Dancing for their supper: Do honeybees adjust their recruitment dance in response to the protein content of pollen?

Abstract

Honeybees use the dance language to communicate the location of profitable food resources to nestmates. During nectar foraging, bees alter the duration of the return phase of the dance to reflect the source's quality. For more profitable resources, the return phase is shorter; this effectively makes the dance 'livelier'. Bees also increase the number of dance circuits when the nectar source is more profitable, and they are more likely to dance for such sources. As a result, the colony focuses on high-quality nectar sources. Here we ask whether foragers similarly adjust aspects of their dance when foraging for pollen according to the pollen's protein content. Pollen is essential for raising brood, and protein content varies substantially across plant species. We offered bees pollen, pollen substitutes or mixtures that differed in protein content and determined whether the duration of the return phase decreased and the number of dance circuits increased with increasing protein content. We further examined whether bees adjust return phase duration based on the protein content of naturally collected pollen. Lastly, we examined whether foragers are more likely to dance for pollen high in protein. Honeybees did not adjust the duration of the return phase or the number of dance circuits when mixtures contained more protein. Similarly, there was no relationship between protein content of natural pollen and return phase duration. Our results suggest that foragers cannot assess pollen's protein content. Bees were more likely to dance when collecting pure pollen, suggesting an important role of pollen-based cues in the regulation of pollen foraging.