ENEMY-INDUCED DISPERSAL IN A PARASITIC WASP

Females of the parasitic wasp Aphidius uzbekistanicus, a specialist ap hid primary parasitoid, react to the presence of their specialist hype rparasitoid enemy Alloxysta victrix by leaving the area. The wasps lea ve to increase their reproductive success, because only their offsprin g, but not the wasps themselves, are threatened by enemy attack. Furth ermore, this dispersal is elicited through the action of volatile chem ical cues produced by the hyperparasitoids. We provide evidence for 6- methyl-5-hepten-2-one being one of the volatiles eliciting dispersal. The tendency of the wasps to leave areas which are being colonized by their enemies reduces their efficiency as aphid antagonists.