HOST ACCEPTANCE BEHAVIOR IN THE EGG PARASITOID TRISSOLCUS-BASALIS (HYMENOPTERA, SCELIONIDAE)

Dynamic optimal diet models predict that both the parasitoid female's experience and/or the condition of its host influence the degree of su perparasitism (oviposition of additional eggs in a host already contai ning one or more eggs). We showed that the scelionid egg parasitoid Tr issolcus basalis can discriminate irrespective of past experience. Tim e spent on host examination was not affected by female's history nor i ts host's condition. Predictions of the dynamic optimal diet models ar e based on the assumption that naive wasps can recognize previously pa rasitized hosts. As criteria for determining this ability, a Markov ch ain model was developed to analyze the behavioral sequences leading to host acceptance. These were found to be associated with the 1(st) and 2(nd) order Markov chains and were clearly influenced by the pre-patc h experience of the parasitoid. The host affinity coefficient, develop ed to evaluate the degree of resemblance between the sequential patter ns of the host acceptance behavior, demonstrated that both naive and e xperienced females of T. basalis were able to distinguish between heal thy and parasitized hosts.