Nectar is one of the most important resources used by bees. It has long been known that some bees concentrate nectar externally, such as honey bees and stingless bees. However, observations of external concentrating behavior in disparate bee groups suggests this behavior is much more widespread. Here, we combine review of the literature, community science data from BugGuide, and personal observations to document the breadth of nectar concentrating behavior in bees. Our results demonstrate that nectar concentrating is widespread in bees and is not limited to particular sexes or taxonomic groups. Nectar concentrating has various purposes, including preparation for long-term storage, modification before adding to larval provisions, removal of excess water for efficient storage in the crop, thermoregulation, and potentially for nest construction. Further, our methods highlight how community science efforts represent an opportunity to both inform the public about bees and to harness that enthusiasm for the collection of scientific data. Using community-gathered data with engaged taxonomic experts, we were able to generate robust and informative scientific data that informs our understanding of the prevalence of nectar concentrating behavior in bees.
