ASN RSS http://amnat.org/ Latest press releases and announcements from the ASN en-us Fri, 20 Apr 2018 05:00:00 GMT 60 “Assessing feeding preference of a consumer guild: partitioning variation among versus within species” http://amnat.org/an/newpapers/SepRhoades-A.html The DOI will be https://dx.doi.org/10.1086/698325 Abstract Interspecific variation in resource use is critical to understanding species diversity, coexistence, and ecosystem functioning. A growing body of research describes analogous intraspecific variation and its potential importance for population dynamics and community outcomes. However, the magnitude of intraspecific variation relative to interspecific variation in key dimensions of consumer-resource interactions remains unknown, and is critical for understanding the importance of this variation for population and community processes. In this study, we examine feeding preference through repeated laboratory choice feeding assays of 444 wild-caught individuals of eight invertebrate grazer species on rocky reefs in northern California, USA. Between-species variation accounted for 25-33% of the total variation in preference for the preferred resource, while between-individual variation accounted for 4-5% of total variation. For two of the eight species, between-individual variation was significantly different from zero and contributed on-average 14% and 17% of the total diet variation, even after accounting for differences due to size and sex. Therefore, even with clearly distinguishable between-species differences in mean preference, diet variation between and within individuals can contribute to the dietary niche width of species and guilds, which may be overlooked by focusing solely on species’ mean resource use patterns. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698325 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698325">Read the Article</a></i></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;">I</span>nterspecific variation in resource use is critical to understanding species diversity, coexistence, and ecosystem functioning. A growing body of research describes analogous intraspecific variation and its potential importance for population dynamics and community outcomes. However, the magnitude of intraspecific variation relative to interspecific variation in key dimensions of consumer-resource interactions remains unknown, and is critical for understanding the importance of this variation for population and community processes. In this study, we examine feeding preference through repeated laboratory choice feeding assays of 444 wild-caught individuals of eight invertebrate grazer species on rocky reefs in northern California, USA. Between-species variation accounted for 25-33% of the total variation in preference for the preferred resource, while between-individual variation accounted for 4-5% of total variation. For two of the eight species, between-individual variation was significantly different from zero and contributed on-average 14% and 17% of the total diet variation, even after accounting for differences due to size and sex. Therefore, even with clearly distinguishable between-species differences in mean preference, diet variation between and within individuals can contribute to the dietary niche width of species and guilds, which may be overlooked by focusing solely on species’ mean resource use patterns. </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, 19 Apr 2018 05:00:00 GMT “Matrix models of hierarchical demography: Linking group- and population-level dynamics in cooperative breeders” http://amnat.org/an/newpapers/AugBateman.html The DOI will be https://dx.doi.org/10.1086/698217 Group matrix models shed light on population dynamics, Allee effects in meerkats and evolution of cooperative breeding For animal species that form social groups, living together can affect individuals’ chances of survival and reproduction. Whether the effects are positive or negative, an individual’s prospects tend to be limited within its group of birth, and many individuals leave in an effort to establish new breeding groups. As a result, understanding changes in population size for social species – several of which, such as African wild dogs and southern resident killer whales, are endangered – requires understanding of what goes on within groups and how individuals fare when they strike out on their own.New work by a team of researchers from Canada, the UK, and Switzerland combines theory and data to shed light on how these considerations play out for meerkats, a species of mongoose native to southern Africa. While past work has theorized that larger meerkat groups may produce more descendants each year than smaller groups (a phenomenon called the “Allee effect”), this new work indicates the opposite. Interestingly, dominant breeding females in larger groups do appear to produce more daughters that go on to breed. Overall, however, population growth seems to be maximized when meerkats form groups of intermediate size. This work presents a new way of analyzing data from social animals. The techniques used may prove valuable in exploring the evolution of sociality and in understanding fluctuations in populations of endangered or threatened species. Abstract For highly social species, population dynamics depend on hierarchical demography that links local processes, group dynamics, and population growth. Here, we describe a stage-structured matrix model of hierarchical demography, which provides a framework for understanding social influences on population change. Our approach accounts for dispersal and affords insight into population dynamics at multiple scales. The method has close parallels to integral projection models, but focuses on a discrete characteristic (group size). Using detailed long-term records for meerkats (Suricata suricatta), we apply our model to explore patterns of local density dependence and implications of group size for group and population growth. Taking into account dispersers, the model predicts a per-capita growth rate for social groups that declines with group size. It predicts that larger social groups should produce a greater number of new breeding groups; thus dominant breeding females (responsible for most reproduction) are likely to be more productive in larger groups. Considering the potential for future population growth, larger groups have the highest reproductive value, but per-capita reproductive value is maximized for individuals in smaller groups. Across a plausible range of dispersal conditions, meerkats&#39; long-run population growth rate is maximized when individuals form groups of intermediate size. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698217 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698217">Read the Article</a></i></b> </p> --> <p><b>Group matrix models shed light on population dynamics, Allee effects in meerkats and evolution of cooperative breeding </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>or animal species that form social groups, living together can affect individuals’ chances of survival and reproduction. Whether the effects are positive or negative, an individual’s prospects tend to be limited within its group of birth, and many individuals leave in an effort to establish new breeding groups. As a result, understanding changes in population size for social species – several of which, such as African wild dogs and southern resident killer whales, are endangered – requires understanding of what goes on within groups and how individuals fare when they strike out on their own.</p><p>New work by a team of researchers from Canada, the UK, and Switzerland combines theory and data to shed light on how these considerations play out for meerkats, a species of mongoose native to southern Africa. While past work has theorized that larger meerkat groups may produce more descendants each year than smaller groups (a phenomenon called the “Allee effect”), this new work indicates the opposite. Interestingly, dominant breeding females in larger groups do appear to produce more daughters that go on to breed. Overall, however, population growth seems to be maximized when meerkats form groups of intermediate size. </p><p>This work presents a new way of analyzing data from social animals. The techniques used may prove valuable in exploring the evolution of sociality and in understanding fluctuations in populations of endangered or threatened species. </p> <hr /><h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">F</span>or highly social species, population dynamics depend on hierarchical demography that links local processes, group dynamics, and population growth. Here, we describe a stage-structured matrix model of hierarchical demography, which provides a framework for understanding social influences on population change. Our approach accounts for dispersal and affords insight into population dynamics at multiple scales. The method has close parallels to integral projection models, but focuses on a discrete characteristic (group size). Using detailed long-term records for meerkats (<i>Suricata suricatta</i>), we apply our model to explore patterns of local density dependence and implications of group size for group and population growth. Taking into account dispersers, the model predicts a per-capita growth rate for social groups that declines with group size. It predicts that larger social groups should produce a greater number of new breeding groups; thus dominant breeding females (responsible for most reproduction) are likely to be more productive in larger groups. Considering the potential for future population growth, larger groups have the highest reproductive value, but per-capita reproductive value is maximized for individuals in smaller groups. Across a plausible range of dispersal conditions, meerkats&#39; long-run population growth rate is maximized when individuals form groups of intermediate size.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 19 Apr 2018 05:00:00 GMT “Multicellularity drives the evolution of sexual traits” http://amnat.org/an/newpapers/SepHanschen.html The DOI will be https://dx.doi.org/10.1086/698301 Multicellularity causes the evolution of sexual traits including anisogamy Sex didn’t always involve males and females. In fact, sex existed before males and females, and many species are still doing it without them. Males and females are defined by the different sizes of gametes they produce, and not all species produce two different sizes of gametes. Why sperm-producing males and egg-producing females evolved from ancestors without differentiated gametes is a major problem in evolutionary biology. Work led by Erik Hanschen that involved scientists at the University of Arizona, Georgia Tech, and the University of Tokyo suggests that the evolution of large, multicellular bodies drove the evolution of male and female sexes. Using the volvocine green algae to test mathematical theory dating back to the 1970s, they showed a positive relationship between body size and derived sexual characters, starting with different sized gametes (sperm and eggs). Larger species are more likely to have internal fertilization, as in mammals, while smaller species have external fertilization, as in most fishes. Body size is also related to the evolution of secondary sexual dimorphism, differences between males and females of the same species beyond their gametes. As in many birds, mammals, and other animals, male and female individuals of some large volvocine algae differ in their physical characteristics. The convergence of these patterns between the volvocine algae and other taxa suggests that the same principles apply to the evolution of the sexes in other groups, including plants and animals. The evolution of males and females, and subsequently of secondary sexual dimorphism, may be an inevitable consequence of the evolution of large, multicellular bodies. Abstract From the male peacock’s tail plumage to the floral displays of flowering plants, traits related to sexual reproduction are often complex and exaggerated. Why has sexual reproduction become so complicated? Why have such exaggerated sexual traits evolved? Early work posited a connection between multicellularity and sexual traits such as anisogamy (i.e., the evolution of small sperm and large eggs). Anisogamy then drives the evolution of other forms of sexual dimorphism. Yet, the relationship between multicellularity and the evolution of sexual traits has not been empirically tested. Given their extensive variation in both multicellular complexity and sexual systems, the volvocine green algae offer a tractable system for understanding the interrelationship of multicellular complexity and sex. Here we show that species with greater multicellular complexity have a significantly larger number of derived sexual traits, including anisogamy, internal fertilization, and secondary sexual dimorphism. Our results demonstrate that anisogamy repeatedly evolved from isogamous multicellular ancestors and that anisogamous species are larger and produce larger zygotes than isogamous species. In the volvocine algae, the evolution of multicellularity likely drives the evolution of anisogamy, and anisogamy subsequently drives secondary sexual dimorphism. Multicellularity may set the stage for the overall diversity of sexual complexity throughout the Tree of Life. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698301 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698301">Read&nbsp;the&nbsp;Article</a> </b></i></p> --> <p><b>Multicellularity causes the evolution of sexual traits including anisogamy </b></p><p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">S</span>ex didn&rsquo;t always involve males and females. In fact, sex existed before males and females, and many species are still doing it without them. Males and females are defined by the different sizes of gametes they produce, and not all species produce two different sizes of gametes. Why sperm-producing males and egg-producing females evolved from ancestors without differentiated gametes is a major problem in evolutionary biology. Work led by Erik Hanschen that involved scientists at the University of Arizona, Georgia Tech, and the University of Tokyo suggests that the evolution of large, multicellular bodies drove the evolution of male and female sexes. Using the volvocine green algae to test mathematical theory dating back to the 1970s, they showed a positive relationship between body size and derived sexual characters, starting with different sized gametes (sperm and eggs). Larger species are more likely to have internal fertilization, as in mammals, while smaller species have external fertilization, as in most fishes. Body size is also related to the evolution of secondary sexual dimorphism, differences between males and females of the same species beyond their gametes. As in many birds, mammals, and other animals, male and female individuals of some large volvocine algae differ in their physical characteristics. The convergence of these patterns between the volvocine algae and other taxa suggests that the same principles apply to the evolution of the sexes in other groups, including plants and animals. The evolution of males and females, and subsequently of secondary sexual dimorphism, may be an inevitable consequence of the evolution of large, multicellular bodies.</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">F</span>rom the male peacock&rsquo;s tail plumage to the floral displays of flowering plants, traits related to sexual reproduction are often complex and exaggerated. Why has sexual reproduction become so complicated? Why have such exaggerated sexual traits evolved? Early work posited a connection between multicellularity and sexual traits such as anisogamy (i.e., the evolution of small sperm and large eggs). Anisogamy then drives the evolution of other forms of sexual dimorphism. Yet, the relationship between multicellularity and the evolution of sexual traits has not been empirically tested. Given their extensive variation in both multicellular complexity and sexual systems, the volvocine green algae offer a tractable system for understanding the interrelationship of multicellular complexity and sex. Here we show that species with greater multicellular complexity have a significantly larger number of derived sexual traits, including anisogamy, internal fertilization, and secondary sexual dimorphism. Our results demonstrate that anisogamy repeatedly evolved from isogamous multicellular ancestors and that anisogamous species are larger and produce larger zygotes than isogamous species. In the volvocine algae, the evolution of multicellularity likely drives the evolution of anisogamy, and anisogamy subsequently drives secondary sexual dimorphism. Multicellularity may set the stage for the overall diversity of sexual complexity throughout the Tree of Life.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 19 Apr 2018 05:00:00 GMT “A probable case of incipient speciation in Schizocosa wolf spiders driven by allochrony, habitat use, and female mate choice” http://amnat.org/an/newpapers/SepGilman.html The DOI will be https://dx.doi.org/10.1086/698302 Behavioral work reveals new incipient species pair in Schizocosa wolf spiders Understanding the mechanisms that produce reproductive isolation and promote speciation has been a major goal of biologists since Darwin. In this paper, researchers report the discovery of a previously unrecognized ongoing speciation process in a well-studied population of wolf spiders in Oxford, Mississippi. The team showed that preferences for different habitat types, differences in maturation time, and female mate choice all contribute to reproductive isolation between sexually ornamented and unornamented spider morphotypes. This work suggests that speciation may not be driven by single mechanisms, but rather by suites of mechanisms operating together. The discovery of a new ongoing speciation process in wolf spiders adds to the short list of systems that scientists can use to study how speciation happens, and suggests that there may be additional species to discover even in well-studied systems. Abstract There is growing evidence that speciation can occur between populations that are not geographically isolated. The emergence of assortative mating is believed to be critical to this process, but how assortative mating arises in diverging populations is poorly understood. The wolf spider genus Schizocosa has become a model system for studying mechanisms of assortative mating. We conducted a series of experiments to identify the factors that control mate pair formation in a Schizocosa population that includes both ornamented and non-ornamented males. We show that the population also includes two previously unrecognized female phenotypes. One female phenotype mates mostly or exclusively with ornamented males, and the other mates mostly or exclusively with unornamented males. Assortative mating within these groups is maintained by differences in maturation time, microhabitat use, and female mate preference. We conclude that the population is not a single species as previously believed, but rather an incipient species pair with multiple overlapping mechanisms of reproductive isolation. The identification of a new incipient species pair in the well-studied and rapidly speciating Schizocosa clade presents new opportunities for the study of speciation without geographic isolation. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698302 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698302">Read the Article</a></i></b> </p> --> <p><b>Behavioral work reveals new incipient species pair in <i>Schizocosa</i> wolf spiders </b></p><p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">U</span>nderstanding the mechanisms that produce reproductive isolation and promote speciation has been a major goal of biologists since Darwin. In this paper, researchers report the discovery of a previously unrecognized ongoing speciation process in a well-studied population of wolf spiders in Oxford, Mississippi. The team showed that preferences for different habitat types, differences in maturation time, and female mate choice all contribute to reproductive isolation between sexually ornamented and unornamented spider morphotypes. This work suggests that speciation may not be driven by single mechanisms, but rather by suites of mechanisms operating together. The discovery of a new ongoing speciation process in wolf spiders adds to the short list of systems that scientists can use to study how speciation happens, and suggests that there may be additional species to discover even in well-studied systems.</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">T</span>here is growing evidence that speciation can occur between populations that are not geographically isolated. The emergence of assortative mating is believed to be critical to this process, but how assortative mating arises in diverging populations is poorly understood. The wolf spider genus <i>Schizocosa</i> has become a model system for studying mechanisms of assortative mating. We conducted a series of experiments to identify the factors that control mate pair formation in a <i>Schizocosa</i> population that includes both ornamented and non-ornamented males. We show that the population also includes two previously unrecognized female phenotypes. One female phenotype mates mostly or exclusively with ornamented males, and the other mates mostly or exclusively with unornamented males. Assortative mating within these groups is maintained by differences in maturation time, microhabitat use, and female mate preference. We conclude that the population is not a single species as previously believed, but rather an incipient species pair with multiple overlapping mechanisms of reproductive isolation. The identification of a new incipient species pair in the well-studied and rapidly speciating <i>Schizocosa</i> clade presents new opportunities for the study of speciation without geographic isolation.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 19 Apr 2018 05:00:00 GMT “Sympatric parasites have similar host-associated, but asynchronous, patterns of diversification” http://amnat.org/an/newpapers/SepBell.html The DOI will be https://dx.doi.org/10.1086/698300 Because parasites are often restricted to just a few hosts with limited opportunities for dispersal, it has been thought that their evolutionary histories might mirror those of their hosts. Detailed investigations, however, are revealing more complex dynamics shaping parasite diversity. By comparing multiple parasites inhabiting the same hosts, researchers can shed light on the forces that drive parasite diversification. In this study, Bell and colleagues find evidence of distinct evolutionary histories in two parasites that infect the same hosts. They explore the genetic relationships within each of two species of roundworm parasites found in a diverse group of hosts, western North American chipmunks. Although both pinworm species have lineages primarily associated with one chipmunk species or a closely related group of chipmunk species, each roundworm species has a distinct evolutionary history. The unique histories are manifested as different relationships among the host associated genetic lineages, as well as distinct timing of divergence events within each parasite species. Comparative investigations such as this suggest that even when parasites share the same host and experience similar environments, different timing and patterns of evolutionary diversification can emerge. Abstract Parasitism is a common symbiotic interaction across diverse natural systems. Using a comparative evolutionary approach, we investigated the contributions of both host phylogeny and abiotic factors towards diversification of phylogenetically independent endoparasites that inhabit essentially the same physical space. We tested for host-parasite and parasite-parasite phylogenetic concordance in western North American chipmunks (Rodentia: Sciuridae) and two distantly related species of pinworms (Nematoda: Oxyurida). Deep structure in molecular phylogenies revealed signals of host-associated divergence in both parasite species, while shallower phylogeographic structure varied between the two parasites. This suggests that although these parasites experienced similar landscapes and cyclic climate processes, temporally distinctive diversification events were associated with differences in the initiation of their association with host lineages. When climate cycles initiate diversification, partially congruent, but asynchronous host-associated parasite phylogenies may emerge. