Effects of oviposition in a non-host species on foraging behaviour of the parasitoid Cotesia glomerata

Parasitoids lay their eggs in or on a host, usually another insect. During foraging, parasitoids can encounter insects that differ in terms of host suitability and quality. At one extreme end of this spectrum are non-hosts that are unsuitable for offspring development. Non-hosts are generally ignored but parasitization does occur and occasionally also results in egg deposition. Here, we investigate how oviposition in a non-host influences subsequent foraging behaviour of a parasitoid and whether this is mediated by learning. Our study system consists of the endoparasitoid Cotesia glomerata and the presumed non-host caterpillar Mamestra brassicae. In the presence of Pieris brassicae hosts and/or their traces (frass), we observed that C. glomerata inserts its ovipositor into M. brassicae caterpillars. Eggs were deposited, but all eggs disappeared within 96h, confirming the non-host status of M. brassicae. In contrast to our expectation, there was no memory retention after oviposition in a...