SELECTIVE ADAPTATION OF THE CUTICULAR HYDROCARBON PROFILES OF THE SLAVE-MAKING ANTS POLYERGUS-RUFESCENS LATR AND THEIR FORMICA-RUFIBARBIS FAB AND FORMICA-CUNICULARIA LATR SLAVES

The results of comparisons between the cuticular hydrocarbon mixtures of the slave-making ants Polyergus rufescens, their Formica rufibarbis and F. cunicularia slaves and between slave and free-living workers ( which were probably related to one another) from each Formica species showed the following. (1) Several products were common to all three sp ecies. (2) Each of the two Formica species had its own particular prod ucts. (3) The Polyergus' cuticular mixture did not contain any species -specific hydrocarbons but had some components in common with either r ufibarbis or cunicularia. Because these products were present in Polye rgus, whichever Formica species they enslaved, Polyergus must be able to synthesize their own cuticular hydrocarbons. (4) Cohabitation with another species as the result of slave making had no qualitative effec ts on the individual cuticular hydrocarbon mixtures: their composition was the same in the Polyergus whether living with F. rufibarbis or F. cunicularia and in the Formica of each species whether free living or enslaved. (5) The Polyergus resembled their Formica slaves, however, due to a tendency to adjust the proportions of some of the common hydr ocarbons to those of their slaves; this tendency seems to have been re ciprocal, although it was less marked in the case of the Formica. (6) The chemical signatures of mixed colonies inhabited by the same slave species depended mainly on the cuticular characteristics of the Formic a slaves but also on those of the Polyergus, which differed from one c olony to another. The finding that cuticular hydrocarbon mixtures of i ndividuals of both species (slaves and slave makers) interacting withi n a mixed colony kept their species-specific hydrocarbons while the pr oportions of the common products showed a tendency to adapt to chose o f che other species suggests that there exists a selective mechanism p robably involving the regulation of the synthesis of these products.