Meeting Abstract
Bees foraging on flowers constitute a model system in the study of animal cognition. Although flowering plants offer a variety of rewards and pollinators must collect multiple types of rewards in order to survive, the literature on bee learning is skewed nearly exclusively towards learning in the context of nectar rewards. Bees in particular must collect two nutritionally complementary floral rewards in order to survive: nectar, their primary source of carbohydrates, and pollen, their primary source of protein. While many flowering plants offer both rewards, 6-8% of angiosperm species offer only pollen rewards. In this study, we asked if bees can learn preferences for pollen-only species and what components of the flower are involved. To ensure that nectar was not involved in learning, we used plant species that offered only pollen as a reward. Using an absolute conditioning protocol, bees were given experience collecting pollen from a single species. Their preference for flowers of that species relative to a second species was tested either one or 24 hours later. We found that the preference of experienced bees was shifted strongly towards the experienced species, relative to the preference of naïve bees. Results of the 24 hour test provided strong evidence of long-term memory. These changes in preference are best explained as associative learning. Additionally, we evaluated the role of corolla and anther in learned preferences. While both the corolla and anther responses are involved, anther responses are more strongly influenced by experience. We discuss how learned preferences, such as those shown here, can influence the evolution of floral traits, particularly with respect to pollen-only species.
