Symposium on Agroacoustics: What Do Fruit Fly Songs Mean?
Many flies, including tephritid fruit flies, produce acoustic courtship signals; however, the message these signals transmit is not always clear. Courtship in general is often considered to be a mechanism for species recognition and the prevention of hybridization. Such a proposition suffers from the rarity of sympatric character displacement, the complexity of displays in some species with few close sympatric relatives and the simplicity of courtships in other species with many close sympatric relatives. The theory that displays are sexually selected advertisements of male qualities that females prefer in a mate faces none of these objections. The acoustic signals of male Caribbean fruit flies can be examined from a sexual selection perspective. Females appear to prefer large mates. Both the "calling" and "precopulatory" songs have characteristics that are correlated to male size and females are more likely to react to songs typical of large males. Studies of fruit fly acoustics may serve agriculture either in the development of attractants or by providing criteria to monitor the sexual competitiveness of insects reared for sterile release programs.