Busy bees pause during total eclipses | Science

On August 21, 2017, residents of all of North America, from the Pacific coast to the Atlantic coast, discontinued their usual activities to experience an eclipse total sun.

And the bees too.

The day of bees begins at sunrise. As long as there is sunshine, drones and bees will remain busy from dawn to dusk. But how do insects react during this rare event when the moon passes directly in front of the sun, casting the daytime world into the shadows? Last year, ecologist Candace Galen of the University of Missouri, a team of researchers and a few hundred college students sought the solution.

Using tiny microphones suspended among the flowers, the team recorded the buzzing bees at all stages of the eclipse. The bees were active and noisy until the last moments before the whole, the part of a total solar eclipse when the moon blocks direct sunlight and that a nocturnal darkness settles on Earth. When all hit, the bees became totally silent in unison.

"It was as if someone had turned off the lights and the bees had stopped flying," says Galen, lead author of the new study published by the Entomological Society of America. "It was abrupt, it was not progressive. It was like falling off a cliff, this steep. "

It is rather unusual for a bee to quit in the middle of the day, unless something like a storm passes. As Galen says, "bumblebees and honey bees have to make hay while the sun is shining". Insects could in fact react in the same way to all events as to the dark storm clouds that are coming.

"These populations are not suitable for eclipses," says Nicole Miller-Struttmann, ecologist of evolution, from Webster University in St. Louis. "A kind of strong evolutionary story does not tell them what to do during an eclipse. This implies that there is another signal to which they are adapted and which they use. "

The sharp drop between buzz and silence was the most dramatic change in the eclipse, but other, more minor changes in the buzzing of bees could give researchers clues about the reaction of insects. As Galen notes, the buzz of bees lasted longer as it became darker and darker. The increase in buzzing length suggests that bees started flying more slowly, that they were doing longer flights, or a combination of both.

"I think if you drive on a road and there's fog, you slow down," says Galen. When visibility is reduced, slowing down helps you process the information and maintain situational awareness – and since the bees did it all of the time, if visibility is zero, you should probably stop. Adjusting the speed to acclimate the senses to a changing environment is a common behavior in many animals, and this has been observed in bees when they fly before sunrise or sunset.

Many animals respond uniquely to a total solar eclipse, but there is a huge lack of research on these behaviors, says Galen. While the excitement about the 2017 eclipse was growing, people started asking him what the animals could do when the darkness came down. She did not know and there was not much to say. The shadow, or the darkest part of the moon's shadow, only covers a given area for a few minutes and total solar eclipses occur randomly all over the planet, mostly over water .

"Eclipse science is so rare. Everything is idiosyncratic, "said Miller-Struttman. "They could do this experiment in several places. These are the best available data regarding the reaction of bees to the eclipse. "

The Great American Eclipse of 2017 was perfect for the study as it had landed more than 16 hours on the ground while she was crossing the country. The team included two student groups in Oregon, one in Idaho and several rural and urban areas of Missouri, recording bees buzzing and sending USB sticks – or, as Galen says, "USBees" – with audio files intended to researchers from the University of Missouri. (Students were also able to analyze the data and, impressively, they corroborated the researcher's findings with an accuracy of 91%.)

Another transcontinental eclipse will occur in 2024 and Galen plans to install microphones in the hives next time, as well as among the flowers to test anecdotal evidence from the 1930s this suggests that the bees return to their hives during the whole.

"The next total solar eclipse will pass through Missouri in 2024," says the conclusion of the new study. "We, bee hunters, including some promising new hires, will be ready."