apr 2019 05:00:00 GMT Outside the Distribution--Pitch your story! Come to the Show! https://amnat.org/announcements/ANNCollider.html Stories are powerful. Whether hilarious or heartbreaking, subversive or soothing, it matters who takes the stage and what stories are told. On June 23, 2019, The Story Collider will host a very special live show at the Evolution Meetings in Providence. This event is co-organized by the Diversity Committees of the ASN, SSB, and SSE with the goal of highlighting the diverse voices of evolutionary biology! Tickets for this event are $15 and available for purchase via the conference registration site.The Story Collider producers and event organizers are now recruiting submissions from story tellers! We are searching for five people to share true, personal stories on the theme Outside the Distribution. All you need at this point is the seed of an idea for your story. It can be about almost anything—an important experiment, a rough day in the field, misadventure, love, loss, and more; but it must be about you. Our format does not include slides or props. It’s not the place for lectures. It’s about lived experiences. Exotic locations and exciting action never hurt, but what we care about is how you’ve grown as a result of the events in your life. If you’re selected for the show, experienced Story Collider producers will work with you for more than a month to help you prepare. Send a brief pitch to stories@storycollider.org&nbsp; with “Evolution Story Idea” in the subject. The deadline for pitches is May 3, 2019. If you are curious or would like some inspiration, read more at https://www.storycollider.org/submissions or browse The Story Collider podcast archive at http://soundcloud.com/the-story-collider. <p>Stories are powerful. Whether hilarious or heartbreaking, subversive or soothing, it matters who takes the stage and what stories are told. On June 23, 2019, The Story Collider will host a very special live show at the Evolution Meetings in Providence. This event is co-organized by the Diversity Committees of the ASN, SSB, and SSE with the goal of highlighting the diverse voices of evolutionary biology!</p> <p>Tickets for this event are $15 and available for purchase via the conference registration site.</p><p>The Story Collider producers and event organizers are now recruiting submissions from story tellers! We are searching for five people to share true, personal stories on the theme <strong>Outside the Distribution</strong>.</p> <p>All you need at this point is the seed of an idea for your story. It can be about almost anything&mdash;an important experiment, a rough day in the field, misadventure, love, loss, and more; but it must be about you. Our format does not include slides or props. It&rsquo;s not the place for lectures. It&rsquo;s about lived experiences. Exotic locations and exciting action never hurt, but what we care about is how you&rsquo;ve grown as a result of the events in your life. If you&rsquo;re selected for the show, experienced Story Collider producers will work with you for more than a month to help you prepare.</p> <p>Send a brief pitch to <a href="mailto:stories@storycollider.org?subject=Evolution%20Story%20Idea">stories@storycollider.org</a>&nbsp; with &ldquo;Evolution Story Idea&rdquo; in the subject. The deadline for pitches is <strong>May 3, 2019</strong>. If you are curious or would like some inspiration, read more at <a href="https://www.storycollider.org/submissions">https://www.storycollider.org/submissions</a> or browse The Story Collider podcast archive at <a href="http://soundcloud.com/the-story-collider.">http://soundcloud.com/the-story-collider.</a></p> Wed, 10 Apr 2019 05:00:00 GMT Call for Symposium Proposals for ASN 2020 at Asilomar, California 3-7 January https://amnat.org/announcements/CallSympASN2018.html The American Society of Naturalists invites proposals for symposia at its stand-alone meeting at Asilomar, in Monterey, California, 3-7 January 2020. Two symposia will be selected. Symposium topics should support the Society’s goal to advance the conceptual unification of the biological sciences and to further knowledge in evolution, ecology, behavior, and organismal biology. Proposals are encouraged on topics that are synthetic and interdisciplinary, or that address important emerging issues in evolution, ecology, and behavior. Proposals should include (1) a title; (2) a description of the symposium topic (one page); (3) a tentative list of speakers, including institutional affiliations; (4) a justification for the symposium explaining why the topic and speakers are appropriate for an ASN meeting, keeping in mind the broader goals of the society (http://www.amnat.org/about/about-the-society.html); and (5) a statement that all proposed invited speakers have agreed to participate. Organizers should plan the symposia to run from approximately 1:30-5:30 pm, and may allocate this time amongst speakers as they wish, reserving time for a coffee break. Proposals must be submitted by midnight Eastern Standard Time on April 5, 2019 by email to kmkay@ucsc.edu as a single pdf attachment and under the subject heading: ASN Asilomar Symposium Proposal. Proposals that include women, young investigators, and individuals from underrepresented groups are especially encouraged. Please note that, as with previous Asilomar meetings, the society does not have funds to pay for travel or lodging expenses of speakers. However, we may consider requests to waive conference registration costs for junior participants in symposia in cases of financial hardship. Nevertheless, speakers should assume that they will likely have to cover their own travel costs. The Society’s selection committee will evaluate proposals based on the likelihood of attracting a substantial audience, the significance and timeliness of the topic, and on the topic’s differing substantively from recent symposia hosted by the Society. All applicants will be notified of the committee’s decision by late April 2019. Kathleen M. Kay ASN Symposium Committee Chair Department of Ecology and Evolutionary Biology University of California, Santa Cruz kmkay@ucsc.edu Accessibility information for Asilomar Convention Center: https://www.visitasilomar.com/discover/accessibility-safety/ Asilomar is an historic location right on the Pacific coast--with older buildings and fairly steep hills in the park. https://www.visitasilomar.com/discover/park-history/ &nbsp; <p>The American Society of Naturalists invites proposals for symposia at its stand-alone meeting at Asilomar, in Monterey, California, 3-7 January 2020. Two symposia will be selected.</p> <p>Symposium topics should support the Society&rsquo;s goal to advance the conceptual unification of the biological sciences and to further knowledge in evolution, ecology, behavior, and organismal biology. Proposals are encouraged on topics that are synthetic and interdisciplinary, or that address important emerging issues in evolution, ecology, and behavior.</p> <p>Proposals should include (1) a title; (2) a description of the symposium topic (one page); (3) a tentative list of speakers, including institutional affiliations; (4) a justification for the symposium explaining why the topic and speakers are appropriate for an ASN meeting, keeping in mind the broader goals of the society (http://www.amnat.org/about/about-the-society.html); and (5) a statement that all proposed invited speakers have agreed to participate. Organizers should plan the symposia to run from approximately 1:30-5:30 pm, and may allocate this time amongst speakers as they wish, reserving time for a coffee break.</p> <p>Proposals must be submitted by midnight Eastern Standard Time on April 5, 2019 by email to <a href="mailto:kmkay@ucsc.edu">kmkay@ucsc.edu</a> as a single pdf attachment and under the subject heading: ASN Asilomar Symposium Proposal. Proposals that include women, young investigators, and individuals from underrepresented groups are especially encouraged.</p> <p>Please note that, as with previous Asilomar meetings, the society does not have funds to pay for travel or lodging expenses of speakers. However, we may consider requests to waive conference registration costs for junior participants in symposia in cases of financial hardship. Nevertheless, speakers should assume that they will likely have to cover their own travel costs.</p> <p>The Society&rsquo;s selection committee will evaluate proposals based on the likelihood of attracting a substantial audience, the significance and timeliness of the topic, and on the topic&rsquo;s differing substantively from recent symposia hosted by the Society. All applicants will be notified of the committee&rsquo;s decision by late April 2019.</p> <p>Kathleen M. Kay<br /> ASN Symposium Committee Chair<br /> Department of Ecology and Evolutionary Biology<br /> University of California, Santa Cruz<br /> <a href="http://kmkay@ucsc.edu">kmkay@ucsc.edu</a></p> <p>Accessibility information for Asilomar Convention Center: <a href="https://www.visitasilomar.com/discover/accessibility-safety/">https://www.visitasilomar.com/discover/accessibility-safety/</a></p> <p>Asilomar is an historic location right on the Pacific coast--with older buildings and fairly steep hills in the park. <a href="https://www.visitasilomar.com/discover/park-history/">https://www.visitasilomar.com/discover/park-history/</a></p> <p>&nbsp;</p> Tue, 19 Mar 2019 05:00:00 GMT ASN Election https://amnat.org/announcements/ASNElections.html The ASN 2019 Elections are underway for tha offices of President, Vice President, and Treasurer. The election website randomizes the order for each person voting, but the names below are in alphabetical order.The PRESIDENT leads the ASN Executive Council and selects the membership of the award and officer nomination committees. The President selects the President’s Award for the “best” paper in The American Naturalist in the past year, gives the ASN Presidential Address and presents the Society’s awards at the annual meeting, and represents the ASN in multiple other ways through the year. The President serves on the Executive Council for five years, including one year as President-Elect and three years as a Past-President. Susan Alberts For me, the American Society of Naturalists holds a special place in the biological sciences, as the oldest society in the world that advances knowledge in the three fields that my work most intersects with: behavior, evolution, and ecology. The cross-disciplinary nature of the society and the high quality of its journal, the American Naturalist, make it a big-tent society where ideas can collide and grow. The role of the society in bringing together these fields represents an enormous opportunity for fostering connectivity across disciplines. I particularly welcome the opportunity to foster ASN’s international profile and its inclusivity of diverse communities, and to contribute to its work in policy. I’m a Professor of Biology at Duke University, and as of 2016 I’m also a Professor of Evolutionary Anthropology and Chair of the Evolutionary Anthropology Department at Duke. I’ve spent 35 years studying wild primates in Kenya as part of the Amboseli Baboon Research Project, based in southern Kenya. I also studied the socioecology of African elephants for 10 years, publishing work on female and male social relationships and mating behavior, and ecological predictors of elephant group dynamics. I received my PhD from University of Chicago, and did postdocs at University of Chicago and Harvard. I’m a Fellow of the American Association for the Advancement of Science and the American Academy of Arts & Sciences. I’ve not been active in the governance of the ASN but have participated in ASN committees, including chairing the E.O. Wilson Award committee in 2017. I’m proud to be a Lifetime Member of the ASN, and I value the opportunity to run for President of the Society. Edmund "Butch" Brodie III I am an evolutionary biologist with wide interests in genetics, behavior, and natural history. I am especially intrigued by how interactions, whether between species, individuals, or genes, alter the evolutionary process from simpler linear predictions. My current work includes integrative approaches to understanding local adaptation within the molecular and geographic landscapes of predator-prey arms races, and a long-term project that explores the connections between social behavior, indirect genetic effects, and multilevel selection in natural populations of forked fungus beetles. I learned the fun (and power) of combining theory, empiricism, and fieldwork through my PhD training at the University of Chicago and a Miller Fellowship at UC Berkeley’s Museum of Vertebrate Zoology. From there, I moved to faculty positions at University of Kentucky and Indiana University before landing in my current position as BFD Runk Professor of Botany and Director of the Mountain Lake Biological Station at the University of Virginia. The ASN has been instrumental in my professional development since graduate school when I published my first American Naturalist paper. In 1992, I was awarded an ASN Young Investigator Prize and got to coauthor a paper selected for the Presidential Award in 2002. The recognition that has meant the most to me in my career was the 2017 E.O. Wilson Naturalist Award. I was an associate editor of The American Naturalist for 17 years before becoming the current Natural History Miscellany Editor. I happily continue to serve the American Naturalist because it is the most thoughtful and efficient journal board and office of the seven publications I have worked with over the years. I worked indirectly with the ASN council during my two terms as the Executive Vice President of the Society for the Study of Evolution. Through that service and the Joint Council, I was able to promote a number of initiatives that expanded student governance, established a code of conduct for Evolution meeting attendees, launched a new journal (Evolution Letters), and provided a variety of new direct benefits to SSE membership. As president of ASN, my main priorities would include expanding student membership, establishing formal networking opportunities to connect junior and senior members, and keeping natural history in the American Society of Naturalists The VICE-PRESIDENT organizes the Vice-President’s Symposium for the annual meeting and edits the special supplement to The American Naturalist that contains the papers derived from the VP Symposium. The Vice-President is also the Society’s liaison for the organizers of the annual meeting. The Vice-President serves as a member of the Executive Council for three years, two as a regular member and one as ex officio member.