Evolution of Chemical Signals as a Premating Isolating Mechanism in a Complex of Terrestrial Salamanders

Abstract

Salamanders in the family Plethodontidae are an important component of forest ecosystems in North America (Burton and Likens, 1975). Species of Plethodon are completely terrestrial amphibians; all aspects of their life history, including courtship and egg deposition, occur on land. Both sexes are believed to be solitary, spending most of their time in cool, moist retreat sites and are active on the surface only when atmospheric conditions are suitably cool and moist (Feder, 1983). My research on chemical communication with pairs of closely related species within this genus has shown that salamanders can identify sex and species through odors. Because Plethodon species are nocturnal, and because sexes and sympatric species are nearly indistinguishable morphologically, it is likely that chemoreception is the most important sensory mode. I suggest that chemical communication functions as a premating isolating mechanism between sympatrically occurring sibling species.