A pause in the buzz: the bees are silent during the total solar eclipse

Credit: Kim de Been / Fotolia

Although millions of Americans have interrupted their daily routines on August 21, 2017 to attend a total solar eclipse, they may not have noticed a similar phenomenon occurring nearby: on the way to the all, the bees have also broken their daily routines.

In an unprecedented study of the influence of a solar eclipse on bee behavior, researchers at the University of Missouri organized a group of citizen scientists and elementary school classrooms in order to set up acoustic monitoring stations to listen to the buzzing or lack of bees bees. the eclipse has passed. The results, published on October 10 in the Annals of the Entomological Society of America, were clear and consistent across the country: bees stopped flying during the period of total solar eclipse.

"We expected, according to some articles in the literature, that the activity of bees diminishes as the light diminishes during the eclipse and reaches a minimum at all," Candace says. Galen, PhD, professor of biological sciences at the University of Missouri. principal investigator of the study. "But we did not think that the change would be so abrupt, that the bees would continue to fly to the totality and only then, they would stop completely." It was as if the lights were extinguishing at the summer camp! This surprised us. "

As anticipation mounted for the eclipse, "it seemed like everyone and his dog were asking me what the animals would do during a total eclipse," says Galen. However, few formal studies have examined the behavior of insects, especially during a solar eclipse, and none have examined bees. Meanwhile, Galen and his colleagues had recently field-tested a system to track bee pollination remotely by listening to the buzzing sound of their flights as they record.

"It seemed like the ideal solution," says Galen. "The tiny microphones and temperature sensors could be placed near the flowers for hours before the eclipse, leaving us free to put on our fancy glasses and enjoy the show."

Supported by a grant from the American Astronomical Society, the project mobilized more than 400 participants – scientists, members of the public, teachers and elementary students – to set up 16 monitoring stations on the path of totality. in Oregon, Idaho and Missouri. At each location, small USB microphones were hung from lanyards near pollinated bee flowers, away from pedestrians and vehicles. In some places, light and temperature data were also captured. The participants then sent the devices to the Galen Laboratory, where the recordings were compared to the eclipse periods of each site and analyzed to determine the number and duration of bee buzzes. The recordings do not differentiate bee species, but participant observations indicate that most bees followed are bumblebees (Bombus genus) or honey bees (Apis mellifera).

Data showed that bees remained active during the partial eclipse phases before and after all, but essentially stopped flying during the entire period. (A single buzz was recorded for all 16 monitoring locations.) However, shortly before and shortly after, bee flights tended to last longer than at the beginning of the phase. pre-total and late. . Galen and his colleagues interpret these longer flight times as an indicator of slower flight under reduced lighting or, possibly, returning bees to their nest.

Bees usually fly more slowly at dusk and return to their colonies at night. The same behavior caused by a solar eclipse provides evidence of how they respond to environmental signals when they occur unexpectedly.

"The eclipse gave us the opportunity to ask if the new environmental context – open skies and mid-day – would change bees' behavioral response to darkness or dim light, as we found , complete darkness causes the same behavior in bees, regardless of timing or context.And this is new information on bee cognition, "says Galen.

Another total solar eclipse in North America is not far off: April 8, 2024. Galen says his team is working to improve its audio analysis software to distinguish flights made by bees in search of food when they leave or return to their colonies. Thus prepared, she hopes to be able to answer the question of whether bees return home when the "lights go out" at any time in 2024.

It will probably not be difficult to find citizen citizens and student volunteers to help them again.

"The total solar eclipse was a treat for the crowd, and it was great fun to attach the bees to research at its tidal wave of enthusiasm," says Galen.

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