CONCLUSION
Honey bees are challenged continuously by environmental and agricultural factors that alter colony demography. Our results demonstrate that the social structure of honeybee colonies affects composition of the gut microbiota. Behavioral differences are associated with internal damage from reactive oxygen species, and changes in gene expression that rely on nutritional state and task. Precocious foragers accrue oxidative damage as a result of intense foraging activity experienced by a physiologically deficient adult worker. The colony-level cost of precocious foraging is extreme and one of many altruistic qualities inherent to social insects. The physiological demands of foraging are best met by older workers that have transitioned to foraging following extended development within the hive. In a healthy colony, the characteristic transition from nurse to forager results in less physiological stress. Consistent with this hypothesis, the ratio abundance of keystone ileum species S. alvi and G. apicolais refined with an extended nursing period, setting the stage for long-lived foragers. As workers age, we propose that the midgut becomes a niche for rapid microbial colonization, with consequences for both individual and colony survival.