Listen: US hit by “cicada-geddon” as broods emerge from underground in rare double event
A rare “cicada-geddon” has hit parts of the US with trillions of insects from two broods emerging at the same time, creating a sound as loud as a jet engine.
Periodical cicadas crawl out from underground every 13 or 17 years, generating a collective song which sounds like a loud, high-pitched buzz.
This spring, parts of the country are experiencing an unusual double dose of the insects not seen for more than 200 years.
In videos of the insects shared on social media, the cicadas can be heard creating a noise so loud it can be heard from metres away.
The two large broods are emerging in the south-eastern US and in central Illinois, to serenade, mate, and lay eggs. They could cross over in north-central Illinois.
John Cooley, a University of Connecticut cicada expert, has dubbed the phenomenon “cicada-geddon”. “Periodical cicadas don’t do subtle,” he previously said.
Mr Cooley uses hearing protection because the sound from the creatures can get so intense.
“It’s up in the 110 decibel range,” Mr Cooley said. “It’d be like putting your head next to a jet. It is painful.”
Periodical cicadas are found only in the eastern US and a few other places. There are 15 different broods that hide away and come out every few years, on 17- and 13-year cycles.
The largest geographic brood in the US is called Brood XIX and comes out every 13 years in the south-east when the ground warms to 17.8C. The bugs are brown at first but darken as they mature.
Meanwhile, Brood XIII comes out every 17 years in Illinois.
The last time these two broods came out together was in 1803. Thomas Jefferson wrote about cicadas in his Garden Book but mistakenly called them locusts.
“We’ve got trillions of these amazing living organisms come out of the earth, climb up on trees and it’s just a unique experience, a sight to behold,” Saad Bhamla, a Georgia Tech biophysicist, said.
“It’s like an entire alien species living underneath our feet and then some prime number years, they come out to say hello.”
Periodical cicadas can hurt young trees and some fruit crops, but damage not widespread and can be prevented.
An even bigger adjacent joint emergence will be when the two largest broods, XIX and XIV, come out together in 2076, Mr Cooley said: “That is the cicada-palooza.”
