A national survey of managed honey bee colony losses in the USA: Results from the Bee Informed Partnership for 2020–21 and 2021–22

Abstract

In recent years, high losses of Western honey bee (Apis mellifera) colonies have been reported in the United States. Because honey bees are important to agricultural systems, it is critical to document when high losses occur and to explore patterns of loss among beekeeper subgroups. We used a voluntary, retrospective questionnaire to ask U.S. beekeepers (backyard, sideline, and commercial) about their colony loss during the 2020-21 and 2021-22 beekeeping seasons. We found that U.S. beekeepers lost 50.8% (38.0-63.1; 95% b.CI) of their colonies in 2020-21, the highest annual (year-long) loss reported to date. During the following year, 2021-22, beekeepers lost 39.0% (31.5-47.9; 95% b.CI) of their colonies, which is close to the average of previously published annual loss rates (40.9%). In contrast to previous years, backyard beekeepers (managing 50 or fewer colonies) had an elevated summer loss across both years and commercial beekeepers (managing >500 colonies) reported "weather" as an important cause of colony loss in the summer of 2021. Our results show that severe colony losses still occur periodically. From these data on colony loss rates, it does not appear that the health of honey bee colonies in the U.S. has improved since this survey began in 2008. We suggest that research should continue to focus on stressors that beekeepers most often perceive to be leading causes of loss-Varroa destructor mites, queen issues, and weather.