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698300 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698300">Read the Article</a></i></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;">B</span>ecause parasites are often restricted to just a few hosts with limited opportunities for dispersal, it has been thought that their evolutionary histories might mirror those of their hosts. Detailed investigations, however, are revealing more complex dynamics shaping parasite diversity. By comparing multiple parasites inhabiting the same hosts, researchers can shed light on the forces that drive parasite diversification. </p><p>In this study, Bell and colleagues find evidence of distinct evolutionary histories in two parasites that infect the same hosts. They explore the genetic relationships within each of two species of roundworm parasites found in a diverse group of hosts, western North American chipmunks. Although both pinworm species have lineages primarily associated with one chipmunk species or a closely related group of chipmunk species, each roundworm species has a distinct evolutionary history. The unique histories are manifested as different relationships among the host associated genetic lineages, as well as distinct timing of divergence events within each parasite species. Comparative investigations such as this suggest that even when parasites share the same host and experience similar environments, different timing and patterns of evolutionary diversification can emerge. </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;">P</span>arasitism is a common symbiotic interaction across diverse natural systems. Using a comparative evolutionary approach, we investigated the contributions of both host phylogeny and abiotic factors towards diversification of phylogenetically independent endoparasites that inhabit essentially the same physical space. We tested for host-parasite and parasite-parasite phylogenetic concordance in western North American chipmunks (Rodentia: Sciuridae) and two distantly related species of pinworms (Nematoda: Oxyurida). Deep structure in molecular phylogenies revealed signals of host-associated divergence in both parasite species, while shallower phylogeographic structure varied between the two parasites. This suggests that although these parasites experienced similar landscapes and cyclic climate processes, temporally distinctive diversification events were associated with differences in the initiation of their association with host lineages. When climate cycles initiate diversification, partially congruent, but asynchronous host-associated parasite phylogenies may emerge. </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, 19 Apr 2018 05:00:00 GMT “On the interplay among ambient temperature, basal metabolic rate, and body mass” http://amnat.org/an/newpapers/OctNaya.html The DOI will be https://dx.doi.org/10.1086/698372 Researchers demonstrate that the effect of temperature on metabolic rate is highly dependent of the size of the sampled species Even though body mass in mammals ranges from a few grams to several tons, more than one-half of extant species weigh less than 100&nbsp;g. Clearly, the distribution of mammals’ body mass in nature is far from follow a normal distribution (panel A on figure at right). But could this highly skewed distribution of body size be affecting our overall impression about the role of different climatic and ecological factors that shape physiological evolution? To answer this question, two researchers from Uruguay (Daniel Naya and Hugo Naya) and one from Australia (Craig White) analyzed if the effect of ambient temperature on basal metabolic rate (BMR) change with the size of the species included in the analysis. And, yes, they found that it does! Specifically, these authors found that for species smaller than about 100&nbsp;g, BMR changed with both body mass and ambient temperature, while for species larger than about 100&nbsp;g BMR only changed with body mass (panel B on figure below). In other words, as authors conclude, a study analyzing all the 458 species in the dataset will affirm that the effect of temperature on BMR is markedly and highly significant, while a study analyzing only the 197 species larger than 100&nbsp;g will affirm that this effect is negligible and not significant. Asked about the implications of this result, Daniel Naya says, “To us, the work is relevant for at least two reasons. First, the specific result obtained for BMR is valuable by itself given the central role of this variable on current ecological and evolutionary theories. Second, and maybe more important, given that most organismal traits scale allometrically with body mass, it could be possible that our current impression of the effect of external factors shaping the evolution of phenotypic traits is hardly affected by the large number of small species in nature.” Abstract One of the most generalized conclusions arising from studies analyzing the ecological variation of energy metabolism in endotherms is the apparent negative correlation between ambient temperature and mass-independent basal metabolic rate (residual BMR). As a consequence, ambient temperature has been considered the most important external factor driving the evolution of residual BMR. It is not clear, however, if this relationship is size dependent, and artifacts such as the biased sampling of body masses in physiological data sets could cause us to overstate the ubiquity of the relationship. Accordingly, here we used published data on body mass (mb), BMR, and annual mean temperature (Tmean) for 458 mammal species (and/or subspecies) to examine the size-dependence of the relationship between temperature and BMR. We found a significant interaction between mb and Tmean as predictors of residual BMR, such that the effect of Tmean on residual BMR decreases as a function of mb. In line with this, the amount of residual variance in BMR explained by Tmean decreased with mb, from 20&nbsp;–&nbsp;30% at body sizes <&nbsp;100&nbsp;g to almost zero at body size >&nbsp;1,000&nbsp;g. These data suggest that our current understanding of the importance of broad-scale variation in ambient temperature as a driver of metabolic evolution in endotherms probably is affected by the large number of small species in both nature and physiological datasets. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698372 </i></p> <!-- <p><i><a href="https://dx.doi.org/10.1086/698372">Read the Article</a></i> </p> --> <p><b>Researchers demonstrate that the effect of temperature on metabolic rate is highly dependent of the size of the sampled species </b></p><p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">E</span>ven though body mass in mammals ranges from a few grams to several tons, more than one-half of extant species weigh less than 100&nbsp;g. Clearly, the distribution of mammals&rsquo; body mass in nature is far from follow a normal distribution (panel A on figure at right). But could this highly skewed distribution of body size be affecting our overall impression about the role of different climatic and ecological factors that shape physiological evolution?</p> <p>To answer this question, two researchers from Uruguay (Daniel Naya and Hugo Naya) and one from Australia (Craig White) analyzed if the effect of ambient temperature on basal metabolic rate (BMR) change with the size of the species included in the analysis. And, yes, they found that it does! Specifically, these authors found that for species smaller than about 100&nbsp;g, BMR changed with both body mass and ambient temperature, while for species larger than about 100&nbsp;g BMR only changed with body mass (panel B on figure below). In other words, as authors conclude, a study analyzing all the 458 species in the dataset will affirm that the effect of temperature on BMR is markedly and highly significant, while a study analyzing only the 197 species larger than 100&nbsp;g will affirm that this effect is negligible and not significant.</p> <p>Asked about the implications of this result, Daniel Naya says, &ldquo;To us, the work is relevant for at least two reasons. First, the specific result obtained for BMR is valuable by itself given the central role of this variable on current ecological and evolutionary theories. Second, and maybe more important, given that most organismal traits scale allometrically with body mass, it could be possible that our current impression of the effect of external factors shaping the evolution of phenotypic traits is hardly affected by the large number of small species in nature.&rdquo;</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">O</span>ne of the most generalized conclusions arising from studies analyzing the ecological variation of energy metabolism in endotherms is the apparent negative correlation between ambient temperature and mass-independent basal metabolic rate (residual BMR). As a consequence, ambient temperature has been considered the most important external factor driving the evolution of residual BMR. It is not clear, however, if this relationship is size dependent, and artifacts such as the biased sampling of body masses in physiological data sets could cause us to overstate the ubiquity of the relationship. Accordingly, here we used published data on body mass (<i>m<span style="bottom: -0.3em; font-size: 70%; position: relative;">b</span></i>), BMR, and annual mean temperature (Tmean) for 458 mammal species (and/or subspecies) to examine the size-dependence of the relationship between temperature and BMR. We found a significant interaction between <i>m<span style="bottom: -0.3em; font-size: 70%; position: relative;">b</span></i> and Tmean as predictors of residual BMR, such that the effect of Tmean on residual BMR decreases as a function of <i>m<span style="bottom: -0.3em; font-size: 70%; position: relative;">b</span></i>. In line with this, the amount of residual variance in BMR explained by Tmean decreased with <i>m<span style="bottom: -0.3em; font-size: 70%; position: relative;">b</span></i>, from 20&nbsp;&ndash;&nbsp;30% at body sizes &lt;&nbsp;100&nbsp;g to almost zero at body size &gt;&nbsp;1,000&nbsp;g. These data suggest that our current understanding of the importance of broad-scale variation in ambient temperature as a driver of metabolic evolution in endotherms probably is affected by the large number of small species in both nature and physiological datasets.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 18 Apr 2018 05:00:00 GMT Sewall Wright Award 2018 http://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 2018 award goes to John McNamara. A list of previous recipients can be found here. John McNamara is a mathematical biologist, whose work has contributed significantly to the conceptual unification of three biological fields: behavior, ecology and evolution. He has developed a general theoretical framework to analyze how individual actions contribute to lifetime reproductive success. This framework provides a rigorously justified common currency for decision-making, while taking into account factors such as physiological changes during an animal’s lifetime. His approach provides a natural way of building more holistic and realistic models of behavior that capture the essential biology of the organism and consider differences between individuals. This framework allows one to predict and understand how evolved behavior depends on state and time. In 1986 Professor McNamara published a seminal paper in the American Naturalist (McNamara, J.M. and Houston, A.I., 1986. The common currency for behavioral decisions. American Naturalist, 127, 358-3780), which changed the field of behavioral ecology and evolution. Prior to this landmark paper foraging behavior was mainly analyzed from a perspective of energy maximization. John established how energy gain, predation risk and other activities can be combined into a common currency that encapsulates the selection pressures acting on decision making. The dependence of future reproductive prospects on current state and sequences of behavior is central to this approach. This approach naturally leads to consideration of optimal sequences of actions where each action can depend on current state, and contributes to future states. This publication introduced state-dependent dynamic models into evolutionary ecology and showed how stochastic dynamic programming can be used to find optimal (evolutionarily stable) strategies. The theoretical framework of state-dependent dynamic models and stochastic dynamic programming has been central to much of the subsequent work of John McNamara, but has also been widely adopted by many others in a diverse array of applications. Examples of applications from John’s own work range from exploring the consequences of the trade-off between foraging and predation, the evolution of daily routines in animal behavior, the behavioral responses to risks, the adaptation to fluctuating environments, the evolutionary importance of individual differentiation and the evolution of state-dependent life histories. To highlight a specific example, John and his long-time collaborator Alasdair Houston used the approach to show that if animals respond to a trade-off between foraging gains and predation risks in a state-dependent manner then it is actually possible that starvation levels increase while predation levels decrease as food supply increases. This influential paper furthermore illustrated the importance of formal models as it revealed the fallacy of the verbal reasoning about this problem that had been practiced previously. <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. The 2018 award goes to John McNamara. <a href="http://www.amnat.org/awards.html#Wright">A list of previous recipients can be found here.</a></p> <p>John McNamara is a mathematical biologist, whose work has contributed significantly to the conceptual unification of three biological fields: behavior, ecology and evolution. He has developed a general theoretical framework to analyze how individual actions contribute to lifetime reproductive success. This framework provides a rigorously justified common currency for decision-making, while taking into account factors such as physiological changes during an animal&rsquo;s lifetime. His approach provides a natural way of building more holistic and realistic models of behavior that capture the essential biology of the organism and consider differences between individuals. This framework allows one to predict and understand how evolved behavior depends on state and time.</p> <p>In 1986 Professor McNamara published a seminal paper in the American Naturalist (McNamara, J.M. and Houston, A.I., 1986. <em>The common currency for behavioral decisions</em>. American Naturalist, 127, 358-3780), which changed the field of behavioral ecology and evolution. Prior to this landmark paper foraging behavior was mainly analyzed from a perspective of energy maximization. John established how energy gain, predation risk and other activities can be combined into a common currency that encapsulates the selection pressures acting on decision making. The dependence of future reproductive prospects on current state and sequences of behavior is central to this approach. This approach naturally leads to consideration of optimal sequences of actions where each action can depend on current state, and contributes to future states. This publication introduced state-dependent dynamic models into evolutionary ecology and showed how stochastic dynamic programming can be used to find optimal (evolutionarily stable) strategies.</p> <p>The theoretical framework of state-dependent dynamic models and stochastic dynamic programming has been central to much of the subsequent work of John McNamara, but has also been widely adopted by many others in a diverse array of applications. Examples of applications from John&rsquo;s own work range from exploring the consequences of the trade-off between foraging and predation, the evolution of daily routines in animal behavior, the behavioral responses to risks, the adaptation to fluctuating environments, the evolutionary importance of individual differentiation and the evolution of state-dependent life histories. To highlight a specific example, John and his long-time collaborator Alasdair Houston used the approach to show that if animals respond to a trade-off between foraging gains and predation risks in a state-dependent manner then it is actually possible that starvation levels increase while predation levels decrease as food supply increases. This influential paper furthermore illustrated the importance of formal models as it revealed the fallacy of the verbal reasoning about this problem that had been practiced previously.</p> <hr /> Tue, 03 Apr 2018 05:00:00 GMT Edward O. Wilson Naturalist Award 2018 http://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 2018, the award was conferred upon Ben Sheldon, the Luc Hoffmann Professor of Ornithology, Director of the Edward Grey Institute, and Head of the Department of Zoology at Oxford University. Professor Sheldon has a prolific and remarkably diverse record of research revolving around ecology, evolution and behavior of birds.&nbsp; Important features of his work are his early and clever use of molecular methods for quantifying reproductive success, his integration of observational studies with experiments that provided critical tests of his hypotheses and his continued inventiveness in developing new observational and experimental methodologies.&nbsp; His earliest research addressed the role of pre- and post-copulatory sexual selection, the latter via sperm competition.&nbsp; He was one of the first to apply new molecular methods for paternity identification and hence more accurate assessment of reproductive success.&nbsp; His studies of collared flycatchers demonstrated, for the first time, that paternal investment in one year could influence investment by the same individuals in display behaviors in a subsequent year providing an empirical link between sexual selection and life history and a rare characterization of the long-term consequences of reproductive investment. &nbsp;&nbsp;Professor Sheldon’s research on sex allocation provides some of the clearest evidence of adaptive variation in sex ratios.&nbsp; While the concept has a long history in theory, Professor Sheldon’s studies are among the few to show that females use appraisals of mates to adjust clutch sex ratios.&nbsp; More recently, Professor Sheldon has combined innovations in social network theory with new techniques to record behavior of many individuals to scale up our understanding of social behavior of birds.&nbsp; His work recording and analyzing groups of thousands of birds reveals previously unknown mechanisms by which network structure influences the ability of winter flocks of great tits to identify novel food patches.&nbsp; Using an experiment in which novel behavior was introduced into different subgroups, Professor Sheldon was able to demonstrate that social learning based on an innovation in a single individual was quickly adopted by entire groups and that these behaviors persisted as stable traditions across generations. &nbsp; <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="http://www.amnat.org/awards.html#Wilson">A list of previous recipients can be found here.</a> In 2018, the award was conferred upon Ben Sheldon, the Luc Hoffmann Professor of Ornithology, Director of the Edward Grey Institute, and Head of the Department of Zoology at Oxford University.</p> <p>Professor Sheldon has a prolific and remarkably diverse record of research revolving around ecology, evolution and behavior of birds.&nbsp; Important features of his work are his early and clever use of molecular methods for quantifying reproductive success, his integration of observational studies with experiments that provided critical tests of his hypotheses and his continued inventiveness in developing new observational and experimental methodologies.&nbsp; His earliest research addressed the role of pre- and post-copulatory sexual selection, the latter via sperm competition.&nbsp; He was one of the first to apply new molecular methods for paternity identification and hence more accurate assessment of reproductive success.&nbsp; His studies of collared flycatchers demonstrated, for the first time, that paternal investment in one year could influence investment by the same individuals in display behaviors in a subsequent year providing an empirical link between sexual selection and life history and a rare characterization of the long-term consequences of reproductive investment. &nbsp;&nbsp;Professor Sheldon&rsquo;s research on sex allocation provides some of the clearest evidence of adaptive variation in sex ratios.&nbsp; While the concept has a long history in theory, Professor Sheldon&rsquo;s studies are among the few to show that females use appraisals of mates to adjust clutch sex ratios.&nbsp; More recently, Professor Sheldon has combined innovations in social network theory with new techniques to record behavior of many individuals to scale up our understanding of social behavior of birds.&nbsp; His work recording and analyzing groups of thousands of birds reveals previously unknown mechanisms by which network structure influences the ability of winter flocks of great tits to identify novel food patches.&nbsp; Using an experiment in which novel behavior was introduced into different subgroups, Professor Sheldon was able to demonstrate that social learning based on an innovation in a single individual was quickly adopted by entire groups and that these behaviors persisted as stable traditions across generations. &nbsp;</p> Tue, 03 Apr 2018 05:00:00 GMT The ASN Student Research Award Recipients for 2018 http://amnat.org/announcements/ANNStuResearchAWA.html &nbsp;Name &nbsp;Institution &nbsp;Research Shannon Carter Rice University Linking phenological synchrony to ecological properties across organizational scales Jay Falk Cornell University Function and maintenance of female variation in a hummingbird Nicole Forrester University of Pittsburgh Evaluating the direct effects of plant polyploidy on the legume-rhizobia mutualism Ryan Greenway Kansas State University The role of mitonuclear incompatibilities during ecological speciation in extremophile poeciliid fishes Marie-Pier H&eacute;bert McGill University Shorter winters: implications for freshwater food webs Anna Hiller Louisiana State University Are mountains really higher in the Tropics? Rachel Moran University of Illinois, Urbana-Champaign Using linkage maps to compare chromosomal structure between two darter species undergoing reinforcement Timothy O&#39;Connor University of California, Berkeley Does co-speciation link plant and insect diversification? Larry Taylor University of California, Berkeley Reconstructing prehistoric whale migration via isotopic analysis of fossil coronulid barnacles Michael Yuan University of California, Berkeley Congruence of genetic, morphological, and cellular convergence in Lesser Antillean anoles 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>&nbsp;Name</td> <td>&nbsp;Institution</td> <td>&nbsp;Research</td> </tr> <tr> <td>Shannon Carter</td> <td>Rice University</td> <td>Linking phenological synchrony to ecological properties across organizational scales</td> </tr> <tr> <td>Jay Falk</td> <td>Cornell University</td> <td>Function and maintenance of female variation in a hummingbird</td> </tr> <tr> <td>Nicole Forrester</td> <td>University of Pittsburgh</td> <td>Evaluating the direct effects of plant polyploidy on the legume-rhizobia mutualism</td> </tr> <tr> <td>Ryan Greenway</td> <td>Kansas State University</td> <td>The role of mitonuclear incompatibilities during ecological speciation in extremophile poeciliid fishes</td> </tr> <tr> <td>Marie-Pier H&eacute;bert</td> <td>McGill University</td> <td>Shorter winters: implications for freshwater food webs</td> </tr> <tr> <td>Anna Hiller</td> <td>Louisiana State University</td> <td>Are mountains really higher in the Tropics?</td> </tr> <tr> <td>Rachel Moran</td> <td>University of Illinois, Urbana-Champaign</td> <td>Using linkage maps to compare chromosomal structure between two darter species undergoing reinforcement</td> </tr> <tr> <td>Timothy O&#39;Connor</td> <td>University of California, Berkeley</td> <td>Does co-speciation link plant and insect diversification?</td> </tr> <tr> <td>Larry Taylor</td> <td>University of California, Berkeley</td> <td>Reconstructing prehistoric whale migration via isotopic analysis of fossil coronulid barnacles</td> </tr> <tr> <td>Michael Yuan</td> <td>University of California, Berkeley</td> <td>Congruence of genetic, morphological, and cellular convergence in Lesser Antillean anoles</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> Mon, 02 Apr 2018 05:00:00 GMT “Metabolic scope as a proximate constraint on individual behavioral variation: effects on ‘personality’, plasticity, and predictability” http://amnat.org/an/newpapers/AugBiro.html The DOI will be https://dx.doi.org/10.1086/697963 Aerobic metabolic scope can constrain expression of animal personality and behavior plasticity Why do some individuals of a given species show consistent levels of average behavior over time and across contexts, while others vary in their behavior? And why do some show highly predictable behavior in a given context, while others vary widely about their average behavioral tendency? Peter Biro and his collaborators here present a novel energetic hypothesis for how minimum and maximum metabolic rates can together constrain the expression of behavioral variation at these different levels, limiting what animals can do in terms of finding food and mates, competing, and avoiding predators. At its core, their hypothesis predicts that individuals with greater aerobic metabolic scope (= maximum − minimum metabolism) have the latitude to express greater variation and plasticity in behavior. The researchers test their hypothesis and show that replicate ‘high-scope’ genotypes of mice are more active on average, more plastic in their behavior, and less predictable than mice with low aerobic scope. This is the first energetic hypothesis to predict and explain individual behavioral variation at all its hierarchical levels: mean (= personality), plasticity, and predictability, and is also supported by preliminary data on mice. Abstract Behavioral ecologists have hypothesized that among-individual differences in resting metabolic rate (RMR) may predict consistent individual differences in mean values for costly behaviors, or for behaviors that affect energy intake rate. This hypothesis has empirical support and presently attracts considerable attention, but notably it does not provide predictions for individual differences in (a) behavioral plasticity or (b) unexplained variation (residual variation from mean individual behavior, here termed predictability). We outline how consideration of aerobic maximum metabolic rate (MMR) and particularly aerobic scope (= MMR − RMR) can be used to simultaneously make predictions about mean, among- and within-individual variation in behavior. We predict that while RMR should be proportional to an individuals’ mean level of sustained behavioral activity (one aspect of its personality), individuals with greater aerobic scope will also have greater scope to express behavioral plasticity and/or greater unpredictability in behavior (= greater residual variation). As a first step towards testing these predictions, we analyze existing activity data from selectively bred lines of mice that differ in both daily activity and aerobic scope. We find that replicate high-scope mice are more active on average, show greater among-individual variation in activity, greater among-individual variation in plasticity, and greater unpredictability. These data provide some tentative first support for our hypothesis, suggesting that further research on this topic would be valuable. