Species Discrimination between Hybridizing and Non-Hybridizing Terrestrial Salamanders

Abstract

Plethodon jordani and P. teyahalee are terrestrial salamanders sympatric at various localities within the Great Smoky Mountains. These two species hybridize in some localities but not in others. Species from hybridizing and non-hybridizing localities were tested in an olfactometer for the ability to distinguish between odors of opposite sex conspecifics and heterospecifics. Male P. jordani and P. teyahalee from the non-hybridizing locality preferred conspecific odors over heterospecific odors, but only male P. teyahalee from the hybridizing locality showed a preference, preferring conspecific odors. Only female P. teyahalee from the non-hybridizing locality showed a significant preference between male odors, preferring heterospecifics. Previous tests had shown that female odor preferences are influenced by their breeding status, and blank tests (no salamander odor vs salamander odor) can be used to determine whether females are attracted to or repelled by male odors. Females of both species from the non-hybridizing locality preferred the blank over conspecific male odors. These results suggest that chemoreception may function as a reproductive isolating mechanism at the non-hybridizing locality. However, at the hybridizing locality only male P. teyahalee appear to be able to discriminate between species odors, suggesting that the lack of an ability to discriminate between species by means of chemical cues may account for the lack of reproductive isolation at this locality.