SCIENCE: A swarm of insects can generate electricity comparable to a thunderstorm

Half a cen­tu­ry ago, Amer­i­can math­e­mati­cian Edward Lorenz won­dered whether a but­ter­fly flap­ping its wings in Brazil could cause a tor­na­do in Texas through a chaot­ic domi­no effect.

If the ques­tion had been, “Do locusts, just by flap­ping their wings, have the pow­er of a thun­der­storm?” It was­n’t, but now I have the answer.

A new study of the effect of beat­ing insect wings on atmos­pher­ic elec­tric fields reveals that many tiny wings charge the air in the same way that swirling water vapor clouds charge the air in a thun­der­storm. became.

This is not to say that we should wor­ry about light­ning-bolt­ing locust cat­a­stro­phes, as in the Bible, but that bio­log­i­cal phe­nom­e­na should be tak­en into account when mod­el­ing local pat­terns of atmos­pher­ic elec­tric fields. You could call it proof.

If you zoom in on the dust and mois­ture in the air of an insect, or the atoms that make up parts of its body, you can see elec­trons fly­ing around like coins in a jog­ging pocket.

When you press hard, these neg­a­tive­ly charged par­ti­cles pop out of their pos­i­tive­ly charged pock­ets, cre­at­ing a dif­fer­ence called a poten­tial difference.

In a storm, small ice par­ti­cles ris­ing in air cur­rents col­lide with larg­er ice par­ti­cles falling to the ground, cre­at­ing a con­vey­or belt of elec­tri­cal charges that exag­ger­ate the poten­tial dif­fer­ence between the top of the cloud, the bot­tom of the cloud, and the ground. there is something

The charge build-up is essen­tial­ly invis­i­ble, but the effect is not. When the gra­di­ent reach­es a tip­ping point, an ion­iza­tion chan­nel is formed, effec­tive­ly bal­anc­ing out what we con­sid­er to be a light­ning run.

Even in the absence of light­ning, areas of con­trast­ing charges can affect the move­ment of ions such as var­i­ous pol­lu­tants and dust.

The mag­ni­tude and posi­tion of the poten­tial dif­fer­ence are deter­mined by var­i­ous fac­tors, such as cloud move­ment, pre­cip­i­ta­tion, and cos­mic ray show­ers, but until now, no one had seri­ous­ly con­sid­ered the effects of bio­log­i­cal phenomena.

“We’ve always looked at how physics influ­ences biol­o­gy,” said Ellard Hunt­ing, a biol­o­gist at the Uni­ver­si­ty of Bris­tol in the UK and the lead author of the study. But at some point I real­ized that biol­o­gy could also influ­ence physics.

“We are inter­est­ed in how dif­fer­ent organ­isms use the ubiq­ui­tous elec­tro­sta­t­ic fields in the environment.

In recent years, it has become clear that inver­te­brates such as insects car­ry a small elec­tri­cal charge rel­a­tive to the sur­round­ing atmos­phere. Baby spi­ders can even use this trick to launch them­selves into the air.

But how this small poten­tial stacks up in the herd has nev­er been mea­sured. So Hunt­ing and his team set out to vis­it a field sta­tion at the Uni­ver­si­ty of Bris­tol School of Vet­eri­nary Med­i­cine, where one of the many bee colonies awaits.

Using elec­tric-field mon­i­tors and a cam­era that mon­i­tors bee den­si­ty, they tracked local elec­tri­cal gra­di­ents in a migrat­ing swarm. For three min­utes, insects flit­ted about, increas­ing the poten­tial dif­fer­ence to 100 volts per meter.

Fur­ther analy­sis con­firmed that the volt­age was relat­ed to the con­cen­tra­tion of bee swarms, allow­ing the researchers to see how the num­ber of bees buzzing through the air at a par­tic­u­lar loca­tion affect­ed the atmos­pher­ic charge. can now be pre­dict­ed with some certainty.

The researchers found this esti­mate to be con­sis­tent with evi­dence from hon­ey­bees, and applied the same rea­son­ing to oth­er swarm­ing insects.

Scal­ing up indi­vid­ual locust loads to plague size, they found that large locust swarms pro­duced load den­si­ties sim­i­lar to thunderstorms.

“Elec­tric charges seem to exist only in the world of physics, but it is impor­tant to know how much nature as a whole per­ceives elec­tric­i­ty in the atmos­phere,” says Giles Har­ri­son, an atmos­pher­ic physi­cist at the Uni­ver­si­ty of Reading.