CHANGES IN THE CUTICULAR HYDROCARBON PROFILE OF THE SLAVE-MAKER ANT QUEEN, Polyergus breviceps EMERY, AFTER KILLING A Formica HOST QUEEN (HYMENOPTERA: FORMICIDAE)

Abstract—Queens of the slave-maker ant, Polyergus breviceps, take over nests of their Formica host species by fatally attacking the resident queen. As workers only begin grooming the P. breviceps queen once she has ceased her attack, we investigated whether a change in parasite queen chemistry may account for the change in worker behavior. Cuticular hydrocarbon profiles of newly mated P. breviceps queens and of queens of their two Formica host species were found to be species-specific. Profiles of newly mated P. breviceps queens that had attacked a Formica queen, however, were virtually identical to the queen profile of the species killed. Mass spectral analysis revealed that the hydrocarbons on the cuticles of newly mated P. breviceps changed from primarily normal alkanes to methyl and di-methyl branched alkanes after attacks. The results suggest that cuticular compounds from the host queen were transferred to the parasite queen during their aggressive interaction. Key Words—Cuticular hydrocarbons, Formicidae, slave-maker, Polyergus bre-viceps, Formica gnava, Formica occulta, colony takeover, queen killing, chem