What's the buzz on cicadas? Faint this year in the suburbs, but wait till 2024

For months, the billions of Brood X cicadas expected this spring have been making headlines. But their arrival - in east central Illinois and other states - won't disrupt life in the suburbs, which is good news for those who prefer outdoor celebrations unaccompanied by cacophonous mating calls.

The suburbs, however, are getting only a temporary reprieve: The Northern Illinois Brood, known as Brood XIII, will emerge in 2024. With that brood - which scientists say consists of more cicadas per acre than anywhere else - the chorus from millions of cicadas could be deafening, according to Fredric Miller, senior scientist of entomology at Lisle's Morton Arboretum.

Miller said people standing a few feet apart may be unable to converse above the din. Anyone planning an outdoor wedding during May or June 2024 might want to reconsider or risk cicadas drowning out their vows.

And while Northern Illinois contends with Brood XIII, a different brood is scheduled to emerge in the southern part of the state, Miller said.

"That will be quite an event," he said. "Mathematically it doesn't happen very often."

There are at least 15 cicada broods. After a lifetime spent underground feeding on tree roots, millions of cicada nymphs typically emerge en masse every 13 or 17 years. Topside, they climb up a tree or shrub, shed their exoskeletons and then mate. The buzzing sound is the males calling to the females who lay their eggs. The eggs hatch, the nymphs burrow underground and the cycle begins again.

The difference in life cycles is thought to be associated with the longevity of the growing season, that period when crops and plants grow successfully, said Philip Nixon, retired University of Illinois Extension entomologist. Longer growing seasons mean the nymphs feed longer, develop faster and emerge sooner, according to Nixon.

He says the advantage of the cicadas' long life cycle, most of which is spent underground, is that it fools predators.

"If you come out in huge numbers and you overwhelm predators every 13 or 17 years you have a great way of surviving that has lasted for millennia," Nixon said.

"There are always what they call stragglers that come out a year or two early or a year late," he said.

Fewer in number, they get picked off by birds or mammals and fail to establish a brood, Nixon says.

Miller describes cicadas as an "ecological novelty" whose role in the ecosystem varies. For some birds and small mammals such as raccoons and skunks, cicadas are a food source, a delicacy available once every 13 or 17 years, he says. But cicadas can damage seedlings, which is why entomologists recommend against planting seedlings or young trees during an emergence, Miller said.

In the meanwhile, suburbanites who want to see swarms before 2024 can catch 2021's Brood X in Edgar, Clark, Crawford and Vermilion counties.