Corazonin responds to nutrient stress and increases flight activity in Apis mellifera workers

Honey bee colonies fail due to a variety of stressors, which threaten food production. A better understanding of the honey bee stress response is needed to reduce these losses. Previous work suggests that the insect neuropeptide hormone corazonin activates fat body catabolism and food-seeking behaviors, which provides the energy to fuel the stress response and mitigate tradeoffs. Here, we tested whether corazonin is involved in the honey bee (Apis mellifera ligustica) stress response and metabolic homeostasis. We tested two hypotheses that (1) honey bee corazonin gene expression increased with dietary stress and (2) the corazonin peptide induced flight activity. Dietary stress, as measured by reduced vitellogenin gene expression, induced stress and the corazonin gene (crz) was expressed more in stressed bees compared to the control bees, confirming that crz responded to this stress. Bees injected in the head with the corazonin peptide also flew more than the control bees, suggesting that corazonin might activate food-seeking behaviors. These results support the idea that corazonin is involved in the honey bee stress response and activates a typical response of stressed colonies: increased flight activity.