Bees got weird during 2017’s total solar eclipse in the U.S.

The end of summer isn’t the only thing that can cause bees to go silent. 

On August 21, 2017, while an estimated 215 million Americans stopped to admire the nation’s first total solar eclipse in more than 40 years, bees stopped too. 

With the help of bee watchers in Oregon, Missouri, and Idaho, a team of researchers led by Candace Galen placed microphones with 16 different monitoring stations around flower patches to analyze the behavioral patterns of bees during the solar eclipse. 

What they found was expected — bumblebees completely stopped flying or working once the sun was fully blacked out by the moon. 

What they didn’t expect, however, was for the shift in bee behavior to be so abrupt, according to the new study published by the team in the Annals of the Entomological Society of America.

The Great American Solar Eclipse captivated 215 million Americans last year.

Before and after totality, when the sun was partially blocked, the bees seemed completely unaffected by the dimming light or the slightly cooler temperature.

Galen said it seemed like everyone was asking her how animals would act during the eclipse, so it made sense to hitch bee research to eclipse enthusiasm. 

Past research has found a wide variety of animals behaviours during total solar eclipses, from chimpanzees who gather to watch to orb-weaving spiders who tear down their webs. But bees haven’t ever been a part of the conversation until now. 

“Bees are adapted to navigate under a range of light conditions, from bright open skies to dim forest understory,” Galen said via email. 

“The same mechanisms that allow them to navigate under dim light in these situations could explain why they are capable of flight in partial phases of the eclipse.” 

It wasn’t until the sun was completely blocked, that the bees went silent. 

“We had not expected that the change would be so abrupt, that bees would continue flying up until totality and only then stop, completely,” Galen said . “It was like ‘lights out’ at summer camp! That surprised us.” 

There’s a reason that people rarely get stung by bees during the night, and it’s pretty simple: Bees can’t really see in total dark. For that reason, Galen said her and her team expected a similar behavior during the total solar eclipse, however it will take more research to know exactly why.

Bumblebees seemed completely unbothered by the dimmed light from the partial coverage of the sun.

And while this information is groundbreaking in many ways, this is still only the first step in understanding bee behavior in this context. 

“The eclipse gave us an opportunity to ask whether the novel environmental context—mid-day, open skies—would alter the bees’ behavioral response to dim light and darkness,” Galen said. 

“As we found, complete darkness elicits the same behavior in bees, regardless of timing or context. And that’s new information about bee cognition.”

America will see another total solar eclipse on April 8, 2024. That’s when researchers will try to figure out how and why the behavior change is so dramatic, as well is if the behavior varies from bee to bee. 

“We should be able to figure out whether more bees are returning home as the eclipse progresses,” Galen said. 

“We might also place microphones inside the colonies where it’s always dark to [determine] whether buzzes made by bees after they enter the nest are similar to buzzes they make at night.”