Behavioral observations of sexual isolation among allopatric populations of the mountain dusky salamander, Desmognathus ochrophaeus

Abstract

Fewer heterotypic encounters than homotypic encounters resulted in insemination of females. Indices of the strength of sexual isolation based on insemination data ranged from 0.26 (lowest) to 0.82 (highest), indicating that mechanisms that confer sexual isolation may evolve during allopatric differentiation, here studied in S Appalachian populations. Heterotypic encounters that progressed as far as the stage of courtship during which the male stimulates the female to mate did so at the same time as homotypic encounters, although the number of the former reaching this stage was lower. The time interval from courtship initiation to insemination was longer in heterotypic encounters. In some crosses, males did not attempt to initiate heterotypic encounters, indicating that this sex is responsible for sexual isolation in these instances. -from Authors