This post has been updated.
For years now, bees have been dropping like flies.
US beekeepers saw 42.1% of their honey bee colonies die off in 2014-2015, according to preliminary results of a US Department of Agriculture survey. Wild bees are also in trouble. In Europe, 9.2% of the continent’s almost 2,000 bee species are facing extinction, according to one assessment.
Now major governmental organizations are taking steps aimed at halting the deaths. Last week the US Environmental Protection Agency proposed new curbs on the use of pesticides some studies have linked to bee deaths. That proposal followed a relatively high-profile push by the Obama administration to tackle the issue, including making 7 million acres (2.8 million hectares) of federal land more friendly to bees. The European Union imposed a moratorium on use of certain pesticides two years ago.
These efforts are not based on altruism: Bees are crucial to the global food supply. Of the 100 crop species that provide 90% of the food in 146 countries, 71% are bee-pollinated, the UN Food and Agriculture Organization estimated in 2005. In the US alone, bees and other pollinators are responsible for $15 billion of crops each year. By some estimates, one of every three bites you take comes courtesy of these buzzing pollinators.
But while there is consensus that action is needed, the efforts are scattered. That’s largely because there is no one single reason that explains why the bees are dying. The EU, for example, is now re-examining its ban, as new science continues to point to other potential culprits.
“The big point is there’s a whole lot of factors that are contributing to it,” says Keith Delaplane, director of the University of Georgia Honey Bee Program. “Part of the work has been trying to untangle that knot.”
Scientists have identified three main culprits for bee losses. A prime suspect is pesticides, specifically the commonly used neonicotinoid pesticides, which attack insects’ nervous systems.
Pesticides, Delaplane says, present a problem for both honeybees and wild bees alike. The neonicotinoid pesticides are a relatively new kind of pesticide, designed specifically to be healthier for mammals. Instead of spraying these pesticides all over fields, letting them kill everything they touch, “neonics” coat the seeds before being planted, allowing them to work their way into the tissues of the seeds and eventually the plant—and only the plant. But, as newer research shows, they come with their own set of problems, like hurting bees.
“Pesticides and beekeeping have been butting heads for 50-plus years,” says David R. Tarpy, a professor at North Carolina State University’s department of entomology. “A pesticide that is really good at killing a pest insect is usually really good at killing off a beneficial insect like honeybees.” But he also stresses that drawing the link between cause and effect is extremely difficult.“[Pesticides are] clearly part of the equation, but we don’t know the relative magnitude.”
Another major problem facing bees is that, like so many species, they have seen major habitat loss. As monocultural agriculture gets ever more popular and urbanization simplifies landscapes, bees lose much of the area where they would have foraged for food or nested. A bee doesn’t need much—Delaplane described an edge of a field where wildflowers grow or even a sunny patch of soil in a forest as habitable space. But those places are disappearing as lawns and fields of corn overtake them.
This is a particular problem for wild bees, but it impacts managed colonies of honeybees as well. These colonies are often trucked in from field to field to pollinate a farmer’s crops. “It’s true that you can move them around and beekeepers can do that, but they don’t always place them in the best setting,” says Tarpy. Not only are many of the crops not nutritious enough on their own, but the weeds that would naturally sprout up between them, which are often more nutritious for bees, have also been eliminated. Just like with humans, “diversity and a good balanced diet is very important for bees,” he says. Our modern landscape is not providing it.
For honeybees, varroa mites are “public enemy number one,” says Delaplane. These mites not only hurt the bees themselves but introduce a wide range of pathogens and other problems when they get into a bee colony.
The mites latch on like ticks or leeches, draining bloodlike hemolymph from their hosts and enfeebling their immune systems. The hive environment—steamy and warm, bees in constant contact—is as perfect for bee pathogens as a day care center is for human pathogens.
Every colony will have some mites, says Dr. Dennis vanEngelsdorp, Assistant Professor of Entomology at the University of Maryland College of Agriculture & Natural Resources. But when left untreated, mites may overrun the entire colony and spread to neighbors’ colonies and destroy those, too.
Pro-bee policies have met with mixed reviews from experts, who generally see it as a good, but small, step forward. Making more federal land bee-friendly—some 7 million acres worth, according to the Obama administration plan—does little to offset the loss of roughly 150 million acres of habitat over the last 30-odd years, experts say.
They both fault the Obama administration for not further restricting pesticides that may be doing harm to bees—the latest proposal only extends already existing regulations—and criticize the European Union’s neonicotinoid pesticide ban as poorly conceived. “It was a political reaction to science that was not as well founded as it could have been,” Tarpy says.
Meanwhile mites remain a sticky issue. Usage of miticides—chemicals that kill mites—might harm the bees themselves.
What you can do
But all hope isn’t lost.
Delaplane says anyone with a backyard can help by planting flowers, especially those that bloom in off-seasons when other flowers don’t, like sunflowers and sages. He also suggests supporting local beekeepers who produce honey in your own neighborhood. And if you see a swarm of bees in your garden, don’t spray them—they’re probably there only temporarily.
“Tread lightly on those poor pollinators,” Delaplane says.
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