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697963 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697963">Read the Article</a></i></b> </p> --> <p><b>Aerobic metabolic scope can constrain expression of animal personality and behavior plasticity </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;">W</span>hy do some individuals of a given species show consistent levels of average behavior over time and across contexts, while others vary in their behavior? And why do some show highly predictable behavior in a given context, while others vary widely about their average behavioral tendency? Peter Biro and his collaborators here present a novel energetic hypothesis for how minimum and maximum metabolic rates can together constrain the expression of behavioral variation at these different levels, limiting what animals can do in terms of finding food and mates, competing, and avoiding predators. </p><p>At its core, their hypothesis predicts that individuals with greater aerobic metabolic scope (= maximum − minimum metabolism) have the latitude to express greater variation and plasticity in behavior. The researchers test their hypothesis and show that replicate ‘high-scope’ genotypes of mice are more active on average, more plastic in their behavior, and less predictable than mice with low aerobic scope. </p><p>This is the first energetic hypothesis to predict and explain individual behavioral variation at all its hierarchical levels: mean (= personality), plasticity, and predictability, and is also supported by preliminary data on mice. </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>ehavioral ecologists have hypothesized that among-individual differences in resting metabolic rate (RMR) may predict consistent individual differences in mean values for costly behaviors, or for behaviors that affect energy intake rate. This hypothesis has empirical support and presently attracts considerable attention, but notably it does not provide predictions for individual differences in (a) behavioral plasticity or (b) unexplained variation (residual variation from mean individual behavior, here termed predictability). We outline how consideration of aerobic maximum metabolic rate (MMR) and particularly aerobic scope (= MMR − RMR) can be used to simultaneously make predictions about mean, among- and within-individual variation in behavior. We predict that while RMR should be proportional to an individuals’ mean level of sustained behavioral activity (one aspect of its personality), individuals with greater aerobic scope will also have greater scope to express behavioral plasticity and/or greater unpredictability in behavior (= greater residual variation). As a first step towards testing these predictions, we analyze existing activity data from selectively bred lines of mice that differ in both daily activity and aerobic scope. We find that replicate high-scope mice are more active on average, show greater among-individual variation in activity, greater among-individual variation in plasticity, and greater unpredictability. These data provide some tentative first support for our hypothesis, suggesting that further research on this topic would be valuable. </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, 02 Apr 2018 05:00:00 GMT “Geographic range dynamics drove ancient hybridization in a lineage of angiosperms” http://amnat.org/an/newpapers/AugFolk.html The DOI will be https://dx.doi.org/10.1086/698120 Phyloclimatic modeling shows past climatic cooling may explain movement of genetic material across thousands of miles In response to past climate change, many species have dramatically shifted in geographic range, resulting in novel plant and animal communities and species interactions. This is predicted to continue in the face of human-caused climate change. The biology of present-day species leaves historical footprints of these past geographic shifts; for species that do not now co-occur, evidence of past biological interactions has been found throughout the Tree of Life. Among these is hybridization—sexual reproduction across species boundaries, which can result in the flow of genetic material across species boundaries and even across long distances. But how could individuals of different species have interbred if they currently lack the opportunity to do so? Folk and coauthors built a new set of computational tools to infer how past climate change would have created new plant communities in the past where hybridization was possible. Folk and coauthors focus on the flowering plant genus Heuchera—common garden plants known also as coral bells. A group of species found in southern California experienced ancient hybridization dating to the Ice Age. This ancient hybridization event resulted in genetic content originating from closely related Mitella (bishop’s cap) plants, today found more than 1000&nbsp;km to the north of California Heuchera. Resolving this remarkable biological scenario helps provide insights on the movement of the North American flora and why hybridization has been so prevalent in its history. Folk and coauthors provide a new framework to test hypotheses about past species contact—even for those totally lacking a fossil record. Even beyond their focus on hybridization, the ability to reconstruct a common geographic history opens new research opportunities—moving from understanding single groups of species in isolation to testing new ideas about past communities of plants and animals and their interactions. Abstract Elucidating the dynamic distribution of organismal lineages has been central to biology since the 19th century, yet the difficulty of combining biogeographic methods with shifts in habitat suitability remains a limitation. This integration, however, is critical to understanding geographic distributions, present and past, as well as the time-extended trajectories of lineages. Here we link previous advances in phyloclimatic modeling to develop a framework that overcomes existing methodological gaps by predicting potential ecological and geographic overlap directly from estimated ancestral trait distributions. We show the utility of this framework by focusing on a clade in the montane angiosperm genus Heuchera, noteworthy in that it experienced ancient introgression from circumboreally distributed species of Mitella, lineages now ~1300 km disjunct. Using this system, we demonstrate an application of ancestral state reconstruction to assess geographic range dynamics in a lineage lacking a fossil record. We test hypotheses regarding inferred past geographic distributions and examine the potential for ancient geographic contact. Application of this multifaceted approach suggest potential past contact between species of Heuchera and Mitella in western North America during cooler periods of the Pleistocene. Integration of niche models and phylogenetic estimates suggests that climatic cooling may have promoted range contact and gene flow between currently highly disjunct species. Our approach has wide applicability for testing hypotheses concerning organismal co-occurrences in deep time. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698120 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698120">Read the Article</a></i></b> </p> --> <p><b>Phyloclimatic modeling shows past climatic cooling may explain movement of genetic material across thousands of miles </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 response to past climate change, many species have dramatically shifted in geographic range, resulting in novel plant and animal communities and species interactions. This is predicted to continue in the face of human-caused climate change. The biology of present-day species leaves historical footprints of these past geographic shifts; for species that do not now co-occur, evidence of past biological interactions has been found throughout the Tree of Life. Among these is hybridization—sexual reproduction across species boundaries, which can result in the flow of genetic material across species boundaries and even across long distances. But how could individuals of different species have interbred if they currently lack the opportunity to do so? Folk and coauthors built a new set of computational tools to infer how past climate change would have created new plant communities in the past where hybridization was possible. </p><p>Folk and coauthors focus on the flowering plant genus <i>Heuchera</i>—common garden plants known also as coral bells. A group of species found in southern California experienced ancient hybridization dating to the Ice Age. This ancient hybridization event resulted in genetic content originating from closely related <i>Mitella</i> (bishop’s cap) plants, today found more than 1000&nbsp;km to the north of California <i>Heuchera</i>. Resolving this remarkable biological scenario helps provide insights on the movement of the North American flora and why hybridization has been so prevalent in its history. </p><p>Folk and coauthors provide a new framework to test hypotheses about past species contact&mdash;even for those totally lacking a fossil record. Even beyond their focus on hybridization, the ability to reconstruct a common geographic history opens new research opportunities&mdash;moving from understanding single groups of species in isolation to testing new ideas about past communities of plants and animals and their interactions.</p><hr/> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">E</span>lucidating the dynamic distribution of organismal lineages has been central to biology since the 19th century, yet the difficulty of combining biogeographic methods with shifts in habitat suitability remains a limitation. This integration, however, is critical to understanding geographic distributions, present and past, as well as the time-extended trajectories of lineages. Here we link previous advances in phyloclimatic modeling to develop a framework that overcomes existing methodological gaps by predicting potential ecological and geographic overlap directly from estimated ancestral trait distributions. We show the utility of this framework by focusing on a clade in the montane angiosperm genus <i>Heuchera</i>, noteworthy in that it experienced ancient introgression from circumboreally distributed species of <i>Mitella</i>, lineages now ~1300 km disjunct. Using this system, we demonstrate an application of ancestral state reconstruction to assess geographic range dynamics in a lineage lacking a fossil record. We test hypotheses regarding inferred past geographic distributions and examine the potential for ancient geographic contact. Application of this multifaceted approach suggest potential past contact between species of <i>Heuchera</i> and <i>Mitella</i> in western North America during cooler periods of the Pleistocene. Integration of niche models and phylogenetic estimates suggests that climatic cooling may have promoted range contact and gene flow between currently highly disjunct species. Our approach has wide applicability for testing hypotheses concerning organismal co-occurrences in deep time.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 28 Mar 2018 05:00:00 GMT “A mechanistic model of ant battles and its consequences for territory scaling” http://amnat.org/an/newpapers/AugAdler.html The DOI will be https://dx.doi.org/10.1086/698121 Mathematical models show that even in ants, the rich get richer. Larger colonies get more than their share of space Throughout much of the temperate world, battles between pavement ants are a common sight, popping up on a sidewalk on one day, slowly shifting position, and then disappearing. What are these ants fighting for? And who wins? Fred Adler, his former undergraduate researcher Sean Quinonez (now finishing medical school), and territorial ant experts Nicola Plowes and Eldridge Adams got together to develop a series of mathematical models to study these questions. They found that if the battle moves away from the colony with a larger number of battling ants, its location will settle down farther from the larger colony. More surprisingly, the mathematical models show that the larger colony always gets more than its fair share of the contested territory; that is, a colony that is twice as large will control more than 2/3 of the space. The strength of this effect depends on how ants join the battle—whether they recruit more ants when they are outnumbered or give up and accept defeat. If colonies grow faster when they have more territory, this creates a situation where the rich get richer, at least until they die and create space for small new colonies. This work provides a framework for the broad question of how resources get divided up among competitors, and how inequality itself can arise and increase. Abstract Territory size in social insects depends on the rules by which border conflicts are resolved. We present three mechanistic mathematical models of conflict, inspired by the behavior of the pavement ant Tetramorium immigrans, to predict the advantage of larger colonies in pairwise contests and the resulting scaling of territory size with worker force. The models track the number of ants in the nest, traveling to and from the boundary, or engaged at the boundary. Ants at the boundary base their recruitment response on the relative numbers of ants from the two colonies. With two colonies, our central result is that the larger colony gains a territory disproportionately larger than the ratio of worker forces would indicate. This disproportionate territory control determines the scaling relation of territory size with worker force in a population. In two dimensions, if territory size were proportional to worker force, the slope of the scaling relation between log territory size and log worker force would be 1.0. With disproportionate territories, this slope is larger, and can be explicitly approximated in terms of model parameters, and is steepest when colonies are packed close to each other, when ants run quickly, or when colonies are small. A steeper slope exaggerates the advantage of larger colonies, creating a positive feedback that could amplify the inequality of the worker force distribution. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698121 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698121">Read the Article</a></i></b> </p> --> <p><b>Mathematical models show that even in ants, the rich get richer. Larger colonies get more than their share of space </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 much of the temperate world, battles between pavement ants are a common sight, popping up on a sidewalk on one day, slowly shifting position, and then disappearing. What are these ants fighting for? And who wins? Fred Adler, his former undergraduate researcher Sean Quinonez (now finishing medical school), and territorial ant experts Nicola Plowes and Eldridge Adams got together to develop a series of mathematical models to study these questions. They found that if the battle moves away from the colony with a larger number of battling ants, its location will settle down farther from the larger colony. More surprisingly, the mathematical models show that the larger colony always gets more than its fair share of the contested territory; that is, a colony that is twice as large will control more than 2/3 of the space. The strength of this effect depends on how ants join the battle&mdash;whether they recruit more ants when they are outnumbered or give up and accept defeat. If colonies grow faster when they have more territory, this creates a situation where the rich get richer, at least until they die and create space for small new colonies. This work provides a framework for the broad question of how resources get divided up among competitors, and how inequality itself can arise and increase. </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>erritory size in social insects depends on the rules by which border conflicts are resolved. We present three mechanistic mathematical models of conflict, inspired by the behavior of the pavement ant <i>Tetramorium immigrans</i>, to predict the advantage of larger colonies in pairwise contests and the resulting scaling of territory size with worker force. The models track the number of ants in the nest, traveling to and from the boundary, or engaged at the boundary. Ants at the boundary base their recruitment response on the relative numbers of ants from the two colonies. With two colonies, our central result is that the larger colony gains a territory disproportionately larger than the ratio of worker forces would indicate. This disproportionate territory control determines the scaling relation of territory size with worker force in a population. In two dimensions, if territory size were proportional to worker force, the slope of the scaling relation between log territory size and log worker force would be 1.0. With disproportionate territories, this slope is larger, and can be explicitly approximated in terms of model parameters, and is steepest when colonies are packed close to each other, when ants run quickly, or when colonies are small. A steeper slope exaggerates the advantage of larger colonies, creating a positive feedback that could amplify the inequality of the worker force distribution. </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, 28 Mar 2018 05:00:00 GMT 2018 Presidential Award http://amnat.org/announcements/ANNPresAwa.html The recipients of the Presidential Award for 2018 are Jahnavi Joshi, Anupama Prakash, and Krushnamegh Kunte, for their paper, "Evolutionary Assembly of Communities in Butterfly Mimicry Rings" in the April 2017 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. In this paper, the authors explore the evolutionary history and assembly of mutualistic Mullerian co-mimicry rings and Batesian parasitic rings in butterflies. Mimicry rings often have both components. &nbsp; The authors test hypotheses about the origin of these different mimicry complexes, whether close relatives are Mullerian or Batesian mimics, or whether mimicry complexes are formed from evolutionarily disparate groups that have converged on the same morph. They also explore the role of island biogeography in the size and assembly of mimicry complexes. They found that Mullerian mimicry rings were typically comprised of close relatives that diversified in clades with shared aposematic signal. In contrast, Batesian mimics generally converged onto patterns of the model, though some Batesian mimics were from sister groups of aposematic species, and some were from different genera and families. While not surprising, mainland rings were larger, had more species, than island rings. Interestingly, of the five rings represented in both mainlands and islands, the ratio of aposematic species to Batesian mimics in mimicry rings was similar across regions. Moreover, the smaller size of island rings appeared to be driven by a smaller number of aposematic mimic species. In sum, this paper provided an original synthesis of the evolutionary origins and assembly of butterlfy mimicry rings, showed that different evolutionary processes build Mullerian co-mimicry and Batesian parasitic mimicry, and placed these patterns in a biogeographic context. Sharon Strauss President, American Society of Naturalists <p>The recipients of the Presidential Award for 2018 are Jahnavi Joshi, Anupama Prakash, and Krushnamegh Kunte, for their paper,<a href="https://doi.org/10.1086/690907"> &quot;Evolutionary Assembly of Communities in Butterfly Mimicry Rings&quot; in the April 2017 issue. </a>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>In this paper, the authors explore the evolutionary history and assembly of mutualistic Mullerian co-mimicry rings and Batesian parasitic rings in butterflies. Mimicry rings often have both components.<br /> &nbsp;<br /> The authors test hypotheses about the origin of these different mimicry complexes, whether close relatives are Mullerian or Batesian mimics, or whether mimicry complexes are formed from evolutionarily disparate groups that have converged on the same morph. They also explore the role of island biogeography in the size and assembly of mimicry complexes. They found that Mullerian mimicry rings were typically comprised of close relatives that diversified in clades with shared aposematic signal. In contrast, Batesian mimics generally converged onto patterns of the model, though some Batesian mimics were from sister groups of aposematic species, and some were from different genera and families. While not surprising, mainland rings were larger, had more species, than island rings. Interestingly, of the five rings represented in both mainlands and islands, the ratio of aposematic species to Batesian mimics in mimicry rings was similar across regions. Moreover, the smaller size of island rings appeared to be driven by a smaller number of aposematic mimic species. In sum, this paper provided an original synthesis of the evolutionary origins and assembly of butterlfy mimicry rings, showed that different evolutionary processes build Mullerian co-mimicry and Batesian parasitic mimicry, and placed these patterns in a biogeographic context.</p> <p>Sharon Strauss<br /> President, American Society of Naturalists</p> Tue, 27 Mar 2018 05:00:00 GMT “Towards understanding the repeated occurrence of associations between melanin-based coloration and multiple phenotypes” http://amnat.org/an/newpapers/AugSanJose-A.html The DOI will be https://dx.doi.org/10.1086/698010 Understanding why melanin pigmentation is related with different animal phenotypes Abstract Melanin is the most widespread pigment in organisms. Melanin-based coloration has been repeatedly observed to be associated with the same traits and in the same direction in different vertebrate and insect species. However, whether any factors that are common to different taxa account for the repeated evolution of melanin-phenotype associations remains unclear. We propose to approach this question from the perspective of convergent and parallel evolution to clarify to what extent different species have evolved the same associations owing to a shared genetic basis and being subjected to similar selective pressures. Our current understanding of the genetic basis of melanin-phenotype associations allows for both convergent and parallel evolution, but this understanding is still limited. Further research is needed to clarify the generality and interdependencies of the different proposed mechanisms (supergenes, pleiotropy based on hormones or neural crest cells). The general ecological scenarios whereby melanin-based coloration is under selection, protection from UV radiation, thermoregulation in cold environments or as a signal of social status, offer a good opportunity to study how melanin-phenotype associations evolve. Reviewing these scenarios shows that some traits associated with melanin-based coloration might be selected together with coloration by also favoring adaptation, but that other associated traits might impede adaptation, which may be indicative of genetic constraints. We therefore encourage further research on the relative role of selection and genetic constraints in shaping multiple melanin-phenotype associations. Placed into a phylogenetic context, this will help clarify to what extent these associations result from convergent or parallel evolutionary processes and why melanin-phenotype associations are so common across the tree of life. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698010 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698010">Read the Article</a></i></b> </p> --> <p><b>Understanding why melanin pigmentation is related with different animal phenotypes </b></p><h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">M</span>elanin is the most widespread pigment in organisms. Melanin-based coloration has been repeatedly observed to be associated with the same traits and in the same direction in different vertebrate and insect species. However, whether any factors that are common to different taxa account for the repeated evolution of melanin-phenotype associations remains unclear. We propose to approach this question from the perspective of convergent and parallel evolution to clarify to what extent different species have evolved the same associations owing to a shared genetic basis and being subjected to similar selective pressures. Our current understanding of the genetic basis of melanin-phenotype associations allows for both convergent and parallel evolution, but this understanding is still limited. Further research is needed to clarify the generality and interdependencies of the different proposed mechanisms (supergenes, pleiotropy based on hormones or neural crest cells). The general ecological scenarios whereby melanin-based coloration is under selection, protection from UV radiation, thermoregulation in cold environments or as a signal of social status, offer a good opportunity to study how melanin-phenotype associations evolve. Reviewing these scenarios shows that some traits associated with melanin-based coloration might be selected together with coloration by also favoring adaptation, but that other associated traits might impede adaptation, which may be indicative of genetic constraints. We therefore encourage further research on the relative role of selection and genetic constraints in shaping multiple melanin-phenotype associations. Placed into a phylogenetic context, this will help clarify to what extent these associations result from convergent or parallel evolutionary processes and why melanin-phenotype associations are so common across the tree of life.