Foraging Experiences Durably Modulate Honey Bees' Sucrose Responsiveness and Antennal Lobe Biogenic Amine Levels.

Foraging exposes organisms to rewarding and aversive events, providing a selective advantage for maximizing the former while minimizing the latter. Honey bees (Apis mellifera) associate environmental stimuli with appetitive or aversive experiences, forming preferences for scents, locations, and visual cues. Preference formation is influenced by inter-individual variation in sensitivity to rewarding and aversive stimuli, which can be modulated by pharmacological manipulation of biogenic amines. We propose that foraging experiences act on biogenic amine pathways to induce enduring changes to stimulus responsiveness. To simulate varied foraging conditions, freely-moving bees were housed in cages where feeders offered combinations of sucrose solution, floral scents, and aversive electric shock. Transient effects were excluded by providing bees with neutral conditions for three days prior to all subsequent assays. Sucrose responsiveness was reduced in bees that had foraged for scented rather than unscented sucrose under benign conditions. This was not the case under aversive foraging conditions, suggesting an adaptive tuning process which maximizes preference for high quality, non-aversive floral sites. Foraging conditions also influenced antennal lobe octopamine and serotonin, neuromodulators involved in stimulus responsiveness and foraging site evaluation. Our results suggest that individuals' foraging experiences durably modify neurochemistry and shape future foraging behaviour.