U.S. Beekeepers Continue to Report High Colony Loss Rates, UMD-led Survey Finds

Beekeepers across the United States lost a staggering 45.5% of their managed honey bee colonies from April 2020 to April 2021, according to preliminary results of the 15th annual survey conducted by the nonprofit Bee Informed Partnership (BIP) led by the University of Maryland. 

The survey results, released yesterday, show the second-highest loss rate since it began in 2006 and highlight the continuing high rates of honey bee colony turnover nationwide. 

Since beekeepers began noticing the disturbing trend in the early 2000s, agricultural agencies, researchers and the beekeeping industry have been working together to understand it and develop best management practices to reduce their losses. The BIP annual colony loss survey has been integral to that process.

“Not all beekeepers are affected at the same intensity, but the turnover rate of colonies is still overall higher than beekeepers deem acceptable,” said Nathalie Steinhauer, BIP’s science coordinator and a postdoctoral researcher in UMD’s Department of Entomology. Normal or acceptable turnover is defined at about 20%.

Loss rates are not the same as population decline, she said. The recent numbers of honey bee colonies in the U.S. are relatively stable despite those high losses, “because beekeepers invest a lot of time and effort to increase their operation size to mitigate their losses.”

Commercial honey bee operations are essential to agricultural production in the U.S., pollinating $15 billion worth of food crops each year. Honey bee colonies are moved around the country to pollinate important agricultural crops such as almonds, blueberries and apples. Minimizing their losses and ensuring the health of both commercial and backyard colonies are critical to food production and supply. 

“Beekeepers of all types consistently lose a high number of colonies each year, which puts a heavy burden on many of them to recoup those losses in time for major pollination events like California almonds,” says Geoffrey Williams, assistant professor of entomology at Auburn University and co-author of the survey. “Colony losses remain elevated, and this year’s annual and summer loss rates are among the highest recorded.”

This past year, winter losses were reported at 32.2%, or 9.6 percentage points higher than last year and 3.9 points higher than the survey average. Summer losses were some of the highest ever reported again this year at 31.1%, which is 0.9 percentage point lower than last year, but 8.6 points higher than the survey average.

The survey asks beekeeping operations of all sizes to track the survival or turnover rates of their honey bee colonies. This year, 3,347 beekeepers managing 192,384 colonies across the country responded to the survey, representing about 7% of the nation’s estimated 2.71 million managed colonies. 

This year, to get a better understanding of different management practices that may lead to loss fluctuations, the BIP team delivered two versions of the survey to cater to different beekeepers. The two surveys found that backyard (managing 50 or fewer colonies) and sideliner (managing 51-500 colonies) operations face both similar and distinct challenges to commercial beekeepers managing more than 500 colonies. While parasitic varroa mites continue to be a major issue for beekeepers regardless of operation size, queen management might be a factor that can lead to variation in seasonal colony losses.

“A colony needs a healthy, fully functioning queen before major pollination events to be productive,” Williams said. “A preliminary look into survey data reveals that commercial beekeepers almost always replace old queens with new ones during the summer, whereas only about half of backyard beekeepers do. Could this explain why commercial beekeepers lose fewer colonies in the subsequent winter than backyard beekeepers? Perhaps, but we need to dig deeper and possibly perform experiments to shed more light on this.”