Surveying the potential pollinators of black cherry

Black cherry (Prunus serotina) is an economically and ecologically valuable tree. Pennsylvania grows the highest quality black cherry in the world, with sales of cherry lumber and products accounting for a significant portion of the state’s timber sales. However, since 2000 the USDA Forest Service and the Pennsylvania Bureau of Forestry have documented a dramatic decline in the regeneration and seed production of black cherry. It has been hypothesized that one of the factors underpinning this decline is a lack of pollination. Black cherry requires insect pollination to produce viable seed, however, little is known about the pollinator communities present in forested landscapes and the services they provide for flowering timber trees such as black cherry. The objective of this study was to determine the potential pollinators of black cherry. During 2020, platform traps were deployed at low and high levels in the canopies of three flowering black cherry trees at four locations across Centre county, PA. Each platform trap consisted of three colored bowls, white, blue, and yellow. Canopy observations were also completed amid flowering, during which all insects interacting with the blooms were hand collected. Observations and hand collections yielded high counts of mining bees (Andrenidae), indicating their potential importance. Conversely, these insects appeared in low counts in bowl traps. These results suggest that standard methods of assessing insect communities in flowering trees (bowl traps) are not sufficient, and thus new approaches need to be developed for large-scale sampling.