Meeting Abstract
Males of many species of animals use bright color patches as visual signals. If sexually dimorphic, these patches are typically found in males that use them to attract mates or to ward off rivals. Color patches used in a mating context may contain costly pigments such as carotenoids that allow them to function as indicators of male quality. Other types of color patches may function as aposematic visual signals to ward off predators, and these may contain less costly pigments that can be synthesized by the animal rather than having to be obtained through the diet like carotenoids. We used acidified pyridine extraction followed by nonpolar solvent transfer and spectrophotometry to determine the presence or absence of carotenoids in color patches of two species of anuran amphibians. Males of both Green Frogs (Lithobates clamitans) and Cope’s Gray Treefrogs (Hyla chrysoscelis) have pigmented throat patches, although only Green Frogs have obvious yellow coloration in the throat patch. We did not detect the presence of carotenoids in throat patches of males of either species, although carotenoids were detected in the dorsal skin of Green Frogs. The male Green Frogs that were available for analysis had relatively weakly pigmented throat patches, possibly below our detection ability for carotenoids. Both sexes of Cope’s Gray Treefrogs possess yellow leg patches that presumably are displayed in an aposematic context. We isolated yellow pigment from these leg patches in the extraction procedure. However, the pigment did not subsequently transfer to the nonpolar solvent, indicating it is not a carotenoid. In future work, we will determine whether other pigments such as melanins or pteridines may be responsible for the yellow color of these leg patches.
