Swarms of western honeybees can generate an electric charge of 1000 volts per meter, which is greater than the voltage density of thunderstorm clouds and electrified dust storms.
|Bee swarms generate electricity Shutterstock/Darios|
Swarming honeybees can generate more electric charge per density than a thunderstorm cloud.
Ellard Hunting of the University of Bristol in the United Kingdom and his team were tracking the weather at a field station near their university when they made the discovery. Despite the fact that there was no storm activity, their electric field monitors detected an increase in atmospheric electric charge. However, nearby western honeybees (Apis mellifera) were swarming, which is behavior the insect's exhibit when looking for a new home.
"When I looked at the data, I was surprised to see that it had such a large effect," Hunting says. Individual bees carry a small charge, but a voltage of this magnitude in swarming honeybees had never been observed before.
The team used additional electric field monitors in conjunction with video cameras to measure the electric field and swarm density while waiting for bees at nearby hives to swarm naturally. The researchers captured three swarms passing through the monitors for approximately three minutes at a time. They discovered that bee swarms generate an electric charge of 100 to 1000 volts per metre. The team discovered that the closer the bees were to each other in the swarms, the stronger the electric field was.
Hunting compared the highest charge of the bees to previous data on meteorological events such as fair-weather storm clouds, thunderstorms, and electrified dust storms, and discovered that dense bee swarms out charged them all. Their charge density was approximately eight times that of a thunderstorm cloud and six times that of an electrified dust storm.
It is unknown whether this ability is beneficial to bees or an unintended consequence of friction between their wings and the air, similar to a person rubbing a balloon on their clothes. According to Victor Manuel Ortega-Jiménez of the University of Maine, the charge could serve an unknown purpose because bees use electric fields to forage for food.
Jiménez wonders if other flying, swarming animals, such as birds and bats, are experiencing the same phenomenon. "These are all intriguing questions that this paper raises," he says.
Journal citation: iScience, DOI: 10.1016/j.isci.2022.105241.