A survey released this week shows a sharp increase in the death of American honey bees.
According to numbers released by the United Stated Department of Agriculture (USDA), 28 percent of bees died this past winter, up six percent from a year ago.
Some economists worry not only about the health of bees, but the impact the increase in deaths could have on food prices. The USDA estimates about 25 percent of the food we eat comes from plants pollinated by honey bees.
However, the USDA also reports there are more honey bees today in the U.S. than there were 10 years ago when concerns over 'Colony Collapse Disorder' began. So is this recent increase in bee deaths an anomaly or part of a more-troubling long-term trend?
'They continue not to do well and we really need to double our efforts to figure out why,' University of Maryland bee scientist and survey leader Dennis vanEngelsdorp said. 'Now you're losing well beyond what's normal.'
The figures come from a survey by the U.S. Department of Agriculture and others. It includes 5,756 beekeepers, which represent about 5 percent of the nation's 2.7 million commercial colonies. However, University of Montana bee scientist Jerry Bromenshenk questioned the reliability of the results because the survey relies on self-reporting. Based on what he heard from people, Bromenshenk suspects losses may be even bigger, especially in the East.
Perhaps even more alarming is that honeybee deaths in the summer now match winter, which traditionally had been when most bees were lost, vanEngelsdorp said.
For 2015-2016, the overall colony loss rate was 44 percent, which is also up from the previous two years, but scientists only started surveying summer deaths in 2010.
What might be behind the losses is worsening varroa mites, just one of several problems scientists have blamed for declining bee populations. Other causes include pesticides, disease and poor nutrition and food supply.
'Varroa was and is — and I'm afraid — will continue to be an enormous problem,' said May Berenbaum of the University of Illinois, who wasn't part of the survey.
Mites kill honeybees and bring in viruses that further weaken hives. And the pesticides used to fight them can reduce immunity to other problems, Berenbaum said in an email.
VanEnglesdorp said one problem is backyard beekeeper hobbyists who don't treat their bees for mites with pesticides, even organic ones. Their hives die and survivors full of mites head to new hives, spreading the problem, he said.
Bromenshenk said he sees the same no-treat problem when local backyard beekeepers take his classes. Bromenshenk said he knows many beekeepers who treat their colonies, do well and then suddenly get overloaded when a no-treat neighbor's hives died.