EFFECTS OF INTRA-PATCH EXPERIENCES ON PATCH TIME, SEARCH TIME AND SEARCHING EFFICIENCY OF THE PARASITOID LEPTOPILINA-CLAVIPES

1. This paper considers the effects of intra-patch experiences, such as contact with kairomone, ovipositions and rejections on the searching behaviour of individual female parasitoids of the species Leptopilina clavipes. 2. Behavioural records were analysed by means of the proportional hazards model (Cox 1972) taking effects of fixed as well as time-varying covariates into account. 3. Analyses were carried out at three levels of resolution: (i) patch leaving and return tendencies; (ii) tendencies to stop and start searching while on the patch; and (iii) the encounter rate during search bouts. 4. Due to the large number of censored observations no conclusions can be drawn about the effect of 'presence of kairomone' on the patch return tendency. 'Number of times off patch' has no effect on the patch return tendency. However, the experienced number of ovipositions or rejections and the 'latest experienced oviposition rate' have a joint effect on this tendency. The 'latest experienced oviposition rate' and one rejection, one oviposition or two ovipositions increase the patch-return tendency. 5. 'Presence of. kairomone' decreases the patch-leaving tendency. 'Number of times off patch' also affects the patch-leaving tendency. When the first encounter is with a parasitized host the leaving tendency increases and after one or two ovipositions this tendency decreases. 6. Ovipositions affect the tendencies to stop and start searching such that a proportionally larger part of time on the patch is allocated to searching. Rejections have an opposite effect. 7. The encounter rate per unit search time increases during a patch visit when ovipositions have occurred. 8. The results of the analysis are discussed in a functional context. Our result (7) indicates that models for optimization should take into account that the searching efficiency is affected by intra-patch experiences.