Description of sexual behaviors ofDrosophila rajasekari : The role of (Z,Z)-7,11-heptacosadiene.

The courtship behaviors and cuticular hydrocarbons ofDrosophila rajasekari are described. Sexually mature males orient, tap, follow, vibrate their abdomens, extend and vibrate their wings, and attempt copulation during courtship. They perform these behaviors in response to immature and matureD. rajasekari of both sexes, and their courtship activities are facilitated by light. The predominant cuticular hydrocarbon found in both sexes is (Z,Z)-7,11-heptacosadiene (HCD), a compound known to be used as a courtship-stimulating sex pheromone by another fruit fly,D. melanogaster. Therefore, it is not surprising thatD. melanogaster males actively court both males and females from theD. rajasekari stock. However, HCD is apparently not used byD. rajasekari as a courtship-stimulating pheromone since matureD. rajasekari males do not courtD. melanogaster females, which produce large quantities of HCD.