The Impact of Floral Diversity on Bumble Bee Colony Development, Pollination Efficacy, and Fruit Production in Tomatoes

Abstract

The environment in which pollinators are reared may influence both their health and their pollination performance. We compared the performance of 12 colonies of bumble bees (Bombus terrestris), each in their own simple (tomato monoculture) or florally diverse (tomatoes, borage, and lavender) arena inside a glasshouse. Foragers were observed daily to determine flower visitation rate to tomato plants, and fruit produced by those plants was weighed to determine pollinator efficacy. We found that colonies reared in florally diverse environments had a higher proportion of foragers overall. Moreover, adding floral resources to a tomato crop resulted in increased total crop yield, whereas individual tomatoes reared in the simple monoculture environment were larger than those in the diverse. These results provide an important step in understanding the extent to which bumble bee health and flower visiting behaviour is influenced by the complexity of the foraging environment, and how a diverse floral environment may enhance pollinator behaviour toward a focal crop plant (e.g., tomatoes).

Keywords: borage, crop pollination, greenhouse pollination, semi-natural environment