Photo credit: USDA

Honeybee keepers reported the loss of 105,240 colonies to colony collapse disorder during the early months of this year, a 76% increase from last year and the highest total since 2016, said the USDA on Monday. The cause of colony collapse, when worker bees abandon a hive and leave behind a queen and plenty of food, is unknown. The phenomenon was first reported in 2006.

The annual Honey Bee Colonies report, based on a survey of beekeepers who have at least five colonies, said there were 2.88 million colonies in the United States on January 1, up 8% from 2019. Varroa mites, a parasite of bees, were again the top stressor of colonies. When it collects data for the report, the USDA asks about varroa mites, other pests and parasites, disease, pesticides, and other stresses.

Colony totals dropped to 2.59 million in 2016, the same year that 114,000 colonies collapsed, the largest loss to colony collapse disorder in the relatively short period the USDA has been compiling the bee report. The disorder is a concern because of the role bees and other pollinators play in food production.

“Pollination by managed honeybee colonies adds at least $15 billion to the value of U.S. agriculture annually through increased yields and superior-quality harvests,” says the USDA.

Researchers believe colony collapse is driven by a variety of factors, including disease-causing pathogens. Colonies can also be weakened by parasites, exposure to pesticides, poor nutrition, loss of habitat, and lack of genetic diversity. Beekeepers lost 44% of their colonies in the year ending this April 1, said the nonprofit Bee Informed Partnership, the second-highest rate since the group began doing surveys in 2006.

Five of seven crops, including apples, blueberries, and cherries, studied in 13 U.S. states “showed evidence that a lack of bees is hampering the amount of food that can be grown,” said the Guardian last week, citing research published by the Royal Society.