Despite getting fewer headlines in recent years, the population of U.S. honeybees has continued to plunge, with billions dying each year from a condition known as colony collapse disorder (CCD). The demise of the bees is now raising greater concerns about the cost to the nation's food supply and the sustainability of the beekeeping industry itself.
Part of the problem, according to a new report by the Department of Agriculture, is that finding a specific cause of CCD remains elusive.
"It's like a perfect storm of reasons," said Kim Kalpan, a public affairs spokesperson for the research service of the U.S. Department of Agriculture.
"We've eliminated that it's one single cause. We're looking at several causes, including parasites, poor nutrition for the bees, viruses and drought conditions," Kaplan said. "We just don't know what it is at this point.
CCD has been around in the U.S. since 2006, when more than one quarter of the 2.4 million honey bee colonies were lost. Each year, more and more bees die.
According to the USDA, bee losses from CCD this past winter were 31.1 percent of all colonies. That's up from 22 percent the previous winter and slightly higher than the previous six-year loss average of 30.5 percent. It's estimated that 10 million beehives have been lost in the last six years at a cost of $2 billion, according to the USDA.