&nbsp; Suzanne Alonzo My research uses a combination of mathematical theory and empirical work on fishes to understand how interactions within and between the sexes affect the evolution of social behaviors and reproductive traits. I am particularly interestedin how variation among individuals is maintained, how and why plasticity evolves, and how both affect evolutionary dynamics and reproductive patterns. I am currently a Full Professor in the Department of Ecology and Evolutionary Biology at the University of California Santa Cruz, before which I spent ten years as a professor at Yale University. I did all of my training in the University of California system, including a B.A. from Berkeley, a Ph.D. from UC Santa Barbara and a NSF Postdoctoral Fellowship in Santa Cruz. The most meaningful awards of my career are my graduate and postdoctoral mentorship prizes, for which my research group nominated me. I was also honored to receive the NSF CAREER award and to have been invited to be a plenary speaker at various meetings (e.g. ISBE, ASAB, EEEF, MMEE). I am currently on the executive council for the International Society for Behavioral Ecology and have served as an associate editor for the American Naturalist, Behavioral Ecology, Evolutionary Ecology, Ecology and Evolution, and as associate editor and as editor for the Proceedings of the Royal Society. I am also involved in various activities related to improving science education and increasing inclusion and equity in our classrooms and in our field.&nbsp; I have been member of ASN since I was a first-year graduate student and have served on the journal’s editorial board and on the society’s nominations committee. As I am an evolutionary biologist and a behavioral ecologist, I think of the American Naturalist as "my" journal and society because it is one of the few places where theory, data, evolution, ecology and behavior all come together so naturally and with such excellence. &nbsp; Loren Rieseberg My lab uses a combination of evolutionary genomic approaches and field and greenhouse experiments to understand the origin and evolution of new species, crops, and weeds, focusing on members of the sunflower family.&nbsp;&nbsp;I am especially interested in the roles of hybridization and chromosomal rearrangements in evolution.&nbsp;&nbsp;&nbsp; I received my PhD in Botany from Washington State University in 1987 and subsequently took positions at the Rancho Santa Ana Botanical Garden (until 1993), Indiana University (until 2006), and at the University of British Columbia, where I am a University Killam Professor and Canada Research Chair in Plant Evolutionary Genomics.&nbsp;My work has been recognized by MacArthur and Guggenheim Fellowships, the David Starr Jordan Prize, Stebbins Medal, and the Darwin-Wallace Medal.&nbsp;I am an elected fellow of the Royal Societies of London and Canada, the Norwegian Academy of Arts and Letters, and the American Academy of Arts and Sciences.&nbsp; I have served on the Council for the American Genetics Association and the Steering Committee for the Biological Sciences Section at AAAS.&nbsp;I am a past-President of the American Genetics Association and the Botanical Society of America, and have served as Chief Editor of Molecular Ecology since 1999.&nbsp;At UBC, I have served as Director of the Biodiversity Research Centre (a cross-UBC community of 66 researchers representing ten academic units) since 2016. Although I have not previously served the ASN, I have spoken at ASN symposia and published frequently in The American Naturalist.&nbsp;I also worked closely with other journal editors to promote data archiving in evolutionary biology and ecology, and to implement these policies in a practical way in The American Naturalist and other evolution and ecology journals.&nbsp; I am interested in working with the ASN to address current challenges facing scientific journals and the societies they fund.&nbsp;Possible areas I would consider for the VP symposium include evolutionary agriculture, invasion evolutionary ecology, and structural variation and evolution.&nbsp; The TREASURER manages the accounts of the ASN, tracks all revenues and expenses, arranges for official annual financial reviews and tax return preparation, files tax returns, makes payments for all annual awards and travel reimbursements related to the annual meeting, keeps track of revisions to the award amounts and reimbursement policies, and prepares the annual Treasurer’s Report. The Treasurer also convenes a Finance Committee comprised of two other members of the Executive Council, for making investment decisions as needed. The Treasurer serves on the Executive Council for six years, three as a regular member and three as Past Treasurer. Vote to approve or disapprove. Rebecca "Becky" Fuller My research focuses broadly on evolution in fishes.&nbsp;Half of our work focuses on the evolution of color patterns, color vision, and phenotypic plasticity in these traits as a function of spatial and temporal variation in lighting environments and the subsequent effects on sexual and natural selection. The other half of our work focuses on speciation in fishes (both darters and killifish) due to the effects of reinforcement, genomic rearrangements, and ecological selection. I obtained a B.S. from the University of Nebraska, studied at Uppsala University in Sweden under a Fulbright Scholarship, obtained an M.S. from Michigan State University, a Ph.D. from Florida State University, and started as an assistant professor at the University of Illinois in 2005.&nbsp;I was a recipient of the ASN Young Investigator Award, an NSF Career Award, and several awards for research and teaching excellence at the University of Illinois. In addition to my service to the American Naturalist (see below), I have served in leadership roles at the University of Illinois and also at the Society for the Study of Evolution.&nbsp;At UI, I serve as our Director of Graduate Studies for my department, I co-organize our seminar on Ecology and Evolution (with Dr. Katy Heath), I serve on our School&#39;s Executive Committee, and I serve on the Executive Committee of the Graduate College.&nbsp;At SSE, I have served as a society councilor, served as an Associate Editor at Evolution, served on the Evolution Education committee, and have helped organize several student award competitions.&nbsp; I have served the American Society of Naturalists in several ways.&nbsp;I helped Dan Bolnick organize the first standalone meeting at Asilomar, served on the Student Research Awards committee for 3 years with one year as the chair, served as the society representative to the Joint Meeting Committee that helps organize the tri-society meeting in the summer (&#39;Evolution Meetings&#39;) for 2 years, and served as an Associate Editor at our journal, The American Naturalist. I helped co-organize a symposium that was focused on using natural history in the classroom with George Gilchrist, and I organized a spotlight symposium focusing on &#39;25 Years of Sensory Drive&#39;. I am honored to be considered for the role of treasurer at the American Naturalist.&nbsp;The basic role of the treasurer is (a) to oversee the bank accounts of the society, (b) to make certain that bills, award checks, and associated paperwork are issued in a reasonable amount of time, (c) to make certain that taxes are filed on time, and (d) to act as a basic watchdog over the society&#39;s finances.&nbsp;My relevant experience in this area comes from my start-up company, "BassInSight" which makes software that mimics the visual experience of largemouth bass. My relevant experience involves making certain that the company does not overspend its accounts and submits its tax forms on time. <p>The ASN 2019 Elections are underway for tha offices of President, Vice President, and Treasurer. The election website randomizes the order for each person voting, but the names below are in alphabetical order.</p><p>The PRESIDENT leads the ASN Executive Council and selects the membership of the award and officer nomination committees. The President selects the President&rsquo;s Award for the &ldquo;best&rdquo; paper in The American Naturalist in the past year, gives the ASN Presidential Address and presents the Society&rsquo;s awards at the annual meeting, and represents the ASN in multiple other ways through the year. The President serves on the Executive Council for five years, including one year as President-Elect and three years as a Past-President.</p> <p style="text-align: center;"><strong>Susan Alberts</strong><strong> </strong></p> <p>For me, the American Society of Naturalists holds a special place in the biological sciences, as the oldest society in the world that advances knowledge in the three fields that my work most intersects with: behavior, evolution, and ecology. The cross-disciplinary nature of the society and the high quality of its journal, the American Naturalist, make it a big-tent society where ideas can collide and grow. The role of the society in bringing together these fields represents an enormous opportunity for fostering connectivity across disciplines. I particularly welcome the opportunity to foster ASN&rsquo;s international profile and its inclusivity of diverse communities, and to contribute to its work in policy.</p> <p>I&rsquo;m a Professor of Biology at Duke University, and as of 2016 I&rsquo;m also a Professor of Evolutionary Anthropology and Chair of the Evolutionary Anthropology Department at Duke. I&rsquo;ve spent 35 years studying wild primates in Kenya as part of the Amboseli Baboon Research Project, based in southern Kenya. I also studied the socioecology of African elephants for 10 years, publishing work on female and male social relationships and mating behavior, and ecological predictors of elephant group dynamics. I received my PhD from University of Chicago, and did postdocs at University of Chicago and Harvard. I&rsquo;m a Fellow of the American Association for the Advancement of Science and the American Academy of Arts &amp; Sciences. I&rsquo;ve not been active in the governance of the ASN but have participated in ASN committees, including chairing the E.O. Wilson Award committee in 2017. I&rsquo;m proud to be a Lifetime Member of the ASN, and I value the opportunity to run for President of the Society.</p> <p style="text-align: center;"><strong>Edmund &quot;Butch&quot; Brodie III</strong></p> <p>I am an evolutionary biologist with wide interests in genetics, behavior, and natural history. I am especially intrigued by how interactions, whether between species, individuals, or genes, alter the evolutionary process from simpler linear predictions. My current work includes integrative approaches to understanding local adaptation within the molecular and geographic landscapes of predator-prey arms races, and a long-term project that explores the connections between social behavior, indirect genetic effects, and multilevel selection in natural populations of forked fungus beetles. I learned the fun (and power) of combining theory, empiricism, and fieldwork through my PhD training at the University of Chicago and a Miller Fellowship at UC Berkeley&rsquo;s Museum of Vertebrate Zoology. From there, I moved to faculty positions at University of Kentucky and Indiana University before landing in my current position as BFD Runk Professor of Botany and Director of the Mountain Lake Biological Station at the University of Virginia.