Mary Coen rubbed her temple and sighed. The chorus of cicadas throbbed in the oak trees, brain-piercingly loud.
“I was hoping they were on the wane, but good God,” she said as she walked to her car Thursday outside Graue Mill in Oak Brook. “It’s dreadful. I don’t mind cicadas. I have no problem with them. They’re friendly. But it’s the noise. By midday, I get a headache. So I’m ready for it to be over.”
In some ways, the cicada experience is just getting started. In northern Illinois, the insects have emerged by the billions, shed their skins and now are ready to mate. That means they’re letting loose with a mating call so loud that it can be heard in speeding cars over the engine, tire and wind noise. “You can’t hear yourself talk,” said Coen, 62, of Downers Grove.
And that noise, measured at decibels comparable to lawn mowers, peaks on summery days like Thursday.
“If you have a period of cool, rainy days like this and you get a hot sunny day, they’ll just come roaring out,” said John Cooley, a University of Connecticut entomologist who uses the kind of mufflers worn at shooting ranges when he’s conducting cicada surveys in heavily populated areas.
There is some good news. The invasion will be over, for the most part, by the 4th of July. And the racket made by periodical cicadas reaches its crescendo in the middle of the day, so nighttime is relatively quiet. Other than that, be patient, the experts say.
“You can always get some ear plugs, you could sing to yourself, turn the TV up real loud or just enjoy it, because it is going to pass,” said Daniel Summers, a Field Museum entomologist.
The cicada cacophony is made by males desperately trying to woo females during their monthlong stints as adults living above earth after 17 years as nymphs underground. They begin to make the noise four or five days after they emerge from the ground and molt.
The sound comes not from their mouths but a pair of ribbed membranes in their abdomen called tymbals, which connect to a series of powerful muscles. Using the muscles to tense and release, the males vibrate the tymbals back and forth like drumheads while their hollow abdomen amplifies the sound like a resonating chamber.
In the Chicago region, three periodical cicada species emerge every 17 years, but two are far more plentiful. Though they look alike, the sounds they make are distinct, even when they’re heard layered on top of each other.
Magicicada septendecim is the larger cicada with orange stripes on its abdomen. Septendecim creates the distant, rolling, ringing drone that is not a typical cicada sound. Magicicada cassini, which has an all-black abdomen, sounds more like the annual cicadas that show up in the dog days of summer with a piercing, shrill buzz that pulses when males synchronize their chorus.
Individually, annual cicadas are just as loud as periodicals, but periodicals come out in overwhelming numbers — so the aggregate is more intense. In an area dense with cicadas, the noise can exceed 90 decibels, about as loud as a bulldozer.
“We go downstairs for breakfast, and right away we can hear them,” said Bill Eveline, 41, who lives on a wooded lot in Lincolnshire. “Then we go outside to our back yard, and it’s like the concert begins.”
Exposure to 91 decibels of sound for two hours, or 94 decibels for one hour, could begin to cause some permanent hearing damage, according to Billy Martin, a hearing scientist at Oregon Health & Science University and director of Dangerous Decibels, a public health campaign designed to reduce noise-induced hearing loss.
Such noise also could cause psychological strain, he said. Powerful, high-pitched, abrasive sounds, such as cicadas, are like fingernails on the chalkboard, and they may cause anxiety, aggravation and high-blood pressure, Martin said. . “Loud sound is very stressful, especially if the sound is annoying and loud,” Martin said. “It’s the double whammy and cicadas, for the most part, are both.”
Wilmette resident Mary White said she can’t even find solace in her own home. She frequently works out of the house for her job with an investment management firm and had to shut the window during a conference call because the whirring was overpowering.
“People tell me they can hear it through the phone,” said White, 41. “They ask what the buzzing is and I tell them it’s the cicadas. It’s distracting. It’s like a constant buzz.”
John Fitzloff, 67, heard it this week in Lombard as he mowed the lawn of a home he’s lived in for 35 years. Cicadas clung to his shoulder and the leg of his jeans. Countless shells from cicada nymphs ringed the base of his American basswood tree. The stench of rotting cicada corpses hung in the air.
“This is definitely the worst of the three [emergences since] I’ve been living here,” Fitzloff said. “The kids in the neighborhood thought it was great, the ones who’d never seen them before, but after a week that wore off.”
Considering them unavoidable, he went about his routine. Halfway down the block, almost every inch of Juliet Hathaway’s lawn was covered in cicadas — alive, dead and molted shells — and the fluttering bugs were dive-bombing onto anyone who encroached. She is late in planting flowers and has put off rolling out the Slip ‘N Slide for her son Jackson, 6.
“I can’t keep the windows open on this side of the house because of the noise and the smell,” said Hathaway, 40, as she swatted a cicada out of her hair. “We’ve got the grossest house on the block.”
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IN THE WEB EDITION: See more photos and videos of cicadas throughout the Chicago area at Cicada Central, chicagotribune.com/cicadas