Exploratory non-floral resource surveys: A novel approach for contemporary bee monitoring with implications for site specific conservation and management

Sampling biases are a well-known aspect associated with survey methodology used to monitor bee communities. Monitoring protocols that don’t consider the biases of methods utilized, risk drawing incomplete or incorrect conclusions about factors that influence bee communities. Therefore, it has been recommended a combination of methods be used to census bee faunas. Surveys in contemporary bee monitoring typically include the passive sampling of bees using “bowl traps”, supplemented with the active hand-netting of bees from floral resources along transects. It is assumed that when combined these methods complement each other’s biases and adequately sample a community, with “bowl traps” attracting and collecting species that researchers may easily miss while hand-netting at flowers. But despite their ability to fill each other’s taxonomic bias, these methods are still functionally biased towards the flower-visiting behaviors of bee species. In this study, we compared the traditional method of netting bees from floral resources with an exploratory non-floral sampling method that targets bees from nesting and mating resources to census bee communities in mid-Missouri. We found that bee communities significantly differed between sampling methods with cleptoparasites being represented in higher richness and abundance within non-floral resource surveys. Additionally, previously unknown details on the natural history of rare bee species were uncovered throughout the course of non-floral surveys. In summary, this work highlights how the reliance on sampling methodology that solely records bee species based on their attraction to floral resources may taxonomically bias communities, as well as obscure the importance of non-floral resources within habitats.