Clare Kenyon
Biologists have made an electrifying discovery: swarming insects, such as bees can impact the electricity in the atmosphere.
What’s more, the electric charge produced can be as much as that which builds up in a thunderstorm cloud.
In trying to understand the way electric charge in the atmosphere changes due to many known factors (such as rain, aerosols, radioactivity, pollution and volcanism), the researchers realised that the contribution from insects was an important, yet little understood part of the puzzle.
“We only recently discovered that biology and static electric fields are intimately linked and that there are many unsuspected links that can exist over different spatial scales, ranging from microbes in the soil, plant-pollinator interactions, to insect swarms and perhaps the global electric circuit,” says first author Ellard Hunting, a biologist at the University of Bristol in the UK.
The impact of the atmosphere’s electric field on animals has been known and extensively studied. Spiders travel hundreds of kilometres to new spaces, bumblebees and hoverflies sense the electricity around flowers in order to choose the best option, and hummingbirds use static electricity to attract pollen to themselves while feeding.
Until now, though, the reverse relationship has remained relatively unstudied.
“We’re interested in how different organisms use the static electric fields that are virtually everywhere in the environment,” says Hunting. “We always looked at how physics influenced biology, but at some point, we realized that biology might also be influencing physics.”
The research was performed at a field station which contained several honeybee hives. When swarming occurred, researchers placed a camera and electric field monitor near the swarm to measure the charge generated. The swarms changed the local atmospheric field by between 100 and 1,000 volts per metre, with denser swarms associated with an increased electric charge.
Empowered by these measurements, the researchers were then able to model swarming events of other insects, including those that swarm on a much larger scale.
“How insect swarms influence atmospheric electricity depends on their density and size,” says co-author Liam O’Reilly. “We also calculated the influence of locusts on atmospheric electricity, as locusts swarm on biblical scales, their influence is likely much greater than honeybees.” The discovery is an important reminder of the interconnectedness of different scientific disciplines, explains co-author Giles Harrison, an atmospheric physicist from the University of Reading. “Interdisciplinarity is valuable here—electric charge can seem like it lives solely in physics, but it is important to know how aware the whole natural world is of electricity in the atmosphere.”