NSF Postdoctoral Fellowship in Biology FY 2020: Linking Micro- and Macroevolutionary Approaches to Understand the Paradox of Polymorphism in Plethodon

Hantak, Maggie, Gainesville FL

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2020, Research Using Biological Collections. The fellowship supports research and training of the fellow that will utilize biological collections in innovative ways. Woodland salamanders can have different color patterns (color polymorphisms) in the same populations. Color types (morphs) are not simply different colors, they also vary in behavior, body form, and ecology. Long-term persistence of multiple color morphs remains an evolutionary puzzle, as previous studies have suggested that selection should either lead to one color morph dominating or formation of separate differently colored species. The aim of this project is to examine the evolution of a striped/unstriped color polymorphism in woodland salamanders using data collected from several U.S. natural history museums. Archived tissue samples will be used to understand the evolutionary relationships of salamanders. The fellow will also take digital images of polymorphic salamanders using high-throughput approaches, which will subsequently be identified as striped or unstriped by community scientists, and through machine learning approaches. The fellowship will facilitate mentorship training and foster opportunities for undergraduates who are interested in research. The fellow will collaborate with local high schools and participate in outreach events to share the results of this research. Within the genus Plethodon, a striped/unstriped color pattern polymorphism has either independently originated 10 times or has been lost in 14 species that are fixed for a single morph. Extensive research on one polymorphic species (P. cinereus) suggests that the color morphs are associated with distinct sets of morphological and ecological traits. Thus, this system presents an ideal opportunity to test: 1) the origin and evolution of the polymorphism; 2) climatic niche overlap between morphs and species with divergent phenotypes; 3) whether there are non-random patterns of co-adapted trait complexes that evolved in Plethodon; and 4) how quickly those traits respond to fluctuating environmental conditions, including rapid environmental changes in the present. Using phylogenetic comparative approaches, the fellow will assess the relationship between intra-specific patterns and macroevolutionary outcomes within Plethodon, which represents a critical next step in understanding the evolution of this widespread polymorphism. This work is enabled by an interdisciplinary approach to use biological collections, while leveraging machine learning, and citizen scientist efforts. The end results will provide essential new knowledge about the evolution of color morphs and the relationship between polymorphism and diversity. Citizen science, mentoring of undergraduate students and outreach will broaden the impact of the project. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.