The Moon Eclipsed the Sun. Then the Bees Stopped Buzzing.

Last year’s Great American Eclipse drew hundreds of millions of eyes to the sky. But while people across the country “oohed” and “aahed” at the phenomenon, it appears the bees went silent.

So found a new study that monitored the acoustic activity of bees before, during and after totality — the moment when the moon completely blocked the sun — during the solar eclipse on Aug. 21, 2017. Researchers at the University of Missouri, along with a small army of elementary school children and other volunteers, collected audio recordings of honeybees, bumblebees and other types of bees as they visited flowers along the path of totality.

The researchers found that while the insects were happily buzzing throughout the day and during the partial phases of the eclipse, the bees went quiet the instant that the total eclipse occurred in their location. Of the 16 monitoring locations the group set up in Oregon, Idaho and Missouri, they identified only a single buzz during totality, compared with a symphony of droning sounds most other times of the day.

“We expected there would be a gradual decrease in the number of buzzes as it got darker and darker, but we didn’t see that,” said Candace Galen, a biologist at the University of Missouri and lead author of the study, which appeared Wednesday in the Annals of the Entomological Society of America. “At totality, they just stopped. It was very surprising.”

They are not sure why the bees stopped buzzing but think it may be related to how the pollinators interpret the drop in light.

Scientists have long investigated how animals react to eclipses. Studies of the 1991 eclipse over Mexico, Central America and South America showed that desert cicadas stopped chirping. Orb-weaving spiders spinning webs began to deconstruct them during totality, only to rebuild them when the sun returned.

Although there were reports from the public that honeybees returned to their hives during the 1932 total solar eclipse, which swept through Canada and parts of Maine, Vermont and New Hampshire, there had not been a large scientific study into bee behavior at totality like this one, according to the authors.

To eavesdrop on the insects, Galen and her volunteers planted microphones about the size of flash drives, which they called “USBees,” into flower patches and gardens that were as far as possible from crowds and traffic. They also placed environmental sensors that recorded the temperature and brightness.

After the eclipse, the scientists and schoolchildren evaluated the data. That meant listening to three-minute audio clips taken from random points before and after totality, as well as a three-minute clip taken during totality. The length of totality at the test sites varied from about 40 seconds in Oregon to about 2 minutes and 30 seconds in Missouri.

“Counting the bee buzzes was a class effort. We all had to listen and tally up what everyone heard,” said Marci Fitzpatrick, a teacher at Shepard Boulevard Elementary School in Columbia, Missouri, whose fifth grade class took part in the study. “They became quite the little bee analysts.”

A bee’s buzz is the result of the insect’s vibrating its wing muscles. So when bees are flying, they are buzzing. Galen had asked the students what they expected would happen during the eclipse. Many of them predicted the bees would confuse totality for nighttime and stop flying.

“We scientists have more fancy ways of saying the same thing, but the kids were pretty much right,” said Galen. “It was a pretty humbling experience for someone with a Ph.D. and 30 years of research experience to have the kids get it correct right from the start.”