Male mating experience and competitive courtship success in Drosophila melanogaster

Abstract

MULTIPLE copulations by Drosophila melanogaster males reduce their fertility¹, even though these males will continue to court and mate after four or five successive matings. This sterility involves depletion of the accessory glands and not of sperm supply² and is only temporary, for when these males are mated 2 or 3 h after the onset of sterility, they once again transfer sperm. A female Drosophila would maximise her reproductive fitness by mating with a male which transfers the most sperm; however, virgin females will copulate with temporarily sterile males when placed in a single-pair situation. Although female Drosophila are capable of discriminating mates on the basis of genotype differences³, it is not known whether they will selectively copulate with fertile males in competition with temporarily sterile males of the same strain. In the experiments reported here, we have examined the relative mating success of experienced males with temporarily reduced fertility and virgin males from the Canton-S strain of D. melanogaster. The data show that when a virgin female is placed with a virgin and an experienced male, she tends to mate with the virgin male. Examination of some possible factors for increased virgin male success, such as time until initiation of courtship, amount of time spent courting, and overall mating speed, showed that for the courtship parameters measured, virgin and experienced males are equal.