Effectiveness of supplementing honey bees with Bombus impatiens (Hymenoptera: Apidae) for pollination of highbush blueberry (Vaccinium corymbosum)

Pollination is a crucial component of fruit production, and in commercial highbush blueberry (Vaccinium corymbosum) this is achieved by using honey bees or bumble bees to supplement the contributions of wild bees. Combining both managed pollinators is expected to provide benefits from variable response to environmental conditions, thereby minimizing pollen limitation and ensuring maximal yield. To determine the potential benefits of adding a pollinator species to highbush blueberry, pollination parameters were compared between fields stocked only with honey bees and those also enhanced by addition of managed bumble bee (Bombus impatiens) colonies. Fruit set and berry weight values were compared between treatments and with distance from the colonies to assess their contributions to yield. We also measured colony activity and the percentage of blueberry pollen in bumble bee pollen loads. These results will help inform how effective commercially reared bumble bees are for highbush blueberry pollination and whether their cost provides an economic return.