Using Calls and Genes to Understand the Taxonomy of Pacific Chorus Frogs
By: Chariya Eligia Cotas, Samantha Sandoval
Department: Biology
Faculty Advisors: Dr. Alejandro Vélez Meléndez, Dr. Colleen Ingram
The rapid advancement of molecular techniques has led to a general overlook of phenotypic and behavioral variation in studies of taxonomy and systematics. Reliance on only one type of data, however, may be problematic. For instance, molecular studies of Pacific chorus frogs display conflicting conclusions on the taxonomic status of this species complex, with some authors claiming Hyliola regilla as a singular species, while others claim it is divided into three: H. regilla, H. sierra, and H. hypochondriaca. In frogs, the mating call produced by males is an important behavioral trait for species delimitation because it is used by females to recognize and select mates from their own species. Our project focuses on analyzing acoustical and genetic data from nine populations of Pacific chorus frogs within the range of H. sierra and H. hypochondriaca to determine which of the conflicting hypotheses is better supported. Our analysis of mitochondrial DNA reveals two monophyletic groups, one comprised of populations in northern California and the other comprised of southern California populations. Importantly, our acoustical analyses show strong differences in the mating call between, but not within, monophyletic groups. Together, results from our genetic and acoustical analyses are consistent with the existence of more than one species. Because frog mating calls often serve as pre-mating isolating mechanisms, differences in call properties may fuel, or maintain, evolutionary divergence among populations of Pacific chorus frogs.