Cuticular hydrocarbons as cues of sex and health condition in Polistes dominula wasps

In the paper wasp Polistes dominula, cuticular hydrocarbons play a critical role to acquire information regarding conspecific individuals. However, the relationship between cuticular hydrocarbons, health status, and male sexually selected traits is poorly investigated. In this study, we characterized the cuticular hydrocarbon profile of adult male and female wasps, infected or not by the strepsipteran endoparasite Xenos vesparum, to assess whether the chemical signature provides information about sex and health status (parasite infection). Moreover, we tested whether the chemical profile reflects male quality as measured via morphological and behavioural (sexually selected) traits at leks. Our results showed that males and females had similar total amount of CHCs, quantitatively different profiles and, to a lesser extent, sex-specific chemical compounds. Cuticular profiles were influenced by the strepsipteran infection, and the effect was stronger in females (the primary host) than in males, according to the physiological castration of female but not of male hosts. Regarding territorial and non-territorial males, no significant difference emerged in their chemical profiles. Furthermore, sex-dimorphic visual signals (size, shape, and asymmetry of abdominal yellow spots) were related to the behavioural displays of territorial males. We hypothesize that cuticular hydrocarbons are potential multi-role cues to assess sex and health status in male and female wasps, in synergy with visual signals and territorial performance in signaling male quality.