VIBRATION-MEDIATED INTERACTIONS IN A HOST-PARASITOID SYSTEM

The aim of this study was to obtain behavioural evidence of vibration- mediated interactions between the apple tentiform leafminer, Phyllonor ycter malella (Ger.) (Lepidoptera, Gracillariidae), and its parasitoid Sympiesis sericeicornis Nees (Hymenoptera, Eulophidae). The experimen tal setup allowed the simultaneous recording on video film of both the parasitoid's and the host's behaviour, thus enabling us to contrast t heir respective responses to the leaf vibrations produced by the other party. We analysed the one-step transition probabilities from one beh avioural state to the next. Active larval movements had a marked influ ence on the parasitoid's behaviour, but feeding and still had no detec table effect. We found no evidence for vibrotaxis on the part of the p arasitoid. Although parasitoid searching behaviour on the leaf surface did not seem to alter the leafminer's behaviour, ovipositor insertion s triggered a characteristic avoidance response. The described interac tions are discussed in the context of the 'princess and monster' model developed in search and game theory.