Pheromonal control of mating patterns in Drosophila melanogaster.

Abstract

Multiple-choice mating tests comparing the mating propensity among and within inbred lines were performed forDrosophila melanogaster. Courtship activity, time to copulation, and assortative mating were all directly correlated with the degree of inbreeding. By the eighth generation of sib mating, there was a 76% incidence of negative assortative mating in multiple-choice tests and a marked reduction of courtship behavior among sibs. Furthermore, absence of sperm in the females of nonreproductive pairs indicated that much of the attrition of inbred lines was due to failure of sibs to mate. When individuals of “sterile cultures” were allowed an opportunity to outcross, most were fertile and exhibited normal mating and courtship activity. Olfactometer tests with either unrelated flies or collected pheromone samples as source material indicated that airborne chemosignals are required for initiation of courtship inD. melanogaster. Visual and audio cues were found to be noncritical inD. melanogaster courtship and mating. Intraspecific qualitative pheromone variation, at one or a few loci, is thought to be functioning as the control mechanism in selective mating.