Managed bumble bees (Bombus impatiens) (Hymenoptera: Apidae) caged with blueberry bushes at high density did not increase fruit set or fruit weight compared to open pollination
Highbush blueberry (Vaccinium corymbosum L.) is an important crop grown throughout Florida. Currently, most blueberry growers use honey bees (Apis mellifera L.) to provide pollination services for highbush blueberries even though bumble bees (Bombus spp.) have been shown to be more efficient at pollinating blueberries on a per bee basis. In general, contribution of bumble bees to the pollination of commercial highbush blueberries in Florida is unknown. Herein we determined if managed bumble bees could contribute to highbush blueberry pollination. There were four treatments in this study: two treatments of caged commercial bumble bee (Bombus impatiens Cresson) low and high weight hives), a treatment excluding all pollinators, and a final treatment which allowed all managed and wild pollinators) in the area have access to the plot. All treatments were located within a blueberry field containing two cultivars of blooming plants, ‘Emerald’ and ‘Millennia’, with each cage containing mature blueberry plants. We gathered data on fruit set, berry weight, and number of seeds produced per When pollinators were excluded, fruit set was significantly lower in both cultivars (<8%) compared to that in of the other treatments (>58%). Berry weight was not significantly different among the treatments, and the number seeds per berry did not show a clear response. This study emphasizes the importance of bumble bees as an effective pollinator of blueberries and the potential beneficial implications of the addition of bumble bees in commercial blueberry greenhouses or high tunnels.