It's Been Another Rough Year for Honeybees

By Katie Valentine, ThinkProgress

12 May 16

n Tuesday, the Bee Informed Partnership released its annual report on total losses of managed honeybees — those kept by beekeepers — across the country. The survey, which asked beekeepers about bee losses between April 2015 and April 2016, showed that U.S. beekeepers lost 44 percent of their colonies in that timeframe. That means that total losses worsened compared to last year’s survey, which reported losses of 42.1 percent.

These losses are a big deal for beekeepers, who collectively say that 18.7 percent is about the maximum amount of bees they can lose without serious economic impacts. They’re also a big deal for the country’s food supply: Crops like almonds, cherries, and blueberries are heavily dependent on honeybees, and the pollination services the insects provide come to $10 to $15 billion in total per year.

The survey, which gathered data from 5,700 beekeepers from 48 states, also found that summer bee losses were elevated for the second year in a row. That’s unusual: As Dennis vanEngelsdorp, co-author of the report and assistant professor of entomology at the University of Maryland, told ThinkProgress last year, summertime should be “paradise” for bees, with plenty of blooming plants to forage from. Some losses in the winter, when temperatures drop and plants aren’t in bloom, are expected — losses in summer aren’t.

VanEngelsdorp said Tuesday that scientists think pesticides could be playing a role in these summer losses — but that’s just a theory, he added via email to ThinkProgress. Poor nutrition may also be part of the problem: In some regions, there aren’t as many flower-rich meadows as there used to be — instead, they’re being plowed to make room for crops and other development. These wildflower fields provide a good source of nutrition for bees, so without them, bees may be becoming less healthy. Researchers are still trying to determine just what is causing bees to die in the summer.

A variety of factors are likely contributing to losses overall. The survey singled out the varroa mite, a tiny parasite that’s been ravaging bee colonies over the last several years. The mite attaches itself to bees and sucks out their circulatory fluid, weakening the bees and spreading diseases, including the deformed wing virus, which causes young bees to develop useless, crumpled-up wings.

“Many backyard beekeepers don’t have any varroa control strategies in place. We think this results in colonies collapsing and spreading mites to neighboring colonies that are otherwise well-managed for mites,” Nathalie Steinhauer, a graduate student in the UMD Department of Entomology and co-author of the report said in a statement. “We are seeing more evidence to suggest that good beekeepers who take the right steps to control mites are losing colonies in this way, through no fault of their own.”

Small-scale beekeepers do have some methods of controlling mite populations — for instance, some dust bees with powdered sugar, which prompts bees to increase their grooming activity and causes the mites to fall off. Beekeepers can use miticides to control the pests, but varroa mites breed extremely quickly and thus build up a resistance to chemicals rapidly. So efforts to combat the mite haven’t been completely successful. Some scientists, however, are trying to find other ways to control the mite: One beekeeper and entomologist in Washington is doing experiments to determine whether mushroom juice could help bees build up a resistance to the mite.

VanEngelsdorp said he and other researchers think that "pesticides that kill some bees, but not the entire colony may cause varroa to be more problematic." The theory behind that is that these pesticides reduce the number of bees in a colony, but don't reduce the number of mites, meaning that there's more mites per bee.

Pesticides have long been considered one of the contributing factors in bees' decline, though like most things surrounding honeybee health, they're still being studied. This year, the Environmental Protection Agency released its first findings on neonicotinoids, a widely-used class of pesticide that's been found in other research to affect bees' brains. The EPA is looking at four neonic pesticides this year, to see how they impact bees. Its first study was on imidacloprid, and it found that the pesticide is harmful to bees in high enough concentrations. Since concentrations differ from crop to crop, the agency found that some crops, like like cotton and citrus, were harmful to bees, but others, like like corn and berries, weren't.

In addition to publishing assessments on three other forms of neonics, the EPA plans to do an assessment of the overall ecological effects of imidacloprid by December of this year. The agency may choose to take action on one or all of these pesticides once the commenting period for them ends. One state hasn't waited for the EPA, however — last month, Maryland became the first state in the nation to enact a partial ban on neonics in an effort to protect honeybees and other pollinators in the state.