Inbreeding depression and male-mating behavior in Drosophila melanogaster.

There have been relatively few studies designed to investigate the effects of inbreeding on behavioral traits. To study this phenomenon, five experimental lines of Drosophila melanogaster made isogenic for chromosome 2 were evaluated for their male-mating ability and, subsequently, male courtship behavior. All lines showed significant reductions in overall mating ability, and males from all of these lines displayed impaired mating behavior, with two lines displaying particularly aberrant courtship patterns. Line 16 displayed an inability to successfully initiate copulation following successful courtship, while line 17 displayed significant reduction in locomotor activity, resulting in virtually no successful courtship or copulatory activity. The implications of these findings for competitive mating ability in wild Drosophila populations are presented. Further, the importance of mating success as a fitness component in the management of potentially highly inbred populations of endangered species is discussed.