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Mon, 26 Mar 2018 05:00:00 GMT “High gut microbiota diversity provides lower resistance against infection by an intestinal parasite in bumblebees” http://amnat.org/an/newpapers/AugNaepflin-A.html The DOI will be https://dx.doi.org/10.1086/698013 Bumblebee microbiota provides clues about parasite susceptibility before infection ++ Also, feces &asymp; gut (samples) Abstract The microbiome, especially the gut flora, is known to affect the interaction between parasites and their hosts. In this context, a parasitic infection can be viewed as an invasion into the pre-existing microbial ecological community. Hence, in addition to the intrinsic defense mechanisms of the host itself, infection success depends on the colonization resistance of the microbiota. In the bumblebee, Bombus terrestris, the microbiota provides resistance to the intestinal parasite, Crithidia bombi, yet which properties actually provide protection remains largely unknown. Here, we show that the community structure of the gut microbiota – in terms of bacterial operational taxonomic units (OTUs) of 16S rRNA gene sequences – prior to parasite exposure can be informative of the eventual infection outcome. Specifically, higher microbiota OTU diversity is associated with less resistance. However, the microbial community structure does not differ between infected and non-infected individuals, or between infected individuals of varying susceptibility. This suggests that parasite infection success depends on the microbiota composition but subsequent changes occur, although the exact alteration that occurs remains elusive. In fact, the bumblebee microbiota is surprisingly unaffected by parasite exposure and infection. Rather, the microbiota-host interaction prior to parasite exposure seems a key mechanism regulating resistance to infection. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/698013 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/698013">Read the Article</a></i></b> </p> --> <p><b>Bumblebee microbiota provides clues about parasite susceptibility before infection ++ Also, feces &asymp; gut (samples) </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;">T</span>he microbiome, especially the gut flora, is known to affect the interaction between parasites and their hosts. In this context, a parasitic infection can be viewed as an invasion into the pre-existing microbial ecological community. Hence, in addition to the intrinsic defense mechanisms of the host itself, infection success depends on the colonization resistance of the microbiota. In the bumblebee, <i>Bombus terrestris</i>, the microbiota provides resistance to the intestinal parasite, <i>Crithidia bombi</i>, yet which properties actually provide protection remains largely unknown. Here, we show that the community structure of the gut microbiota – in terms of bacterial operational taxonomic units (OTUs) of 16S rRNA gene sequences – prior to parasite exposure can be informative of the eventual infection outcome. Specifically, higher microbiota OTU diversity is associated with less resistance. However, the microbial community structure does not differ between infected and non-infected individuals, or between infected individuals of varying susceptibility. This suggests that parasite infection success depends on the microbiota composition but subsequent changes occur, although the exact alteration that occurs remains elusive. In fact, the bumblebee microbiota is surprisingly unaffected by parasite exposure and infection. Rather, the microbiota-host interaction prior to parasite exposure seems a key mechanism regulating resistance to infection. </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, 26 Mar 2018 05:00:00 GMT “Evidence for trait-based dominance in occupancy among fossil taxa and the decoupling of macroecological and macroevolutionary success” http://amnat.org/an/newpapers/SepWagner-A.html The DOI will be https://dx.doi.org/10.1086/697642 Fossil marine genera suggest that traits shared by related species encourage denser occupancy of geographic ranges Abstract Biological systems provide examples of differential success among taxa, from ecosystems with a few dominant species (ecological success) to clades that possess far more species than sister-clades (macroevolutionary success). “Macroecological success,” the occupation by a species or clade of an unusually high numbers of areas, has received less attention. If macroecological success reflects heritable traits, then successful species should be related. Genera comprised of species possessing those traits should occupy more areas than genera with comparable species richness that lack the traits. Alternatively, if macroecological success reflects autapomorphic traits, then generic occupancy should be a byproduct of species richness among genera and occupancy of constituent species. We test this using Phanerozoic marine invertebrates. Although temporal patterns of species and generic occupancy are strongly correlated, inequality in generic occupancy typically is greater than expected. Genus-level patterns cannot be explained solely with species level patterns. Within individual intervals, deviations between observed and expected generic occupancy correlate with the number of lithological units (stratigraphic formations), particularly after controlling for geographic range and species-richness. However, elevated generic occupancy is unrelated or negatively associated with either generic geographic ranges or within genus species-richness. Our results suggest that shared traits among congeneric species encourage short term macroecological success without generating short-term macroevolutionary success. A broad niche may confer high occupancy, but does not necessarily promote speciation. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697642 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697642">Read the Article</a></i></b> </p> --> <p><b>Fossil marine genera suggest that traits shared by related species encourage denser occupancy of geographic ranges </b></p><h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">B</span>iological systems provide examples of differential success among taxa, from ecosystems with a few dominant species (ecological success) to clades that possess far more species than sister-clades (macroevolutionary success). &ldquo;Macroecological success,&rdquo; the occupation by a species or clade of an unusually high numbers of areas, has received less attention. If macroecological success reflects heritable traits, then successful species should be related. Genera comprised of species possessing those traits should occupy more areas than genera with comparable species richness that lack the traits. Alternatively, if macroecological success reflects autapomorphic traits, then generic occupancy should be a byproduct of species richness among genera and occupancy of constituent species. We test this using Phanerozoic marine invertebrates. Although temporal patterns of species and generic occupancy are strongly correlated, inequality in generic occupancy typically is greater than expected. Genus-level patterns cannot be explained solely with species level patterns. Within individual intervals, deviations between observed and expected generic occupancy correlate with the number of lithological units (stratigraphic formations), particularly after controlling for geographic range and species-richness. However, elevated generic occupancy is unrelated or negatively associated with either generic geographic ranges or within genus species-richness. Our results suggest that shared traits among congeneric species encourage short term macroecological success without generating short-term macroevolutionary success. A broad niche may confer high occupancy, but does not necessarily promote speciation.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 21 Mar 2018 05:00:00 GMT Results of the 2018 Election http://amnat.org/announcements/ANNelectionResults.html My interests are in evolutionary biology and ecology.&nbsp; My research focuses on the evolution of&nbsp; mating system and the role of mating system shifts in speciation in plants, mutualism and mutualism disruption by invasive species, and demographic and population modeling. These research projects intersect in my interest in deeper questions about the effects of human’s actions across the globe in altering the tempo and mode of evolution, and the sustainability and conservation of biodiversity. I received my Bachelor’s of Science degree from the University of Michigan, where I was inspired by the dazzling diversity, forms and functions of plants. I received my Masters and PhD degrees from the University of Chicago, where I learned how the interaction of ecology and evolutionary forces shaped those dazzling forms. Directly from Chicago, I took a faculty position at Michigan State University where I became a tenured associate professor, then moved to the University of Pittsburgh where I became a full professor in 2001. I joined the University of Tennessee, Knoxville (UTK) in 2015 as Professor and Head of the Department of Ecology and Evolutionary Biology. I was invited to serve as program director in the Division of Environmental Biology at the National Science Foundation (2009-2010) and I currently serve on the Faculty of 1000. I co-led two National Evolution Synthesis Center (NESCent) Working Groups, and served as a member of the NSF microMORPH: Microevolutionary Molecular and Organismic Research in Plant History Research Coordination Network Steering Committee 2010-2017, the Botanical Society of America Merit Awards Committee 2011-2014, and as associate editor for the journals Evolution, Journal of Ecology and The American Naturalist. As a graduate student, I joined ASN (loved to discuss graphs with unlabeled axes), and while serving as one of three Editors for The American Naturalist (2012-2015), I advocated for instating the double blind manuscript review process that the journal now employs. My experiences in a faculty mentoring matrix program at UTK and graduate student mentoring and diversity programs at U Pittsburgh and UTK, in working groups, and my life experiences, reinforce my belief in the power of human networks to increase individual and group success and happiness. I would work to develop of new mentoring opportunities for ASN scientists at all career levels that foster their professional and personal goals and help to build a stronger, more inclusive community within ASN.My research focuses on the ecology and evolution of infectious diseases, particularly in aquatic systems. I have studied the causes and consequences of rapid evolution of hosts in response to disease outbreaks, as well as the effects of food webs on disease. More recently, my work has begun to focus on the impacts of global change on infectious diseases, as well as on multihost-multipathogen interactions. I received my PhD from Michigan State University and did a postdoc at the University of Wisconsin before beginning my first faculty position at Georgia Tech; I am now an Associate Professor of Ecology and Evolutionary Biology at the University of Michigan. I received the President’s Early Career Award for Scientists and Engineers from President Obama and the Ecological Society of America’s Mercer Award (for a paper published in AmNat!), and am currently a Public Engagement Fellow with AAAS. I have been an Associate Editor for the American Naturalist since 2015 and served on the American Naturalist Editor-in-Chief Selection committee in 2016. I was the Vice-Chair and then Chair of the Ecological Society of America’s (ESA) Aquatic Ecology Section, was a member of ESA’s Grants and Fellowships committee, and am currently the chair of ESA’s Mercer Award subcommittee. I am a co-creator of DiversifyEEB (which aims to highlight ecologists and evolutionary biologists who are women and/or underrepresented minorities) and of EEBMentorMatch (which aims to provide grad school and fellowship applicants with feedback on their application materials). I also serve on the Advisory Board of 500 Women Scientists, which aims to transform leadership, diversity, and public engagement in science. The ASN website notes that the “American Society of Naturalists emphasizes the value of interdisciplinary research and collaborations between diverse biologists to achieve conceptual unification across the biological sciences.” This is exactly why I want to serve the ASN – there is much to be gained by integrating across ecology, evolutionary biology, and behavior, and it is imperative that we work to make science more diverse and inclusive. My planned symposium would focus on insights gained from system-based research, including work on well-established systems as well as on more recently established systems, integrating across ecology, evolution, and behavior.I study ecological and evolutionary community assembly, with a focus on understanding when and why the structure and function of communities are contingent on the history of species immigration. Over the past 15 years, I have used experimental, theoretical, and observational methods, involving bacteria, protists, fungi, plants, and animals. Currently, microbes that inhabit floral nectar are my primary study system. I earned a bachelor&#39;s degree from Waseda University in 1996, a master&#39;s degree from the University of Tokyo in 1998, and a PhD from the University of Tennessee, Knoxville, in 2003. I was a postdoc at Landcare Research, New Zealand (2003-2005) and an Assistant Professor at the University of Hawaii at Manoa (2006-2008) before joining the Stanford University faculty in 2008. I received NSF CAREER, OPUS, and Dimensions of Biodiversity awards, and a Science Prize for Inquiry-Based Instruction from AAAS. I have served as a handling editor (Ecology Letters, Oikos, and PLoS ONE), a symposium organizer (ESA), a review panel member (NSF), and a graduate student representative (University of Tennessee EEB Dept; though a long time ago!). I attended two of the past stand-alone ASN conferences and have published three papers in the American Naturalist (Wittmann and Fukami, forthcoming; Fukami et al. 2017; Olito and Fukami 2009), served as the external reviewer for manuscripts submitted to the journal, and had my graduate student (Devin Leopold) receive an ASN Student Research Award. Serving as ASN Secretary would be a great opportunity to contribute to the society that has published many of the papers that inspired and influenced my research deeply. The stimulating, friendly, and informal atmosphere at the ASN stand-alone conferences that I attended has reinforced my feeling that this is the society that I would like to consider my intellectual home, and I would be excited to help the society continue to thrive. <p>My interests are in evolutionary biology and ecology.&nbsp; My research focuses on the evolution of&nbsp; mating system and the role of mating system shifts in speciation in plants, mutualism and mutualism disruption by invasive species, and demographic and population modeling. These research projects intersect in my interest in deeper questions about the effects of human&rsquo;s actions across the globe in altering the tempo and mode of evolution, and the sustainability and conservation of biodiversity. I received my Bachelor&rsquo;s of Science degree from the University of Michigan, where I was inspired by the dazzling diversity, forms and functions of plants. I received my Masters and PhD degrees from the University of Chicago, where I learned how the interaction of ecology and evolutionary forces shaped those dazzling forms. Directly from Chicago, I took a faculty position at Michigan State University where I became a tenured associate professor, then moved to the University of Pittsburgh where I became a full professor in 2001. I joined the University of Tennessee, Knoxville (UTK) in 2015 as Professor and Head of the Department of Ecology and Evolutionary Biology. I was invited to serve as program director in the Division of Environmental Biology at the National Science Foundation (2009-2010) and I currently serve on the Faculty of 1000.</p> <p>I co-led two National Evolution Synthesis Center (NESCent) Working Groups, and served as a member of the NSF microMORPH: Microevolutionary Molecular and Organismic Research in Plant History Research Coordination Network Steering Committee 2010-2017, the Botanical Society of America Merit Awards Committee 2011-2014, and as associate editor for the journals Evolution, Journal of Ecology and The American Naturalist. As a graduate student, I joined ASN (loved to discuss graphs with unlabeled axes), and while serving as one of three Editors for The American Naturalist (2012-2015), I advocated for instating the double blind manuscript review process that the journal now employs. My experiences in a faculty mentoring matrix program at UTK and graduate student mentoring and diversity programs at U Pittsburgh and UTK, in working groups, and my life experiences, reinforce my belief in the power of human networks to increase individual and group success and happiness. I would work to develop of new mentoring opportunities for ASN scientists at all career levels that foster their professional and personal goals and help to build a stronger, more inclusive community within ASN.</p><p>My research focuses on the ecology and evolution of infectious diseases, particularly in aquatic systems. I have studied the causes and consequences of rapid evolution of hosts in response to disease outbreaks, as well as the effects of food webs on disease. More recently, my work has begun to focus on the impacts of global change on infectious diseases, as well as on multihost-multipathogen interactions. I received my PhD from Michigan State University and did a postdoc at the University of Wisconsin before beginning my first faculty position at Georgia Tech; I am now an Associate Professor of Ecology and Evolutionary Biology at the University of Michigan. I received the President&rsquo;s Early Career Award for Scientists and Engineers from President Obama and the Ecological Society of America&rsquo;s Mercer Award (for a paper published in AmNat!), and am currently a Public Engagement Fellow with AAAS.</p> <p>I have been an Associate Editor for the American Naturalist since 2015 and served on the American Naturalist Editor-in-Chief Selection committee in 2016. I was the Vice-Chair and then Chair of the Ecological Society of America&rsquo;s (ESA) Aquatic Ecology Section, was a member of ESA&rsquo;s Grants and Fellowships committee, and am currently the chair of ESA&rsquo;s Mercer Award subcommittee. I am a co-creator of DiversifyEEB (which aims to highlight ecologists and evolutionary biologists who are women and/or underrepresented minorities) and of EEBMentorMatch (which aims to provide grad school and fellowship applicants with feedback on their application materials). I also serve on the Advisory Board of 500 Women Scientists, which aims to transform leadership, diversity, and public engagement in science.</p> <p>The ASN website notes that the &ldquo;American Society of Naturalists emphasizes the value of interdisciplinary research and collaborations between diverse biologists to achieve conceptual unification across the biological sciences.&rdquo; This is exactly why I want to serve the ASN &ndash; there is much to be gained by integrating across ecology, evolutionary biology, and behavior, and it is imperative that we work to make science more diverse and inclusive. My planned symposium would focus on insights gained from system-based research, including work on well-established systems as well as on more recently established systems, integrating across ecology, evolution, and behavior.</p><p>I study ecological and evolutionary community assembly, with a focus on understanding when and why the structure and function of communities are contingent on the history of species immigration. Over the past 15 years, I have used experimental, theoretical, and observational methods, involving bacteria, protists, fungi, plants, and animals. Currently, microbes that inhabit floral nectar are my primary study system. I earned a bachelor&#39;s degree from Waseda University in 1996, a master&#39;s degree from the University of Tokyo in 1998, and a PhD from the University of Tennessee, Knoxville, in 2003. I was a postdoc at Landcare Research, New Zealand (2003-2005) and an Assistant Professor at the University of Hawaii at Manoa (2006-2008) before joining the Stanford University faculty in 2008. I received NSF CAREER, OPUS, and Dimensions of Biodiversity awards, and a Science Prize for Inquiry-Based Instruction from AAAS.</p> <p>I have served as a handling editor (Ecology Letters, Oikos, and PLoS ONE), a symposium organizer (ESA), a review panel member (NSF), and a graduate student representative (University of Tennessee EEB Dept; though a long time ago!). I attended two of the past stand-alone ASN conferences and have published three papers in the American Naturalist (Wittmann and Fukami, forthcoming; Fukami et al. 2017; Olito and Fukami 2009), served as the external reviewer for manuscripts submitted to the journal, and had my graduate student (Devin Leopold) receive an ASN Student Research Award. Serving as ASN Secretary would be a great opportunity to contribute to the society that has published many of the papers that inspired and influenced my research deeply. The stimulating, friendly, and informal atmosphere at the ASN stand-alone conferences that I attended has reinforced my feeling that this is the society that I would like to consider my intellectual home, and I would be excited to help the society continue to thrive.</p> Wed, 21 Mar 2018 05:00:00 GMT “Sex allocation theory for facultatively sexual organisms inhabiting seasonal environments: the importance of bet-hedging” http://amnat.org/an/newpapers/AugGerber-A.html The DOI will be https://dx.doi.org/10.1086/697727 Abstract Adaptive explanations for dormancy often invoke bet-hedging, where reduced mean fitness can be adaptive if it associates with reduced fitness variance. Sex allocation theory typically ignores variance effects and focuses on mean fitness. For many cyclical parthenogens, these themes become linked, as only sexually produced eggs undergo dormancy needed to survive harsh conditions. We ask how sex allocation and the timing of sex evolve when this constraint exists in the form of a trade-off between asexual reproduction and sexual production of dormant eggs—the former being crucial for within-season success, the latter for survival across seasons. We show that male production can be temporally separated from or co-occur with sex, depending on whether direct (time) or indirect (population density) cues of the season’s end are available, and whether population growth is density-dependent. Sex generally occurs late in the season, but is induced earlier in unpredictable environments. When only indirect cues are available, the temporal spread of sex, and with it the production of dormant stages, is even larger, and given sufficient mortality leads to endogenous population cycles in which frequent sex coincides with high densities. In all scenarios, algorithms maximizing geometric mean fitness have reduced fitness variance compared to a hypothetical non-bet-hedger, confirming that the timing of male production and sex in facultative seasonal settings can be bet-hedging traits. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697727 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697727">Read the Article</a></i></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;">A</span>daptive explanations for dormancy often invoke bet-hedging, where reduced mean fitness can be adaptive if it associates with reduced fitness variance. Sex allocation theory typically ignores variance effects and focuses on mean fitness. For many cyclical parthenogens, these themes become linked, as only sexually produced eggs undergo dormancy needed to survive harsh conditions. We ask how sex allocation and the timing of sex evolve when this constraint exists in the form of a trade-off between asexual reproduction and sexual production of dormant eggs—the former being crucial for within-season success, the latter for survival across seasons. We show that male production can be temporally separated from or co-occur with sex, depending on whether direct (time) or indirect (population density) cues of the season’s end are available, and whether population growth is density-dependent. Sex generally occurs late in the season, but is induced earlier in unpredictable environments. When only indirect cues are available, the temporal spread of sex, and with it the production of dormant stages, is even larger, and given sufficient mortality leads to endogenous population cycles in which frequent sex coincides with high densities. In all scenarios, algorithms maximizing geometric mean fitness have reduced fitness variance compared to a hypothetical non-bet-hedger, confirming that the timing of male production and sex in facultative seasonal settings can be bet-hedging traits. </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, 21 Mar 2018 05:00:00 GMT 2018 American Naturalist Student Paper Award http://amnat.org/announcements/ANNStuPaperAwa.html The American Naturalist Student Paper Award is for work that was published in 2017 and that was performed primarily by the first author and primarily while she or he was an undergraduate or graduate student. There were over fifty eligible papers.