ABSENCE OF ODOR LEARNING IN THE STEMBORER PARASITOID COTESIA FLAVIPES

Parasitic wasps are commonly found to learn olfactory and visual cues that are associated with successful host location. For many parasitoid s the cues that are associated with hosts vary in space and time, and are therefore unpredictable. An ability to learn allows the wasp to co ncentrate on those cues that will lead it to new hosts most effectivel y in a particular area. In contrast, parasitoids that forage in a pred ictable homogeneous environment and/or make only a few foraging decisi ons do not need to learn and should rely on innate responses to specif ic cues. The role of learning in host foraging was studied in Cotesia flavipes (Hymenoptera: Braconidae), a parasitoid of stemborer larvae w ith an ecology where learning is expected to be of low adaptive value. There was no evidence that C. flavipes uses odour learning in host-mi cro-habitat location. There was no significant effect of the developme nt and emergence environment on the response level or preference towar ds the odour of infested plants. Neither was there evidence that exper ience with a particular plant-host complex during foraging influences subsequent foraging decisions in C. flavipes females. The absence of l earning in C. flavipes, which seems an exception among the parasitoids studied, is discussed in relation to its ecology. (C) 1997 The Associ ation for the Study of Animal Behaviour.