Brain gene expression of foraging behaviour and social environment in Ceratina calcarata
Rudimentary social systems have the potential to both advance our understanding of how complex sociality may have evolved, and our understanding of how changes in social environment may influence gene expression and cooperation. Recently studies of primitively social Hymenoptera have greatly expanded empirical evidence for the role of social environment in shaping behaviour and gene expression. Here we compare brain gene expression profiles of foragers across social contexts in the small carpenter bee, Ceratina calcarata. We conducted experimental manipulations of field colonies to examine gene expression profiles among social contexts including foraging mothers, regular daughters, and worker-like dwarf eldest daughters (DEDs) in the presence and absence of mothers. Our analysis found significant differences in gene expression associated with female age, body size and social environment, including circadian clock gene dyw, hexamine, and genes involved in the regulation of juvenile hormone and chemical communication. We also found candidate genes differentially expressed in our study also associated with division of labour, including foraging, in other primitively and advanced eusocial insects. Our results offer evidence for the role the regulation of key developmental hormones and circadian rhythms in producing cooperative behaviour in rudimentary insect societies.