The host location behaviour of two closely related bethylid parasitoids was investigated under laboratory conditions. Although both species of parasitoid attack the coffee berry borer (CBB) Hypothenemus hampei Ferrari, they differ in their diet breadth. In Y-tube olfactometer bioassays, we investigated the behavioural responses of Cephalonomia stephanoderis (Betrem), a parasitoid with a narrower diet breadth, and Cephalonomia hyalinipennis (Ashmead), a parasitoid with a wider diet breadth, to the coffee–CBB complex volatiles. The results revealed that the responses differed for the two species. In single- and dual-choice tests, C. stephanoderis was attracted to volatiles emitted by CBB-infested coffee berries, dust/frass and CBB immature stages, whereas C. hyalinipennis was not attracted to any cues from plant–host complex offered.
