Effect of incomplete oviposition by different parasitoid species on host fitness.

Abstract

Some parasitoids tend to reject their host after probing it with their ovipositor. Initially called pseudoparasitism, this incomplete host attack has been largely disregarded in the literature of hymenopteran parasitoids. Here, we used the parasitoids Aphytis melinus and Aphytis chrysomphali (Hymenoptera: Aphelinidae) and their common host Aonidiella aurantii (Hemiptera: Diaspididae) to evaluate: i) the frequency of these incomplete ovipositions and ii) their effect on host fitness. We hypothesize that host rejection after probing is more frequent for coevolved parasitoids (A. melinus) that search in patches with hosts of low quality (younger hosts), when compared with non-coevolved parasitoids (A. chrsysomphali) and that this probes are more lethal for younger hosts. Our results show that host rejection after probing is a common behavior in both parasitoids and it should be considered in future biological control programs as a mortality factor. Moreover, and contrary to expected, both parasitoids tended to probe and reject the same number of hosts independently of host quality. From the point of view of the host, these attacks caused the mortality of the immature instar whereas ~60% of the adult hosts survived to the attacks. The survivorship depended on the parasitoid species and the duration of the probes.