Aphelinus varipes is reported to have a wide host range, attacking more than 40 species of aphids, and a wide geographic distribution, being endemic throughout Eurasia and perhaps in North America. However, we found that Aphelinus varipes from different hosts (Diuraphis noxia versus Rhopalosiphum padi) and geographic regions (France versus Georgia in the former USSR) showed different patterns of parasitism when exposed to five aphid species. Some host species were not attacked at all by some wasp populations. When we attempted to cross these populations, most females from most populations rejected males from other populations. The only crosses where some females accepted alien males involved those from allopatric populations. Morphometric analyses of antennae, wings and dorsal sclerites of the mesosoma conducted separately for males and females show that samples from these four host/location combinations have distinctly different morphologies. Comparisons of antennae, wings and mesosomal features between hosts in each location and between locations for each host show that very particular regions of the forms are consistently involved. Preliminary data for 28S-D2, COI, COII and ITS2 DNA loci are presented for two specimens from each host/location combination and Aphelinus asychis, the outgroup. Only COI and ITS2 are phylogenetically informative within the varipes complex. The majority of the substitutions occur as terminal autapomorphies within species and there is little evidence for common ancestry of species. Together our data suggest that they are sibling species that have diverged greatly in host use and courtship, but much less so in morphology and some putatively highly variable DNA sequences.
Species 1: Hymenoptera Aphelinidae Aphelinus varipes
Keywords: biological control, aphid parasitoids
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