</p> <p>The ASN has been instrumental in my professional development since graduate school when I published my first American Naturalist paper. In 1992, I was awarded an ASN Young Investigator Prize and got to coauthor a paper selected for the Presidential Award in 2002. The recognition that has meant the most to me in my career was the 2017 E.O. Wilson Naturalist Award. I was an associate editor of The American Naturalist for 17 years before becoming the current Natural History Miscellany Editor. I happily continue to serve the American Naturalist because it is the most thoughtful and efficient journal board and office of the seven publications I have worked with over the years. I worked indirectly with the ASN council during my two terms as the Executive Vice President of the Society for the Study of Evolution. Through that service and the Joint Council, I was able to promote a number of initiatives that expanded student governance, established a code of conduct for Evolution meeting attendees, launched a new journal (Evolution Letters), and provided a variety of new direct benefits to SSE membership. As president of ASN, my main priorities would include expanding student membership, establishing formal networking opportunities to connect junior and senior members, and keeping natural history in the American Society of Naturalists</p> <hr /><p>The VICE-PRESIDENT organizes the Vice-President&rsquo;s Symposium for the annual meeting and edits the special supplement to <em>The American Naturalist</em> that contains the papers derived from the VP Symposium. The Vice-President is also the Society&rsquo;s liaison for the organizers of the annual meeting. The Vice-President serves as a member of the Executive Council for three years, two as a regular member and one as ex officio member.&nbsp;</p> <p style="text-align: center;"><strong>Suzanne Alonzo</strong></p> <p>My research uses a combination of mathematical theory and empirical work on fishes to understand how interactions within and between the sexes affect the evolution of social behaviors and reproductive traits. I am particularly interestedin how variation among individuals is maintained, how and why plasticity evolves, and how both affect evolutionary dynamics and reproductive patterns.</p> <p>I am currently a Full Professor in the Department of Ecology and Evolutionary Biology at the University of California Santa Cruz, before which I spent ten years as a professor at Yale University. I did all of my training in the University of California system, including a B.A. from Berkeley, a Ph.D. from UC Santa Barbara and a NSF Postdoctoral Fellowship in Santa Cruz. The most meaningful awards of my career are my graduate and postdoctoral mentorship prizes, for which my research group nominated me. I was also honored to receive the NSF CAREER award and to have been invited to be a plenary speaker at various meetings (e.g. ISBE, ASAB, EEEF, MMEE).</p> <p>I am currently on the executive council for the International Society for Behavioral Ecology and have served as an associate editor for the American Naturalist, Behavioral Ecology, Evolutionary Ecology, Ecology and Evolution, and as associate editor and as editor for the Proceedings of the Royal Society. I am also involved in various activities related to improving science education and increasing inclusion and equity in our classrooms and in our field.&nbsp; I have been member of ASN since I was a first-year graduate student and have served on the journal&rsquo;s editorial board and on the society&rsquo;s nominations committee. As I am an evolutionary biologist and a behavioral ecologist, I think of the American Naturalist as &quot;my&quot; journal and society because it is one of the few places where theory, data, evolution, ecology and behavior all come together so naturally and with such excellence. &nbsp;</p> <p style="text-align: center;"><strong>Loren Rieseberg</strong></p> <p>My lab uses a combination of evolutionary genomic approaches and field and greenhouse experiments to understand the origin and evolution of new species, crops, and weeds, focusing on members of the sunflower family.&nbsp;&nbsp;I am especially interested in the roles of hybridization and chromosomal rearrangements in evolution.&nbsp;&nbsp;&nbsp;</p> <p>I received my PhD in Botany from Washington State University in 1987 and subsequently took positions at the Rancho Santa Ana Botanical Garden (until 1993), Indiana University (until 2006), and at the University of British Columbia, where I am a University Killam Professor and Canada Research Chair in Plant Evolutionary Genomics.&nbsp;My work has been recognized by MacArthur and Guggenheim Fellowships, the David Starr Jordan Prize, Stebbins Medal, and the Darwin-Wallace Medal.&nbsp;I am an elected fellow of the Royal Societies of London and Canada, the Norwegian Academy of Arts and Letters, and the American Academy of Arts and Sciences.&nbsp;</p> <p>I have served on the Council for the American Genetics Association and the Steering Committee for the Biological Sciences Section at AAAS.&nbsp;I am a past-President of the American Genetics Association and the Botanical Society of America, and have served as Chief Editor of <em>Molecular Ecology</em> since 1999.&nbsp;At UBC, I have served as Director of the Biodiversity Research Centre (a cross-UBC community of 66 researchers representing ten academic units) since 2016. Although I have not previously served the ASN, I have spoken at ASN symposia and published frequently in <em>The American Naturalist</em>.&nbsp;I also worked closely with other journal editors to promote data archiving in evolutionary biology and ecology, and to implement these policies in a practical way in <em>The American Naturalist </em>and other evolution and ecology journals.&nbsp;</p> <p>I am interested in working with the ASN to address current challenges facing scientific journals and the societies they fund.&nbsp;Possible areas I would consider for the VP symposium include evolutionary agriculture, invasion evolutionary ecology, and structural variation and evolution.&nbsp;</p> <hr /><p>The TREASURER manages the accounts of the ASN, tracks all revenues and expenses, arranges for official annual financial reviews and tax return preparation, files tax returns, makes payments for all annual awards and travel reimbursements related to the annual meeting, keeps track of revisions to the award amounts and reimbursement policies, and prepares the annual Treasurer&rsquo;s Report. The Treasurer also convenes a Finance Committee comprised of two other members of the Executive Council, for making investment decisions as needed. The Treasurer serves on the Executive Council for six years, three as a regular member and three as Past Treasurer. Vote to approve or disapprove.</p> <p style="text-align: center;"><strong>Rebecca &quot;Becky&quot; Fuller</strong></p> <p>My research focuses broadly on evolution in fishes.&nbsp;Half of our work focuses on the evolution of color patterns, color vision, and phenotypic plasticity in these traits as a function of spatial and temporal variation in lighting environments and the subsequent effects on sexual and natural selection. The other half of our work focuses on speciation in fishes (both darters and killifish) due to the effects of reinforcement, genomic rearrangements, and ecological selection.</p> <p>I obtained a B.S. from the University of Nebraska, studied at Uppsala University in Sweden under a Fulbright Scholarship, obtained an M.S. from Michigan State University, a Ph.D. from Florida State University, and started as an assistant professor at the University of Illinois in 2005.&nbsp;I was a recipient of the ASN Young Investigator Award, an NSF Career Award, and several awards for research and teaching excellence at the University of Illinois.</p> <p>In addition to my service to the American Naturalist (see below), I have served in leadership roles at the University of Illinois and also at the Society for the Study of Evolution.&nbsp;At UI, I serve as our Director of Graduate Studies for my department, I co-organize our seminar on Ecology and Evolution (with Dr. Katy Heath), I serve on our School&#39;s Executive Committee, and I serve on the Executive Committee of the Graduate College.&nbsp;At SSE, I have served as a society councilor, served as an Associate Editor at Evolution, served on the Evolution Education committee, and have helped organize several student award competitions.&nbsp;</p> <p>I have served the American Society of Naturalists in several ways.&nbsp;I helped Dan Bolnick organize the first standalone meeting at Asilomar, served on the Student Research Awards committee for 3 years with one year as the chair, served as the society representative to the Joint Meeting Committee that helps organize the tri-society meeting in the summer (&#39;Evolution Meetings&#39;) for 2 years, and served as an Associate Editor at our journal, The American Naturalist. I helped co-organize a symposium that was focused on using natural history in the classroom with George Gilchrist, and I organized a spotlight symposium focusing on &#39;25 Years of Sensory Drive&#39;.</p> <p>I am honored to be considered for the role of treasurer at the American Naturalist.&nbsp;The basic role of the treasurer is (a) to oversee the bank accounts of the society, (b) to make certain that bills, award checks, and associated paperwork are issued in a reasonable amount of time, (c) to make certain that taxes are filed on time, and (d) to act as a basic watchdog over the society&#39;s finances.&nbsp;My relevant experience in this area comes from my start-up company, &quot;BassInSight&quot; which makes software that mimics the visual experience of largemouth bass. My relevant experience involves making certain that the company does not overspend its accounts and submits its tax forms on time.</p> <hr /> Thu, 14 Mar 2019 05:00:00 GMT Sewall Wright Award 2019 https://amnat.org/announcements/ANNWrightaward.html The Sewall Wright Award, established in 1991, is given annually and honors a senior but still active investigator who is making fundamental contributions to the Society&#39;s goals, namely, promoting the conceptual unification of the biological sciences. The 2019 Sewall Wright Award honors Jonathan B. Losos, the William H. Danforth Distinguished University Professor, at Washington University, and the Director of the Living Earth Collaborative, a collaboration between Washington University, the Missouri Botanical Garden, and the St. Louis Zoo Jonathan is known for his integrative approach to the study of evolutionary diversification and for his seminal work with Anolis lizards.&nbsp; This work spans field and laboratory studies of rapid evolution, and includes studies of behavior, ecology and phylogenetics. One of his best-known and most widely cited articles is his 1998 Science paper that addresses the enduring dichotomy between historical contingency versus predictability in evolutionary biology. In this study Jonathan and collaborators studied Anolis lizards and elegantly demonstrated that they have repeatedly and independently evolved the same ecomorphs on different islands in the Caribbean when they are faced with the same ecological conditions. This and subsequent work on the evolution of other traits including performance, biomechanical, and behavioral traits in these populations have resulted in Anolis lizards literally becoming a textbook example of the repeatability of adaptive radiation in natural populations. Jonathan has made numerous other fundamental contributions to the study of adaptive radiation and biodiversity, including the evolutionary genetics of biological invasions. However, his influence is not restricted solely to studies published in the primary scientific literature. For example, he is a coauthor of the widely used textbook Biology (Raven et al.) and has also published books and articles targeted towards the more general reader, the latest being the beautiful and highly readable book Improbable Destinies: Fate, Chance, and the Future of Evolution (Penguin Random House, 2017). Jonathan has served as the President of the American Society of Naturalists in 2010 and as the Editor-in-Chief of the society’s flagship journal The American Naturalist from 2002-06. His career has taken him from his first faculty position at Washington University, to Harvard University as the Curator in Herpetology at the university’s Museum of Comparative Zoology, and in 2018, back again to Washington University as the founding director of the Living Earth Collaborative, a partnership between Washington University, the Saint Louis Zoo, and the Missouri Botanical Garden. He is a member of the National Academy of Sciences and a fellow of the American Academy of Arts & Sciences, as well as the recipient of the Daniel Giraud Elliot Medal, the Theodosius Dobzhansky Prize, the Edward O. Wilson Naturalist Award, and the David Starr Jordan Prize. Troy Day and Monica Geber, on behalf of the Sewall Wright Award Committee https://biology.wustl.edu/people/jonathan-losos A list of previous recipients can be found here. &nbsp; <p>The Sewall Wright Award, established in 1991, is given annually and honors a senior but still active investigator who is making fundamental contributions to the Society&#39;s goals, namely, promoting the conceptual unification of the biological sciences.</p> <p>The 2019 Sewall Wright Award honors Jonathan B. Losos, the William H. Danforth Distinguished University Professor, at Washington University, and the Director of the Living Earth Collaborative, a collaboration between Washington University, the Missouri Botanical Garden, and the St. Louis Zoo</p> <p>Jonathan is known for his integrative approach to the study of evolutionary diversification and for his seminal work with Anolis lizards.