&nbsp; The recipient of the 2018 award is Meredith Cenzer for her paper, "Maladaptive Plasticity Masks the Effects of Natural Selection in the Red-Shouldered Soapberry Bug" (Am Nat 190:521-533).&nbsp;In the 1980s, populations of this insect were locally adapted to feed on the seeds of a native host plant and an introduced host plant; by 2014, local differentiation in beak length had been lost, likely as a consequence of increased gene flow. In this work, Dr. Cenzer leveraged a unique opportunity to quantify maladaptive plasticity and explore its consequences; she designed and executed difficult experiments and capitalized on an unexpected result to draw big and convincing conclusions. We particularly appreciated how her study incorporates measures of selection, population effects (presumably genetic), and common-garden rearing to quantify plasticity. We found her paper to be an elegant combination of ecology, evolution, behavior, and natural history. While it focuses on a single system, maladaptive plasticity is so rarely investigated that we became convinced that hers will come to be considered a landmark study. It is particularly sophisticated work for a single-authored graduate student publication. (Read her summary here:&nbsp;http://amnat.org/an/newpapers/OctCenzer.html) Kimberly Gilbert, for her paper Local adaptation interacts with expansion load during range expansion: maladaptation reduces expansion load (coauthored by Nathaniel Sharp, Amy Angert, Gina Conte, Jeremy Draghl, Frederic Guillaume, Anna Hargreaves, Remi Matthey-Doret, and Michael Whitlock). Dr. Gilbert completed this work as a graduate student of Mike Whitlock’s at UBC and is currently a postdoctoral fellow at the University of Bern, Switzerland. This paper takes a classic American Naturalist-style approach to range limits and expansion, modeling independent effects of two genetic processes and then their interaction. In Dan Bolnick’s words, “this fits in the tried and true “Reese’s’ peanut butter cups” approach to science: take two good ideas and merge them for something new.” The results have broad and timely implications for conservation. We found the paper itself to be beautifully written, not an easy accomplishment given the complex set of issues she explores.(Lay summary here: http://amnat.org/an/newpapers/AprGilbert.html) Thomas Haaland, for his paper Differential allocation revisited: when should mate quality affect parental investment? (coauthored by Jonathan Wright, Bram Kuijpur, and Irja Ratikainen). He did this work as a graduate student of Wright and Ratikainen at the Norwegian Institute of Science and Technology, where he is still based. Starting with an historical narrative, he identifies a clear inconsistency that has persisted in the literature for decades with regard to differential allocation of resources to offspring by females in response to male quality (DA). The paper offers a comprehensive unifying framework, then develops models to parse the contributions of different factors to DA. We were impressed by the way Mr. Haaland attempted to link this work to what is known about DA in nature. We believe that this study will start a new era of studying DA as an ecological and evolutionary process.(Lay summary here: http://amnat.org/an/newpapers/OctHaaland.html) Judith L. Bronstein, Editor-in-Chief, 2017 Yannis Michalakis, Editor Alice Winn, Editor with the 2018 in-coming editors Daniel Bolnick, in-coming Editor-in-Chief Russell Bonduriansky, in-coming Editor <p><em>The American Naturalist </em>Student Paper Award is for work that was published in 2017 and that was performed primarily by the first author and primarily while she or he was an undergraduate or graduate student. There were over fifty eligible papers.&nbsp;</p> <p>The recipient of the 2018 award is Meredith Cenzer for her paper, &quot;<a href="https://www.journals.uchicago.edu/doi/abs/10.1086/693456">Maladaptive Plasticity Masks the Effects of Natural Selection in the Red-Shouldered Soapberry Bug</a>&quot; (Am Nat 190:521-533).&nbsp;In the 1980s, populations of this insect were locally adapted to feed on the seeds of a native host plant and an introduced host plant; by 2014, local differentiation in beak length had been lost, likely as a consequence of increased gene flow. In this work, Dr. Cenzer leveraged a unique opportunity to quantify maladaptive plasticity and explore its consequences; she designed and executed difficult experiments and capitalized on an unexpected result to draw big and convincing conclusions. We particularly appreciated how her study incorporates measures of selection, population effects (presumably genetic), and common-garden rearing to quantify plasticity. We found her paper to be an elegant combination of ecology, evolution, behavior, and natural history. While it focuses on a single system, maladaptive plasticity is so rarely investigated that we became convinced that hers will come to be considered a landmark study. It is particularly sophisticated work for a single-authored graduate student publication. (Read her summary here:&nbsp;<a href="http://amnat.org/an/newpapers/OctCenzer.html">http://amnat.org/an/newpapers/OctCenzer.html</a>)</p> <hr /><ul> <li><strong>Kimberly Gilbert,</strong> for her paper <a href="https://www.journals.uchicago.edu/doi/full/10.1086/690673"><strong>Local adaptation interacts with expansion load during range expansion: maladaptation reduces expansion load</strong></a> (coauthored by Nathaniel Sharp, Amy Angert, Gina Conte, Jeremy Draghl, Frederic Guillaume, Anna Hargreaves, Remi Matthey-Doret, and Michael Whitlock). Dr. Gilbert completed this work as a graduate student of Mike Whitlock&rsquo;s at UBC and is currently a postdoctoral fellow at the University of Bern, Switzerland. This paper takes a classic <em>American Naturalist</em>-style approach to range limits and expansion, modeling independent effects of two genetic processes and then their interaction. In Dan Bolnick&rsquo;s words, &ldquo;this fits in the tried and true &ldquo;Reese&rsquo;s&rsquo; peanut butter cups&rdquo; approach to science: take two good ideas and merge them for something new.&rdquo; The results have broad and timely implications for conservation. We found the paper itself to be beautifully written, not an easy accomplishment given the complex set of issues she explores.(Lay summary here: <a href="http://amnat.org/an/newpapers/AprGilbert.html">http://amnat.org/an/newpapers/AprGilbert.html)</a></li> <li><strong>Thomas Haaland</strong>, for his paper <a href="https://www.journals.uchicago.edu/doi/full/10.1086/693484"><strong>Differential allocation revisited: when should mate quality affect parental investment?</strong></a> (coauthored by Jonathan Wright, Bram Kuijpur, and Irja Ratikainen). He did this work as a graduate student of Wright and Ratikainen at the Norwegian Institute of Science and Technology, where he is still based. Starting with an historical narrative, he identifies a clear inconsistency that has persisted in the literature for decades with regard to differential allocation of resources to offspring by females in response to male quality (DA). The paper offers a comprehensive unifying framework, then develops models to parse the contributions of different factors to DA. We were impressed by the way Mr. Haaland attempted to link this work to what is known about DA in nature. We believe that this study will start a new era of studying DA as an ecological and evolutionary process.(Lay summary here: <a href="http://amnat.org/an/newpapers/OctHaaland.html">http://amnat.org/an/newpapers/OctHaaland.html)</a></li> </ul> <p>Judith L. Bronstein, Editor-in-Chief, 2017<br /> Yannis Michalakis, Editor<br /> Alice Winn, Editor</p> <p>with the 2018 in-coming editors</p> <p>Daniel Bolnick, in-coming Editor-in-Chief<br /> Russell Bonduriansky, in-coming Editor</p> Mon, 19 Mar 2018 05:00:00 GMT “Adaptive foraging of pollinators can promote pollination of a rare plant species” http://amnat.org/an/newpapers/AugBenadi.html The DOI will be https://dx.doi.org/10.1086/697582 Contrary to previous knowledge, an IBM shows that adaptive foraging of pollinators could promote plant coexistence Most flowering plant species rely on animals for pollination and in exchange, animals obtain floral food resources such as nectar and pollen. Consequently, pollinator foraging decisions have a direct impact on plant reproductive success. Although the decisions of some animal pollinators are guided by innate preferences for a single type of flower, the vast majority of species have the flexibility to visit many flower types and are capable of rapidly and flexibly adjusting their flower selection strategy based on current floral conditions and past foraging experiences (memory). Yet, surprisingly few studies to date have considered the potential consequences of such flexible decision-making for pollinator-mediated ecological processes in plants. Previous studies suggested that adaptively foraging pollinators generally prefer abundant plant species over rarer ones and are less efficient in transferring pollen of rare plant species compared to more abundant species. This implies that the reproduction of rare plant species relying on animal pollination could be compromised, which could eventually lead to their extinction. To better understand the role of adaptive foraging of pollinators for reproduction of rare plant species, Gita Benadi from the University of Freiburg (Germany) and Robert J. Gegear from Worcester Polytechnic Institute (USA) developed a computer simulation model of individual animals moving from flower to flower. Contrary to previous studies, their simulations suggest that under certain conditions, adaptive foraging of pollinators can favor pollination of a rare plant species. An important improvement of their model over previous approaches is that it accounts for limited information and memory of individual foragers. In the article, they show that foragers with realistically limited information about the distribution of floral resources forage in a way which favors pollination of the rarer plant species, while perfectly informed animals prefer the more abundant flowering plant. In addition, they demonstrate that even with perfectly informed pollinators, a rarer plant species benefits more from offering a high resource amount per flower than a more abundant one. These findings help to understand under which conditions rare plant species relying on animal pollination can persist, and when they are in danger of extinction. Abstract Most pollinators have the foraging flexibility to visit a wide variety of plant species. Yet, few studies of pollinator-mediated processes in plants have considered the effects of variation in individual foraging patterns on plant reproductive success. In this study, we use an individual-based model of pollinator foraging economics to predict how visitation rates and pollination success of two co-flowering plant species change with their frequency (relative abundance). Whereas previous studies suggested that adaptive foraging of pollinators always favors pollination of abundant plant species (positive frequency dependence), here we show that under certain conditions the per-capita pollination success of a rare plant species can exceed that of a more abundant species. Specifically, when the overall flower density is sufficiently high and pollinators’ perception ranges are sufficiently large, animals with limited memory of previously encountered rewards forage in a way which favors pollination of the rarer plant species. Moreover, even with perfectly informed foragers a rare plant species benefits more from offering a higher floral reward than a more abundant species. Our results show that adaptive foraging of individual pollinators can have important implications for plant community dynamics and the persistence of rare plant species. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697582 </i></p> <!-- <p><a href="https://dx.doi.org/10.1086/697582">Read&nbsp;the&nbsp;Article</a> </p> --> <p><b>Contrary to previous knowledge, an IBM shows that adaptive foraging of pollinators could promote plant coexistence </b></p><p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">M</span>ost flowering plant species rely on animals for pollination and in exchange, animals obtain floral food resources such as nectar and pollen. Consequently, pollinator foraging decisions have a direct impact on plant reproductive success. Although the decisions of some animal pollinators are guided by innate preferences for a single type of flower, the vast majority of species have the flexibility to visit many flower types and are capable of rapidly and flexibly adjusting their flower selection strategy based on current floral conditions and past foraging experiences (memory). Yet, surprisingly few studies to date have considered the potential consequences of such flexible decision-making for pollinator-mediated ecological processes in plants. Previous studies suggested that adaptively foraging pollinators generally prefer abundant plant species over rarer ones and are less efficient in transferring pollen of rare plant species compared to more abundant species. This implies that the reproduction of rare plant species relying on animal pollination could be compromised, which could eventually lead to their extinction.</p> <p>To better understand the role of adaptive foraging of pollinators for reproduction of rare plant species, Gita Benadi from the University of Freiburg (Germany) and Robert J. Gegear from Worcester Polytechnic Institute (USA) developed a computer simulation model of individual animals moving from flower to flower. Contrary to previous studies, their simulations suggest that under certain conditions, adaptive foraging of pollinators can favor pollination of a rare plant species. An important improvement of their model over previous approaches is that it accounts for limited information and memory of individual foragers. In the article, they show that foragers with realistically limited information about the distribution of floral resources forage in a way which favors pollination of the rarer plant species, while perfectly informed animals prefer the more abundant flowering plant. In addition, they demonstrate that even with perfectly informed pollinators, a rarer plant species benefits more from offering a high resource amount per flower than a more abundant one. These findings help to understand under which conditions rare plant species relying on animal pollination can persist, and when they are in danger of extinction.</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">M</span>ost pollinators have the foraging flexibility to visit a wide variety of plant species. Yet, few studies of pollinator-mediated processes in plants have considered the effects of variation in individual foraging patterns on plant reproductive success. In this study, we use an individual-based model of pollinator foraging economics to predict how visitation rates and pollination success of two co-flowering plant species change with their frequency (relative abundance). Whereas previous studies suggested that adaptive foraging of pollinators always favors pollination of abundant plant species (positive frequency dependence), here we show that under certain conditions the per-capita pollination success of a rare plant species can exceed that of a more abundant species. Specifically, when the overall flower density is sufficiently high and pollinators&rsquo; perception ranges are sufficiently large, animals with limited memory of previously encountered rewards forage in a way which favors pollination of the rarer plant species. Moreover, even with perfectly informed foragers a rare plant species benefits more from offering a higher floral reward than a more abundant species. Our results show that adaptive foraging of individual pollinators can have important implications for plant community dynamics and the persistence of rare plant species.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 14 Mar 2018 05:00:00 GMT “Integrating genetic and demographic effects of connectivity on population stability: the case of hatchery trucking in salmon” http://amnat.org/an/newpapers/AugDedrick.html The DOI will be https://dx.doi.org/10.1086/697581 Just as investing money in multiple stocks can provide more stable returns than investing in one stock, having multiple sub-populations that act independently can lead to a more stable overall population in a natural system, a phenomenon known as the “portfolio effect”. The ability of a population to behave as a portfolio, however, might decrease with increased connectivity (exchange) between sub-populations due to two processes. First, connectivity might directly couple sub-populations. Second, connectivity and increased interbreeding between sub-populations might make sub-populations more genetically similar in traits that influence the potential for independent responses to changes in the environment in time. An example of the potential for increased connectivity to decrease the portfolio effect is Chinook salmon in the California Central Valley. Salmon populations are distinct in freshwater, where fish hatch and rear, then combine in the ocean before separating again when adult salmon return to rivers to breed. The salmon populations once showed a strong portfolio that has become weaker in recent decades, including a recent fishery collapse due to all sub-populations declining simultaneously. One possible reason for the lost portfolio is the practice of trucking juvenile hatchery fish downstream for release. Trucking juvenile fish increases survival by bypassing the high-mortality migration route from rivers to the ocean, but it also increases connectivity among rivers because the fish do not have the experience to know which river to return to as breeding adults. Using a model, the authors find that trucking can lead to a tradeoff between an increased average population size and a weakened portfolio. This tradeoff is substantially stronger, and the capacity for a weakened portfolio greater, when accounting for the genetic effects of increased connectivity than when ignoring genetic effects. Therefore, restoration of genetic diversity might be central to restoring the portfolio effect in Central Valley Chinook salmon. Abstract Connectivity among populations can have counteracting effects on population stability. Demographically, connectivity can rescue local populations but increase the synchrony across populations. Genetically, connectivity can counteract drift locally but homogenize genotypes across populations. Population independence and diversity underlies system-level buffering against environmental variability, termed the portfolio effect. The portfolio effect has declined in California fall-run Chinook salmon, possibly in part due to the trucking of juvenile hatchery-reared fish for downstream release, which reduces juvenile mortality but increases the connectivity between rivers. We use a dynamical population model to test whether this increased connectivity can explain the loss of the portfolio effect and quantify the relative demographic and genetic contributions to portfolio effect erosion. In the model, populations experience different within-population environmental conditions and the same time-variable ocean conditions, the response to which can depend on a quantitative genetic trait. We find that increased trucking for one population's hatchery can lead to a loss of the portfolio effect, with a system-level trade-off between increased average abundance and increased variability in abundance. This trade-off is much stronger when we include the effects of genetic homogenization than when we consider demographic synchronization alone. Therefore, genetic homogenization can outweigh demographic synchrony in determining the system-level effect of connectivity. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697581 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697581">Read&nbsp;the&nbsp;Article</a></i> </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;">J</span>ust as investing money in multiple stocks can provide more stable returns than investing in one stock, having multiple sub-populations that act independently can lead to a more stable overall population in a natural system, a phenomenon known as the “portfolio effect”. The ability of a population to behave as a portfolio, however, might decrease with increased connectivity (exchange) between sub-populations due to two processes. First, connectivity might directly couple sub-populations. Second, connectivity and increased interbreeding between sub-populations might make sub-populations more genetically similar in traits that influence the potential for independent responses to changes in the environment in time. An example of the potential for increased connectivity to decrease the portfolio effect is Chinook salmon in the California Central Valley. Salmon populations are distinct in freshwater, where fish hatch and rear, then combine in the ocean before separating again when adult salmon return to rivers to breed. The salmon populations once showed a strong portfolio that has become weaker in recent decades, including a recent fishery collapse due to all sub-populations declining simultaneously. One possible reason for the lost portfolio is the practice of trucking juvenile hatchery fish downstream for release. Trucking juvenile fish increases survival by bypassing the high-mortality migration route from rivers to the ocean, but it also increases connectivity among rivers because the fish do not have the experience to know which river to return to as breeding adults. Using a model, the authors find that trucking can lead to a tradeoff between an increased average population size and a weakened portfolio. This tradeoff is substantially stronger, and the capacity for a weakened portfolio greater, when accounting for the genetic effects of increased connectivity than when ignoring genetic effects. Therefore, restoration of genetic diversity might be central to restoring the portfolio effect in Central Valley Chinook salmon. </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;">C</span>onnectivity among populations can have counteracting effects on population stability. Demographically, connectivity can rescue local populations but increase the synchrony across populations. Genetically, connectivity can counteract drift locally but homogenize genotypes across populations. Population independence and diversity underlies system-level buffering against environmental variability, termed the portfolio effect. The portfolio effect has declined in California fall-run Chinook salmon, possibly in part due to the trucking of juvenile hatchery-reared fish for downstream release, which reduces juvenile mortality but increases the connectivity between rivers. We use a dynamical population model to test whether this increased connectivity can explain the loss of the portfolio effect and quantify the relative demographic and genetic contributions to portfolio effect erosion. In the model, populations experience different within-population environmental conditions and the same time-variable ocean conditions, the response to which can depend on a quantitative genetic trait. We find that increased trucking for one population's hatchery can lead to a loss of the portfolio effect, with a system-level trade-off between increased average abundance and increased variability in abundance. This trade-off is much stronger when we include the effects of genetic homogenization than when we consider demographic synchronization alone. Therefore, genetic homogenization can outweigh demographic synchrony in determining the system-level effect of connectivity.