Since 1990, they had awaited the mysterious cue. It arrived just after dusk.
Every few inches, another orange-brown cicada nymph climbed out of the soil and marched toward anything tall: a tree, a weed, a fence or a sign. The teeming mass scaled up, as high as it could go. They cracked their way through skins and stretched their ghost-white wings. Before morning, most of them had turned black and prepared to unleash an unholy sound.
In some Chicago suburbs, periodical cicadas have been crawling out of the soil and leaving piles of their discarded exoskeletons at the base of trees for more than a week. But the intensity of the emergence picked up, and the areas where it is occurring spread widely after weekend rains loosened the dirt, easing the insects’ passage from the subterranean world they’ve inhabited for 17 years.
On Monday, biologist John Cooley estimated up to 100,000 surrounded a single tree at Bemis Woods Forest Preserve in Western Springs. Over the last two decades, Cooley has witnessed every periodical cicada emergence in the country — three broods that appear every 13 years and a dozen that show up every 17. But the abundance he saw Monday was, he said, “as impressive as I’ve ever seen.”
“This is pretty insanely dense,” said Cooley, a University of Connecticut entomologist who is helping to map the Illinois emergence for National Geographic. “This is as dense as you’ll ever see it. The local mass emergences have begun. There’s no doubt.”
By Monday, cicadas coated trees at The Morton Arboretum in Lisle and yards in Palos Heights, Oak Brook and Chicago’s Beverly neighborhood, where sea gulls gorged themselves on an easy feast. They also had begun to emerge in suburbs north of the city, such as Deerfield and Winnetka, where the ground has been slower to warm up to about 64 degrees — the trigger, scientists believe, that pushes cicadas above earth to begin a loud and lusty month.
But in the city, where the infestation is expected to be less intense, residents haven’t been hearing as much buzz.
The sounds of picnics, bike rides and paddleboats — not mating insects — provided the ambient noise Monday afternoon at Lincoln Park, where many city-dwellers said they had yet to see or hear from the winged creatures despite a fair amount of media buildup.
“I was thinking there would be a decent amount of them in the park. But so far, nothing,” said Eric Griffin, 29, of Lincoln Park, adding that he’s been listening intently for them. “I’m kind of looking, almost anxiously, to see what’s going to happen.”
Jana Borchardt, too, said she has yet to see the cicadas.
Borchardt, of Old Town, bristled at the suggestion of eating the bugs, but said she’d consider taking video of them with her cell phone and posting it on YouTube.
“I did hear on the news they’re coming,” said Borchardt, 37. “I don’t like bugs. I’m not looking forward to seeing them. I’d be fine if they passed the city by.”
Before it’s over — roughly around the 4th of July — the invasion will no doubt bug the heck out of some and enchant others.
Scientists have measured crescendos of the distinct whirring and buzzing noises made by males as they try to attract mates at 96 decibels, as loud as a jet flying close overhead, loud enough that biologists such as Cooley avoid ear pain by wearing gun mufflers used at shooting ranges. Annual cicadas that show up during the dog days of summer are louder individually, but periodic cicadas arrive in much greater numbers and collectively produce a louder racket.
For the most part, that chorus has not yet kicked in. Cicadas begin the mating call — made using structures in their abdomens called tymbals — about five days after emerging from the ground.
As more mature adults come of age, the volume will increase exponentially. On hot, sunny days, the buzzing sound will synchronize.
“This whole forest will be pulsing,” said Cooley.
And yet, the experience may pass right by some Chicago area residents. In some neighborhoods that are heavily developed or built on top of former cornfields, residents will see no sign of cicadas at all. While they’ve already overrun some suburbs, some people are still waiting for their first glimpse of those beady little red eyes.
The mass emergence typically takes more than a week, according to Gene Kritsky, an entomologist at the College of Mount St. Joseph in Cincinnati.
“It’s like the dam bursting, but all the water doesn’t go through at once,” he said. “The greater Chicago area is a big place and the kind of variation we’re seeing is not surprising. There’s no question the emergence has started, it’s started in force, and this is the slow buildup in numbers.”
Some like Shawn Parks, 25, of Lakeview, will have to continue to wait for the bugs to show up near him — if they do at all.
“I thought they were supposed to be here last week,” he said. “There was kind of a big hype about them.”
