Cicadas are a noisy, natural part of summer

There's nothing to fear when it comes to cicadas.

You don't have to take any precautions. The experts have no tips to help you deal with them.

The bottom line is this: They're unavoidable every summer, as one brood or another of annual cicadas emerges for four to six weeks, singing loud and proud as they mate and lay hundreds of eggs. And they're nearly harmless, both to our trees and to our ears, say experts in insects, the environment and the science of hearing.

Even every 17 years, when a much larger crop of periodical cicadas hits the region, the story's the same. Despite the atypically loud nature of their whirring-chirping-screeching sounds, cicadas are a natural part of life in northern Illinois. So, as one suburban entomologist says, “observe and enjoy.”

“They're just an annual phenomenon,” said Fredric Miller, a senior scientist in entomology at the Morton Arboretum in Lisle. “They just kind of remind us that summer's winding down.”

This year's cicadas are what's referred to as “Dog Day Cicadas,” Miller said, a type of insect that lives underground for two to 10 years as a nymph, then emerges for a short aboveground life of mating and nestling eggs into tree trunks.

“They show up in July and August,” Miller said, with some sticking around as late as September. “They get quite noisy.”

But that sound and fury is nothing compared with the spectacle the region experienced in 2007 and is set to see (and hear) again in 2024. That's when the calendar brings a separate breed called periodical cicadas, which emerge all at once in much higher numbers and make much more noise. But they have the same goal as the annuals - find mates, lay eggs, continue the species.

“They follow this very set, almost-like-clockwork pattern, where every 17 years, you get huge emergences,” said Andres Ortega, an ecologist with the DuPage County Forest Preserve District. “There are hundreds of thousands or millions emerging within that year.”

Periodical cicadas typically start earlier in the season, emerging from their burrows in May or June for a short adult life of four to six weeks, dying by July. Then, even when it's the year of the 17-year periodicals, a brood of annuals will emerge to make more noise for the rest of the summer.

The sound creates nostalgia for some, like Miller, who said he remembers them fondly as a fixture of his back-to-school days growing up in the Midwest. But they spell a disturbance to others, says Dr. Regina Dziewior, an audiologist at Hearing Care of Palatine.

“Some people might just say, 'I can't stand the sound of cicadas,'” she said. “Others might say, 'They're the sound of summer.'”

While the nuisance doesn't come at a certain decibel level, Dziewior said she empathizes with those who find the cicada mating cry “really annoying and loud.”

When 17-year cicadas emerge, she said, their calls can be as intense as 100 decibels.

“That's as loud as a car stereo playing at max volume,” she said. “It's definitely loud.”

If the hum of 17-year periodical cicadas were present in a work environment, where people must stay for hours at a time, the Occupational Safety and Health Administration would require hearing protection, she said. That regulation kicks in at 90 decibels for exposure lasting eight hours.

But in the outdoor environment, she said, cicadas are unlikely to harm anyone's hearing because people wouldn't subject themselves to the clatter for “an extreme amount of time.”

Cicada facts

Periodical cicadasDifferent species of these insects emerge every 13 years and every 17 years across parts of the eastern U.S.; in northern Illinois, they occur every 17 years.Life span: 13 or 17 years underground as nymphs; four to six weeks above ground as adultsEmergence: May to JulySize: Three-quarters of an inch to 1½ inches longLast emerged: 2007Next emergence: 2024Body color: Jet blackWing color: Orange and transparentEye color: Red

Annual cicadasSome of these insects emerge from underground each year across the region.Life span: Two to 10 years underground as nymphs, with some nymphs emerging every year; four to six weeks above ground as adultsEmergence: July to SeptemberSize: 1½ to 2½ inches longBody color: Greenish-blackWing color: Silvery and translucentEye color: BlackSources: The Morton Arboretum, DuPage County Forest Preserve District, Chicago Botanic Garden