</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, 14 Mar 2018 05:00:00 GMT “Evolution and manipulation of vector host choice” http://amnat.org/an/newpapers/JulyGandon.html The DOI will be https://dx.doi.org/10.1086/697575 A new theoretical framework to study the epidemiology, the evolution and the manipulation of vector host choice behavior Imagine you are a female mosquito. You are the vector of a pathogen that infects a vertebrate host you feed upon. You have the choice between feeding on an uninfected host or on a host infected by this pathogen. Which host should you pick for your next blood meal? Now, imagine that you are the pathogen. You have the potential to modify the preference of the female mosquito by modifying the scent of the infected host, but also, more directly, by modifying the decision of mosquitoes once they become infected. What should you do? Answering these questions and understanding the evolution host preference is key for the epidemiology of vector-borne diseases. A growing number of experimental studies are revealing the diversity of behavioral preference of vector species from a broad range of pathosystems. In this paper, Sylvain Gandon develops a theoretical framework to study the evolution and the manipulation of vector behavior. This analysis shows that many factors are acting on the evolution of these traits: the fitness costs of the infection, the prevalence of the infection in the different hosts, whether or not the female mosquito is already infected, whether the pathogen manipulating the mosquito is currently infecting the mosquito or the vertebrate host. The model yields multiple evolutionary outcomes and explains the diversity of host choice behaviors observed in different vector-borne diseases. In particular, this analysis helps understand why several pathogens have evolved manipulation strategies that vary with the infectious status of their vector species, while other pathogens seem unable to evolve such complex conditional strategies. Abstract The transmission of many animal and plant diseases relies on the behavior of arthropod vectors. In particular, the specific preference for infected or uninfected hosts observed in many vector species is expected to affect the circulation of vector-borne diseases. Here I develop a theoretical framework to study the epidemiology and the evolution of the manipulation of host choice behavior of vectors. I show that vector preference strategies have dramatic epidemiological consequences. I also explore the evolution of vector host choice under different scenarios regarding the control of the vector behavior by the pathogen. This analysis yields multiple evolutionary outcomes and explains the diversity of host choice behaviors observed in a broad range of vector-borne diseases. In particular, this analysis helps understand why several pathogens have evolved manipulation strategies that vary with the infectious status of their vector species while other pathogens seem unable to evolve such complex conditional strategies. I argue that contrasting the behavior of infected and uninfected vectors is key to reveal mechanistic constraints acting on the evolution of the manipulation of vector behavior. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697575 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697575">Read the Article</a></i></b> </p> --> <p><b>A new theoretical framework to study the epidemiology, the evolution and the manipulation of vector host choice behavior </b></p><p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">I</span>magine you are a female mosquito. You are the vector of a pathogen that infects a vertebrate host you feed upon. You have the choice between feeding on an uninfected host or on a host infected by this pathogen. Which host should you pick for your next blood meal? Now, imagine that you are the pathogen. You have the potential to modify the preference of the female mosquito by modifying the scent of the infected host, but also, more directly, by modifying the decision of mosquitoes once they become infected. What should you do?</p> <p>Answering these questions and understanding the evolution host preference is key for the epidemiology of vector-borne diseases. A growing number of experimental studies are revealing the diversity of behavioral preference of vector species from a broad range of pathosystems. In this paper, Sylvain Gandon develops a theoretical framework to study the evolution and the manipulation of vector behavior. This analysis shows that many factors are acting on the evolution of these traits: the fitness costs of the infection, the prevalence of the infection in the different hosts, whether or not the female mosquito is already infected, whether the pathogen manipulating the mosquito is currently infecting the mosquito or the vertebrate host. The model yields multiple evolutionary outcomes and explains the diversity of host choice behaviors observed in different vector-borne diseases. In particular, this analysis helps understand why several pathogens have evolved manipulation strategies that vary with the infectious status of their vector species, while other pathogens seem unable to evolve such complex conditional strategies.</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">T</span>he transmission of many animal and plant diseases relies on the behavior of arthropod vectors. In particular, the specific preference for infected or uninfected hosts observed in many vector species is expected to affect the circulation of vector-borne diseases. Here I develop a theoretical framework to study the epidemiology and the evolution of the manipulation of host choice behavior of vectors. I show that vector preference strategies have dramatic epidemiological consequences. I also explore the evolution of vector host choice under different scenarios regarding the control of the vector behavior by the pathogen. This analysis yields multiple evolutionary outcomes and explains the diversity of host choice behaviors observed in a broad range of vector-borne diseases. In particular, this analysis helps understand why several pathogens have evolved manipulation strategies that vary with the infectious status of their vector species while other pathogens seem unable to evolve such complex conditional strategies. I argue that contrasting the behavior of infected and uninfected vectors is key to reveal mechanistic constraints acting on the evolution of the manipulation of vector behavior.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 14 Mar 2018 05:00:00 GMT “Collector motion affects particle capture in physical models and in wind pollination” http://amnat.org/an/newpapers/JulyMcCombe.html The DOI will be https://dx.doi.org/10.1086/697551 Particle capture efficiency on moving collectors determined by flow (Reynolds no.) and particle dynamics (Stokes no.) Many ecological processes, such as wind and water pollination and filter feeding, involve the capture of particles suspended in a fluid – air and water. Despite the ecological and economic importance of these processes (e.g., many of our crop plants and trees are pollinated by wind), particle capture has been mostly studied on stationary rather than moving collectors. This is somewhat surprising given the flow-induced movements of plants visible on windy days. Using some insights from numerical models of particle capture on moving collectors, researchers at the University of Guelph have expanded this field by using a combination of empirical studies of a physical model in the lab and a wind pollination study in a field of timothy grass (Phleum pretense) in which they experimentally restricted the motion of plants in different ways. They found that moving collectors captured more particles than stationary ones in the lab as did moving plants in the field. The scale of the impact, however, depended on the flow environment around the moving collector, and the characteristics of the particle. This realization was used to resolve a controversy about the importance of plant movement in pollination success and the ways in which pollen are captured in the wind. Incorporating the ecology of flow-induced movements into the study of particle capture provides a better understanding of the rate and importance of these biological processes, which have been hitherto underestimated. Abstract Particle capture is important for ecological processes in aquatic and terrestrial ecosystems. The current model is based on a stationary collector for which predictions about capture efficiency (&eta;; flux of captured particles&nbsp;: flux of particles) are based on the collector flow environment (i.e., collector Reynolds number, Rec; inertial&nbsp;: viscous forces). This model does not account for the movement of collectors in nature. We examined the effect of collector motion (transverse and longitudinal to the flow) on &eta; using a cylindrical model in the lab and the grass species, Phleum pratense, in the field. Collector motion increased &eta; (up to 400% and 20% in the lab and field, respectively) and also affected the spatial distribution of particles on collectors, especially at low Rec. The effect was greatest for collectors moving transversely at large magnitude, which encountered more particles with higher relative momentum. These results, which differ from the stationary model, can be predicted by considering both Rec and the particle dynamics given by the Stokes number (Stk; particle stopping distance&nbsp;: collector radius) and helped to resolve an existing controversy about pollination mechanisms. Collector motion should be considered in wind pollination and other ecological processes involving particle capture. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697551 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697551">Read&nbsp;the&nbsp;Article</a></i></b> </p> --> <p><b>Particle capture efficiency on moving collectors determined by flow (Reynolds no.) and particle dynamics (Stokes no.) </b></p><p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">M</span>any ecological processes, such as wind and water pollination and filter feeding, involve the capture of particles suspended in a fluid &ndash; air and water. Despite the ecological and economic importance of these processes (e.g., many of our crop plants and trees are pollinated by wind), particle capture has been mostly studied on stationary rather than moving collectors. This is somewhat surprising given the flow-induced movements of plants visible on windy days.</p> <p>Using some insights from numerical models of particle capture on moving collectors, researchers at the University of Guelph have expanded this field by using a combination of empirical studies of a physical model in the lab and a wind pollination study in a field of timothy grass (<i>Phleum pretense</i>) in which they experimentally restricted the motion of plants in different ways.</p> <p>They found that moving collectors captured more particles than stationary ones in the lab as did moving plants in the field. The scale of the impact, however, depended on the flow environment around the moving collector, and the characteristics of the particle. This realization was used to resolve a controversy about the importance of plant movement in pollination success and the ways in which pollen are captured in the wind.</p> <p>Incorporating the ecology of flow-induced movements into the study of particle capture provides a better understanding of the rate and importance of these biological processes, which have been hitherto underestimated.</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">P</span>article capture is important for ecological processes in aquatic and terrestrial ecosystems. The current model is based on a stationary collector for which predictions about capture efficiency (<i>&eta;</i>; flux of captured particles&nbsp;: flux of particles) are based on the collector flow environment (i.e., collector Reynolds number, <i>Re<span style="bottom: -0.3em; font-size: 70%; position: relative;">c</span></i>; inertial&nbsp;: viscous forces). This model does not account for the movement of collectors in nature. We examined the effect of collector motion (transverse and longitudinal to the flow) on <i>&eta;</i> using a cylindrical model in the lab and the grass species, <i>Phleum pratense</i>, in the field. Collector motion increased <i>&eta;</i> (up to 400% and 20% in the lab and field, respectively) and also affected the spatial distribution of particles on collectors, especially at low <i>Re<span style="bottom: -0.3em; font-size: 70%; position: relative;">c</span></i>. The effect was greatest for collectors moving transversely at large magnitude, which encountered more particles with higher relative momentum. These results, which differ from the stationary model, can be predicted by considering both <i>Re<span style="bottom: -0.3em; font-size: 70%; position: relative;">c</span></i> and the particle dynamics given by the Stokes number (<i>Stk</i>; particle stopping distance&nbsp;: collector radius) and helped to resolve an existing controversy about pollination mechanisms. Collector motion should be considered in wind pollination and other ecological processes involving particle capture.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 07 Mar 2018 06:00:00 GMT “Genomic contingencies and the potential for local adaptation in a hybrid species” http://amnat.org/an/newpapers/JulyRunemark.html The DOI will be https://dx.doi.org/10.1086/697563 Limits to hybridization derived variation are determined by the interplay of local adaptation and genomic constraints Hybridization is increasingly recognized as an important evolutionary force providing novel variation, the working material for natural selection. The ability of hybrid species to form phenotypes with novel trait combinations, intermediate trait values, or transgressive trait values exceeding those of the parental species, and thereby occupy niches different from those of the parent species, is well documented. The potential for populations of a hybrid species to adapt to local conditions by differential sorting of the variation inherited from the parent species remains poorly understood, though. Potentially, genomic contingencies arising from recombination of genetic admixture may constrain the evolvability of hybrids. By using a combination of genomic and phenotypic analyses, researchers Anna Runemark, Laura Piñeiro Fernández, Fabrice Eroukhmanoff, and Glenn-Peter Sætre from the University of Oslo investigated how ecological factors and genomic contingencies affect beak morphology in the Italian sparrow (Passer italiae). The Italian sparrow is a hybrid species that originated from interbreeding between the house sparrow (Passer domesticus) and the Spanish sparrow (Passer hispaniolensis). The researchers used island populations of hybrid Italian sparrows from Crete, Corsica, and Sicily that differ genetically and are likely to have originated from independent hybridization events to test if beak morphology was best explained by adaptation to local diet or climate variables or the island of origin, reflecting potential genomic contingencies. They found that while beak size was best explained by local temperature variation, beak shape was best explained by a model including both local precipitation regime and the island of origin. These findings suggest that beak morphology in the Italian sparrow results from an interaction between selection for local adaptation and selection for a functional hybrid genome. Abstract Hybridization is increasingly recognized as a potent evolutionary force. Though additive genetic variation and novel combinations of parental genes theoretically increase the potential for hybrid species to adapt, few empirical studies have investigated the adaptive potential within a hybrid species. Here, we address whether genomic contingencies, adaptation to climate or diet best explain divergence in beak morphology using genomically diverged island populations of the homoploid hybrid Italian sparrow Passer italiae from Crete, Corsica, and Sicily. Populations vary significantly in beak morphology, both between and within islands of origin. Temperature seasonality best explains population divergence in beak size. Interestingly, beak shape along all significant dimensions of variation was best explained by annual precipitation, genomic composition and their interaction, suggesting a role for contingencies. Moreover, beak shape similarity to a parent species correlates with proportion of the genome inherited from that species, consistent with the presence of contingencies. In conclusion, adaptation to local conditions and genomic contingencies arising from putatively independent hybridization events jointly explain beak morphology in the Italian sparrow. Hence, hybridization may induce contingencies and restrict evolution in certain directions dependent on the genetic background. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697563 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697563">Read the Article</a></i></b> </p> --> <p><b>Limits to hybridization derived variation are determined by the interplay of local adaptation and genomic constraints </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;">H</span>ybridization is increasingly recognized as an important evolutionary force providing novel variation, the working material for natural selection. The ability of hybrid species to form phenotypes with novel trait combinations, intermediate trait values, or transgressive trait values exceeding those of the parental species, and thereby occupy niches different from those of the parent species, is well documented. The potential for populations of a hybrid species to adapt to local conditions by differential sorting of the variation inherited from the parent species remains poorly understood, though. Potentially, genomic contingencies arising from recombination of genetic admixture may constrain the evolvability of hybrids. </p> <p>By using a combination of genomic and phenotypic analyses, researchers Anna Runemark, Laura Piñeiro Fernández, Fabrice Eroukhmanoff, and Glenn-Peter Sætre from the University of Oslo investigated how ecological factors and genomic contingencies affect beak morphology in the Italian sparrow (<i>Passer italiae</i>). The Italian sparrow is a hybrid species that originated from interbreeding between the house sparrow (<i>Passer domesticus</i>) and the Spanish sparrow (<i>Passer hispaniolensis</i>). </p><p>The researchers used island populations of hybrid Italian sparrows from Crete, Corsica, and Sicily that differ genetically and are likely to have originated from independent hybridization events to test if beak morphology was best explained by adaptation to local diet or climate variables or the island of origin, reflecting potential genomic contingencies. They found that while beak size was best explained by local temperature variation, beak shape was best explained by a model including both local precipitation regime and the island of origin. These findings suggest that beak morphology in the Italian sparrow results from an interaction between selection for local adaptation and selection for a functional hybrid genome.</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>ybridization is increasingly recognized as a potent evolutionary force. Though additive genetic variation and novel combinations of parental genes theoretically increase the potential for hybrid species to adapt, few empirical studies have investigated the adaptive potential within a hybrid species. Here, we address whether genomic contingencies, adaptation to climate or diet best explain divergence in beak morphology using genomically diverged island populations of the homoploid hybrid Italian sparrow <i>Passer italiae</i> from Crete, Corsica, and Sicily. Populations vary significantly in beak morphology, both between and within islands of origin. Temperature seasonality best explains population divergence in beak size. Interestingly, beak shape along all significant dimensions of variation was best explained by annual precipitation, genomic composition and their interaction, suggesting a role for contingencies. Moreover, beak shape similarity to a parent species correlates with proportion of the genome inherited from that species, consistent with the presence of contingencies. In conclusion, adaptation to local conditions and genomic contingencies arising from putatively independent hybridization events jointly explain beak morphology in the Italian sparrow. Hence, hybridization may induce contingencies and restrict evolution in certain directions dependent on the genetic background. </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, 06 Mar 2018 06:00:00 GMT “A framework for simultaneous tests of abiotic, biotic, and historical drivers of species distributions: empirical tests for North American wood-warblers based on climate and pollen” http://amnat.org/an/newpapers/AugSanin-A.html The DOI will be https://dx.doi.org/10.1086/697537 Abstract Understanding how abiotic, biotic and historical factors shape species distributions remains a central question in ecology, but studies linking biotic factors to continental-scale patterns remain scarce. Here, we present a novel framework for simultaneously testing patterns expected when abiotic, biotic or historical factors drive species range limits. We use ecological niche models to produce empirical estimates of the “Biotic, Abiotic, and Movement” paradigm (BAM diagrams), which previously had only been used theoretically. Based on climatic and pollen data, as well as explicit consideration of dispersal limitations, we implement the framework for a group of North American birds (Oreothlypis warblers) with clear habitat associations. Because the pollen-based predictor variables characterize vegetation, they represent biotic factors needed by each bird species. Although continental-scale patterns of distribution traditionally are attributed to abiotic factors, only one species matched the hypothesis of solely abiotic drivers. In contrast, pollen-based models indicate biotic drivers for two species, correctly predicting their absence in climatically suitable areas. These results highlight the feasibility of considering and quantifying potential effects of biotic interactions on species ranges, especial when interactions can be decoupled from abiotic factors. Furthermore, the availability of pollen data now and in the Holocene highlights the potential of these data to be used to predict range shifts of other organisms tightly dependent on particular vegetation types. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697537 </i></p> <!-- <p><a href="https://dx.doi.org/10.1086/697537">Read&nbsp;the&nbsp;Article</a> </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;">U</span>nderstanding how abiotic, biotic and historical factors shape species distributions remains a central question in ecology, but studies linking biotic factors to continental-scale patterns remain scarce. Here, we present a novel framework for simultaneously testing patterns expected when abiotic, biotic or historical factors drive species range limits. We use ecological niche models to produce empirical estimates of the “Biotic, Abiotic, and Movement” paradigm (BAM diagrams), which previously had only been used theoretically. Based on climatic and pollen data, as well as explicit consideration of dispersal limitations, we implement the framework for a group of North American birds (<i>Oreothlypis</i> warblers) with clear habitat associations. Because the pollen-based predictor variables characterize vegetation, they represent biotic factors needed by each bird species. Although continental-scale patterns of distribution traditionally are attributed to abiotic factors, only one species matched the hypothesis of solely abiotic drivers. In contrast, pollen-based models indicate biotic drivers for two species, correctly predicting their absence in climatically suitable areas. These results highlight the feasibility of considering and quantifying potential effects of biotic interactions on species ranges, especial when interactions can be decoupled from abiotic factors. Furthermore, the availability of pollen data now and in the Holocene highlights the potential of these data to be used to predict range shifts of other organisms tightly dependent on particular vegetation types. </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, 06 Mar 2018 06:00:00 GMT “Evolution of complex asexual reproductive strategies in jellyfish” http://amnat.org/an/newpapers/JulySchndlrMyr-A.html The DOI will be https://dx.doi.org/10.1086/697538 High extinction risk drives the evolution of diverse reproduction strategies in jellyfish polyps in a theoretical model Abstract Many living organisms in terrestrial and aquatic ecosystems rely on multiple reproductive strategies to reduce the risks of extinction in variable environments. Examples are provided by the polyp stage of several bloom-forming jellyfish species, which can reproduce asexually using different “budding” strategies. These strategies broadly fall into three categories: 1) fast localized reproduction, 2) dormant cysts, or 3) motile and dispersing buds. Similar functional strategies are also present in other groups of species. However, mechanisms leading to the evolution of this rich reproductive diversity are yet to be clarified. Here we model how risk of local population extinction and differential fitness of alternative modes of asexual reproduction could drive the evolution of multiple reproductive modes as seen in jellyfish polyps. Depending on environmental parameters, we find that evolution leads to a unique evolutionary stable strategy, where in general multiple reproductive modes coexist. As the extinction risk increases, this strategy shifts from a pure budding mode to a dual strategy, and finally to one characterized by allocation into all three modes. We identify relative fitness-dependent thresholds in extinction risk where these transitions can occur and discuss our predictions in light of observations on polyp reproduction in laboratory and natural systems. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697538 </i></p> <!-- <p><b></i><a href="https://dx.doi.org/10.1086/697538">Read&nbsp;the&nbsp;Article</a> </i></b></p> --> <p><b>High extinction risk drives the evolution of diverse reproduction strategies in jellyfish polyps in a theoretical model </b></p><h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">M</span>any living organisms in terrestrial and aquatic ecosystems rely on multiple reproductive strategies to reduce the risks of extinction in variable environments. Examples are provided by the polyp stage of several bloom-forming jellyfish species, which can reproduce asexually using different &ldquo;budding&rdquo; strategies. These strategies broadly fall into three categories: 1) fast localized reproduction, 2) dormant cysts, or 3) motile and dispersing buds. Similar functional strategies are also present in other groups of species. However, mechanisms leading to the evolution of this rich reproductive diversity are yet to be clarified. Here we model how risk of local population extinction and differential fitness of alternative modes of asexual reproduction could drive the evolution of multiple reproductive modes as seen in jellyfish polyps. Depending on environmental parameters, we find that evolution leads to a unique evolutionary stable strategy, where in general multiple reproductive modes coexist. As the extinction risk increases, this strategy shifts from a pure budding mode to a dual strategy, and finally to one characterized by allocation into all three modes. We identify relative fitness-dependent thresholds in extinction risk where these transitions can occur and discuss our predictions in light of observations on polyp reproduction in laboratory and natural systems.