Playing Matchmaker: Sexual Isolation Between Sympatric Eurycea in Northern Georgia

In northern Georgia, Brown-backed Salamanders (Eurycea aquatica) and Blue Ridge Two-Lined Salamanders (Eurycea cf. wilderae) are sympatric and do not appear to hybridize. In these same populations, male Eurycea cf. wilderae exhibit a reproductive polymorphism, with “searching” males hypothesized to have an advantage in locating potential mates. To evaluate sexual isolation between these two species, we collected animals from Johns Mountain, Georgia and maintained them in the laboratory for behavioral trials. We used GoPro cameras to film inter- and intraspecific courtship trials and scored trials for the successful transfer of a spermatophore. We also conducted two types of t-maze trials. First, we tested whether males of each species preferred of a conspecific female vs. a heterospecific female. Second, we tested whether searching or guarding male E. cf. wilderae were more successful at locating a conspecific female scent. Here, we present preliminary results from these experiments and comment upon the implications for understanding the evolution of reproductive behaviors and sexual isolation in Eurycea