&nbsp; This work spans field and laboratory studies of rapid evolution, and includes studies of behavior, ecology and phylogenetics. One of his best-known and most widely cited articles is his 1998 <em>Science</em> paper that addresses the enduring dichotomy between historical contingency versus predictability in evolutionary biology. In this study Jonathan and collaborators studied Anolis lizards and elegantly demonstrated that they have repeatedly and independently evolved the same ecomorphs on different islands in the Caribbean when they are faced with the same ecological conditions. This and subsequent work on the evolution of other traits including performance, biomechanical, and behavioral traits in these populations have resulted in Anolis lizards literally becoming a textbook example of the repeatability of adaptive radiation in natural populations.</p> <p>Jonathan has made numerous other fundamental contributions to the study of adaptive radiation and biodiversity, including the evolutionary genetics of biological invasions. However, his influence is not restricted solely to studies published in the primary scientific literature. For example, he is a coauthor of the widely used textbook <em>Biology</em> (Raven et al.) and has also published books and articles targeted towards the more general reader, the latest being the beautiful and highly readable book <em>Improbable Destinies: Fate, Chance, and the Future of Evolution</em> (Penguin Random House, 2017).</p> <p>Jonathan has served as the President of the American Society of Naturalists in 2010 and as the Editor-in-Chief of the society&rsquo;s flagship journal <em>The American Naturalist</em> from 2002-06. His career has taken him from his first faculty position at Washington University, to Harvard University as the Curator in Herpetology at the university&rsquo;s Museum of Comparative Zoology, and in 2018, back again to Washington University as the founding director of the Living Earth Collaborative, a partnership between Washington University, the Saint Louis Zoo, and the Missouri Botanical Garden. He is a member of the National Academy of Sciences and a fellow of the American Academy of Arts &amp; Sciences, as well as the recipient of the Daniel Giraud Elliot Medal, the Theodosius Dobzhansky Prize, the Edward O. Wilson Naturalist Award, and the David Starr Jordan Prize.</p> <p><br /> Troy Day and Monica Geber, on behalf of the Sewall Wright Award Committee</p> <p><a href="https://biology.wustl.edu/people/jonathan-losos">https://biology.wustl.edu/people/jonathan-losos</a></p> <p><a href="https://www.amnat.org/awards.html#Wright">A list of previous recipients can be found here.</a></p> <hr /> <p>&nbsp;</p> Thu, 14 Mar 2019 05:00:00 GMT Edward O. Wilson Naturalist Award 2019 https://amnat.org/announcements/ANNWilsonAward.html The E. O. Wilson Naturalist Award is awarded annually to an active mid-career scientist who has made significant contributions to the knowledge of a particular ecosystem or group of organisms, and who through this work has illuminated key principles of evolutionary biology and an enhanced appreciation of natural history.&nbsp;A list of previous recipients can be found here. In 2019, the award was conferred upon Anurag Agrawal, the James A. Perkins Professor of Environmental Studies, at Cornell University. In Chapter 3 of the Origin of Species (“Struggle for existence”) Charles Darwin argued that the primary cause of evolution is antagonistic interactions among species.&nbsp; Anurag Agrawal’s career has been built on the elaboration of this argument in the context of interactions between plants and insects.&nbsp; The sum of his life’s work to date is a mapping and fantastic complexity of the ongoing arms race between plants and their diverse chemical and physical defenses against herbivores and the ways herbivores overcome those defenses then turn them into weapons for their own protection against predators.&nbsp; To this complexity he adds the interactions among different species of herbivores as they compete for the common plant resource.&nbsp; His research program thus captures the multi-dimensional network of interactions originally envisioned by Darwin, but with the modern dimensions of chemistry, physiology, genetics, epigenetics, phylogenetics and community ecology that shape how these interactions occur.&nbsp; He embodies the ideal of the “Edward Osborne Wilson Naturalist Award” with his characterization of this complexity, motivated by his observations of natural history.&nbsp; He expands on this ideal with synthetic reviews that address the underlying principles and create bridges among disciplines.&nbsp; He has gone even further by making this science accessible to a general audience in the form of a prize winning book – Monarch and Milkweeds. Dr. Agrawal has sustained a special focus on milkweeds (Asclepias spp.) and their specialized herbivores, including monarch butterflies (Danaus plexippus), aphids (Aphis spp.) and beetles (Tetraopes spp.).&nbsp;&nbsp;&nbsp; He has developed and deployed research tools for characterizing these interactions at levels that range from microevolutionary studies of populations to macroevolutionary studies of the entire Asclepias genus to even broader studies of flowering plants and insects.&nbsp; At one level, he and his students and collaborators have performed detailed experimental studies that characterize the details of the physical and chemical defenses plants mount against insects and how the insects deal with them.&nbsp; This interaction includes assessing the diversity of cardenolides produced by milkweeds and the enzymatic defenses of the insects.&nbsp; The plant side involves a combination of constitutive and induced responses which are in turn shaped by tradeoffs between them and other features of the plant lifecycle, such as regrowth after herbivore damage.&nbsp; The insect side includes the enzymatic detoxification of plant poisons, the sequestration and modification of the poisons in their own defense, and their direct and indirect interactions with each other as they consume a shared resource.&nbsp; At a higher level of complexity, he has explored the consequences of genetic diversity among plants within a population and discovered that there is safety in diversity in the form of reduced herbivore damage.&nbsp; At yet a higher level of complexity, he has characterized the evolution of defense mechanisms across the dozens of species that comprise the genus Asclepias and characterized the relationship between the evolution of plant defenses and species diversity. In spanning this range of biological organization, he has characterized the importance of phenotypic plasticity and tradeoffs among different defenses in shaping evolution.&nbsp; He has amplified our understanding of co-evolution, constraint and convergence in shaping both microevolution and macroevolution.&nbsp;&nbsp; He has addressed all of these general issues in perspectives, synthetic reviews, symposia at national and international conferences, and special issues in leading journals, often in ways that create bridges among otherwise unconnected areas of endeavor.&nbsp; He has been a successful mentor to a large number of graduate students and post-docs who have developed independent research programs and gone on to successful careers of their own.&nbsp; His leadership in promoting science includes serving as a Special Features editor of Ecology and chairing a review of NSF’s Population and Community Ecology panel.&nbsp; His research has appeared almost exclusively in the most highly ranked journals in our discipline and the most exclusive inter-disciplinary journals. &nbsp; Dr. Agrawal’s appreciation of natural history, translation of that appreciation into diverse forms of empirical studies of adaptation and evolution, skilled communication of his ideas to technical and general audiences, and leadership in the scientific community are what define him as this year’s recipient of the Wilson Award. David Reznick (Chair), Jenn Rudgers, Joseph Travis &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; https://ecologyandevolution.cornell.edu/anurag-agrawal <p>The E. O. Wilson Naturalist Award is awarded annually to an active mid-career scientist who has made significant contributions to the knowledge of a particular ecosystem or group of organisms, and who through this work has illuminated key principles of evolutionary biology and an enhanced appreciation of natural history.&nbsp;<a href="https://www.amnat.org/awards.html#Wilson">A list of previous recipients can be found here.</a></p> <p>In 2019, the award was conferred upon Anurag Agrawal, the James A. Perkins Professor of Environmental Studies, at Cornell University.</p> <p>In Chapter 3 of the <em>Origin of Species</em> (&ldquo;Struggle for existence&rdquo;) Charles Darwin argued that the primary cause of evolution is antagonistic interactions among species.&nbsp; Anurag Agrawal&rsquo;s career has been built on the elaboration of this argument in the context of interactions between plants and insects.&nbsp; The sum of his life&rsquo;s work to date is a mapping and fantastic complexity of the ongoing arms race between plants and their diverse chemical and physical defenses against herbivores and the ways herbivores overcome those defenses then turn them into weapons for their own protection against predators.&nbsp; To this complexity he adds the interactions among different species of herbivores as they compete for the common plant resource.&nbsp; His research program thus captures the multi-dimensional network of interactions originally envisioned by Darwin, but with the modern dimensions of chemistry, physiology, genetics, epigenetics, phylogenetics and community ecology that shape how these interactions occur.&nbsp; He embodies the ideal of the &ldquo;Edward Osborne Wilson Naturalist Award&rdquo; with his characterization of this complexity, motivated by his observations of natural history.&nbsp; He expands on this ideal with synthetic reviews that address the underlying principles and create bridges among disciplines.&nbsp; He has gone even further by making this science accessible to a general audience in the form of a prize winning book &ndash; Monarch and Milkweeds.</p> <p>Dr. Agrawal has sustained a special focus on milkweeds (Asclepias spp.) and their specialized herbivores, including monarch butterflies (Danaus plexippus), aphids (Aphis spp.) and beetles (Tetraopes spp.).&nbsp;&nbsp;&nbsp; He has developed and deployed research tools for characterizing these interactions at levels that range from microevolutionary studies of populations to macroevolutionary studies of the entire Asclepias genus to even broader studies of flowering plants and insects.&nbsp; At one level, he and his students and collaborators have performed detailed experimental studies that characterize the details of the physical and chemical defenses plants mount against insects and how the insects deal with them.&nbsp; This interaction includes assessing the diversity of cardenolides produced by milkweeds and the enzymatic defenses of the insects.&nbsp; The plant side involves a combination of constitutive and induced responses which are in turn shaped by tradeoffs between them and other features of the plant lifecycle, such as regrowth after herbivore damage.&nbsp; The insect side includes the enzymatic detoxification of plant poisons, the sequestration and modification of the poisons in their own defense, and their direct and indirect interactions with each other as they consume a shared resource.&nbsp; At a higher level of complexity, he has explored the consequences of genetic diversity among plants within a population and discovered that there is safety in diversity in the form of reduced herbivore damage.&nbsp; At yet a higher level of complexity, he has characterized the evolution of defense mechanisms across the dozens of species that comprise the genus Asclepias and characterized the relationship between the evolution of plant defenses and species diversity.</p> <p>In spanning this range of biological organization, he has characterized the importance of phenotypic plasticity and tradeoffs among different defenses in shaping evolution.&nbsp; He has amplified our understanding of co-evolution, constraint and convergence in shaping both microevolution and macroevolution.&nbsp;&nbsp; He has addressed all of these general issues in perspectives, synthetic reviews, symposia at national and international conferences, and special issues in leading journals, often in ways that create bridges among otherwise unconnected areas of endeavor.&nbsp; He has been a successful mentor to a large number of graduate students and post-docs who have developed independent research programs and gone on to successful careers of their own.&nbsp; His leadership in promoting science includes serving as a Special Features editor of Ecology and chairing a review of NSF&rsquo;s Population and Community Ecology panel.