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 01 Mar 2018 06:00:00 GMT “Generation time in structured populations” http://amnat.org/an/newpapers/JulyEllner-A.html The DOI will be https://dx.doi.org/10.1086/697539 New analysis shows several measures of generation time in structured populations are unexpectedly equal in many cases Abstract Generation time is an intuitively simple concept, but for structured populations there are multiple definitions, and no general understanding of how they relate to each other. Fran&ccedil;ois Bienvenu and St&eacute;phane Legendre, in their note “A New Approach to the Generation Time in Matrix Population Models,” appearing in the June 2015 issue of The&nbsp;American Naturalist, introduced a new measure of generation time Ta, the average time between birth events in an ancestral lineage, and derived the remarkably simple formula Ta = &lambda; (vT w)/(vT F w) for any matrix model, where F is the fecundity matrix and v,w are reproductive value and stable population structure. Here I generalize their formula and interpretations of Ta to continuous or continuous-discrete population structure, and derive similar formulas for three other established generation time measures: average parent age across all births at one time (Ā), and mean parent age at birth events for a cohort (&mu;1) or generation (Tc). The new formulas reveal that these differently-defined measures are unexpectedly often identical in value, and clarify when they differ. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697539 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697539">Read&nbsp;the&nbsp;Article</a></b></i> </p> --> <p><b>New analysis shows several measures of generation time in structured populations are unexpectedly equal in many cases </b></p><h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">G</span>eneration time is an intuitively simple concept, but for structured populations there are multiple definitions, and no general understanding of how they relate to each other. Fran&ccedil;ois Bienvenu and St&eacute;phane Legendre, in their note &ldquo;A New Approach to the Generation Time in Matrix Population Models,&rdquo; appearing in the June 2015 issue of <i>The&nbsp;American Naturalist</i>, introduced a new measure of generation time <i>T<span style="bottom: -0.3em; font-size: 70%; position: relative;">a</span></i>, the average time between birth events in an ancestral lineage, and derived the remarkably simple formula <i>T<span style="bottom: -0.3em; font-size: 70%; position: relative;">a</span> = &lambda; (v<span style="top: -0.3em; font-size: 70%; position: relative;">T</span> w)/(v<span style="top: -0.3em; font-size: 70%; position: relative;">T</span> F w)</i> for any matrix model, where <i>F</i> is the fecundity matrix and <i>v,w</i> are reproductive value and stable population structure. Here I generalize their formula and interpretations of <i>T<span style="bottom: -0.3em; font-size: 70%; position: relative;">a</span></i> to continuous or continuous-discrete population structure, and derive similar formulas for three other established generation time measures: average parent age across all births at one time (<i>Ā</i>), and mean parent age at birth events for a cohort (<i>&mu;<span style="bottom: -0.3em; font-size: 70%; position: relative;">1</span></i>) or generation (<i>T<span style="bottom: -0.3em; font-size: 70%; position: relative;">c</span></i>). The new formulas reveal that these differently-defined measures are unexpectedly often identical in value, and clarify when they differ.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Thu, 01 Mar 2018 06:00:00 GMT “Models on the Runway: how do we make replicas of the world?” http://amnat.org/an/newpapers/JulyZuk-A.html Read the Article Abstract Aodels are universal in science, both as theoretical formulations of reality and as model systems, representatives of other organisms. A recent paper on how scientists view the world divides our work into the mind, the lab, and the field, and suggests that models must not be conflated with reality. But in practice, these distinctions are blurred. For example, are flour beetles a model system for other insects, when their natural habitat is the same as the way they live in the lab? In addition, models can become restrictive when they are viewed as archetypes, making us over-generalize about the world and ignoring meaningful variation. The study of sexual conflict in insects illustrates some of the pitfalls of relying on Drosophila as a model system for sexual selection. Microbes can be used as models for populations and communities, and are also essential parts of larger biological systems. Finally, some models are not meant to replicate the world, but are worlds unto themselves in which diverse possibilities can be directly observed. More forthcoming papers &raquo; <p><a href="https://dx.doi.org/10.1086/697508"><i>Read the Article</i></a></p> <!-- <p><a href="https://dx.doi.org/10.1086/697508">Read&nbsp;the&nbsp;Article</a> </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;">A</span>odels are universal in science, both as theoretical formulations of reality and as model systems, representatives of other organisms. A recent paper on how scientists view the world divides our work into the mind, the lab, and the field, and suggests that models must not be conflated with reality. But in practice, these distinctions are blurred. For example, are flour beetles a model system for other insects, when their natural habitat is the same as the way they live in the lab? In addition, models can become restrictive when they are viewed as archetypes, making us over-generalize about the world and ignoring meaningful variation. The study of sexual conflict in insects illustrates some of the pitfalls of relying on Drosophila as a model system for sexual selection. Microbes can be used as models for populations and communities, and are also essential parts of larger biological systems. Finally, some models are not meant to replicate the world, but are worlds unto themselves in which diverse possibilities can be directly observed. </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, 26 Feb 2018 06:00:00 GMT “The role of pleiotropy in the evolutionary maintenance of positive niche construction” http://amnat.org/an/newpapers/JulyChisholm-A.html The DOI will be https://dx.doi.org/10.1086/697471 Pleiotropy allows the evolutionary maintenance of positive niche construction in the face of free riders Abstract Organisms often modify their environments to their advantage through a process of niche construction. Environments that are improved through positive niche construction can be viewed as a public good. If free riders appear that do not contribute to the shared resource and therefore do not incur any associated costs, the constructed niche may become degraded resulting in a tragedy of the commons and the extinction of niche constructors. Niche construction can persist if free riders are excluded, for example if niche constructors monopolise the resource they produce to a sufficient degree. We suggest, however, that the problem of free riders remains because it is possible that non-niche constructors with an enhanced ability to access the resource appear and invade a population of constructors. Using mathematical models we show that positive niche construction can be maintained if it is inextricably linked to a mechanism that makes free riding costly, such as a trait that confers a benefit to only niche constructors. We discuss this finding in terms of genetic interactions and illustrate the principle with a two locus model. We conclude that positive niche construction can both evolve and be maintained when it has other beneficial effects via pleiotropy. This situation may apply generally to the evolutionary maintenance of cooperation. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697471 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697471">Read the Article</a></i></b> </p> --> <p><b>Pleiotropy allows the evolutionary maintenance of positive niche construction in the face of free riders </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;">O</span>rganisms often modify their environments to their advantage through a process of niche construction. Environments that are improved through positive niche construction can be viewed as a public good. If free riders appear that do not contribute to the shared resource and therefore do not incur any associated costs, the constructed niche may become degraded resulting in a tragedy of the commons and the extinction of niche constructors. Niche construction can persist if free riders are excluded, for example if niche constructors monopolise the resource they produce to a sufficient degree. We suggest, however, that the problem of free riders remains because it is possible that non-niche constructors with an enhanced ability to access the resource appear and invade a population of constructors. Using mathematical models we show that positive niche construction can be maintained if it is inextricably linked to a mechanism that makes free riding costly, such as a trait that confers a benefit to only niche constructors. We discuss this finding in terms of genetic interactions and illustrate the principle with a two locus model. We conclude that positive niche construction can both evolve and be maintained when it has other beneficial effects via pleiotropy. This situation may apply generally to the evolutionary maintenance of cooperation. </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, 21 Feb 2018 06:00:00 GMT “Life-history multistability caused by size-dependent mortality” http://amnat.org/an/newpapers/JulyTaborsky-A.html The DOI will be https://dx.doi.org/10.1086/697412 Life-history multistability is induced by negative & positive size-dependent mortality and by predator-poor communities Abstract Body size is a key determinant of mortality risk. In natural populations, a broad range of relation-ships are observed between body size and mortality, including positive and negative correlations. Previous evolutionary modelling has shown that negatively size-dependent mortality can result in life-history bistability, with early maturation at small size and late maturation at large size repre-senting alternative fitness optima. Here we present a general analysis of conditions under which such life-history bistabilities can occur, reporting the following findings. First, alternative fitness optima can be found for any arbitrarily chosen forms of mortality functions, including functions according to which mortality smoothly declines with size. Second, while bistabilities occur more readily under negatively size-dependent mortality, our analysis reveals that they can also emerge under positively size-dependent mortality, a feature missed in earlier work. Third, any sharp drop of mortality with size facilitates bistability. Fourth, if the mortality regime involves more than one such sharp drop, multistable life histories can occur, with alternative fitness optima straddling each of the drops. Paradoxically, our findings imply that, fifth, a species-poor predator communi-ty capable of creating a ‘rugged’ mortality regime is conducive to evolutionary multistability, which could act as a stepping stone toward prey life-history diversification, whereas a species-rich predator community that results in a smoothly varying mortality regime may prevent diversi-fication through this pathway. More forthcoming papers &raquo; <p><i>The DOI will be https://dx.doi.org/10.1086/697412 </i></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697412">Read&nbsp;the&nbsp;Article</a> </i></b></p> --> <p><b>Life-history multistability is induced by negative & positive size-dependent mortality and by predator-poor communities </b></p><h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">B</span>ody size is a key determinant of mortality risk. In natural populations, a broad range of relation-ships are observed between body size and mortality, including positive and negative correlations. Previous evolutionary modelling has shown that negatively size-dependent mortality can result in life-history bistability, with early maturation at small size and late maturation at large size repre-senting alternative fitness optima. Here we present a general analysis of conditions under which such life-history bistabilities can occur, reporting the following findings. First, alternative fitness optima can be found for any arbitrarily chosen forms of mortality functions, including functions according to which mortality smoothly declines with size. Second, while bistabilities occur more readily under negatively size-dependent mortality, our analysis reveals that they can also emerge under positively size-dependent mortality, a feature missed in earlier work. Third, any sharp drop of mortality with size facilitates bistability. Fourth, if the mortality regime involves more than one such sharp drop, multistable life histories can occur, with alternative fitness optima straddling each of the drops. Paradoxically, our findings imply that, fifth, a species-poor predator communi-ty capable of creating a &lsquo;rugged&rsquo; mortality regime is conducive to evolutionary multistability, which could act as a stepping stone toward prey life-history diversification, whereas a species-rich predator community that results in a smoothly varying mortality regime may prevent diversi-fication through this pathway.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Wed, 21 Feb 2018 06:00:00 GMT “Multivariate sexual selection on ejaculate traits under sperm competition” http://amnat.org/an/newpapers/JulyLymbery.html Read the Article We show patterns of multivariate selection on ejaculates, revealing potential for evolution under sperm competition In many species, the occurrence of female multiple mating (for internal fertilizers) or multi-individual spawning (for external fertilizers) leads to competition for fertilizations among ejaculates from rival males (sperm competition). Theory predicts that this should lead to sexual selection on ejaculate traits (e.g. sperm number, size, and speed) that provide males with a competitive advantage. However, it has traditionally been difficult to assess such patterns, for two reasons. First, competitive interactions often vary among different rival ejaculates, as well as between different ejaculates and females. This means estimates of a male’s competitive fertilization success are often relative to the specific rival ejaculates and females he is paired with, rather than reflecting a male’s overall fitness compared to the larger population. Second, it is typically challenging to identify which male’s sperm has been successful at fertilization. Therefore, competitive fertilization success is often estimated by offspring paternity, which can be confounded by post-fertilization factors (e.g., offspring viability). In the current study, the authors overcome these challenges using a novel experimental system: the broadcast-spawning mussel Mytilus galloprovincialis. The authors replicated large multi-male, multi-female spawning events, and measured the competitive fertilization success of ejaculates from individual males using fluorescent sperm dyes. By using eggs and ejaculates from many individuals in each reproductive event, the authors provided realistic estimates of male reproductive fitness compared to the population. By measuring multiple ejaculate traits of each male, the study characterized complex patterns of multivariate selection on combinations of sperm size, speed, and swimming path straightness. Importantly, this study provides evidence that there are overall patterns of sexual selection on multiple ejaculate traits, and therefore the potential for adaptive evolution under sperm competition. Abstract The widespread prevalence of sperm competition means that ejaculates face intense sexual selection. However, prior investigations of sexual selection on gametes have been hampered by two difficulties: (1) deriving estimates of relative fitness from sperm competition trials that are comparable across rival male and female genotypes; and (2) obtaining measures of competitive fertilization success that are not confounded by post-zygotic effects. Here, we exploit the experimental tractability of a broadcast spawning marine invertebrate to overcome these challenges and characterise multivariate sexual selection on sperm traits when multiple ejaculates compete. In multi-male spawning events, we tracked real-time success of sperm using fluorescent tags that are visible inside fertilized eggs. We then used multivariate selection analyses to identify patterns of linear and non-linear sexual selection on multiple sperm morphology and motility traits. Specifically, we found non-linear selection against divergent combinations of sperm length, velocity and swimming path linearity. These patterns likely reflect the way different swimming strategies allow sperm to locate and track eggs. Our results demonstrate that there are overall patterns of selection on ejaculates across a biologically realistic range of ejaculate-ejaculate and ejaculate-female interactions; therefore, there is the potential for adaptive evolution of ejaculate traits under sperm competition. More forthcoming papers &raquo; <p><a href="https://dx.doi.org/10.1086/697447"><strong><i>Read the Article</i></strong></a></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697447">Read the Article</a></i></b> </p> --> <p><b>We show patterns of multivariate selection on ejaculates, revealing potential for evolution under sperm competition </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 many species, the occurrence of female multiple mating (for internal fertilizers) or multi-individual spawning (for external fertilizers) leads to competition for fertilizations among ejaculates from rival males (sperm competition). Theory predicts that this should lead to sexual selection on ejaculate traits (e.g. sperm number, size, and speed) that provide males with a competitive advantage. However, it has traditionally been difficult to assess such patterns, for two reasons. First, competitive interactions often vary among different rival ejaculates, as well as between different ejaculates and females. This means estimates of a male’s competitive fertilization success are often relative to the specific rival ejaculates and females he is paired with, rather than reflecting a male’s overall fitness compared to the larger population. Second, it is typically challenging to identify which male’s sperm has been successful at fertilization. Therefore, competitive fertilization success is often estimated by offspring paternity, which can be confounded by post-fertilization factors (e.g., offspring viability). </p> <p>In the current study, the authors overcome these challenges using a novel experimental system: the broadcast-spawning mussel <i>Mytilus galloprovincialis</i>. The authors replicated large multi-male, multi-female spawning events, and measured the competitive fertilization success of ejaculates from individual males using fluorescent sperm dyes. By using eggs and ejaculates from many individuals in each reproductive event, the authors provided realistic estimates of male reproductive fitness compared to the population. By measuring multiple ejaculate traits of each male, the study characterized complex patterns of multivariate selection on combinations of sperm size, speed, and swimming path straightness. Importantly, this study provides evidence that there are overall patterns of sexual selection on multiple ejaculate traits, and therefore the potential for adaptive evolution under sperm competition. </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 widespread prevalence of sperm competition means that ejaculates face intense sexual selection. However, prior investigations of sexual selection on gametes have been hampered by two difficulties: (1) deriving estimates of relative fitness from sperm competition trials that are comparable across rival male and female genotypes; and (2) obtaining measures of competitive fertilization success that are not confounded by post-zygotic effects. Here, we exploit the experimental tractability of a broadcast spawning marine invertebrate to overcome these challenges and characterise multivariate sexual selection on sperm traits when multiple ejaculates compete. In multi-male spawning events, we tracked real-time success of sperm using fluorescent tags that are visible inside fertilized eggs. We then used multivariate selection analyses to identify patterns of linear and non-linear sexual selection on multiple sperm morphology and motility traits. Specifically, we found non-linear selection against divergent combinations of sperm length, velocity and swimming path linearity. These patterns likely reflect the way different swimming strategies allow sperm to locate and track eggs. Our results demonstrate that there are overall patterns of selection on ejaculates across a biologically realistic range of ejaculate-ejaculate and ejaculate-female interactions; therefore, there is the potential for adaptive evolution of ejaculate traits under sperm competition. </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, 21 Feb 2018 06:00:00 GMT “Collapse, tipping points and spatial demographic structure arising from the adopted migrant life history” http://amnat.org/an/newpapers/JulyRogers-A.html Read the Article Socially learned behavior may influence fish dynamics like collapse and tipping points Abstract The roles of dispersal and recruitment have long been a focal point in ecology and conservation. The adopted migrant hypothesis proposes a life history in which social learning transmits migratory knowledge between generations of iteroparous fish. Specifically, juveniles disperse from the parental spawning site, encounter and recruit to a local adult population, and learn migration routes between spawning and foraging habitats by following older, experienced fish. Although the adopted migrant life history may apply to many species of pelagic marine fishes, there is scant theoretical or empirical work on the consequent population dynamics. We developed and analyzed a mathematical model of this life history in which the recruitment of juveniles depends on the relative abundance of the local populations and recruitment overlap, which measures the ease with which juveniles are recruited by a non-parental population. We demonstrate that the adopted migrant life history can maintain spatial demographic structure among local populations, that it can also predispose local populations to collapse when a tipping point is crossed, and that recovery after collapse is impaired by reduced recruitment at small local population sizes. More forthcoming papers &raquo; <p><strong><a href="https://dx.doi.org/10.1086/697488">Read the Article</a></strong><!