Cues of dominance hierarchy, fertility and nestmate recognition in the primitively eusocial wasp Mischocyttarus parallelogrammus (Vespidae: Polistinae: Mischocyttarini)

Chemical communication is pivotal for social insects to ensure proper functioning of their colonies. Cuticular hydrocarbons (CHCs) are the most well-known class of compounds used to regulate different types of behavioural interaction within a social context. Queens of highly eusocial insects rely on the use of chemical communication to keep their reproductive monopoly, whereas queens of primitively eusocial insects often exert physical control to maintain reproductive dominance. However, in the past years, ample evidence has demonstrated that primitively eusocial insects also use chemical compounds to communicate. Based on this evidence, we aimed to elucidate whether CHCs carry some information regarding female hierarchical position, ovary activation and nestmate recognition in the primitively eusocial wasp Mischocyttarus parallelogrammus. Additionally, females were classified by their ovary activation. Finally, the cuticular profiles of females originating from different nests were compared to check whether CHCs convey information about their nest of origin. Our results confirmed that the chemical composition of alpha and subordinate females differed significantly in post-worker emergence nests, but that alpha and beta females surprisingly were not chemically different from each other in either of the colony phases. Furthermore, females with activated ovaries expressed a chemical profile distinct from that of females with non-activated ovaries. Lastly, we showed that CHCs might convey information about nest origin, since females hailing from different nests showed distinct chemical profiles. Based on our results, we conclude that CHCs might play a critical role in the nest-functioning of M. parallelogrammus, since they mirror social status.