US beekeepers continue to report high colony loss rates, no clear improvement
University of Maryland
These losses mark the second highest loss rate the survey has recorded since it began in 2006 (6.1 percentage points higher than the average annual loss rate of 39.4%).
The survey results highlight the continuing high rates of honey bee colony turnover. The high loss rate was driven by both elevated summer and winter losses this year, with no clear progression toward improvement for beekeepers and their colonies.
BIP hopes to use the survey results to better understand
how colony losses are experienced by beekeepers, and what can be done to reduce
losses in future seasons.
Since beekeepers began noticing
higher losses in their colonies in the early 2000s, agricultural agencies,
researchers, and the beekeeping industry have been working together to
understand why and develop best management practices to reduce their losses.
The BIP annual colony loss survey, which has been conducted since 2006, has
been integral to that process.
"This year's survey results show that colony losses are still high," says Nathalie Steinhauer, BIP's science coordinator and a post-doctoral researcher in the University of Maryland Department of Entomology.
"Not all beekeepers are affected at the
same intensity, but the turnover rate of colonies is still overall higher than
beekeepers deem acceptable [normal or acceptable turnover is defined at about
20%]. We should remember, however, that loss rates are not the same as
population decline. The recent numbers of honey bee colonies in the U.S. are
relatively stable despite those high losses, but that's 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 is 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%, which is 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 points 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 effort helps to keep a finger on the pulse
of what is going on with beekeepers to identify why high losses are persisting.
"Though we see fluctuations
from year to year, the worrisome part is we see no progression towards a
reduction of losses," says Steinhauer.
"The long-term efforts of the
BIP's annual survey are so important to monitoring honey bee colony losses and
beekeeper management over time, and hopefully to identifying key practices that
are protective for colonies," stresses Williams. "Because of the
close connection of honey bees to the environment, the survey's long-term data
may lend itself to insights into how changes in land-use and weather impact the
beekeeping industry too. These are really understudied areas at the
moment."
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) beekeeping 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,"
explains Williams. "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."
While the survey suggests that
beekeepers are remaining responsive to the current best management practices
and health concerns of their colonies, the loss data shows little progress.
"We see in the survey signs that beekeepers are adjusting their practices over time," says Steinhauer.
"We also see that their perception of risk is changing. The level of
acceptable loss, which was originally around 15% in earlier years of the
survey, has crept up to 23% this year. So that tells us beekeepers are thinking
about those factors that affect honey bee health more actively. We also see
some beneficial changes in agricultural practices that could affect honey bee
health, like changes in spray recommendations. But there are still a lot of
issues that are left unaddressed. It seems we're running to stand still because
beekeepers are changing their practices, and yet we still don't see a clear
improvement in their loss rates."
BIP stresses that the lack of
improvement in losses is a clear call for more attention and efforts to be paid
on finding solutions, especially concerning varroa mites. The BIP annual loss
survey continues to be an important part of documenting the data necessary to
drive future research, best management practice recommendations, and support
for honey bee health.
"We hope to continue BIP's
survey effort to record colony losses experienced by U.S. beekeepers and
explore beekeepers' management practices," ensures Steinhauer. "We
have a general idea of what practices are associated with higher success, but
the devil is in the details, and we need to understand why the implementation
of some practices are more successful in some cases than others. Of course
beekeepers also need the support of the public and political sectors. We need
to recreate environments that are conducive to healthy bees, and that will
benefit both honey bees and native bees or other wild pollinators."
The survey is conducted by the Bee
Informed Partnership with data collected and analyzed by the University of
Maryland and Auburn University. Survey results are available here on the Bee
Informed Partnership website, with a summary provided below.
Winter Loss Estimates:
- 1 October 2020 -- 1 April 2021: 32.2% losses
- 9.6 percentage points higher than winter 2019-2020: 22.6%
- 3.9 percentage points higher than average winter loss (2006-2021): 28.3%
Summer Loss Estimates:
- 1 April 2020 -- 1 October 2020: 31.1% losses
- 0.9 percentage points lower than summer 2019: 32.1%
- 8.6 percentage points higher than average summer loss (2010-2020): 22.8%
Total Annual Loss Estimates:
- 1 April 2020 -- 1 April 2021: 45.5% losses
- 1.8 percentage points higher than 2019-2020: 43.7%
- 6.1 percentage points higher than average annual loss (2010-2021): 39.4%
Loss Comparison by Beekeeper
Category:
- Backyard beekeepers (manage 50 or fewer colonies): 27.0% summer vs. 42.0% winter losses
- Sideliner (manage 51-500 colonies): 19.5% summer vs. 31.9% winter losses
- Commercial (manage more than 500 colonies): 30.9% summer vs. 32.9% winter losses