Queen honey bee (Apis mellifera) survival and colony performance after overwintering mated queens indoors

Honey bee, Apis mellifera L. (Hymenoptera: Apidae) winter colony mortality has reached sustained high levels and beekeepers depend on the availability of mated honey bee queens in early spring to recoup colony losses. Unfortunately, importing mated queens from other countries is currently the only reliable option meeting the demands of commercial beekeeping each spring in Canada. However, relying on queen imports brings another set of challenges, as supply chains can be disrupted, border crossings closed, imports prohibited, and the transportation of live animals can be stressful. This study explored the potential for Canadian beekeepers to supply queens in early spring by overwintering queens in queen banks that mated the previous summer. Queens were overwintered indoors in five queen banks. The following spring, the overwintered banked queens and a group of newly mated imported queens were introduced to colonies to evaluate queen introduction success and colony performance and survival over the following year. Queen survival in overwintered queen banks was low, with only 15% queen survival overall. Sperm viability of the banked queens prior to overwintering in queen banks was 30% higher than queens post-overwintering in queen banks. However, queen introduction success in the spring 2021, colony size, honey yield, and winter survival did not differ among queens that overwintered in queen banks and newly mated queens that were imported that spring. These results suggest banked overwintered queens have comparable performance to newly mated imported queens; although, overwintering mated queens in queen banks is risky, as entire queen banks can be lost, significantly reducing queen survival and the availability of mated queens in early spring.