VERMILION COUNTY, Ill. (WCIA) — It’s a process nearly two decades in the making.
“It’s quite an impressive phenomenon,” said Dr. Chris Dietrich with the Illinois Natural History Survery.
That phenomenon is the impending emergence of Brood X cicadas.
“In areas where they’re present, they’re hard to miss because there are a lot of them,” explained Dietrich. “Very, very dense populations; very loud calling.”
They’re so plentiful, in fact, they overwhelm predators.
“They come out at these really, really long intervals as adults and there’s never enough predators around at any given place to eat them all because the predators just get full,” Dietrich said.
The insects are not inherently dangerous, but their call can be deafening if you’re too close.
“They’re mostly just removing some nutrients from the roots and they’re fed on by various other creatures: birds, snakes, skunks, raccoons, various kinds of rodents and small mammals,” said Dietrich.
While these periodical plant-eating pests are unpleasantly loud, they’re gone in weeks, preparing to re-emerge in another prime-numbered year.
“They’ll be out for about a month and then they’ll just sort of gradually disappear,” Dietrich said.
That’s because they’re here to mate.
“They just come out once every 17 years so the adults can come out and lay eggs,” said Dietrich.
But if you were hoping it was going to be another 17 years before another big brood is back — bad news.
“We actually have, in 2024, there are two broods,” Dietrich explained. “Two very big broods coming out that will be covering most of the state.”
That includes a large northern brood of 17-year cicadas and a southern brood of 13-year cicadas.
“Stay tuned, there’s more excitement to come in a few years.” Dietrich said.