Chemical Mimicry in an Obligate Predator of Carpenter Ants (Hymenoptera: Formicidae)

Abstract

Cuticular hydrocarbons have been identified from worker and immature forms of the carpenter ant, Camponotus modoc Wheeler, and from larval and adult forms of the syrphid, Microdon piperi Knab. The larval stages of the flies are highly integrated myrmecophiles, despite their also being obligate predators of the ant brood. Both immature and adult forms of the ants contain the same hydrocarbon components, but in stage-specific proportions. M. piperi larvae possess cuticular hydrocarbon components identical to those of their host ants, and have no other discernible hydrocarbon components. The percentage composition of the hydrocarbons from larval M. piperi closely mimics that of larval C. modoc. In contrast, adult M. piperi have many cuticular hydrocarbon components that are not found on the ants; these flies are immediately attacked by the ants if they are discovered in the nest. Several highly unusual monomethyl- and dimethyl-(Z)-4-alkenes, found both in ants and flies, were identified.