COMPARING THE FORAGING BEHAVIOR OF THE HONEY BEE Apis mellifera L. AND THE SOUTH AMERICAN NATIVE BUMBLEBEE Bombus atratus F., IN HIGHBUSH BLUEBERRY Vaccinium corymbosum L. CROPS

CECILIA ESTRAVIS BARCALA; FLORENCIA PALOTTINI; IVANA MACRI; FARINA, WALTER M.

Berlin

Simposio; XI International Symposium on Pollination; 2018

Honey bees are the main pollinators of highbush blueberry crops, which include cultivars of varying degrees of pollinator dependency and diverse flower morphologies challenging the foraging efficiency of honey bees. The native bumblebee is an alternative pollinator increasingly managed in this crop. Our aim was to compare the foraging behavior of both species, at the individual and population level, in two different blueberry varieties. After describing the floral traits, we assessed the density of bees on the crop (grown under high tunnels), considering the distribution of colonies. Additionally, we monitored individual foraging visits, type of the exploited resource and floral constancy. Results show that both cultivars presented similar floral morphology and nectar quality. At the individual level, each pollinator species collected resources differentially. Bumblebees visited a higher number of flowers and gathered pollen in a greater proportion throughout the day. Both species exhibited high floral constancy. At population level, the number of honey bees per tunnel was significantly higher, and was not affected by the presence of bumblebee colonies. In conclusion, despite the superior individual foraging behavior of bumblebees, honey bees, due to its large population, performed as a convenient pollinator of blueberry.