Tests for sexual isolation among sympatric salamanders of the genus Desmognathus

Populations of the dusky salamanders Desmognathus ochrophaeus (Cope), D. imitator (Dunn) and D. santeetlah (Tilley) (Amphibia: Caudata: Plethodontidae) are sympatric at the locality of Indian Gap in the Great Smoky Mountains of eastern North America.In order to determine the extent of sexual isolation ( = sexual behavioural incompatibility) among these species, individuals of both sexes of all three species were collected and subjected to both intra-and interspecific courtship trials in the laboratory.Sexual isolation was very strong between D. ochrophaeus and D. imitator.Sexual isolation was complete between D. ochrophaeus and D. santeetlah, and between D. santeetlah and D. imitator.Mechanisms which prevent interspecific mating are highly developed in these salamanders, and likely are responsible (at least in part) for the apparent absence of hybridization and introgression among these species.