Abstract

Color polymorphism is common in many species, and color morph frequency is affected by differences in ecological and evolutionary pressures on each color morph. Plethodon cinereus, the Red-Backed Salamander, has two common color morphs, striped and unstriped, that vary in frequency among populations. Plethodon cinereus color morphs differ in their escape behaviors when exposed to predators and in their tail autotomization rates; this may result from differential predation. Although these previous studies indirectly implicated differential predation, we directly tested the hypothesis that color morphs differed in survival and whether one morph was depredated at a higher rate. We determined the survival of each color morph over 3 yr with the use of mark–recapture data. We first compared frequencies of color morphs in juveniles and adults, and then estimated whether color morphs had different survival rates with the statistical program MARK. We found that frequency of striped salamanders was lower in adults than in juveniles, implying that fewer striped individuals survived to adulthood. In addition, color and age best explained survival probability during spring, but not fall, seasons. To test the effects of color morph on predation experimentally, we used clay models to determine the effects of avian and mammalian predators. We found more attacks on striped clay models by avian predators compared to the unstriped models, but we found no difference in attacks by mammals. Overall, these results support the hypothesis that there is differential predation in P. cinereus, with more predation on, and lower survival in, the striped morph.

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