Biosystematics of theCotesia flavipescomplex (Hymenoptera: Braconidae): interspecific hybridization, sex pheromone and mating behaviour studies

Mating behaviour, sex pheromone attraction and reciprocal breeding ofCotesia flavipesCameron (Hymenoptera: Braconidae),C. sesamiae(Cameron) andC. chilonis(Matsumura) were studied. These three putative species comprise theCotesia flavipescomplex. Wing fanning and antennal vibration were the initial courtship signals from the males. Antennal stroking by the male was also an important contact signal and a prerequisite to successful mounting and copulation. Interspecific crosses revealed that males ofC. flavipesexhibited courtship behaviour, and mounted and copulated with females ofC. chilonisandC. sesamiae; the males transferred sperm but progeny from these crosses did not include females. Males ofC. sesamiaecopulated with females ofC. chilonisand the progeny included viable females. The progeny backcrosses of the hybrid females to male parents also included viable females. Sex pheromone experiments were conducted in a Y-tube olfactometer and in large field cages. Males and females ofC. flavipesperceived and responded to odours emitted by the opposite sex. There was no significant response to odours from conspecific individuals of the same sex in any of the three species. Pheromone bioassays in field cages using sticky traps baited with live virginC. flavipesfemales attracted conspecific males.