PHEROMONE-MEDIATED MATING IN THE APHID PARASITOID, APHIDIUS NIGRIPES (HYMENOPTERA, APHIDIDAE)

Mating in the aphid parasitoid, Aphidius nigripes, is mediated by a fe male sex pheromone that stimulates both upwind flight and courtship be havior by males. There is no evidence of any overt behavior associated with the release of the pheromone, but bioassay results, using female extracts, suggest that the pheromone is produced in the abdomen, alth ough it may be actively released from the entire body surface. Age doe s not appear to have a major influence on either pheromone production by the female or on male responsiveness. However, field data suggest t he presence of a strong diel periodicity in the emission of and/or rec eptivity to the pheromone. Laboratory bioassay results indicated diel changes in the male response but more refined techniques are needed to determine if such periodicity exists in pheromone production by femal es. Following mating, female pheromone production is significantly red uced. The potential use of the parasitoid sex pheromone in integrated management of aphids is discussed.