Cuticular hydrocarbons and reproductive status in the social wasp Polistesdominulus

Most species of social insect are characterized by a reproductive division of labor among morphologically specialized individuals. In contrast, there exist many species where all individuals are morphologically identical and dominance relationships determine which individuals mate and/or reproduce. In newly founded multiple-foundress associations of the social wasp Poliste s dominulus, foundresses establish dominance hierarchies where the top-rank ed (alpha) female monopolizes egg laying. The possibility that chemical cue s are used for recognition of egg-laying individuals has not been explored in this wasp. Using non-destructive techniques, we examined the relationshi p between ovarian activity and the proportions of cuticular hydrocarbons of three female types (dominant and subordinate foundresses and workers) in 1 1 colonies. Immediately after nest foundation, no differences were found be tween alpha and subordinate females. In contrast, at worker emergence, alph a females were statistically distinguishable from both subordinates and wor kers. We experimentally removed the alpha female in 5 of the original nests and reanalyzed hydrocarbon proportions of the new dominant individual. Rep lacement individuals were all found to acquire a cuticular signature charac teristic of the alpha female. This suggests that cuticular hydrocarbons are used as cues of ovarian activity in P. dominulus, and we discuss our resul ts in terms of a switch from behavioral dominance to chemical signaling in this wasp.