By John Biemer and Courtney Flynn
CHICAGO, IL–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.
John Cooley estimated up to 100,000 surrounded a single tree at Bemis Woods Forest Preserve in Western Springs, IL. 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 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.”
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.
For many children at Winnetka’s Village Green Park, the inch-long, plentiful bugs were an amusing distraction. Daniel McNerney, 8, plucked four nymphs from the knotty bark of a nearby elm and set them atop a long, curved stick.
“I’ve named them Jim, Jimmy, Johnny and John,” he said proudly. “They look cool. It’s awesome when you get to see them fly out of their shell.” His sister, Maureen, 6, was not enamored.
Before it’s over — roughly around the 4th of July — the invasion will no doubt bug the heck out of some Chicagoans and enchant others. There are some 6,000 cicada species worldwide, but just seven species that emerge in periodic intervals. All of them are found in the United States: east of the Great Plains, south of the Great Lakes and north of Florida.
“This is the only place in the world anything like this happens,” Cooley said. “There are [no other insects] that combine periodicity with long life cycles, massive, dense emergences and these charismatic behaviors.”
And not often does such an unusual natural phenomenon occur in one’s front yard. Just after dusk, Melissa Laudadio watched her lawn come alive. So many nymphs had popped up in her River Forest front yard that you could hear them clawing toward the giant oak. Her son, Cosmo, 4, was dressed in his Batman Halloween costume and collecting them with a green net and letting them go.
“My neighbors are like, ‘What’s he still doing outside?’ ” Laudadio said. “It’s a special occasion. The cicadas are coming!”
Cicadas do not bit–they do not have jaws–and they are not known to carry diseases. But if they are nearby in great numbers, they will not be ignored.
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.
For now, it is just a background sound in places where some came out early, such as Elmhurst, La Grange and Bemis Woods. 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 some Chicago area residents right by. 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, particularly those with old-growth trees, others are still waiting for their first glimpse of those beady little red eyes.
By its nature, the emergence pattern is patchy because soil temperatures vary considerably around the area, or even within the same park. Thousands of cicadas may have burst out around an isolated tree surrounded by grass in direct sunlight, while at the edge of the woods, a few steps away, thousands more wait underground.
The mass emergence typically takes more than a week, according to Gene Kritsky, an entomologist at the College of Mt. St. Joseph in Cincinnati and one of the nation’s leading cicada experts.
“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.”
By the end of June, most of those same cicadas will be dead, but the females will have tucked countless eggs into slits in the trunks and branches of trees. Later this summer, ant-sized nymphs will hatch and tunnel underground to emerge again in 2024.
“If you come down here one night in late July, early August, they’ll be raining down like rain drops,” Cooley said. “They’ll start the cycle again and most people will forget they’re around.” –Chicago Tribune