Studies of reproductive behavior can help reveal patterns of sexual isolation and clarify species boundaries. In northern Georgia, Blue Ridge Two-lined Salamanders (Eurycea cf. wilderae) and Brown-backed Salamanders (Eurycea aquatica) are syntopic but do not hybridize. Within this region, Eurycea cf. wilderae males exhibit a reproductive polymorphism, with “searching” males that appear adapted for terrestrial courtship and “guarding” males that appear adapted for aquatic mate-guarding. To understand better how inter- and intraspecific reproductive variation might contribute to sexual isolation between E. aquatica and E. cf. wilderae, we staged T-maze trials and courtship trials, and we conducted preliminary analyses of sex hormones from noninvasive fecal samples. We found that males of both species preferred conspecific female scents to heterospecific female scents, but that searching male E. cf. wilderae were not better than guarding males at locating a conspecific female scent. We also found evidence for strong propensity asymmetry, with male and female E. cf. wilderae much more likely than E. aquatica to engage in courtship behaviors in the lab. Still, we observed some instances of heterospecific courtship through spermatophore transfer. Finally, we found evidence for higher fecal testosterone concentrations in males than females and higher concentrations in guarding male than in searching male E. cf. wilderae. Together, our data provide further insight into the reproductive ecologies of and the nature of reproductive isolation between Eurycea aquatica and Eurycea cf. wilderae.

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