The male and female first instar larvae of Anaphes victus and A. listronoti (Hymenoptera, Mymaridae)

Abstract

 Anaphes victus and A. listronoti are two closely related species, respectively solitary and gregarious parasitoids of eggs of the carrot weevil Listronotus oregonensis (Coleoptera, Curculionidae). Both species are sympatric, and the regulation of super- and multiparasitism that occurs regularly in this host is done by larval fights between the mymariform first instar larvae. The morphology of both male and female first instar larvae of A. victus and A. listronoti is described using scanning electron microscopy. Both species have first instar larvae of the mymariform type and present sexual dimorphism. The main difference between the two species is that larvae of A. victus are clearly segmented while larvae of A. listronoti show no visible segmentation. Male larvae of both species have two types of perioral hooks, longer and less dense dorsal setae than females and developed undertail spines. Female larvae of both species have short abdominal setae. These morphological differences are discussed in the context of intra- and interspecific larval competition.