Olfactory responses of Microctonus aethiopoides loan, an adult parasitoid of the alfalfa weevil, Hypera postica (Gyllenhal) : A matter of host location

Microctonus aethiopoides is an important parasitoid in the biological control program of the alfalfa weevil, Hypera postica, a pest of alfalfa. Basic biological information about female M. aethiopoides orientation toward its host habitat was assessed in Y-tube olfactometer choice arena. The response of the parasitoid to volatiles from the microhabitat complex, adult weevil, host frass, healthy plants, naturally damaged plants, artificially damaged plants and control odors were tested. The parasitoid was attracted to the host-plant complex of cues representing the microhabitat in most trials, while the response to other odor sources as a means of locating the host were discussed.