Generalists and specialists of brood parasitism in spider wasps (Hymenoptera: Pompilidae). Pompilidae

Based on emergence records from trap nests and naturally occurring nests, we determined the brood parasitism behaviour of Irenangelus punctipleuris (Pompilidae, Ceropalinae) for the first time and that of Dipogon (Nipponodipogon) nagasei (Pompilidae, Pepsinae) as a complement to a previous study. The former species was found to parasitize Auplopus carbonarius and A. pygialis (Pompilidae, Pepsinae), while the latter species was found to parasitize Di. (Deuteragenia) sperconsus (Pepsinae). When using the well-established system of categories of brood parasitism in Pompilidae, Irenangelus corresponds to type A brood parasitism (highwayman) and Nipponodipogon corresponds to type B brood parasitism (sneak thief). In comparison with brood parasitism in birds, we proposed new concepts, namely generalists and specialists of brood parasitism, which correspond to type A and type B brood parasites, respectively. We discussed the differences in the behavioural patterns and morphological features between the two types. We also confirmed the proposed concepts by their molecular phylogenetic positions.