Inhibition of male sexual behavior after interacting with a mated female Running head: Male sexual inhibition: behavioral hypotheses

A male’s reproductive success is generally highly dependent on his mating success. Nevertheless, there may be times during a male’s life when his sexual responsiveness ebbs. In the parasitic wasp Spalangia endius, after a male mates, he shows a temporary decrease in his sexual responsiveness to even virgin females. We examined behavioral mechanisms for the decrease. 1) Decreased sexual responsiveness is not simply a result of habituation to attractive features of females during mating. If it was, males that had courted dead virgin females for substantially longer than during a normal mating should have been detectably less sexually responsiveness than males that had not courted, but they were not. 2) Decreased sexual responsiveness also is not a learned aversion to females that results from female brush-off, in which females use their hind legs to dislodge mounted males after copulation. Sexual responsiveness was reduced by mating regardless of brush-off. 3) Male S. endius are known to avoid mounting mated females, and surprisingly, the responsiveness of a virgin male decreased even when he had briefly approached and then retreated from an already mated female, i.e., even in the absence of mounting or copulation. This suggests that the aversive stimulus that causes males to retreat from mated females is also involved in the male’s subsequent sexual inhibition.