Cuticular and glandular chemistry are correlated with ovary size in two populations of the facultatively social carpenter bee, Xylocopa sonorina

Abstract Chemical communication plays a critical role in the organization of insect societies. Although the identity and function of chemical signals in eusocial species have been well-characterized, there is still relatively little understood about the role that chemical communication plays in insects with the simplest forms of social organization. Generally, it is hypothesized that the complex chemical signals of eusocial species evolved from existing fertility-linked chemical variation in solitary species, which then facilitated the formation of reproductive hierarchies as social complexity increased and the reproductive division of labor evolved. Here, we characterize the cuticular and Dufour’s gland chemistry of the facultatively social large carpenter bee, Xyolocopa sonorina , which can form small, fluid social groups that often consist of non-kin and assess whether chemistry is correlated with changes in reproductive status in two populations. We find that compounds from the cuticle and Dufour’s gland show strong correlations with ovary size in both populations. Overall, our results demonstrate that the cuticular and Dufour’s gland chemistry contains reproductive information that could be useful in mediating social interactions in small, simple insect societies.