INCREASED HOST ACCEPTANCE IN EXPERIENCED FEMALES OF THE PARASITOID BRACHYMERIA-INTERMEDIA - WHICH TYPES OF OVIPOSITION BEHAVIOR CONTRIBUTE TO EXPERIENCE

Brachymeria intermedia (Nees) (Hymenoptera: Chalcididae) is a solitary endoparasitoid of the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae). The probability that a wasp will parasitise this host is increased if she had a previous oviposition experience. We investig ated which types of pre-oviposition and oviposition behaviour induced this change by comparing the acceptance behaviour of wasps with zero t o five oviposition experiences as well as wasps with various partial h ost handling experiences (from no contact with a host to one complete oviposition sequence). The percentage of females accepting the host in creased gradually with both the number of previous oviposition experie nces and the amount of handling of a single host. Furthermore, the nai ve females were less likely (44%) to walk to the host than females wit h a variety of experiences (72-100%). A single antennal contact with t he host was sufficient to increase the probability of walking to the h ost. Additional handling and additional oviposition experiences furthe r elevated the propensity to oviposit. Thus, the modification of the a cceptance behaviour through experience was essentially a gradual proce ss in which antennal contact with a pupa was a major element. It is su ggested that naive wasps learned the host odour when they first antenn ated a pupa. As a result, they were attracted to the host odour in sub sequent encounters.