BRC-BIO: Disentangling drivers of color morph responses to climate change in a model salamander species

University Of Dayton, Dayton OH

Investigators

Abstract

Animal coloration represents an easily identifiable biological trait that can be traced over space and time, making it an ideal characteristic to monitor with climate change pressures. Within a single species, multiple color variants (morphs) can exist, and these individuals with distinct colors typically differ in other aspects of their ecology or behavior, including thermal biology. The Eastern Red-backed Salamander is one of the most abundant terrestrial vertebrates in the northeastern United States and possesses two common color morphs (striped and unstriped). Populations of this species vary greatly in the frequency of these two color morphs across its widespread range. The morphs are known to vary in multiple traits, such as diet and body size, but we currently lack an understanding of how climate change is influencing trait variation and color morph frequency across the species range. The aim of this work is to examine whether the two morphs of the Eastern Red-backed Salamander differ in temperature-dependent traits, including thermal physiology, body size, and behavior, under different climate conditions. This research will provide pertinent information on not only how color morphs are maintained, but also how the existence of multiple morphs may support species resilience in the face of rapid environmental change. To accomplish the goals of this research, undergraduate students will play a key role in collecting data and will gain skills in bioinformatics, animal collection in the field, working with specimens in natural history collections, and lab-based behavioral and physiology studies. Amphibian coloration will be a centralized feature in community outreach with local city libraries and metroparks. Animals with color polymorphisms provide a unique system for studying species responses to climate change. Intraspecific color morphs contain discrete color pattern variations that can be traced over space and time. Further, morphs are comprised of co-adapted sets of traits, and differ in several elements of their biology, including aspects of their thermal ecology. The aim of this project is to examine thermally-related correlated traits of a color polymorphic species across environmental gradients to assess how distinct morphs respond to rapid climate change pressures. The focal species for this project is the Eastern Red-backed Salamander, Plethodon cinereus, which has a widespread geographic distribution across northeastern North America and is color polymorphic throughout its range. Past research on the polymorphism in P. cinereus demonstrates that two color morphs (striped and unstriped) occupy distinct ecological niches, but their co-adapted trait sets are variable spatially and temporally. Missing is a mechanistic understanding of the adaptive differences between morphs and how changing climatic conditions contribute to color morph frequency variation. The specific aims for this work are to: 1) examine differences in co-adapted morphological trait change over space and time in relation to climate fluctuations; 2) investigate the links between color morph and physiology under various temperature treatments; and 3) test for variation in color morph behavioral responses to rapidly increasing temperatures. This work not only expands upon previous research on the color polymorphism in P. cinereus but also integrates novel physiological and behavioral studies with support from established collaborators and undergraduate students. 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.