Can pollen supplementation mitigate the impact of nutritional stress on honey bee colonies?

Abstract

One of the main driving forces of the Apis mellifera colony losses reported worldwide is the nutritional stress associated with monoculture areas. We previously demonstrated under field conditions that nutritional stress that occurred during the fall impacts honey bee colony strength and health in the short and long-term. Pollen supplementation to colonies during a nutritionally stressful period increased adult and brood populations and decreased the infection level of Nosema ceranae. When brood production continues in the winter season, pollen supplementation during this period could be another strategy to help colonies recover from the negative impact of the nutritional stress that occurred in the fall. Thus, in this study, we analyzed if supplementing colonies with polyfloral pollen in winter could be a useful strategy to mitigate fall nutritional stress. Firstly, colonies were exposed to a natural nutritional stress scenario. Secondly, they were relocated and divided into two experimental groups: one group was supplemented with polyfloral pollen, while the other remained as a control. The strength and health of the colonies were analyzed. Pollen supplementation increased adults and brood populations in the coldest months and it did not affect the infection level of Nosema spp. or RNA viruses. These results suggest that the negative impact of nutritional stress during the fall is difficult to mitigate during the winter.