Qualitative and quantitative differences in cuticular hydrocarbons betweenlaboratory and field colonies of Pogonomyrmex barbatus

Ants held in the laboratory and field ants of the species Pogonomyrmex barb atus have quantitative differences in their cuticular hydrocarbons and a qu alitative difference in their methyl-branched hydrocarbons. Laboratory-held workers showed twice the hydrocarbon content as field ants. This differenc e was mainly due to higher amounts of straight-chain alkanes and methyl-bra nched alkanes in laboratory ants, whereas the proportion of the alkenes rem ained the same for both groups. In addition to the absence of some hydrocar bons in the field colonies, one of the methyl-branched hydrocarbons differe d in amount and branching pattern between the two groups of ants. Whereas, notable peaks of 2-methylalkanes were identified in ants kept in the labora tory, these compounds could not be identified in ants living in their natur al habitat. However, a trace amount of 4-methyltriacontane was found in lie u of the 2-methyltriacontane counterpart in field ants. Possible explanatio ns for both qualitative and quantitative differences are discussed. Publish ed by Elsevier Science Inc.