Variation in Chemical Composition of Cuticular and Nonpolar Compounds of Venom of Apoica pallens and Polistes versicolor

Abstract

Although cuticular hydrocarbons and venom are important to the evolutionary success of social behavior, studies that investigated these compounds in tropical social wasps are rare. Thus, the aim of this study was to compare the cuticular chemical composition and the nonpolar portion of venom of Apoica pallens, a swarm-founding wasp and Polistes versicolor an independent-founding wasp. Gas chromatography coupled to mass spectrometry (GC/MS) technique was used. In the samples of A. pallens, 66 compounds were identified on the cuticle and 87 in venom, 13 are unique of the cuticle and 26 of venom. In the samples of P. versicolor, 85 compounds were identified on the cuticle and 60 in venom, 10 are exclusive of the cuticle and 5 of venom. The results show that, although they present different foundation types and organize in colonies with significantly different population number, the variation in chain length of compounds is relatively similar. In addition, in both types of samples of both species, the most representative class of compounds in content and number are the branched alkanes, which are recognized as the most effective during interactions between nestmates. However, there is greater similarity in content of shared compounds between samples of cuticle and venom of A. pallens, suggesting that because it is a species that is organized in more populous colonies, it may have a more elaborate signaling system based on volatile compounds of venom.