A review of global trends in the study types used to investigate bee nesting biology

Abstract

Nesting resources are key inputs for the survival and reproduction of bees. However, relatively little work has been done on threats bees face from a nesting-biology perspective, with most studies focusing on floral resources. Much of what is known about bee nesting is thought to come from opportunistic observations within descriptive, natural history studies, but the relative contribution of these and ecological or artificial experimental studies remains unquantified. Via a systematic literature search, we quantified the contribution of different study types to our current knowledge on bee nesting biology and how bees face threats related to their nesting habits. From 2000 screened articles, we found that all study types contributed to our total knowledge in complementary ways. Natural history studies constituted most studies (∼60%) and were the primary study type investigating specific nest site characteristics, nest architecture, and nesting behavior. Conversely, ecological studies (27%) provided more information about threats bees face, while artificial experimental studies (13%) predominantly tested mechanisms or highly-specific behaviors. Ground-nesting species were underrepresented in all study types (33%), especially in ecological and artificial experimental studies. Overall, natural history studies form the foundation of our knowledge on bee nesting, and ecological and artificial experimental studies enable us to extend and test related hypotheses in rigorous frameworks. Future work will benefit greatly from efforts to synthesize and standardize measurements and methods both within and across these study types, enabling a more comprehensive assessment of threats bees face and more effective management and conservation.

Keywords

• Apoidea
• Hymenoptera
• Bee biology
• Life history
• Natural history
• Traits