Olfactory host location in the rusty grain beetle parasitoid Cephalonomia waterstoni (Gahan) (Hymenoptera: Bethylidae)

Parasitoids can suppress populations of their host and thus play a primary role in Integrated Pest Management. The parasitic wasp Cephalonomia waterstoni Gahan (Hymenoptera: Bethylidae) is a natural enemy of the rusty grain beetle Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae). In the stored product environment, stimuli deriving from plant products, damaged plant products and hosts might be important for host location by the parasitoids. We tested the response of female parasitoids to odours deriving from infested and uninfested plant products, the grain dust produced by feeding primary pests, and various life stages of the rusty grain beetle. The olfactory response of C. waterstoni was found to be strongly elicited both by chemicals emitted by the dust, adult C. waterstoni and C. waterstoni third and fourth instar larvae. Our findings may contribute towards biological control of C. ferrugineus and the chemical ecology of olfactory host location by C. waterstoni.