Differences in color learning between pollen- and sucrose-rewarded bees

What bees learn during pollen collection, and how they might discriminate between flowers on the basis of the quality of this reward, is not well understood. Recently we showed that bees learn to associate colors with differences in pollen rewards. Extending these findings, we present here additional evidence to suggest that the strength and time-course of memory formation may differ between pollen- and sucrose-rewarded bees. Color-na€ıve honeybees, trained with pollen or sucrose rewards to discriminate colored stimuli, were found to differ in their responses when recalling learnt information after reversal training. Such differences could affect the decision-making and foraging dynamics of individual bees when collecting different types of floral rewards. The ability of bees to learn the location of profitable flower patches and the features of highly rewarding flowers is an adapta-tion to efficiently exploit flowers as a variable food source.1-5 This learning-based flower constancy has been widely studied in nec-tar-foraging pollinators5-7 and is likely to have been a powerful evolutionary driver in the dominance of nectar as the main reward type in modern angiosperms.8-10 However, insect pollination pre-dates the emergence of nectar-producing organs, and not all flow