Spare to share? How does interindividual variation in metabolic rate influence food sharing in the honeybee?

A central benefit of group living is the cooperative acquisition and sharing of resources but the costs associated with these processes can set up a potential conflict between individual and group level fitness. Within a honeybee colony, the task of resource acquisition is relegated to the foragers and any interindividual differences in their metabolic rate and the consequent carbohydrate demand may pose a constraint on the amount of resources they can contribute to the colony. We investigated whether the carbohydrate demand of a forager is a function of her metabolic rate and if this impacts the amount of food she shares with the nestmates. Our results show that the sucrose consumption rates of foragers with high metabolic rates did not meet their carbohydrate demand, placing them at an energy deficit while those with lower metabolic rates had an energy surplus. Our food sharing experiments showed a trend but did not detect a significant difference among individuals with different consumption rates in terms of the amount of food they shared with their nestmates. These results suggest that honeybee foragers with different metabolic rates are likely to differ in terms of whether they have an energy surplus or deficit, but more long-term datasets may be required to detect how this may influence food sharing.