Sexual divergence within desmognathine salamanders (Plethodontidae)

Paul Verrell and Kimberley Herring
Zoology Department
Washington State University
Pullman, WA 99164-4236

Recent systematic revision of salamanders in the Desmognathus ochrophaeus complex of the southern Appalachian Mountains recognizes three new species, diagnosed using allozyme data. We tested for interspecific sexual incompatibility in the laboratory among populations of D. ocoee (southwest NC), D. carolinensis (west-central NC) and D.orestes (southwest VA). Successful mating was significantly less likely in inter- than in intra-specific sexual encounters for three pairwise crosses staged among the taxa. Detailed ethological analyses of the contents of intraspecific courtship revealed significant quantitative differences among species, especially in male displays used to 'persuade' females to mate. We suggest that interspecific mating may be infrequent because males fail to persuade heterospecific females to become fully responsive. Our data indicate that, in addition to being genetically independent, these three species are sexually incompatible and behaviorally divergent.