Genetic Distance and Age Affect the Cuticular Chemical Profilesof the Clonal Ant Cerapachys biroi

International audienceAlthough cuticular hydrocarbons (CHCs) havereceived much attention from biologists because of theirimportant role in insect communication, few studies haveaddressed the chemical ecology of clonal species of eusocialinsects. In this study we investigated whether and how differencesin CHCs relate to the genetics and reproductive dynamicsof the parthenogenetic ant Cerapachys biroi. We collectedindividuals of different ages and subcastes from several coloniesbelonging to four clonal lineages, and analyzed theircuticular chemical signature. CHCs varied according to coloniesand clonal lineages in two independent data sets, andcorrelations were found between genetic and chemical distancesbetween colonies. This supports the results of previousresearch showing that C. biroi workers discriminate betweennestmates and non-nestmates, especially when they belong todifferent clonal lineages. In C. biroi, the production of individualsof a morphological subcaste specialized in reproductionis inversely proportional to colony-level fertility. Aschemical signatures usually correlate with fertility and reproductiveactivity in social Hymenoptera, we asked whetherCHCs could function as fertility-signaling primer pheromonesdetermining larval subcaste fate in C. biroi. Interestingly, andcontrary to findings for several other ant species, fertility andreproductive activity showed no correlation with chemicalsignatures, suggesting the absence of fertility related CHCs.This implies that other cues are responsible for subcastedifferentiation in this species