Population diversity in cuticular hydrocarbons and mtDNA in a mountain social wasp.

Nestmate recognition is a common phenomenon in social insects that typically is mediated by cuticular hydrocarbons. Geographical variation in cuticular hydrocarbons has been observed, although the pattern of variation is not consistent across species and is usually related to the biology and ecology of the different species. Polistes biglumis (Hymenoptera: Vespidae) is a social wasp that lives in high mountains where populations are separated by significant geographical barriers. Here we investigated the level of chemical variation among populations of P. biglumis in the Alps, and shed light on the phylogeography of this species. Populations could be discriminated by means of their cuticular hydrocarbon profiles, which showed a pattern consistent with the isolation-by-distance hypothesis. Molecular data highlighted two areas with different levels of haplotype diversity, although all wasps belonged to the same species. These results suggest that the populations of P. biglumis in the Alps are geographically isolated from one another, favoring their genetic and chemical differentiation.