The Pollination efficiency and foraging behavior of Bombus pauloensis (Hymenoptera: Apidae) on two highbush blueberry cultivars (Vaccinium corymbosum)

Abstract

Bombus pauloensis Friese is a promising managed bumblebee that can pollinate crops in South America. Highbush blueberry (Vaccinium corymbosum L.) is a recently introduced and economically promising crop cultivated in open fields or greenhouses in Colombia. Although this crop is known to be pollinator-dependent, the efficiency of local pollinators in this geographic area has yet to be established. This study aimed to establish the pollination effectiveness and foraging behavior of B. pauloensis in two of the most common cultivars of highbush blueberries planted in a high Andean region of Colombia. We hand-reared and located B. pauloensis colonies in two different plantations of Sharpblue (open field) and Biloxi (greenhouse) cultivars. The time spent per flower and the number of flowers visited per minute of 300 foragers were registered to characterize the foraging behavior in both cultivars. Pollen analysis was performed once from corbicular loads, larvae, larval cells, and colony feces to identify the pollen sources collected by colonies located in the Sharpblue crop. Analysis of fruit quality was performed to establish the effect of B. pauloensis pollination. Foragers visited blueberry flowers with a corolla aperture of more than 3mm in both cultivars but spent more time visiting Biloxi than Sharpblue flowers. B. pauloensis pollination reduced the ripening time and increased the fresh and dry weight and the number of true seeds in both cultivars. Our results provide evidence that B. pauloensis pollination can improve the fruit quality in the blueberry cultivars evaluated here in Colombia, making it an efficient native pollinator for a promising commercial species.

Keywords

• native bees
• Ecology
• fruit quality
• palynology