Borago officinalis attracts the aphid parasitoid Aphidius colemani (Hymenoptera: Braconidae)

Aphid parasitoids are often observed to gather around borages (Borago officinalis) used as banker plants in strawberry greenhouse. The attraction of Aphidius colemani as a model aphid parasitoid was observed in response to borage. An aphid generalist parasitoid, A. colemani, shows a preference based on their experience after hatching from mummies of the host-plant volatiles on which their host aphids are reared. A. colemani colonies reared on three host plant-aphid systems (borage/green peach aphid; Japanese radish/green peach aphid; barley/oat bird cherry aphid). A 4-arm olfactometer was used to test the preference of female A. colemani for several plants (infested Japanese radish; infested barley; infested, uninfested and mechanically-damaged borage). Females from each group showed a preference for the plant on which their hosts had been reared and also infested borage regardless of the host plant/aphid system. These results suggested that volatiles from aphid-infested borage attract A. colemani.