New Scientist reveals an accidental discovery that happened when a passing swarm of bees got close to a weather station on a clear day – and the sensors noted a jump in atmospheric electricity:
The team deployed additional electric field monitors in combination with video cameras to measure the electric field and swarm density, and waited for the bees at nearby hives to naturally swarm. The researchers recorded three swarms passing the monitors for around 3 minutes at a time. They found that the bee swarms created an electric charge ranging from 100 to 1000 volts per metre. By analysing the proximity of bees to each other in the swarms, the team found that the denser the swarm, the stronger the electric field was.
[University of Bristol biophysicist Ellard] Hunting compared the bees’ highest charge to previous data on meteorological events like fair-weather storm clouds, thunderstorms and electrified dust storms, and found dense bees swarms outcharged them all. Their charge density was around eight times as great as a thunderstorm cloud and six times as great as an electrified dust storm.