Nectar concentrating behavior by bees (Hymenoptera Anthophila)

Nectar is one of the most important resources used by bees. It has long been known that some bees concentrate nectar externally with their mouthparts, including honey bees and stingless bees. However, observations of this behavior in disparate bee groups suggest this behavior is widespread. Here, we combine accounts and images from publications, community science portals, and our field observations to document the breadth of nectar concentrating behavior in bees. We find this behavior to be taxonomically widespread, with observations of nectar concentrating behavior documented in 51 genera in six families. It is especially conspicuous in halictid and hylaeine bees. Nectar concentrating has various purposes, including preparation for long-term storage in hives, modification before adding to larval provisions, removal of excess water for efficient storage in the crop, thermoregulation, and potentially for nest construction. Our methods highlight how community science images validated by experts represent a rapidly growing source for aggregating novel behavioral data.