Avoidance of parasitized host by female wasps of Aphidius gifuensis (Hymenoptera: Braconidae): The role of natal rearing effects and host availability?

Natal rearing experience of animals may affect their behaviors, such as, habitat selection and oviposition decision. As part of the overall fitness of insect parasitoids, successful host discrimination (distinguishing parasitized hosts from unparasitized hosts) is of paramount importance. In this study we examined whether and how parasitoids’ natal rearing experience would affect their host discrimination ability according to host availability. We established separate colonies of Aphidius gifuensis Ashmead by continually reared on two hosts, Sitobion avenae F. and Myzus persicae (Suzler), and quantified self superparasitism and self superparasitism vs parasitism ratio for the four combinations of parasitoid colonies and host species (S. aveane and M. persicae) at four host densities (30, 50, 100, or 150 per plant). Results showed that self superparasitism of M. persicae by A. gifuensis reared on S. avenae was significantly higher than by those reared on M. persicae, no matter the host densities was 30, 50, 100, or 150. Aphidius gifuensis reared on M. persicae significantly superparasitized more S. avenae than those reared on S. aveane only when host density was 30. Self superparasitism vs parasitism ratio of A. gifuensis from both colonies were always lower on natal hosts than on new hosts, and the difference was more pronounced as the host density decreased. These results suggested that natal rearing effects is important on host discrimination and oviposition decision of the parasitoid A. gifuensis. These effects promoted the parasitoid's host adaptation and made them confer greater fitness. This article is protected by copyright. All rights reserved