A review and updated classification of pollen gathering behavior in bees (Hymenoptera: Apoidea).

Authors: PORTMAN, ZACHARY - University Of Minnesota; ORR, MICHAEL - Chinese Academy Of Sciences; Griswold, Terry

Submitted to: Journal of Hymenoptera Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2019
Publication Date: 8/30/2019
Citation: Portman, Z.M., Orr, M.C., Griswold, T.L. 2019. A review and updated classification of pollen gathering behavior in bees (Hymenoptera: Apoidea). Journal of Hymenoptera Research. 71:171-208. https://doi.org/10.3897/jhr.71.32671.
DOI: https://doi.org/10.3897/jhr.71.32671

Interpretive Summary: The ability of bees to gather pollen is essential for reproduction. Understanding how bees accomplish this is challenging for a number of reasons: Bees are small and active so it is difficult to see how they are gathering pollen from flowers. The actions they use to gather pollen are complex. The vocabulary that has been used to describe pollen gathering behavior has not been precise. The same term has been used for different actions and different words have been used for the same action. Here we provide videos of different ways bees gather pollen and provide a standardized vocabulary for the various behaviors. While bees sometimes gather pollen incidentally on their bodies, the focus is on active pollen gathering. There are six specific pollen gathering methods: scraping with the extremities, buzzing, rubbing with the body (including rubbing with the underside of the abdomen, rubbing with the face, tapping, and rasping. Bee species differ in which method they use and specific examples are provided for each. Sometimes a bee species combines more than one method to create complex ways of gathering pollen. This classification sets the groundwork for further research on how plastic behaviors are in different species. It also provides a framework for assessing the relative effectiveness of different pollen gathering behaviors.

Technical Abstract: Pollen is the primary protein and nutrient source for bees and they employ many different behaviors to gather it. Numerous terms have been coined to describe pollen gathering behaviors, creating confusion as many terms are not clearly-defined or overlap with existing terms. There is a need for a clear yet flexible classification that enables accurate, succinct descriptions of pollen gathering behaviors to enable meaningful discussion and comparison. Here, we classify the different pollen gathering behaviors into two main classes: active and incidental pollen collection. Active pollen collection is subdivided into six behaviors: scraping with the extremities, buzzing, rubbing with the body and/or scopae, rubbing with the face, tapping, and rasping. In addition to the active and incidental pollen gathering behaviors, many bees have an intermediate step in which they temporarily accumulate pollen on a discrete patch of specialized hairs. Each behavior is described and illustrated with video examples. Many of these behaviors can be further broken down based on the variations found in different bee species. Different species or individual bees mix and match these pollen collecting behaviors depending on their behavioral plasticity and host plant morphology. Taken together, the different behaviors are combined to create complex behavioral repertoires built on a foundation of simple and basic steps. This classification sets the groundwork for further research on various topics, including behavioral plasticity in different species, comparisons between generalists and specialists, and the relative effectiveness of different pollen gathering behaviors.