Insemination Temporarily Inhibits Sexual Responsiveness in Female Salamanders (Desmognathus Ochrophaeus)

Abstract

AbstractAfter successful courtship and mating in the mountain dusky salamander (Desmognathus ochrophaeus), sperm masses remained externally visible in the cloacae of females for as long as 24 h (Experiment 1). When mated females were exposed to males for a second time, they appeared to be attractive and were subjected to courtship, but they seldom became inseminated (Experiment 2). Courtship and mating appear to result in a temporary inhibition of female sexual responsiveness. Females whose sperm masses were removed on the morning following successful insemination were more likely to become inseminated during a second encounter than were females whose masses were left in situ (Experiment 3). This suggests that it is the presence of a sperm mass, not simply exposure to stimulation produced by males during courtship, that inhibits female sexual responsiveness. In Experiment 4, a small styrofoam ball was placed into the cloacae of females with no recent courtship experience. When paired with males, females bearing "surrogate" sperm masses exhibited lowered courtship frequencies similar to those of recently-mated females, suggesting that physical stimulation of the female cloaca is sufficient to inhibit female sexual responsiveness. Subtle manipulation of female sexual responsiveness by males probably does not occur in Desmognathus ochrophaeus.