By JOSHUA A. BICKEL, ISABELLA O’MALLEY and JENNIFER McDERMOTT

WILLIAMSPORT, Ohio (AP) — Sweat covers Isaac Barnes’s face under his beekeeper’s veil as he hauls boxes of honeycomb from his hives to his truck. It’s a workout in what feels like a sauna as the late-morning June temperatures rise.

Though Barnes was hot, his bees were even hotter. Their body temperatures can be up to 27 degrees Fahrenheit higher than the air around them. As global temperatures rise under climate change, scientists are trying to better understand the effects on managed and wild bees as they pollinate crops, gather nectar, make honey and reproduce.

They noticed flying bees gathering nectar avoided overheating on the hottest days by using fewer but harder wingbeats to keep their body temperature below dangerous levels, according to a study published last year. Scientists also say that bees — like people — may also cope by retreating to a cooler environment such as the shade or their nest.

“Just like we go into the shade, or we sweat or we might work less hard, bees actually do the exact same thing so they can avoid the heat,” said Jon Harrison, an environmental physiologist at Arizona State University and one of the study’s authors.

But that means the bees aren’t able to do what they normally do, said Kevin McCluney, a biology professor at Bowling Green State University.

“They’re not going out and getting more nectar. They’re not mating. They’re not doing the things that bees would otherwise do,” McCluney said.

Heat is just one challenge for critical pollinator

Generally, most bees are heat-tolerant, but as the climate warms, some experts think their ability to fend off disease and gather food might become harder. And habitat loss, increased use of pesticides, diseases and lack of forage for both managed and wild bees are all listed as potential contributors to the global decline of bees and other pollinators.

“If you’re not well-fed, and your body is intoxicated with pesticides and you have lots of diseases in your body, you’re going to be less heat-tolerant than if you were healthy,” said Margarita López-Uribe, a pollinator health expert at Pennsylvania State University.

Earlier this year, preliminary results from the annual U.S. Beekeeping Survey found that beekeepers lost almost 56% of their managed colonies, the highest loss since the survey started in 2010.

Almost all of the managed honeybee colonies in the U.S. are used to pollinate agricultural crops such as almonds, apples, cherries and blueberries. Fewer pollinators can lead to less pollination and potentially lower yields.

“It’s a very fragile system if you think about it,” López-Uribe said. “Because if something goes wrong, you have these super high-value crops that won’t get enough bees for pollination.”

Losing hives at Honeyrun Farms

Back at Barnes’ hives in Ohio, thousands of honeybees fly around as he gathers boxes to take back to his farm for honey production. Nearby, a couple of his bees land on milkweed flowers, a rare bit of plant diversity in an area dominated by corn and soybean fields.

For Barnes, who operates Honeyrun Farm with his wife, Jayne, one of the challenges heat can pose to his 500 honeybee hives is fending off parasitic mites that threaten the bees. If temperatures get too hot, he can’t apply formic acid, an organic chemical that kills the mites. If it’s applied when it’s too hot, the bees could die.

Last year they lost almost a third of the 400 hives they sent to California to help pollinate commercial almond groves. Barnes thinks those hives may have been in poor health ahead of pollination because they were unable to ward off mites when it was hot months earlier.

“Dead hives aren’t pollinating the almonds,” he said. “It’s a real ripple effect that stems back from the heat in the summertime.”

Sometimes the heat helps. Here in Ohio, Barnes’ hives last summer produced a bumper crop of honey as they feasted on nearby soybean nectar as the plants bloomed in the heat. Still, the lack of diverse plants for bees to forage in an area dominated by corn and soybean fields isn’t ideal.

And even the native blooms are appearing erratically, Barnes said. In autumn, his bees search for food on goldenrod, but those blooms are appearing later. And even then, he has supplemented his hive with additional food to keep them healthy into the winter.

“Every single plant that blooms is something that the bee can use,” Barnes said. “And every single plant is affected by climate change.”

Research that may aid bees is in peril

It’s only in the last decade that people have become aware of the magnitude of the pollinator decline globally, said Harrison, of Arizona State University. Data is limited on how much climate change and heat stress is contributing to pollinator decline.

“It’s a relatively new focus for biology,” he said. “I think it’s super important, but it’s not being studied a ton.”

The Trump administration’s proposed budget would eliminate the research program that funds the USGS Bee Lab, which supports the inventory, monitoring and natural history of the nation’s wild bees. Other grants for bee research are also in jeopardy.

U.S. Sen. Jeff Merkley of Oregon said America’s pollinators are in “grave danger,” and he’ll fight for the federal funding. Pollinators contribute to the health of the planet, the crops we grow and the food we eat, he said.

“Rather than taking bold action to protect them, the Trump administration has proposed a reckless budget that would zero out funding for critical research aimed at saving important pollinators,” he said in a statement to The Associated Press.

Harrison said his research on this topic would come to a halt if cuts are made to his federal funding, and it would be more difficult in general for scientists to study the disappearance of bees and other pollinators and improve how they prevent these losses. Not being able to manage these pollinator deaths could cause the price of fruits, vegetables, nuts, coffee and chocolate to jump or become scarce.

“Hopefully, even if such research is defunded in the U.S., such research will continue in Europe and China, preventing these extreme scenarios,” said Harrison.

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