This story is part of National Geographic's special eight-month Future of Food series.
Despite brutal weather in much of the nation, the die-off of honeybees over the winter of 2013-2014 was significantly lower than the average annual losses recorded over the previous seven winters, according to a new report from the U.S. Department of Agriculture.
Even so, the USDA's survey of beekeepers found that nearly a quarter of the bees in managed honeybee colonies—a total of 23.2 percent nationwide—perished from October 2013 to April 2014.
That was far better than the average annual loss of 29.6 percent reported since 2007, and the 30.5 percent loss recorded during the winter of 2012-2013. But it's appreciably higher than the threshold of 18.9 percent losses that beekeepers consider economically sustainable, the USDA said.
"This year's survey results, while encouraging, do not provide much comfort because it is not known why the bees seemed to do better this past winter than previous winters," said Gene Robinson, director of the Institute for Genomic Biology and an entomology expert at the University of Illinois at Urbana-Champaign. "We can't rest until we really understand the factors that drive differences in losses."
In a Harvard study released last week, researchers reported what they called "convincing evidence" that neonicotinoid pesticides used on crops are linked to colony collapse disorder, a phenomenon in which adult bees simply disappear from their hives. (See "The Plight of the Honeybee.")
"If we want to produce fruits and nuts in the U.S., we need a healthy bee population," said Dennis vanEngelsdorp, a University of Maryland assistant professor who is the leader of the survey and director of the Bee Informed Partnership.
Robinson told National Geographic that the colony numbers need to be stabilized in order to "safeguard our food supply." Honeybees pollinate plants that produce about a third of the food Americans eat, including apples, almonds, watermelons, and beans.
VanEngelsdorp said measures that might help stem bee losses would include a reevaluation of pesticide use, the maintenance of clean forage for sire bees, and better control of Varroa mites, the most damaging pest to honeybees. "Everyone should buy local honey, stop spraying herbicides on their lawn, and plant a pollinator garden," he said.
Chensheng Lu, who led the recent Harvard study, is not feeling optimistic that a solution is on the horizon. "The USDA has not mentioned how it will implement measures or policies to curb the continuing losses of bee colonies," said Lu, an associate professor of environmental exposure biology in the Harvard School of Public Health. "Keep in mind that not just bees are in decline; birds, fireflies, and others are also in decline."
The USDA has announced plans to host a summit in October to discuss the nutrition and forage needs of pollinators.