A membership society whose goal is to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance the conceptual unification of the biological sciences.
The recipient of the ASN Outstanding Student Poster Award at the ASN’s conference at Evolution, June 2025, is Sarah K. Swiston (Washington University in St. Louis) for the poster, “The ellipse model for phylogenetic inference of range evolution.” Congratulations!
Poster Abstract: Phylogenetic methods of historical biogeography model the evolution of species ranges in order to reconstruct how species may have moved and split through time. To characterize species ranges, existing approaches typically discretize space, or model a set of points. Here, we present EMPIRE, an ellipse-based, continuous-space model of range evolution that incorporates range size, location, and orientation, as well as different range inheritance scenarios at speciation. Under a Bayesian likelihood-based framework, we use the model to infer rate parameters, ancestral ranges, and discrete cladogenetic event types from data. We validate the model using simulations, and apply EMPIRE to investigate the evolution of the Australian Sphenomorphine skinks.
Honorable mention for the ASN Outstanding Student Poster Award, June 2025, goes to Louisa Bartkovich (University of Toronto) for the poster “Decoupling the effects of warming and canopy cover on reproductive phenology in a spring ephemeral.” Congratulations!
Poster Abstract: The seasonal timing of resource availability and biotic interactions strongly influences life history transitions in plant species, particularly for species dependent on brief periods of optimal growing conditions. In temperate deciduous forests, spring ephemeral wildflowers may display heightened vulnerability to environmental change, as their window for annual growth and reproduction is determined by the timing of (1) snowmelt and (2) canopy closure. However, few studies have isolated the independent effects of temperature-driven shifts in these two key seasonal events on spring ephemeral species. To address this gap, we investigated how shifts in spring light availability influenced the flowering time of the spring ephemeral Erythronium americanum. We also investigated how shifting light regimes alter selection on flowering time in this species. Populations of E. americanum emerge in early spring and flower for approximately eight days before the canopy closes. In our study, we simulated early canopy closure on natural populations with shade structures at the University of Toronto's Koffler Scientific Reserve (KSR) in Newmarket, Ontario. We recorded the timing of life history transitions and measured aboveground fitness proxies for roughly 1700 plants to estimate selection on flowering time. We expect that early canopy closure will result in fitness consequences by limiting individual carbon budgets and seed production. Understanding how understory plant species may respond to changing environmental conditions can help inform conservation strategies and management of biodiversity in temperate forests under global change.
Honorable mention for the ASN Outstanding Student Poster Award, June 2025, goes to Robert Ernst (Georgia Institute of Technology) for the poster “Citizen science data reveal how Brown-headed Cowbird host use changes across its geographic range.” Congratulations!
Poster Abstract: Avian nest parasitism occurs when a female bird lays her eggs in another bird’s nest to use that bird as a “foster parent” and raise her chicks for her. The Brown-headed Cowbird (Molothrus ater) is the predominant avian nest parasite in North America, and is known to have strong evolutionary and ecological effects on its hosts. Yet little is known about the geographic distribution of cowbird hosts across North America. To solve this problem, we extracted 16,000+ observations of Brown-headed Cowbird hosts from across the continent from the eBird database. Using this data, we quantified the most commonly parasitized hosts across the entire range, documenting how cowbirds use different hosts in different regions. We also explored how Brown-headed Cowbird host use changes throughout the breeding season. This work explores how large citizen science databases can be used to answer questions about species interactions over large areas that would be difficult or impossible to do as independent research studies.
Limnologist and Past President Ruth Patrick in a stream
The ASN Outstanding Student Poster Award was established in 2012 to recognize a student who has presented an outstanding poster at the annual meeting or at the stand-alone meeting of the American Society of Naturalists.
It was established in memory of Ruth Patrick, a renowned limnologist, past president of the American Society of Naturalists (1975), and Lifetime Honorary Member of the ASN.
