The cicada-geddon is here. It’s the biggest bug emergence in centuries.

Hello and welcome to Climate Watch. I am Natalia Gutiérrez , Climate engagement manager at AP. Today, we'll explore one of nature's most intriguing insects: cicadas. While some may find them bothersome due to their loud buzzing, scientists say understanding these creatures reveals their wonder.

This year, an extraordinary event is set to unfold as trillions of red-eyed periodical cicadas emerge in numbers not seen in centuries.

Periodical cicadas, with their synchronized emergence every 13 or 17 years, orchestrate a collective chorus as loud as jet engines. They stay buried year after year, until they surface and take over a landscape, covering houses with shed exoskeletons and making the ground crunchy. Let's answer some common cicadas questions based on reporting by AP science writer Seth Borenstein .

WHEN WILL THIS HAPPEN?

This spring, the United States will witness an extraordinary event: a rare double dose of cicadas poised to invade certain regions, an occurrence dubbed "cicada-geddon" by University of Connecticut expert John Cooley. The last time these two broods emerged simultaneously was in 1803, during Thomas Jefferson's presidency.

They emerge when the ground warms to 64 degrees (17.8 degrees Celsius), which is happening earlier than it used to because of climate change, entomologists said. Before 1950 they used to emerge at the end of May; now they’re coming out weeks earlier.

WHAT DO THEY EAT?

Cicadas feed on a tree’s xylem, which carry water and some nutrients. The cicada gets so much fluid that it has a lot of liquid waste to get rid of. It does so thanks to a special muscle that creates a jet of urine that flows faster than in most any other animal, even humans.

WHERE WILL THEY BE?

The largest brood in the nation, known as Brood XIX, emerges every 13 years and is poised to sweep through the Southeast, having already left countless boreholes in Georgia's red clay. It’s a sure sign of the coming cicada occupation.

Shortly after, another brood, Brood XIII, which emerges every 17 years, will inundate Illinois. The convergence of these two broods will create an unprecedented spectacle, according to Paula Shrewsbury, an entomologist from the University of Maryland.

“And when you put those two together… you would have more than anywhere else any other time,” Shrewsbury said.

These hideaway cicadas are found only in the eastern United States and a few tiny other places. Among the 15 broods emerging on 17- and 13-year cycles, these two broods may overlap in a small area near central Illinois, entomologists note.

HOW MANY?

The numbers that will come out this year – averaging around 1 million per acre over hundreds of millions of acres across 16 states – are mind-boggling. Easily hundreds of trillions, maybe quadrillions, John Cooley said.

There will be lots of them, but remember that cicadas have been in America for millions of years, even before human existence. They are just silently feeding on tree roots underground, patiently awaiting their cue to emerge and breed.

“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,” said Georgia Tech biophysicist Saad Bhamla.

Does knowing more about these amazing insects make you less scared of them? Let us know in the comments!

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This newsletter was written and produced by climate engagement manager Natalia Gutiérrez .

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