Evaluating the strength of western honey bee (Apis mellifera L.) colonies fed pollen substitutes over winter

Western honey bees (Apis mellifera L.) need good nutrition to combat multiple stressors. Beekeepers often feed artificial protein diets (i.e. pollen substitutes) when their colonies lack natural pollen resources. However, it is unclear whether pollen substitutes improve honey bee colony strength and health during pollen dearths and when no pollen stores are available, as can occur during late fall and winter. We fed 56 managed honey bee colonies one of two commercially available pollen substitutes (AP23(R) and MegaBee(R)) or no diet (control) over the late fall and winter in north-central Florida under a simulated pollen dearth and when the colonies lacked pollen stores. We determined the change in adult bee mass and the final brood mass of each colony throughout the feeding period. On average, colonies in each of the three treatment groups experienced a loss in total adult bee mass during the feeding period, which is typical of colonies during winter. Nevertheless, colonies that received AP23 lost significantly less adult bee mass than did control colonies, with colonies that received MegaBee having a loss in adult bee mass intermediate to those of the other two groups. The AP23 and MegaBee colonies had significantly greater brood mass than did control colonies. When accounting for total change in colony biomass (adult bee mass + brood mass), the AP23 group lost significantly less mass than did control colonies, with the MegaBee colonies having a mass loss intermediate to those of the other two groups. Colonies consumed significantly more AP23 than they consumed MegaBee. Collectively, our data suggest that it may be beneficial for beekeepers in warm climates to feed pollen substitutes to stressed honey bee colonies over winter to lessen the loss in total colony biomass.

Automated summary

A study showed that feeding pollen substitutes to stressed honey bee colonies during winter can reduce the loss in total colony biomass and improve brood mass, with AP23 being more effective in this aspect.