Host Approaching Behavior in a Parasitoid Wasp (Hymenoptera: Ichneumonidae) as Influenced by Physiological State and Host Type

Abstract

The present study highlighted the interactions of host type and physiological state (i.e., the number of mature eggs a female carries) in determining a parasitoid’s host-finding behavior, using the solitary endoparasitoid Itoplectis naranyae (Hymenoptera: Ichneumonidae). Females took much shorter time to approach and attack healthy hosts of high-value than empty hosts of no-value, discriminating between the host types from a short distance. Variance of the time was much greater for empty hosts. A striking difference was detected in the influence of physiological state on wasp behavior; females with greater egg loads approached an empty host more quickly in order to examine its suitability for oviposition whereas egg load effects were not found for healthy hosts. Thus, egg load was involved in variation of the host-finding behavior but its effects depended on host types. We discuss the adaptive significance of the context dependent effects of egg load on parasitoid behavior