Bad for Bees

A lot of the food you eat would never have made it to your plate if not for bees. Along with other pollinators, these busy bugs help produce about one-third of the world’s crops. Without bees, many flowering plants couldn’t produce seeds, nuts, fruits, or vegetables. But bees could be in danger. That’s because many farmers spray crops with common pesticides called neonicotinoids. The chemicals kill harmful insects—but some scientists worry they’re also hurting helpful bees.

You can thank bees for much of the food you eat. It wouldn’t have made it to your plate without them. Bees and other pollinators help produce about one-third of the world’s crops. Many flowering plants couldn’t make seeds, nuts, fruits, or vegetables without bees. But bees could be in danger. That’s because many farmers spray crops with common pesticides called neonicotinoids. The chemicals kill harmful insects. But some scientists worry they’re hurting helpful bees too.

Neonicotinoids became popular partly because they are safer for birds and mammals than older pesticides. Farmers apply neonicotinoids to about 95 percent of the corn grown in the U.S., half of the soybeans, and many fruit and vegetable crops. The chemicals are neurotoxins. They kill insects by disrupting their nervous systems—the network that transmits signals throughout the body (see Killer Chemicals). The pesticides are highly soluble in water. The roots of crops absorb the dissolved neonicotinoids from water in soil.

When bees feed on sweet nectar from the flowers of plants treated with neonicotinoids, the insects get exposed to them. The bees then turn the tainted nectar into honey, which is laced with the chemicals. Scientists recently tested 198 honey samples from every continent except Antarctica and found that 75 percent contained neonicotinoids. No samples had levels known to harm humans, but about a third contained levels dangerous to bees.

Why did neonicotinoids became popular? One reason is they’re safer for birds and mammals than older pesticides. Farmers put neonicotinoids on about 95 percent of the corn grown in the U.S. They also use it on half of the soybeans and many fruit and vegetable crops. The chemicals are neurotoxins. They kill insects by disrupting their nervous systems. That’s the network that carries signals throughout the body (see Killer Chemicals). The pesticides easily dissolve in water. Then the roots of crops soak them up.

Bees feed on sweet nectar from flowers. If the plants were treated with neonicotinoids, the insects get exposed to them. The bees turn this tainted nectar into honey that contains the chemicals. Not long ago, scientists tested 198 honey samples from every continent except Antarctica. They found neonicotinoids in 75 percent of the samples. No samples had levels known to harm humans. But about a third had levels dangerous to bees.

Growing evidence shows that, in low doses, neonicotinoids can affect bees’ disease-fighting immune systems, as well as their ability to communicate, fly, reproduce, and navigate. At high doses, the chemicals can kill the insects.

Concern over the pesticides has led regulators to take action. The European Union banned certain neonicotinoids on some crops and is considering a complete ban. The U.S. Environmental Protection Agency is conducting a safety review of the chemicals, including their effects on pollinators.

Protecting these insects is important, says Dave Goulson, a bee biologist at the University of Sussex in England. “If we didn’t have pollinators, we wouldn’t have tomatoes, chili peppers, blueberries, coffee, or chocolate,” he says. In short, life would be a lot less sweet without bees.

More and more evidence shows that low doses of neonicotinoids can harm bees. They affect bees’ immune systems, which fight disease. The chemicals also affect bees’ ability to communicate, fly, reproduce, and navigate. High doses can kill the insects.

Worry over the pesticides has led to action. The European Union banned certain neonicotinoids on some crops. It’s thinking about a complete ban. The U.S. Environmental Protection Agency is looking at the safety of the chemicals, including their effects on pollinators.

Dave Goulson is a bee biologist at the University of Sussex in England. He says it’s important to protect bees. “If we didn’t have pollinators, we wouldn’t have tomatoes, chili peppers, blueberries, coffee, or chocolate,” he says. In short, life would be a lot less sweet without bees.