Energetic state regulates the exploration-exploitation trade-off in honeybees

摘要

The nutritional state of an animal has a significant influence on whether it forages for energy or for information. How should foragers divide their time between exploiting known food patches and exploring new food sources? Using an experiment in which we presented starved and fed honeybee foragers with rewards that differed in their values and their degree of familiarity to the bees, we showed that individuals invest more time in exploitation when hungry and more time in exploration when fed.Foragers must divide their time between consuming known resources (exploitation) and learning about new resources (exploration). As opposed to classical optimal foraging theory, the information primacy hypothesis predicts that only starved animals will show higher levels of exploitation, whereas more satiated animals will show higher levels of exploration. We tested these predictions in honeybee foragers using a conditioning assay to make them associate different odors with sucrose rewards that differed in values and the certainty of these values, and then testing their choice between these rewards at different levels of hunger. Fed bees showed higher sampling and a lower consumptive effort compared with starved bees. Fed bees also showed a higher preference for rewards with completely uncertain values (novel rewards) but not for rewards with only partially uncertain values. These results show that the energetic state of an animal and therefore the relative values of food and information can dictate a switch between exploration and exploitation during foraging. We discuss these results in the context of how a change in the relative investments into these 2 aspects of foraging due to a lack of nutrition can have a detrimental effect on life history and why it is therefore important to explicitly distinguish between exploration and exploitation.