Reproductive strategies under multiparasitism in natural populations of the parasitoid wasp Nasonia (Hymenoptera)

Parasitoid Nasonia wasps adjust their progeny sex ratio to the presence of conspecifics to optimize their fitness. Another trait under female control is the induction of offspring diapause. We analysed progeny sex ratios and the proportion of diapausing offspring of individual Nasonia females in host patches parasitized by two species, Nasonia vitripennis and Nasonia giraulti, in North American field populations using microsatellite fingerprinting. Both Nasonia species produced similar sex ratios on hosts that were co-parasitized by their own species as by the other species, indicating that females do not distinguish between con- and heterospecific clutches. The sex ratios of the diapause and adult fractions of mixed broods from single females were not correlated. We found further indications that N. vitripennis females take the emergence time of the offspring into account in their sex allocation. The reproductive strategies of Nasonia under multiparasitism are largely adaptive, but also partially constrained by information.

Behavioral and genetic characteristics of a new species of Nasonia

Nasonia (Hymenoptera: Pteromalidae) is a genus of parasitoid wasps, which is fast emerging as a model system for evolutionary, genetic, developmental and host–endosymbiont interaction studies. In this study, we report a new species, Nasonia oneida, distinguish its behavioral, genetic and morphological features, and characterize its pre-mating and post-mating isolation with the other Nasonia species. Phylogenetic analyses indicate that N. oneida is the sister species to Nasonia giraulti with its own uniquely distinct cuticular hydrocarbon profiles, behavioral characteristics and subtle morphological differences. An important characteristic of N. oneida is the strong mate discrimination shown by the females against all the other Nasonia species. A genetic analysis of this phenotype by interspecies hybridization indicates that this strong discriminating phenotype is recessive. A formal species description of N. oneida Raychoudhury & Desjardins is also provided.