Meeting Abstract
An open question in color polymorphic species is why morph frequencies are variable among populations. Little work has been done to examine geographic patterns in polymorphisms, with most studies focusing on a single population. The Eastern Red-backed Salamander, Plethodon cinereus, has a widespread distribution in the northeastern United States and southeastern Canada, and is color polymorphic throughout portions of its range. Two color morphs are common: a ‘striped’ morph that has a red stripe overlaid on a black dorsum, and an ‘unstriped’ morph that is completely black. Previous studies on single populations of P. cinereus have suggested that the two morphs differ in elements of their ecology, behavior, and physiology, yet a mechanistic understanding of the ecological differences between the morphs, and the evolutionary processes that maintain the polymorphism, remains unclear. In northern Ohio, many populations with varying morph frequencies of P. cinereus exist. Here, we established six sites that varied in morph frequency, including two populations that are monomorphic for unstriped (95-100% unstriped), two that are polymorphic, and two that are striped. At each site 100 porcelain tiles (1 ft2) were placed in a grid. These cover objects provided repeatable, standardized, high quality territories for the salamanders. We gathered ecological data from each site to determine if morphs were divergent in dietary composition and whether they assortatively mate by color. Our results demonstrate that while there was spatial and temporal variation in diet, morphs did not differ in dietary prey composition or volume. Conversely, we found that color morphs assortatively mated by color in two of three polymorphic populations. Overall, this study provides essential data for understanding variation in ecological interactions between the morphs over space and time.
