Sandy DeBano, Oregon State University entomologist and PNW Research Station collaborator, describes methods to capture bees along Meadow Creek, Starkey Experimental Forest and Range. USDA Forest Service photo by Mary Rowland.
Native bees are declining worldwide, but conserving or restoring their habitat requires better understanding of bee-flower associations. High-quality bee habitat includes flowers that provide pollen and nectar preferred by bees. However, little data exist about which plants are commonly used by bees in the Pacific Northwest, or if bees prefer certain plant characteristics over others.
To learn more, scientists examined bee and plant communities in an Oregon riparian ecosystem. Their purpose was to determine which plants are most frequently visited by bees, identify plants preferred by bees, and examine how native status, flower color, and floral morphology of plant species affect the types of bee visitors.
They found that many blooming plants received a diverse set of bee visitors, but some plants had a higher number and species richness of visiting bees than others. No plant species in the study area seemed limited to visitation by a small set of specialist bees. The number and type of visiting bees were not influenced by the plant’s native status (i.e., native vs. introduced). However, the shape of the flower—but not color—significantly affected the types of bees visiting plants. Bilaterally symmetrical and medium tubular flowers, with nectar and pollen typically more difficult to reach, attracted larger bees with longer tongues, while smaller and more easily accessible flowers attracted smaller bees with shorter tongues.
These results suggest that certain plants are particularly useful for supporting abundant and diverse bee communities, and high diversity in the morphology of blooming plants is a key factor to consider when restoring riparian areas for bee pollinators.
Roof, S.M.; S. J. DeBano, S.J.; Rowland; M.M.; Burrows, S. 2018. Associations between blooming plants and their bee visitors in a riparian ecosystem in eastern Oregon. Northwest Science. 92: 119-135. https://doi.org/10.3955/046.092.0205.