Nearly a quarter of the country’s managed honeybee colonies were lost last summer in the U.S. and even more were lost this winter, according to a report issued this week by the Bee Informed Partnership.
Why are they disappearing? Bee Informed data points to parasitic mites and more.
This nonprofit organization is a collaboration between the Bee Labs at Auburn University and the University of Maryland. It has monitored colony loss since 2007 and summer colony losses have been observed since 2010.
“Although the total number of honey bee colonies in the country has remained relatively stable over the last 20 years… loss rates remain high, indicating that beekeepers are under substantial pressure to recover from losses by creating new colonies every year,” said the group.
According to the U.S. Department of Agriculture, honeybees pollinate $15 billion worth of crops in the U.S. annually. These include more than 130 types of fruits, nuts, and vegetables. Additionally, they also produce around $3.2 million worth of honey.
From last April through last October, an estimated 24.9% of managed colonies were lost. Then, from last October through this April, an estimated 37.4% of managed colonies in the United States were lost, based on the survey of 3,006 beekeepers with 314,000 colonies. That’s around 12% of the estimated 2.7 million colonies in the country.
“This winter loss rate was 13.2 percentage points in excess of the previous winter loss rate,” said Bee Informed. In fact, it was the second highest year of winter loss after 2018-2019 (37.7%).
Overall, from April 2022 to this April, nearly half of all colonies – an estimated 48.2% – were lost, 8.5 percentage points higher than the 12-year average. A parasite known as “varroa” (the Varroa destructor mite, and its associated viruses) was the leading cause of honeybee colony loss during the winter.
“This mite weakens honey bees by sucking hemolymph (“blood”) from its host and by transmitting bee pathogens,” according to Pollinator Partnership.
In the summer, “queen issues” were cited as the major reason for colony loss, per the Bee Informed report. Pollinator Partnership explained that queens – the only honeybees in a colony with developed ovaries – can severely impact colony health.
“Queens with low egg-laying capacity can limit the numbers of health workers produced, while unhealthy queens can die or be killed by workers, causing a break in brood rearing that again limits colony growth and productivity,” it said. “Poor quality queens are consistently cited by beekeepers as a major factor underlying colony failure, and a longitudinal study of colonies indicated that loss of a queen or lack of laying by a queen was one of the two factors linked to colony loss. Several factors seems to impact queen quality, including rearing conditions and mating number.”
Adverse weather was another factor cited by backyard, sideline and commercial beekeepers. Starvation was also cited by backyard and sideline beekeepers.
Bee Informed also tracks honeybee colony losses by state with its colony loss map. It is currently displaying winter 2021-22 data that showed Pennsylvania lost an estimated 38.27% of colonies, which was on the higher side but still lower than New Hampshire, the state with the highest percentage at around 77%.
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