&nbsp; His research has appeared almost exclusively in the most highly ranked journals in our discipline and the most exclusive inter-disciplinary journals. &nbsp;</p> <p>Dr. Agrawal&rsquo;s appreciation of natural history, translation of that appreciation into diverse forms of empirical studies of adaptation and evolution, skilled communication of his ideas to technical and general audiences, and leadership in the scientific community are what define him as this year&rsquo;s recipient of the Wilson Award.</p> <p>David Reznick (Chair), Jenn Rudgers, Joseph Travis</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><a href="https://ecologyandevolution.cornell.edu/anurag-agrawal">https://ecologyandevolution.cornell.edu/anurag-agrawal</a></p> Thu, 14 Mar 2019 05:00:00 GMT “Biotic interactions contribute to the geographic range limit of an annual plant: herbivory and phenology mediate fitness beyond a range margin” https://amnat.org/an/newpapers/JuneBenning.html The DOI will be https://dx.doi.org/10.1086/703187 Using multiple lines of evidence, Benning et al. show how biotic interactions can contribute to geographic range limits Palm trees don’t grow in Minnesota, and you won’t find any redwoods in Texas. These limits to species’ distributions are one of the most readily apparent ecological phenomena, but are poorly understood. And as environments change worldwide, conservationists and policy makers increasingly need to know how these environmental changes will affect species distributions. Benning et al. show that for a California endemic plant, herbivory by small mammals may play a large role in setting the plant’s range limit. The researchers have been working with the plant Clarkia xantiana ssp. xantiana for over a decade in the southern Sierra Nevada foothills of California. In a previous experiment where they transplanted seeds outside the range limit in order to see if they could survive there, they noticed that many of the plants were eaten by rabbits and hares. However, plants at the center of the range were rarely eaten. Benning et al. were interested in three main questions: 1) how does the probability of herbivory change going from the center to beyond the range limit; 2) how much does this fatal herbivory lower average fitness in transplanted populations outside the range edge; and 3) is there a specific trait that makes the plant more susceptible to herbivory? Using both field and simulation approaches, they found a sharp increase in herbivory near the range edge, which led to large decreases in fitness outside the range, and found evidence that the slow development of C.&nbsp;x.&nbsp;xantiana exposes it to high rates of herbivory outside its range. Together, these results provide one of the most comprehensive explorations of how biotic interactions can influence large-scale distributions. Abstract Species’ geographic distributions have already shifted during the Anthropocene. However, we often do not know what aspects of the environment drive range dynamics, much less which traits mediate organisms’ responses to these environmental gradients. Most studies focus on possible climatic limits to species’ distributions and have ignored the role of biotic interactions, despite theoretical support for their importance in setting distributional limits. We used field experiments and simulations to estimate contributions of mammalian herbivory to a range boundary in the Californian annual plant Clarkia xantiana ssp. xantiana. A steep gradient of increasing probability of herbivory occurred across the boundary, and a reanalysis of prior transplant experiments revealed that herbivory drove several-fold declines in lifetime fitness at and beyond the boundary. Simulations showed that populations could potentially persist beyond the range margin in the absence of herbivory. Using data from a narrowly sympatric subspecies, C.&nbsp;x.&nbsp;parviflora, we also showed that delayed phenology is strongly associated with C.&nbsp;xantiana ssp. xantiana’s susceptibility to herbivory and low fitness beyond its border. Overall, our results provide some of the most comprehensive evidence to date of how the interplay of demography, traits, and spatial gradients in species interactions can produce a geographic range limit, and lend empirical support to recent developments in range limits theory. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703187 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703187">Read the Article</a></i> </p> --> <p><b>Using multiple lines of evidence, Benning et al. show how biotic interactions can contribute to geographic range limits </b></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">P</span>alm trees don’t grow in Minnesota, and you won’t find any redwoods in Texas. These limits to species’ distributions are one of the most readily apparent ecological phenomena, but are poorly understood. And as environments change worldwide, conservationists and policy makers increasingly need to know how these environmental changes will affect species distributions. Benning et al. show that for a California endemic plant, herbivory by small mammals may play a large role in setting the plant’s range limit. </p><p>The researchers have been working with the plant <i>Clarkia xantiana</i> ssp. <i>xantiana</i> for over a decade in the southern Sierra Nevada foothills of California. In a previous experiment where they transplanted seeds outside the range limit in order to see if they could survive there, they noticed that many of the plants were eaten by rabbits and hares. However, plants at the center of the range were rarely eaten. Benning et al. were interested in three main questions: 1) how does the probability of herbivory change going from the center to beyond the range limit; 2) how much does this fatal herbivory lower average fitness in transplanted populations outside the range edge; and 3) is there a specific trait that makes the plant more susceptible to herbivory? Using both field and simulation approaches, they found a sharp increase in herbivory near the range edge, which led to large decreases in fitness outside the range, and found evidence that the slow development of <i>C.&nbsp;x.&nbsp;xantiana</i> exposes it to high rates of herbivory outside its range. Together, these results provide one of the most comprehensive explorations of how biotic interactions can influence large-scale distributions. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">S</span>pecies’ geographic distributions have already shifted during the Anthropocene. However, we often do not know what aspects of the environment drive range dynamics, much less which traits mediate organisms’ responses to these environmental gradients. Most studies focus on possible climatic limits to species’ distributions and have ignored the role of biotic interactions, despite theoretical support for their importance in setting distributional limits. We used field experiments and simulations to estimate contributions of mammalian herbivory to a range boundary in the Californian annual plant <i>Clarkia xantiana</i> ssp. <i>xantiana</i>. A steep gradient of increasing probability of herbivory occurred across the boundary, and a reanalysis of prior transplant experiments revealed that herbivory drove several-fold declines in lifetime fitness at and beyond the boundary. Simulations showed that populations could potentially persist beyond the range margin in the absence of herbivory. Using data from a narrowly sympatric subspecies, <i>C.&nbsp;x.&nbsp;parviflora</i>, we also showed that delayed phenology is strongly associated with <i>C.&nbsp;xantiana</i> ssp. <i>xantiana</i>’s susceptibility to herbivory and low fitness beyond its border. Overall, our results provide some of the most comprehensive evidence to date of how the interplay of demography, traits, and spatial gradients in species interactions can produce a geographic range limit, and lend empirical support to recent developments in range limits theory. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Tue, 12 Mar 2019 05:00:00 GMT “Habitat saturation results in joint-nesting female coalitions in a social bird” https://amnat.org/an/newpapers/JuneBarve.html Read the Article Sisters unite! Acorn woodpecker females joint nest in saturated habitats influencing fitness in both males and females Acorn woodpeckers live in close-knit family groups and have one of the most complex breeding systems of any bird. In about 20% of family groups, up to three related females may lay eggs in a nest together and raise the chicks cooperatively with one or more related males, a behavior known as joint nesting or cooperative polyandry and known in only 0.2% of all bird species. Based on demographic data collected over 35 years (1982-2016) at the Hastings Natural History Reservation in central coastal California, the authors quantified the costs and benefits of joint nesting to attempt to explain why some woodpecker females exhibit this rare behavior. They found that the incidence of joint nesting was more common in years when the population was high, all the breeding territories were occupied, and opportunities for a female to nest on her own very unlikely. Although forming joint nests reduces the number of offspring each female can produce compared to when she nests alone, such females make the “best of a bad situation” by nesting jointly with their mother or sister rather than not nesting at all. Additionally, females that decide to nest jointly do so in groups where there are two or more breeder males, thus increasing the number of caregivers and, hence, the total number of chicks that females can successfully raise. Years of population boom may have therefore been an important mechanism driving the evolution of such highly social behaviors like joint nesting in acorn woodpeckers. Abstract Joint nesting by females and cooperative polyandry—cooperatively breeding groups with a male-biased breeder sex ratio—are little-understood, rare breeding systems. We tested alternative hypotheses of factors potentially driving these phenomena in a population of joint-nesting acorn woodpeckers (Melanerpes formicivorus). During periods of high population density and, thus low independent breeding opportunities, acorn woodpecker females formed joint-nesting coalitions with close kin. Coalitions were typically associated with groups with a male bias. We found strong evidence for both inter- and intra-sexual conflict, as joint nesting conferred a fitness benefit to some males, a significant fitness cost to females, and no gain in per capita reproductive output for either sex. Such conflict, particularly the cost to females, may be an important reason why joint nesting is rare among cooperatively breeding taxa. More forthcoming papers &raquo; <p><i><a href="https://dx.doi.org/10.1086/703188">Read the Article</a></i> </p> <p><strong>Sisters unite! Acorn woodpecker females joint nest in saturated habitats influencing fitness in both males and females </strong></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">A</span>corn woodpeckers live in close-knit family groups and have one of the most complex breeding systems of any bird. In about 20% of family groups, up to three related females may lay eggs in a nest together and raise the chicks cooperatively with one or more related males, a behavior known as joint nesting or cooperative polyandry and known in only 0.2% of all bird species. Based on demographic data collected over 35 years (1982-2016) at the Hastings Natural History Reservation in central coastal California, the authors quantified the costs and benefits of joint nesting to attempt to explain why some woodpecker females exhibit this rare behavior. They found that the incidence of joint nesting was more common in years when the population was high, all the breeding territories were occupied, and opportunities for a female to nest on her own very unlikely. Although forming joint nests reduces the number of offspring each female can produce compared to when she nests alone, such females make the “best of a bad situation” by nesting jointly with their mother or sister rather than not nesting at all. Additionally, females that decide to nest jointly do so in groups where there are two or more breeder males, thus increasing the number of caregivers and, hence, the total number of chicks that females can successfully raise. Years of population boom may have therefore been an important mechanism driving the evolution of such highly social behaviors like joint nesting in acorn woodpeckers. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">J</span>oint nesting by females and cooperative polyandry—cooperatively breeding groups with a male-biased breeder sex ratio—are little-understood, rare breeding systems. We tested alternative hypotheses of factors potentially driving these phenomena in a population of joint-nesting acorn woodpeckers (<i>Melanerpes formicivorus</i>). During periods of high population density and, thus low independent breeding opportunities, acorn woodpecker females formed joint-nesting coalitions with close kin. Coalitions were typically associated with groups with a male bias. We found strong evidence for both inter- and intra-sexual conflict, as joint nesting conferred a fitness benefit to some males, a significant fitness cost to females, and no gain in per capita reproductive output for either sex. Such conflict, particularly the cost to females, may be an important reason why joint nesting is rare among cooperatively breeding taxa. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Tue, 12 Mar 2019 05:00:00 GMT “Adaptive differences in circadian clock gene expression patterns and photoperiodic diapause induction in Nasonia vitripennis” https://amnat.org/an/newpapers/JuneDallaBenetta.html Read the Article Knock down of the clock gene period changes the pace and the phase of the circadian clock and delays diapause response In 2017, the Nobel prize in medicine was awarded for the discovery of the endogenous circadian clock, that enables organisms from bacteria to plants and animals to exhibit biological rhythms adapted to daily (circadian) and annual environmental oscillations. Studies on the genetics of the clock have revealed much complexity and variation. The Marie Skłodowska-Curie Initial Training Network (ITN) INsecTIME was initiated to train early scientists to investigate the (neuro)genetics that underlie biological timing. Here we report variation in circadian clock gene expression patterns in the parasitoid wasp Nasonia vitripennis. This wasp has a photoperiodically induced larval dormancy state called diapause When adult females experience certain critically short daylight conditions, which is dependent on geographical location, they produce diapausing larvae that resume development when conditions are favorable. The study reveals that geographical differences in circadian clock gene regulation under different photoperiods may play a role in regulating this seasonal adaptation. In particular the expression of the clock gene period is important for setting the pace and the phase of Nasonia daily rhythms as well as in the timer mechanism responsible for diapause induction. This shows that genes of the circadian clock are involved in seasonal timing as well, and therefore links the evolution of circadian and circannual adaptive mechanisms. Abstract Day length (photoperiod) and temperature oscillate daily and seasonally and are important cues for season-dependent behavior. Larval diapause of the parasitoid Nasonia vitripennis is maternally induced following a certain number of days (switch point) of a given critical photoperiod (CPP). Both the switch point and CPP follow a latitudinal cline in European N.&nbsp;vitripennis populations. We previously showed that allelic frequencies of the clock gene period correlate with this diapause induction cline. Here, we report that circadian expression of four clock genes, period (per), cryptochrome-2 (cry-2), clock (clk) and cycle (cyc), oscillates as a function of photoperiod and latitude of origin in wasps from populations from the extremes of the cline. Expression amplitudes are lower in northern wasps, indicating a weaker, more plastic, clock. Northern wasps also have a later onset of activity and longer free running rhythms in constant conditions. Per RNAi caused speeding up of the circadian clock, changed the expression of other clock genes and delayed diapause in both southern and northern wasps. These results point towards adaptive latitudinal clock-gene expression differences and to a key role of per in the timing of photoperiodic diapause induction of N.&nbsp;vitripennis. More forthcoming papers &raquo; <p><i><a href="https://dx.doi.org/10.1086/703159">Read the Article</a></i> </p> <p><strong>Knock down of the clock gene period changes the pace and the phase of the circadian clock and delays diapause response </strong></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">I</span>n 2017, the Nobel prize in medicine was awarded for the discovery of the endogenous circadian clock, that enables organisms from bacteria to plants and animals to exhibit biological rhythms adapted to daily (circadian) and annual environmental oscillations. Studies on the genetics of the clock have revealed much complexity and variation. The Marie Skłodowska-Curie Initial Training Network (ITN) INsecTIME was initiated to train early scientists to investigate the (neuro)genetics that underlie biological timing. Here we report variation in circadian clock gene expression patterns in the parasitoid wasp <i>Nasonia vitripennis</i>. This wasp has a photoperiodically induced larval dormancy state called diapause When adult females experience certain critically short daylight conditions, which is dependent on geographical location, they produce diapausing larvae that resume development when conditions are favorable. The study reveals that geographical differences in circadian clock gene regulation under different photoperiods may play a role in regulating this seasonal adaptation. In particular the expression of the clock gene <i>period</i> is important for setting the pace and the phase of <i>Nasonia</i> daily rhythms as well as in the timer mechanism responsible for diapause induction. This shows that genes of the circadian clock are involved in seasonal timing as well, and therefore links the evolution of circadian and circannual adaptive mechanisms. <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">D</span>ay length (photoperiod) and temperature oscillate daily and seasonally and are important cues for season-dependent behavior. Larval diapause of the parasitoid <i>Nasonia vitripennis</i> is maternally induced following a certain number of days (switch point) of a given critical photoperiod (CPP). Both the switch point and CPP follow a latitudinal cline in European <i>N.&nbsp;vitripennis</i> populations. We previously showed that allelic frequencies of the clock gene <i>period</i> correlate with this diapause induction cline. Here, we report that circadian expression of four clock genes, <i>period (per), cryptochrome-2 (cry-2), clock (clk)</i> and <i>cycle (cyc)</i>, oscillates as a function of photoperiod and latitude of origin in wasps from populations from the extremes of the cline. Expression amplitudes are lower in northern wasps, indicating a weaker, more plastic, clock. Northern wasps also have a later onset of activity and longer free running rhythms in constant conditions. <i>Per</i> RNAi caused speeding up of the circadian clock, changed the expression of other clock genes and delayed diapause in both southern and northern wasps. These results point towards adaptive latitudinal clock-gene expression differences and to a key role of <i>per</i> in the timing of photoperiodic diapause induction of <i>N.&nbsp;vitripennis</i>. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Fri, 08 Mar 2019 06:00:00 GMT “Species’ range dynamics affect the evolution of spatial variation in plasticity under environmental change” https://amnat.org/an/newpapers/JuneSchmid-A.html The DOI will be https://dx.doi.org/10.1086/703171 An alternative to the climate variability hypothesis: Geographic clines in plasticity evolve during range dynamics Abstract While clines in environmental tolerance and phenotypic plasticity along a single species’ range have been reported repeatedly and are of special interest in the context of adaptation to environmental changes, we know little about their evolution. Recent empirical findings in ectotherms suggest that processes underlying dynamic species’ ranges can give rise to spatial differences in environmental tolerance and phenotypic plasticity within species. We used individual-based simulations to investigate how plasticity and tolerance evolve in the course of three scenarios of species’ range shifts and range expansions on environmental gradients. We found that regions of a species’ range which experienced a longer history or larger extent of environmental change generally exhibited increased plasticity or tolerance. Such regions may be at the trailing edge when a species is tracking its ecological niche in space (e.g., in a climate change scenario) or at the front edge when a species expands into a new habitat (e.g., in an expansion/invasion scenario). Elevated tolerance and plasticity in the distribution center was detected when asymmetric environmental change (e.g., polar amplification) led to a range expansion. However, tolerance and plasticity clines were transient and slowly flattened out after range dynamics because of genetic assimilation. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/703171 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/703171">Read the Article</a></i> </p> --> <p><b>An alternative to the climate variability hypothesis: Geographic clines in plasticity evolve during range dynamics </b></p><h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">W</span>hile clines in environmental tolerance and phenotypic plasticity along a single species’ range have been reported repeatedly and are of special interest in the context of adaptation to environmental changes, we know little about their evolution. Recent empirical findings in ectotherms suggest that processes underlying dynamic species’ ranges can give rise to spatial differences in environmental tolerance and phenotypic plasticity within species. We used individual-based simulations to investigate how plasticity and tolerance evolve in the course of three scenarios of species’ range shifts and range expansions on environmental gradients. We found that regions of a species’ range which experienced a longer history or larger extent of environmental change generally exhibited increased plasticity or tolerance. Such regions may be at the trailing edge when a species is tracking its ecological niche in space (e.g., in a climate change scenario) or at the front edge when a species expands into a new habitat (e.g., in an expansion/invasion scenario). Elevated tolerance and plasticity in the distribution center was detected when asymmetric environmental change (e.g., polar amplification) led to a range expansion. However, tolerance and plasticity clines were transient and slowly flattened out after range dynamics because of genetic assimilation.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 28 Feb 2019 06:00:00 GMT “A practical guide to the study of distribution limits” https://amnat.org/an/newpapers/JuneWilli.html Read the Article A practical guide to studying distribution limits, emphasizing recently proposed genetic constraints Constraints on adaptation are an important explanation for the tremendous diversity of species on Earth. This may seem surprising – after all, adaptation also leads to the evolution of new species. But adaptive limits prevent species from evolving ever-larger ecological niches, and hence ensure that species are confined to restricted geographic distributions. This, in part, explains why different species occur in different geographic regions. This argument suggests that the causes of range limits are a key to understanding the maintenance of biodiversity. According to theory, there are several plausible explanations for range limits, but empirical tests are too limited to reach any general conclusions. This article is a guide to the study of range limits that should be applicable to any organism. It emphasizes the degradation of habitat quality near the edge of the range, the consequences of small population size and fragmentation at the edge, genetic factors that may obstruct adaptation at the range edge, and the importance of synthesizing different explanations within an eco-evolutionary framework. Abstract Factors that limit the geographic distribution of species are broadly important in ecology and evolutionary biology, and understanding distribution limits is imperative for predicting how species will respond to environmental change. Good data indicate that factors such as dispersal limitation, small effective population size, and isolation are sometimes important. But empirical research highlights no single factor that explains the ubiquity of distribution limits. In this article, we outline a guide to tackling distribution limits that integrates established causes, such as dispersal limitation and spatial environmental heterogeneity, with understudied causes such as mutational load and genetic or developmental integration of traits limiting niche expansion. We highlight how modeling and quantitative genetic and genomic analyses can provide insight into sources of distribution limits. Our practical guide provides a framework for considering the many factors likely to determine species distributions and how the different approaches can be integrated to predict distribution limits using eco-evolutionary modeling. The framework should also help predict distribution limits of invasive species and under climate change. More forthcoming papers &raquo; <p><i><a href="https://dx.doi.org/10.1086/703172">Read the Article</a></i> </p> <p><strong>A practical guide to studying distribution limits, emphasizing recently proposed genetic constraints </strong></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">C</span>onstraints on adaptation are an important explanation for the tremendous diversity of species on Earth. This may seem surprising – after all, adaptation also leads to the evolution of new species. But adaptive limits prevent species from evolving ever-larger ecological niches, and hence ensure that species are confined to restricted geographic distributions. This, in part, explains why different species occur in different geographic regions. This argument suggests that the causes of range limits are a key to understanding the maintenance of biodiversity. According to theory, there are several plausible explanations for range limits, but empirical tests are too limited to reach any general conclusions. This article is a guide to the study of range limits that should be applicable to any organism. It emphasizes the degradation of habitat quality near the edge of the range, the consequences of small population size and fragmentation at the edge, genetic factors that may obstruct adaptation at the range edge, and the importance of synthesizing different explanations within an eco-evolutionary framework. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">F</span>actors that limit the geographic distribution of species are broadly important in ecology and evolutionary biology, and understanding distribution limits is imperative for predicting how species will respond to environmental change. Good data indicate that factors such as dispersal limitation, small effective population size, and isolation are sometimes important. But empirical research highlights no single factor that explains the ubiquity of distribution limits. In this article, we outline a guide to tackling distribution limits that integrates established causes, such as dispersal limitation and spatial environmental heterogeneity, with understudied causes such as mutational load and genetic or developmental integration of traits limiting niche expansion. We highlight how modeling and quantitative genetic and genomic analyses can provide insight into sources of distribution limits. Our practical guide provides a framework for considering the many factors likely to determine species distributions and how the different approaches can be integrated to predict distribution limits using eco-evolutionary modeling. The framework should also help predict distribution limits of invasive species and under climate change. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 28 Feb 2019 06:00:00 GMT “The evolution of indiscriminate altruism in a cooperatively breeding mammal” https://amnat.org/an/newpapers/JuneDuncan.html Read the Article Why do animals cooperate? One of the most powerful explanations for the evolution of cooperation is kin selection theory, which suggests that altruism may evolve when cooperative behaviors are directed towards genetic relatives. Meerkats, a species of cooperatively breeding mongoose, exhibit a wide range of cooperative behaviors; they babysit and feed the newly born pups of other individuals, look out for predators, and work to maintain hiding holes and sleeping burrows for the group. In this paper, researchers from the University of Cambridge analyzed data from a long-term study of meerkats in the Southern Kalahari Desert, South Africa. They find that although meerkat helpers cooperate extensively, individual helpers do not appear to provide more assistance to more closely related kin – they are indiscriminate altruists. Why is this the case? The researchers hypothesize that in groups of high genetic relatedness (as seen in meerkats), natural selection could favor indiscriminate altruism over kin-discriminate altruism if individuals frequently make mistakes in estimating their relatedness to group mates. However, in groups of lower genetic relatedness (such as humans), indiscriminate altruism is unlikely to evolve, even when kin-recognition is prone to substantial error. This provides an explanation for both the evolution of indiscriminate altruism in meerkats and the association between group relatedness and kin-discriminate altruism reported across vertebrates more generally. Abstract Kin selection theory suggests that altruistic behaviors can increase the fitness of altruists when recipients are genetic relatives. Although selection can favor the ability of organisms to preferentially cooperate with close kin, indiscriminately helping all group mates may yield comparable fitness returns if relatedness within groups is very high. Here, we show that meerkats (Suricata suricatta) are largely indiscriminate altruists who do not alter the amount of help provided to pups or group mates in response to their relatedness to them. We present a model showing that indiscriminate altruism may yield greater fitness payoffs than kin discrimination where most group members are close relatives and errors occur in the estimation of relatedness. The presence of errors in the estimation of relatedness provides a feasible explanation for associations between kin discriminative helping and group relatedness in eusocial and cooperatively breeding animals. More forthcoming papers &raquo; <p><i><a href="https://dx.doi.org/10.1086/703113">Read the Article</a></i> </p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">W</span>hy do animals cooperate? One of the most powerful explanations for the evolution of cooperation is kin selection theory, which suggests that altruism may evolve when cooperative behaviors are directed towards genetic relatives. Meerkats, a species of cooperatively breeding mongoose, exhibit a wide range of cooperative behaviors; they babysit and feed the newly born pups of other individuals, look out for predators, and work to maintain hiding holes and sleeping burrows for the group. In this paper, researchers from the University of Cambridge analyzed data from a long-term study of meerkats in the Southern Kalahari Desert, South Africa. They find that although meerkat helpers cooperate extensively, individual helpers do not appear to provide more assistance to more closely related kin – they are indiscriminate altruists. Why is this the case? The researchers hypothesize that in groups of high genetic relatedness (as seen in meerkats), natural selection could favor indiscriminate altruism over kin-discriminate altruism if individuals frequently make mistakes in estimating their relatedness to group mates. However, in groups of lower genetic relatedness (such as humans), indiscriminate altruism is unlikely to evolve, even when kin-recognition is prone to substantial error. This provides an explanation for both the evolution of indiscriminate altruism in meerkats and the association between group relatedness and kin-discriminate altruism reported across vertebrates more generally. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">K</span>in selection theory suggests that altruistic behaviors can increase the fitness of altruists when recipients are genetic relatives. Although selection can favor the ability of organisms to preferentially cooperate with close kin, indiscriminately helping all group mates may yield comparable fitness returns if relatedness within groups is very high. Here, we show that meerkats (<i>Suricata suricatta</i>) are largely indiscriminate altruists who do not alter the amount of help provided to pups or group mates in response to their relatedness to them. We present a model showing that indiscriminate altruism may yield greater fitness payoffs than kin discrimination where most group members are close relatives and errors occur in the estimation of relatedness. The presence of errors in the estimation of relatedness provides a feasible explanation for associations between kin discriminative helping and group relatedness in eusocial and cooperatively breeding animals. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 28 Feb 2019 06:00:00 GMT “How does the evolution of universal ecological traits affect population size? Lessons from simple models” https://amnat.org/an/newpapers/JuneAbrams.html Read the Article Theory shows that adaptive evolution should frequently decrease population size, even in simple systems Does evolutionary change via natural selection usually increase population size? Do maladaptive processes (e.g., deleterious mutations) generally decrease population size? Many biologists would answer both questions in the affirmative, while acknowledging some exceptions. Nevertheless, many simple and widely used ecological models predict that adaptation via natural selection should often reduce population size (and that maladaptive processes should have the opposite effect). Both processes can be termed ‘adaptive decline’. Adaptive change in any of the three basic ecological properties that characterize all biological species—rate of taking up resources, rate of converting them to offspring, and probability of survival—is expected to lead to an ‘overly high’ rate of resource uptake; i.e., a rate greater than that which maximizes its population size. Overly high uptake rates may cause lower population size due to three mechanisms: (1) higher death rates or lower conversion efficiencies due to tradeoffs with uptake ability; (2) decreased productivity of the resource due to its lower population size; and/or (3) decreased productivity due to increased defense by the resource. Models predict that species experiencing a new environment are almost equally likely to increase or decrease their equilibrium population size as a result of their subsequent adaptive evolution. Even new genotypes that only affect all of the basic ecological properties in a fitness-increasing manner can decrease population size via decreased resource productivity or increased resource defense. Unfortunately, changes in population size during a period of adaptive genetic change are seldom measured, and we know little about the occurrence of overexploitation. If adaptive decline is in fact rare, it implies that our most widely used models of predator-prey or consumer-resource interactions are missing some element that is key to understanding how population sizes change as a consequence of evolution. The author, Peter Abrams, became interested in this topic while working on its ecological analogue, i.e., when environmental change causes an immediate harm to individuals of a species, but nevertheless increases its ultimate population size. Abstract This article argues that adaptive evolutionary change in a consumer species should frequently decrease (and maladaptive change should increase) population size, producing ‘adaptive decline’. This conclusion is based on analysis of multiple consumer-resource models that examine evolutionary change in consumer traits affecting the universal ecological parameters of attack rate, conversion efficiency, and mortality. Two scenarios are investigated. Under one, evolutionary equilibrium is initially maintained by opposing effects on the attack rate and other growth-rate parameters; the environment or trait is perturbed and the trait then evolves to a new (or back to a previous) equilibrium. Here evolution exhibits adaptive decline in up to one-half of all cases. The other scenario assumes a genetic perturbation having purely fitness-increasing effects. Here, adaptive decline in the consumer requires that the resource be self-reproducing and overexploited, and requires a sufficient increase in the attack rate. However, if the resource exhibits adaptive defense via behavior or evolution, adaptive decline may characterize consumer traits affecting all parameters. Favorable environmental change producing parameter shifts similar to those produced by adaptive evolution has similar counter-intuitive effects on consumer population size. Many different food web models have already been shown to exhibit such counterintuitive changes in some species. More forthcoming papers &raquo; <p><i><a href="https://dx.doi.org/10.1086/703155">Read the Article</a></i> </p> <p><strong>Theory shows that adaptive evolution should frequently decrease population size, even in simple systems </strong></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">D</span>oes evolutionary change via natural selection usually increase population size? Do maladaptive processes (e.g., deleterious mutations) generally decrease population size? Many biologists would answer both questions in the affirmative, while acknowledging some exceptions. Nevertheless, many simple and widely used ecological models predict that adaptation via natural selection should often reduce population size (and that maladaptive processes should have the opposite effect). Both processes can be termed ‘adaptive decline’. Adaptive change in any of the three basic ecological properties that characterize all biological species—rate of taking up resources, rate of converting them to offspring, and probability of survival—is expected to lead to an ‘overly high’ rate of resource uptake; i.e., a rate greater than that which maximizes its population size. Overly high uptake rates may cause lower population size due to three mechanisms: (1) higher death rates or lower conversion efficiencies due to tradeoffs with uptake ability; (2) decreased productivity of the resource due to its lower population size; and/or (3) decreased productivity due to increased defense by the resource. Models predict that species experiencing a new environment are almost equally likely to increase or decrease their equilibrium population size as a result of their subsequent adaptive evolution. Even new genotypes that only affect all of the basic ecological properties in a fitness-increasing manner can decrease population size via decreased resource productivity or increased resource defense. Unfortunately, changes in population size during a period of adaptive genetic change are seldom measured, and we know little about the occurrence of overexploitation. If adaptive decline is in fact rare, it implies that our most widely used models of predator-prey or consumer-resource interactions are missing some element that is key to understanding how population sizes change as a consequence of evolution. </p> <p>The author, Peter Abrams, became interested in this topic while working on its ecological analogue, i.e., when environmental change causes an immediate harm to individuals of a species, but nevertheless increases its ultimate population size. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">T</span>his article argues that adaptive evolutionary change in a consumer species should frequently decrease (and maladaptive change should increase) population size, producing ‘adaptive decline’. This conclusion is based on analysis of multiple consumer-resource models that examine evolutionary change in consumer traits affecting the universal ecological parameters of attack rate, conversion efficiency, and mortality. Two scenarios are investigated. Under one, evolutionary equilibrium is initially maintained by opposing effects on the attack rate and other growth-rate parameters; the environment or trait is perturbed and the trait then evolves to a new (or back to a previous) equilibrium. Here evolution exhibits adaptive decline in up to one-half of all cases. The other scenario assumes a genetic perturbation having purely fitness-increasing effects. Here, adaptive decline in the consumer requires that the resource be self-reproducing and overexploited, and requires a sufficient increase in the attack rate. However, if the resource exhibits adaptive defense via behavior or evolution, adaptive decline may characterize consumer traits affecting all parameters. Favorable environmental change producing parameter shifts similar to those produced by adaptive evolution has similar counter-intuitive effects on consumer population size. Many different food web models have already been shown to exhibit such counterintuitive changes in some species. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 28 Feb 2019 06:00:00 GMT “Assessing behavioral associations in a hybrid zone through social network analysis: Complex assortative behaviors structure associations in a hybrid quail population” https://amnat.org/an/newpapers/JuneZonana.html Read the Article RFID data and social network analyses link phenotype and fine-scale social structure in a hybrid quail population Animals must identify, attract, and compete for mates before reproducing. These mating behaviors strongly influence whether closely related species will hybridize in areas where they co-occur. Yet, our understanding of how behavior affects hybridization between species is hindered by the fact that mating occurs within a complex web of social interactions that are challenging to characterize. The social structure in which animals live determines who they will encounter as potential mates and competitors, and therefore shapes the opportunity for hybridization. In this study, Zonana et al. combine high-resolution behavioral data (captured with RFID tags) and network analyses to test how sex, mass, and plumage traits correlate with social structure across an entire breeding, hybrid population of quail. Their study takes place within the hybrid zone between the California and Gambel’s quail, where the species’ ranges overlap in the deserts and mountains of Southern California. The authors find that social associations between these gregarious birds are strongest and most prevalent between individuals of the opposite sex, and these male-female associations disproportionately occur between individuals with similar mass and plumage traits that are shared by both males and females. Yet, the quail's social networks are random with respect to plumage traits that differ between the two species. The authors discuss how these complex patterns of behavior may facilitate hybridization between these species. The study demonstrates how network analyses can be used to test the influence of multiple traits on social associations (within and between both sexes and species) in natural, breeding populations. The authors’ framework provides a promising approach towards better understanding how animal behavior drives genetic exchange between populations and species. Abstract Behavior can strongly influence rates and patterns of hybridization between animal populations and species. Yet few studies have examined reproductive behaviors in natural hybrid zones within the fine-scale social structure in which they take place. We use radio-frequency identification (RFID) tags with social network analyses to test whether phenotypic similarity in plumage and mass correlate with social behavior throughout a breeding season in a California and Gambel’s quail hybrid zone. We use a novel approach to partition phenotypic variation in a way that does not confound differences between sexes and species, and illustrate the complex ways that phenotype and behavior structure the social environment, mating opportunities, and male-male associations. Associations within the admixed population were random with respect to species-specific plumage, but showed strong patterns of assortment based upon sexually dimorphic plumage, monomorphic plumage, and mass. Weak behavioral reproductive isolation in this admixed population may be the result of complex patterns of phenotypic assortment based upon multiple traits, rather than a lack of phenotypic discrimination. More generally, our results inform the utility of social network analyses for analyzing behavioral factors affecting genetic exchange between populations and species. More forthcoming papers &raquo; <p><i><a href="https://dx.doi.org/10.1086/703158">Read the Article</a></i> </p> <p><strong>RFID data and social network analyses link phenotype and fine-scale social structure in a hybrid quail population </strong></p><p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">A</span>nimals must identify, attract, and compete for mates before reproducing. These mating behaviors strongly influence whether closely related species will hybridize in areas where they co-occur. Yet, our understanding of how behavior affects hybridization between species is hindered by the fact that mating occurs within a complex web of social interactions that are challenging to characterize. The social structure in which animals live determines who they will encounter as potential mates and competitors, and therefore shapes the opportunity for hybridization. In this study, Zonana et al. combine high-resolution behavioral data (captured with RFID tags) and network analyses to test how sex, mass, and plumage traits correlate with social structure across an entire breeding, hybrid population of quail. Their study takes place within the hybrid zone between the California and Gambel’s quail, where the species’ ranges overlap in the deserts and mountains of Southern California. The authors find that social associations between these gregarious birds are strongest and most prevalent between individuals of the opposite sex, and these male-female associations disproportionately occur between individuals with similar mass and plumage traits that are shared by both males and females. Yet, the quail's social networks are random with respect to plumage traits that differ between the two species. The authors discuss how these complex patterns of behavior may facilitate hybridization between these species. The study demonstrates how network analyses can be used to test the influence of multiple traits on social associations (within and between both sexes and species) in natural, breeding populations. The authors’ framework provides a promising approach towards better understanding how animal behavior drives genetic exchange between populations and species. </p> <hr /> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">B</span>ehavior can strongly influence rates and patterns of hybridization between animal populations and species. Yet few studies have examined reproductive behaviors in natural hybrid zones within the fine-scale social structure in which they take place. We use radio-frequency identification (RFID) tags with social network analyses to test whether phenotypic similarity in plumage and mass correlate with social behavior throughout a breeding season in a California and Gambel’s quail hybrid zone. We use a novel approach to partition phenotypic variation in a way that does not confound differences between sexes and species, and illustrate the complex ways that phenotype and behavior structure the social environment, mating opportunities, and male-male associations. Associations within the admixed population were random with respect to species-specific plumage, but showed strong patterns of assortment based upon sexually dimorphic plumage, monomorphic plumage, and mass. Weak behavioral reproductive isolation in this admixed population may be the result of complex patterns of phenotypic assortment based upon multiple traits, rather than a lack of phenotypic discrimination. More generally, our results inform the utility of social network analyses for analyzing behavioral factors affecting genetic exchange between populations and species. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 28 Feb 2019 06:00:00 GMT “Macroevolutionary patterning in glucocorticoids suggests different selective pressures shape baseline and stress-induced levels” https://amnat.org/an/newpapers/JuneVitousek.html Read the Article New analysis suggests consistency in how some selective pressures shape glucocorticoid hormones across tetrapods Abstract Glucocorticoid (GC) hormones are important phenotypic mediators across vertebrates, but their circulating concentrations can vary markedly. Here we investigate macroevolutionary patterning in GC levels across tetrapods by testing seven specific hypotheses about GC variation, and evaluating whether the supported hypotheses reveal consistent patterns in GC evolution. If selection generally favors the “supportive” role of GCs in responding effectively to challenges, then baseline and/or stress-induced GCs may be higher in challenging contexts. Alternatively, if selection generally favors “protection” from GC-induced costs, GCs may be lower in environments where challenges are more common or severe. The predictors of baseline GCs were all consistent with supportive effects: levels were higher in smaller organisms, and in those inhabiting more energetically demanding environments. During breeding, baseline GCs were also higher in populations and species with fewer lifetime opportunities to reproduce. The predictors of stress-induced GCs were instead more consistent with the protection hypothesis: during breeding, levels were lower in organisms with fewer lifetime reproductive opportunities. Overall, these patterns indicate a surprising degree of consistency in how some selective pressures shape GCs across broad taxonomic scales; at the same time, in challenging environments selection appears to operate on baseline and stress-induced GCs in distinct ways. More forthcoming papers &raquo; <p><i><a href="https://dx.doi.org/10.1086/703112">Read the Article</a></i> </p> <p><strong>New analysis suggests consistency in how some selective pressures shape glucocorticoid hormones across tetrapods </strong></p><!-- <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">A</span> </p> <hr /> --> <h3>Abstract</h3> <p><span style="float: left; font-size: 40px; line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-weight: bold;">G</span>lucocorticoid (GC) hormones are important phenotypic mediators across vertebrates, but their circulating concentrations can vary markedly. Here we investigate macroevolutionary patterning in GC levels across tetrapods by testing seven specific hypotheses about GC variation, and evaluating whether the supported hypotheses reveal consistent patterns in GC evolution. If selection generally favors the “supportive” role of GCs in responding effectively to challenges, then baseline and/or stress-induced GCs may be higher in challenging contexts. Alternatively, if selection generally favors “protection” from GC-induced costs, GCs may be lower in environments where challenges are more common or severe. The predictors of baseline GCs were all consistent with supportive effects: levels were higher in smaller organisms, and in those inhabiting more energetically demanding environments. During breeding, baseline GCs were also higher in populations and species with fewer lifetime opportunities to reproduce. The predictors of stress-induced GCs were instead more consistent with the protection hypothesis: during breeding, levels were lower in organisms with fewer lifetime reproductive opportunities. Overall, these patterns indicate a surprising degree of consistency in how some selective pressures shape GCs across broad taxonomic scales; at the same time, in challenging environments selection appears to operate on baseline and stress-induced GCs in distinct ways. </p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"> <span style="font-size: large; font-family: Georgia;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 28 Feb 2019 06:00:00 GMT