Male Diachasma alloeum parasitoids from two host species of tephritid fruit flies respond equally to female-produced sex pheromone.

摘要

Diachasma alloeum is a braconid wasp that parasitizes hawthorn-infesting Rhagoletis pomonella and blueberry-infesting Rhagoletis mendax, both tephritid fruit fly sibling species. The behavioural responses of male D. alloeum originating from both fruit fly host species to hexane extracts of conspecific females originating from both host species and females of various mating status are investigated in a laboratory Y-tube olfactometer. Male D. alloeum originating from either R. mendax or R. pomonella respond to one whole-body, female equivalent hexane extract in equal frequency as to a live, virgin female; this response is at least 7.5-fold greater than to solvent controls. Male D. alloeum originating from R. mendax or R. pomonella are attracted to hexane extracts of female D. alloeum abdomens but not to extracts of the head and thorax regions. Virgin D. alloeum females attract significantly more male D. alloeum originating from either host species compared with mated females of the same age. Copulation behaviour between same host and mixed host pairs appears to be identical. Male D. alloeum are equally responsive to the female-produced sex pheromone of female D. alloeum, irrespective of females' host-species origin, suggesting that these host-specific populations can potentially interbreed..