Variation in water and sucrose responsiveness during the foraging season affects proboscis extension learning in honey bees

Honey bee foragers often show a variation in laboratory proboscis extension learning during the foraging season, making comparisons between experiments difficult. We analysed whether the seasonal variation in learning performance was related to a variation in sucrose responsiveness in pollen and non-pollen foragers. Pollen foragers were very responsive to water and sucrose throughout the season. Non-pollen foragers were overall less responsive and showed more variation. Sucrose responsiveness strongly correlated with tactile and olfactory learning performance in pollen and non-pollen foragers throughout the season. Learning performance was significantly better when sucrose responsiveness was high than when it was low. We suggest conditioning bees that have uniform sucrose responsiveness throughout the season to reduce experimental variance.