Intraspecific variation of cuticular hydrocarbons in the eusocial wasp Polybia sericea (Hymenoptera: Vespidae)

Cuticular hydrocarbon profiles reveal geographic chemotypes in stingless bees (Hymenoptera: Meliponini)

Cuticular hydrocarbon (CHCs) variation has been detected in various insect taxa, but the potential contribution of cuticular compounds for analyzing intraspecific diversity at the population level has been little explored. Here we assess for the first time intraspecific variation in the CHC profile of stingless bees, using the species Melipona beecheii and Nannotrigona perilampoides. The objective is determining whether intraspecific variation can be useful for population identification. We found species-specific chemical patterns and extensive variation within each species. Notably, chemotypes were significantly associated to geographic origin in N. perilampoides but less so in M. beecheii and we discuss possible explanations for these patterns. Our results support the use of CHCs in conjunction with other methods in emerging problems such as undetected colony mobilization across regions. As CHCs are involved in several aspects of stingless bee recognition and interactions, it would be essential to unravel how these chemical signatures evolve across populations.

Cuticular hydrocarbons as caste-linked cues in Neotropical swarm-founding wasps

Wasps (Vespidae) are important organisms to understand the evolution of social behaviour. Wasps show different levels of sociality, which includes solitary to highly eusocial organisms. In social insect species, queens and workers differ in physiology and morphology. The Neotropical swarm-founding wasps (Epiponini) show a variety of caste syndromes. In this clade, the caste-flexibility is a unique characteristic, in which workers can become queens and swarm to start a new nest. The investigation of the caste system comparing several Epiponini species show a clear-cut morphological distinction between queens and workers, with a morphological continuum between queens and workers. However, whether cuticular hydrocarbons (CHCs) are used as cues for caste recognition in swarm-founding wasps is still unknown. We studied whether CHCs may display caste-linked differences in eleven species of Epiponini wasps and if CHCs differences would follow morphological patterns. Our results suggest that queens and workers of Epiponini wasps are chemically different from each other at two levels, qualitatively and quantitatively, or merely quantitatively. This variation seems to exist regardless of their morphological traits and may be useful to help us understanding how chemical communication evolved differently in these species.