Comparative study of the ability of parasitic wasps of the Anisopteromalus calandrae (Howard) species complex (Hymenoptera: Pteromalidae) to modify searching behaviour

The hypothesis of a relationship between the degree of dietary specialization and learning ability in parasitoids was tested on two species of the genus Anisopteromalus Ruschka. A. calandrae (Howard) parasitizes a broad range of hosts, while Anisopteromalus sp. attacks only anobiid beetles inhabiting stored products. Their original host ranges do not overlap, however both species normally develop on alternative hosts in laboratory. Rearing A. calandrae on the alternative host, Lasioderma serricorne (F.), results in decreasing its olfactory reaction to the original one, Sitophilus granarius (L.). On the contrary, no natal host effect was detected in Anisopteromalus sp. In A. calandrae, experience of parasitizing any host has a sufficient impact on its searching behaviour and may invert reactions to both original and alternative hosts. Meanwhile, only effect of the original host (L. serricorne) parasitizing was revealed in Anisopteromalus sp. The results are in agreement with the hypothesis examined: the generalist A. calandrae is more capable of learning compared to the specialist Anisopteromalus sp.