Meeting Abstract
Plants attract pollinators with visually complex displays and reward them with nutritionally complex resources. Ever since Karl von Frisch’s Nobel Prize-winning work in the early 1900s, study of how bees learn these floral stimuli has emerged as an important model system for the study of learning, memory and foraging. However, nearly every study of bee cognition to date has used a sole reward, nectar, which serves as bees’ main source of carbohydrates. However, bees also collect pollen from plants as their only source of protein. Surprisingly, little is known regarding whether bees can learn about flowers based on pollen rewards, and how this might interact with their ability to learn nectar associations. As plants may reward bees with nectar, pollen, or both resources, bees’ relative ability to learn and remember floral features has implications for both their own foraging efficiency as well as conspecific pollen transfer for the plant. In a series of lab-based color learning experiments using artificial flowers, we show for the first time that bumblebees (Bombus impatiens) can learn to associate multiple visual cues with a pure pollen reward, and that these associations are remembered long-term. We found that bees can ‘cope’ with learning about these two reward types simultaneously when collecting each from different flowers, but that the presence of both nectar and pollen on a flower impaired a bee’s ability to learn the pollen-color association. These results have implications for understanding the functional ecology of floral rewards and raise more general questions about how animals learn when multiple rewards are available— a common but underexplored feature of foraging in natural environments.
