Scientists say warming climate is putting bees at risk

Bees are generally heat-tolerant. Even so, the warming climate is putting them at risk.

As global temperature rise, scientists are trying to understand how heat affects bees. 

It's an important question because the bees are critical to the fruit, vegetables, nuts and other foods that humans need. 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. 

Scientists have found that bees fly differently during extreme heat and may also cope the same way humans do — by finding a cooler environment. But they aren't able to do as much as they normally do, and scientists worry that heat makes the bees more vulnerable to disease. 

Kevin McCluney, a biology professor at Bowling Green State University in Ohio, has studied how heat affects bees, and his team found that bees tend to dehydrate before they overheat. And when bees are stressed, they search for shade or water instead of pollinating crops or other plants, and could also affect their ability to reproduce. 

"One of the most interesting things we found, is that the vast majority of the species that we are looking at, as their body temperature heats up, which happens as the environment warms up, they become dehydrated. And that was sort of unexpected," McCluney says. "And then when we looked at sort of their limits, like how much heating can they tolerate, how much dehydration can they tolerate, what we found is, as they got hotter, as their body temperatures got hotter, they became close to their dehydration limits way before they reached their overheating limits.” 

And when the bees’ environment gets stressful, they spend their time searching for shade or water instead of pollinating.  

Another concern is a lack of bee diversity in certain environments, McCluney says.

"The bee diversity does decline when it becomes more urban, when you have more pavement, but if you plant more flowers, it erases that decline. So it could be as simple as planting more flowers. Planting more flowers that bloom at different times of year that provide nectar and pollen resources for the bees at different times of year. That could be the biggest solution.” 

Data is limited on how much climate change and heat stress is contributing to pollinator decline. 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.