-- <p><b><i><a href="https://dx.doi.org/10.1086/697488">Read the Article</a></i></b> </p> --></p> <p><b>Socially learned behavior may influence fish dynamics like collapse and tipping points </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;">T</span>he roles of dispersal and recruitment have long been a focal point in ecology and conservation. The adopted migrant hypothesis proposes a life history in which social learning transmits migratory knowledge between generations of iteroparous fish. Specifically, juveniles disperse from the parental spawning site, encounter and recruit to a local adult population, and learn migration routes between spawning and foraging habitats by following older, experienced fish. Although the adopted migrant life history may apply to many species of pelagic marine fishes, there is scant theoretical or empirical work on the consequent population dynamics. We developed and analyzed a mathematical model of this life history in which the recruitment of juveniles depends on the relative abundance of the local populations and recruitment overlap, which measures the ease with which juveniles are recruited by a non-parental population. We demonstrate that the adopted migrant life history can maintain spatial demographic structure among local populations, that it can also predispose local populations to collapse when a tipping point is crossed, and that recovery after collapse is impaired by reduced recruitment at small local population sizes. </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, 21 Feb 2018 06:00:00 GMT “Eco-evolutionary dynamics of ecological stoichiometry in plankton communities” http://amnat.org/an/newpapers/JulyBranco.html Read the Article (open access) Nitrogen and phosphorus are two key nutrients that limit the growth of plants, macroalgae, and phytoplankton in many ecosystems across the globe. Nitrogen and phosphorus contents in phytoplankton cells of lakes and oceans are often quite variable, and largely appear to reflect nutrient availability in their environment. Yet, there are also some interesting patterns. In particular, the nitrogen-to-phosphorus ratio (N:P ratio) of freshwater phytoplankton is, on average, considerably higher than that of marine phytoplankton. Moreover, the N:P ratio of freshwater phytoplankton tends to be higher than the body N:P ratio of freshwater zooplankton, whereas the N:P ratio of marine phytoplankton tends to be lower than that of marine zooplankton. What might explain these intriguing large-scale patterns? Pedro Branco, Martijn Egas, Jim Elser, and Jef Huisman investigate this problem with a mathematical model that describes eco-evolutionary dynamics of the N:P ratio of phytoplankton in plankton communities. The model assumes that phytoplankton evolve their physiological investment in the uptake of nitrogen and phosphorus. Moreover, the model takes into account that many zooplankton species graze selectively, as they prefer to feed on phytoplankton with a N:P ratio matching their own nutritional demands. In the absence of zooplankton, the model predicts that phytoplankton optimize their investment in nitrogen and phosphorus uptake, such that their growth rate becomes co-limited by both nutrients. In the presence of zooplankton, however, evolution favors phytoplankton that are not only able to thrive at the prevailing nutrient conditions, but also suppress their grazing losses. In particular, selective grazing by nitrogen-demanding copepods favors evolution of phosphorus-rich phytoplankton (i.e., phytoplankton with low N:P ratios). Since copepods dominate the zooplankton communities of marine environments, they may contribute to the relatively low N:P ratios of phytoplankton in marine ecosystems. Conversely, selective grazing by phosphorus-demanding cladocerans like the water flea Daphnia favors evolution of nitrogen-rich phytoplankton (i.e., with high N:P ratios). Cladocerans are known to be particularly widespread in freshwater environments, and thus may contribute to the predominance of phytoplankton with relatively high N:P ratios in lakes. In total, these results show that selective grazing by zooplankton species can have a major impact on the N:P stoichiometry of phytoplankton in lakes and oceans. Abstract Nitrogen (N) and phosphorus (P) limit primary production in many aquatic ecosystems, with major implications for ecological interactions in plankton communities. Yet it remains unclear how evolution may affect the N:P stoichiometry of phytoplankton-zooplankton interactions. Here, we address this issue by analyzing an eco-evolutionary model of phytoplankton-zooplankton interactions with explicit nitrogen and phosphorus dynamics. In our model, investment of phytoplankton in nitrogen versus phosphorus uptake is an evolving trait, and zooplankton display selectivity for phytoplankton with N:P ratios matching their nutritional requirements. We use this model to explore implications of the contrasting N:P requirements of copepods versus cladocerans. The model predicts that selective zooplankton strongly affect the N:P ratio of phytoplankton, resulting in deviations from their optimum N:P ratio. Specifically, selective grazing by nitrogen-demanding copepods favors dominance of phytoplankton with low N:P ratios, whereas phosphorus-demanding cladocerans favor dominance of phytoplankton with high N:P ratios. Interestingly, selective grazing by nutritionally balanced zooplankton leads to the occurrence of alternative stable states (ASS), where phytoplankton may evolve either low, optimum or high N:P ratios depending on initial conditions. These results offer a new perspective on commonly observed differences in N:P stoichiometry between plankton of freshwater versus marine ecosystems, and indicate that selective grazing by zooplankton can have a major impact on the stoichiometric composition of phytoplankton. More forthcoming papers &raquo; <p><a href="https://www.journals.uchicago.edu/doi/full/10.1086/697472"><strong>Read the Article (open access)</strong></a></p> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">N</span>itrogen and phosphorus are two key nutrients that limit the growth of plants, macroalgae, and phytoplankton in many ecosystems across the globe. Nitrogen and phosphorus contents in phytoplankton cells of lakes and oceans are often quite variable, and largely appear to reflect nutrient availability in their environment. Yet, there are also some interesting patterns. In particular, the nitrogen-to-phosphorus ratio (N:P ratio) of freshwater phytoplankton is, on average, considerably higher than that of marine phytoplankton. Moreover, the N:P ratio of freshwater phytoplankton tends to be higher than the body N:P ratio of freshwater zooplankton, whereas the N:P ratio of marine phytoplankton tends to be lower than that of marine zooplankton. What might explain these intriguing large-scale patterns?</p> <p>Pedro Branco, Martijn Egas, Jim Elser, and Jef Huisman investigate this problem with a mathematical model that describes eco-evolutionary dynamics of the N:P ratio of phytoplankton in plankton communities. The model assumes that phytoplankton evolve their physiological investment in the uptake of nitrogen and phosphorus. Moreover, the model takes into account that many zooplankton species graze selectively, as they prefer to feed on phytoplankton with a N:P ratio matching their own nutritional demands.</p> <p>In the absence of zooplankton, the model predicts that phytoplankton optimize their investment in nitrogen and phosphorus uptake, such that their growth rate becomes co-limited by both nutrients. In the presence of zooplankton, however, evolution favors phytoplankton that are not only able to thrive at the prevailing nutrient conditions, but also suppress their grazing losses. In particular, selective grazing by nitrogen-demanding copepods favors evolution of phosphorus-rich phytoplankton (i.e., phytoplankton with low N:P ratios). Since copepods dominate the zooplankton communities of marine environments, they may contribute to the relatively low N:P ratios of phytoplankton in marine ecosystems. Conversely, selective grazing by phosphorus-demanding cladocerans like the water flea <i>Daphnia</i> favors evolution of nitrogen-rich phytoplankton (i.e., with high N:P ratios). Cladocerans are known to be particularly widespread in freshwater environments, and thus may contribute to the predominance of phytoplankton with relatively high N:P ratios in lakes. In total, these results show that selective grazing by zooplankton species can have a major impact on the N:P stoichiometry of phytoplankton in lakes and oceans.</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">N</span>itrogen (N) and phosphorus (P) limit primary production in many aquatic ecosystems, with major implications for ecological interactions in plankton communities. Yet it remains unclear how evolution may affect the N:P stoichiometry of phytoplankton-zooplankton interactions. Here, we address this issue by analyzing an eco-evolutionary model of phytoplankton-zooplankton interactions with explicit nitrogen and phosphorus dynamics. In our model, investment of phytoplankton in nitrogen versus phosphorus uptake is an evolving trait, and zooplankton display selectivity for phytoplankton with N:P ratios matching their nutritional requirements. We use this model to explore implications of the contrasting N:P requirements of copepods versus cladocerans. The model predicts that selective zooplankton strongly affect the N:P ratio of phytoplankton, resulting in deviations from their optimum N:P ratio. Specifically, selective grazing by nitrogen-demanding copepods favors dominance of phytoplankton with low N:P ratios, whereas phosphorus-demanding cladocerans favor dominance of phytoplankton with high N:P ratios. Interestingly, selective grazing by nutritionally balanced zooplankton leads to the occurrence of alternative stable states (ASS), where phytoplankton may evolve either low, optimum or high N:P ratios depending on initial conditions. These results offer a new perspective on commonly observed differences in N:P stoichiometry between plankton of freshwater versus marine ecosystems, and indicate that selective grazing by zooplankton can have a major impact on the stoichiometric composition of phytoplankton.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Tue, 20 Feb 2018 06:00:00 GMT “Adaptive divergence in a defense symbiosis driven from the top down” http://amnat.org/an/newpapers/JulyHeath.html Read the Article Adaptive-radiation studies have focused on resource competition, but enemies drive phenotypic diversity in gall midges Across North America in the backyards, gardens, roadsides, and reclaimed prairies exists an intricately knit ecological system that is generally unnoticed by those passing by. The gall midge, Asteromyia carbonifera (Diptera: Cecidomyiidae) forms fungal galls on the leaves of tall goldenrod (Solidago altissima). These are not typical plant galls but composed of fungus growing on plant leaves. The flies are little agriculturalists. The fungus grows around the fly larva and protects it from tiny parasitic wasps. The larva uses the fungus as its food source, but as it feeds it causes the fungus to grow into several different forms, which the authors call morphotypes. These Asteromyia gall midges are adaptively radiating into multiple genetically distinct lineages on the same host plant that vary in their gall forms, and it is the ecological selective drivers of this “adaptive radiation” that Heath et al. seek to uncover. The process of adaptive radiation, in which one ancestral lineage adaptively diversifies into multiple ecologically distinct species, may underlie much of the diversity of organisms on earth. Most studies of adaptive radiation in natural systems have focused on consumer-resource interactions and competition, but in this study, researchers show that enemies are a potent source of selection that helps to drive adaptive divergence among populations of gall midges on goldenrod plants. Food resources, in this system, are not limiting and there is little or no direct competition among the midges. What is limiting is refuge from attack by their parasitic wasp enemies. Thus, the midges have evolved distinctly different forms that are associated with protection from different wasp species. Even more interesting is that natural selection by these parasitic wasps on gall form is ongoing and still very strong, providing both a window into past processes of diversification and a divination of future adaptive diversification in this gall midge lineage. This process of adaptive diversification driven from the top-down due to enemies (rather than the bottom-up) may help to explain the enormous diversity of plant-feeding insects generally. Abstract Most studies of adaptive radiation in animals focus on resource competition as the primary driver of trait divergence. The roles of other ecological interactions in shaping divergent phenotypes during such radiations have received less attention. We evaluate natural enemies as primary agents of diversifying selection on the phenotypes of an actively diverging lineage of gall midges on tall goldenrod. In this system, the gall of the midge consists of a biotrophic fungal symbiont that develops on host-plant leaves and forms distinctly variable protective carapaces over midge larvae. Through field studies, we show that fungal gall morphology, which is induced by midges (i.e., it is an extended phenotype) is under directional and diversifying selection by parasitoid enemies. Overall, natural enemies disruptively select for either small or large galls, mainly along the axis of gall thickness. These results imply that predators are driving the evolution of phenotypic diversity in symbiotic defense traits in this system, and that divergence in defensive morphology may provide ecological opportunities that help to fuel the adaptive radiation of this genus of midges on goldenrods. This enemy-driven phenotypic divergence in a diversifying lineage illustrates the potential importance of consumer-resource and symbiotic species interactions in adaptive radiation. More forthcoming papers &raquo; <p><a href="https://dx.doi.org/10.1086/697446"><strong><i>Read the Article</i></strong></a></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697446">Read&nbsp;the&nbsp;Article</a> </i></b></p> --> <p><b>Adaptive-radiation studies have focused on resource competition, but enemies drive phenotypic diversity in gall midges </b></p><p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">A</span>cross North America in the backyards, gardens, roadsides, and reclaimed prairies exists an intricately knit ecological system that is generally unnoticed by those passing by. The gall midge, <i>Asteromyia carbonifera</i> (Diptera: Cecidomyiidae) forms fungal galls on the leaves of tall goldenrod (<i>Solidago altissima</i>). These are not typical plant galls but composed of fungus growing on plant leaves. The flies are little agriculturalists. The fungus grows around the fly larva and protects it from tiny parasitic wasps. The larva uses the fungus as its food source, but as it feeds it causes the fungus to grow into several different forms, which the authors call morphotypes. These <i>Asteromyia</i> gall midges are adaptively radiating into multiple genetically distinct lineages on the same host plant that vary in their gall forms, and it is the ecological selective drivers of this &ldquo;adaptive radiation&rdquo; that Heath et al. seek to uncover.</p> <p>The process of adaptive radiation, in which one ancestral lineage adaptively diversifies into multiple ecologically distinct species, may underlie much of the diversity of organisms on earth. Most studies of adaptive radiation in natural systems have focused on consumer-resource interactions and competition, but in this study, researchers show that enemies are a potent source of selection that helps to drive adaptive divergence among populations of gall midges on goldenrod plants. Food resources, in this system, are not limiting and there is little or no direct competition among the midges. What is limiting is refuge from attack by their parasitic wasp enemies. Thus, the midges have evolved distinctly different forms that are associated with protection from different wasp species. Even more interesting is that natural selection by these parasitic wasps on gall form is ongoing and still very strong, providing both a window into past processes of diversification and a divination of future adaptive diversification in this gall midge lineage. This process of adaptive diversification driven from the top-down due to enemies (rather than the bottom-up) may help to explain the enormous diversity of plant-feeding insects generally.</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">M</span>ost studies of adaptive radiation in animals focus on resource competition as the primary driver of trait divergence. The roles of other ecological interactions in shaping divergent phenotypes during such radiations have received less attention. We evaluate natural enemies as primary agents of diversifying selection on the phenotypes of an actively diverging lineage of gall midges on tall goldenrod. In this system, the gall of the midge consists of a biotrophic fungal symbiont that develops on host-plant leaves and forms distinctly variable protective carapaces over midge larvae. Through field studies, we show that fungal gall morphology, which is induced by midges (i.e., it is an extended phenotype) is under directional and diversifying selection by parasitoid enemies. Overall, natural enemies disruptively select for either small or large galls, mainly along the axis of gall thickness. These results imply that predators are driving the evolution of phenotypic diversity in symbiotic defense traits in this system, and that divergence in defensive morphology may provide ecological opportunities that help to fuel the adaptive radiation of this genus of midges on goldenrods. This enemy-driven phenotypic divergence in a diversifying lineage illustrates the potential importance of consumer-resource and symbiotic species interactions in adaptive radiation.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Tue, 20 Feb 2018 06:00:00 GMT “Branch thinning and the large-scale, self-similar structure of trees” http://amnat.org/an/newpapers/JulyHellstroem.html Read the Article Researchers present a model for wood-litter production that assumes a branch carrying capacity and allows analytical predictions The intricate branching patterns of trees have fascinated humans throughout recorded history. In this international study, researchers from Sweden and Australia propose that these patterns can be understood as the result of independent branches growing and reaching a maximum carrying capacity, after which subbranches are discarded from the tree. This elementary principle is used to develop a simple, yet powerful, analytical theory of tree growth that is used to make predictions on branching structure and the rate and size-distribution of discarded branches. Offering support for their new perspective, the predictions of the analytical model are compared with empirical measurements from two different sources and found to be in agreement. By allowing explicit calculations on wood-litter production, these results potentially enable more explicit modelling of woody tissues in ecosystems worldwide, with implications for the build-up of flammable fuel, nutrient cycling, and understanding of plant growth. The institutions participating in the study are Ume&aring; University, Sweden, M&auml;lardalen University, Sweden; the University of New South Wales, Australia; and Macquarie University, Australia. For further information about the study, please contact &Aring;ke Br&auml;nnstr&ouml;m (ake.brannstrom@umu.se, phone +46-72-5232554) or Daniel Falster (daniel.falster@unsw.edu.au, phone +61 2 9385 8431). Abstract Branch formation in trees has an inherent tendency towards exponential growth, but exponential growth in the number of branches cannot continue indefinitely. It has been suggested that trees balance this tendency towards expansion by also losing branches grown in previous growth cycles. Here, we present a model for branch formation and branch loss during ontogeny that builds on the phenomenological assumption of a branch carrying capacity. The model allows us to derive approximate analytical expressions for the number of tips on a branch, the distribution of growth modules within a branch, and the rate and size-distribution of tree wood-litter produced. Although limited availability of data makes empirical corroboration challenging, we show that our model can fit field observations of Red Maple, Acer rubrum, and note that the age distribution of discarded branches predicted by our model is qualitatively similar to an empirically observed distribution of dead and abscised branches of Balsam Poplar, Populus balsamifera. By showing how a simple phenomenological assumption—that the number of branches a tree can maintain is limited—leads directly to predictions on branching structure and the rate and size-distribution of branch loss, these results potentially enable more explicit modelling of woody tissues in ecosystems worldwide, with implications for the build-up of flammable fuel, nutrient cycling, and understanding of plant growth. More forthcoming papers &raquo; <p><strong><a href="https://dx.doi.org/10.1086/697429"><i>Read the Article</i></a></strong></p> <!-- <p><b><i><a href="https://dx.doi.org/10.1086/697429">Read&nbsp;the&nbsp;Article</a> </i></b> </p> --> <p><b>Researchers present a model for wood-litter production that assumes a branch carrying capacity and allows analytical predictions </b></p><p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">T</span>he intricate branching patterns of trees have fascinated humans throughout recorded history. In this international study, researchers from Sweden and Australia propose that these patterns can be understood as the result of independent branches growing and reaching a maximum carrying capacity, after which subbranches are discarded from the tree. This elementary principle is used to develop a simple, yet powerful, analytical theory of tree growth that is used to make predictions on branching structure and the rate and size-distribution of discarded branches. Offering support for their new perspective, the predictions of the analytical model are compared with empirical measurements from two different sources and found to be in agreement. By allowing explicit calculations on wood-litter production, these results potentially enable more explicit modelling of woody tissues in ecosystems worldwide, with implications for the build-up of flammable fuel, nutrient cycling, and understanding of plant growth.</p> <p>The institutions participating in the study are Ume&aring; University, Sweden, M&auml;lardalen University, Sweden; the University of New South Wales, Australia; and Macquarie University, Australia. For further information about the study, please contact &Aring;ke Br&auml;nnstr&ouml;m (ake.brannstrom@umu.se, phone +46-72-5232554) or Daniel Falster (daniel.falster@unsw.edu.au, phone +61 2 9385 8431).</p> <hr /> <h3>Abstract</h3> <p><span style="line-height: 25px; padding-top: 4px; padding-right: 2px; padding-left: 2px; font-family: Garamond; font-size: 40px; font-weight: bold; float: left;">B</span>ranch formation in trees has an inherent tendency towards exponential growth, but exponential growth in the number of branches cannot continue indefinitely. It has been suggested that trees balance this tendency towards expansion by also losing branches grown in previous growth cycles. Here, we present a model for branch formation and branch loss during ontogeny that builds on the phenomenological assumption of a branch carrying capacity. The model allows us to derive approximate analytical expressions for the number of tips on a branch, the distribution of growth modules within a branch, and the rate and size-distribution of tree wood-litter produced. Although limited availability of data makes empirical corroboration challenging, we show that our model can fit field observations of Red Maple, <i>Acer rubrum</i>, and note that the age distribution of discarded branches predicted by our model is qualitatively similar to an empirically observed distribution of dead and abscised branches of Balsam Poplar, <i>Populus balsamifera</i>. By showing how a simple phenomenological assumption&mdash;that the number of branches a tree can maintain is limited&mdash;leads directly to predictions on branching structure and the rate and size-distribution of branch loss, these results potentially enable more explicit modelling of woody tissues in ecosystems worldwide, with implications for the build-up of flammable fuel, nutrient cycling, and understanding of plant growth.</p> <div style="float: right;"><a href="http://www.amnat.org/an/newpapers.html"><span style="font-family: Georgia; font-size: large;"><i>More forthcoming papers</i> &raquo;</span></a></div> Tue, 20 Feb 2018 06:00:00 GMT 2018 Jasper Loftus-Hills Young Investigator Awards http://amnat.org/announcements/ANNwinYIA.html The American Society of Naturalist’s Young Investigator Award is in honor of Jasper Loftus-Hills, a young scientist who died tragically 3 years after receiving his PhD. This award goes to applicants who completed their PhD three years preceding the application deadline or are in their last year of a PhD program. Jeremy Fox, chair of the nominating committee, has written a blog about the experience: There were 77 applicants, believed to be the largest number ever. As he says, "The strength and diversity of the winners reflect the strength and diversity of the applicant pool, both in terms of their research areas and demographics." We are pleased to announce that this year’s recipients of the ASN Young Investiagor Awards are: &bull;&nbsp;&nbsp; &nbsp;Rachel Germain: http://germainlab.weebly.com/ &bull;&nbsp;&nbsp; &nbsp;Aaron Comeault: https://comeaultresearch.wordpress.com/ &bull;&nbsp;&nbsp; &nbsp;Rachael Bay: https://rachaelbay.wordpress.com/ &bull;&nbsp;&nbsp; &nbsp;Gijsbert Werner: http://www.gijsbertwerner.com/ We very much looking forward to their participation in the ASN YIA symposium at the annual meeting in Montpellier this summer. &nbsp; <p>The American Society of Naturalist&rsquo;s Young Investigator Award is in honor of Jasper Loftus-Hills, a young scientist who died tragically 3 years after receiving his PhD. This award goes to applicants who completed their PhD three years preceding the application deadline or are in their last year of a PhD program.</p> <p>Jeremy Fox, chair of the nominating committee, has <a href="https://dynamicecology.wordpress.com/2018/02/19/the-winners-of-the-asn-jasper-loftus-hills-young-investigator-awards-have-been-announced/">written a blog</a> about the experience: There were 77 applicants, believed to be the largest number ever. As he says, &quot;The strength and diversity of the winners reflect the strength and diversity of the applicant pool, both in terms of their research areas and demographics.&quot;</p> <p>We are pleased to announce that this year&rsquo;s recipients of the ASN Young Investiagor Awards are:</p> <p>&bull;&nbsp;&nbsp; &nbsp;Rachel Germain: <a href="http://germainlab.weebly.com/">http://germainlab.weebly.com/</a><br /> &bull;&nbsp;&nbsp; &nbsp;Aaron Comeault: <a href="https://comeaultresearch.wordpress.com/">https://comeaultresearch.wordpress.com/</a><br /> &bull;&nbsp;&nbsp; &nbsp;Rachael Bay:<a href="https://rachaelbay.wordpress.com/"> https://rachaelbay.wordpress.com/</a><br /> &bull;&nbsp;&nbsp; &nbsp;Gijsbert Werner: <a href="http://www.gijsbertwerner.com/">http://www.gijsbertwerner.com/</a></p> <p>We very much looking forward to their participation in the ASN YIA symposium at the annual meeting in Montpellier this summer.</p> <p>&nbsp;</p> Mon, 19 Feb 2018 06:00:00 GMT