Cicada brood is scientists' map quest
Like bugs' lives, effort fast, frenzied, short
By John Biemer
Tribune staff reporter
Published June 23, 2007
John Cooley pulled into Highland Park for one last check on the cicadas. He was in a race against time. The mighty chorus was petering out, the culmination of a 17-year cycle that reaches a one-month climax with billions of red-eyed insects molting, mating and laying eggs.
It also was the end to a hectic four weeks for Cooley and a dozen others who had fanned out throughout a four-state region, driving through suburbs and down country roads, all the time listening for that unmistakable buzz. With one last day Thursday, Cooley looped north to Fox Lake, then down through Woodstock and west to Rock Cut State Park near Rockford.
His mission, sponsored by National Geographic, was to mark detailed coordinates for the distribution of Brood XIII and improve on current data, some of it more than a century old and unreliable enough that some southern Michiganders expected an emergence this year that never arrived. It's an effort that has been greatly facilitated by improved technology since the last emergence in 1990 -- including cell phones, global positioning systems and interactive Web maps.
But good, old-fashioned hard work is still needed.
To be precise, Cooley, a University of Connecticut entomologist, stopped as often as every tenth of a mile in likely cicada areas, such as old-growth forests. He would turn off the engine, listen out the open window and record his observations with a hand-held GPS. In some areas, such as Bull Valley, the cicada chorus was still loud enough that he did not even stop his Ford Explorer.
"This is kind of high-speed, last-gasp mapping," he said. Cooley's one-month window of opportunity to study northern Illinois' periodical cicadas has now drawn to a close. The few remaining from the great multitude of a few weeks ago are now, Cooley said, "the walking dead." The periodical cicada chorus will not break out here again until 2024.
"The emergence is a frenzy," Cooley said. "[Cicadas] have to accomplish all they have to accomplish as adults in three weeks. Time is of the essence. So they're pressed for time. We're always pressed for time. We're running around like mad during these emergences, doing our experiments, making our maps and before you know it, it's done."
Cooley, 39, flew back east Friday after a four-week journey searching out cicadas from Springfield to central Iowa and southern Wisconsin. He put more than 5,500 miles on his Explorer and 2,000 miles on the car he rented while a mechanic fixed the Ford's broken fuel pump. All the while, he camped out or slept in the back seat on a makeshift mattress made from acoustic foam. Many of his meals consisted of cereal.
"People think we're lunatics," he said. "We have normal lives, but during this month we live these bizarre nomadic lives. For this one month, we're completely off the wall."
But what may sound like lunacy to some serves an important scientific purpose, he said. Without detailed maps, biologists cannot tell if the cicadas' range is expanding or contracting. A sizable emergence, he said, may serve as a bio-indicator of healthy trees in a healthy ecosystem.
"They're patchy here in Chicago," he said. "Well, have they always been patchy or is the patchiness a sign of trouble?"
Cooley has observed periodical cicada emergences around the country -- three broods that appear every 13 years and a dozen that show up every 17 -- since the last one here in 1990. National Geographic's $20,000 grant helped cover costs for about a dozen people who assisted him, including fellow academics and amateur enthusiasts. The money mostly went toward gas.
Scientists have long depended on civilian help in documenting the extent of an emergence. After all, there were -- and continue to be -- limits on the time and manpower available to scour territories of periodical broods, the largest of which stretches from Missouri to the Carolinas.
Years ago, the methods were rudimentary. In the early 1890s and early 1900s, the Bureau of Entomology, then a division of the U.S. Department of Agriculture, sent out thousands of postcards to school superintendents, science teachers and mail carriers, hoping they would report cicada sightings, according to Gene Kritsky, an entomologist at the College of Mt. St. Joseph in Cincinnati.
Maps generated in that era are still in use -- despite questions about whether citizens accidentally reported annual "dog-day" cicadas instead of periodical ones or marked an entire county as having them when there were only a few in one place.
Citizen reports, including Web maps from the Lake County Forest Preserve and the Chicago Tribune, are helpful, but also limited because they tend to confirm where cicadas are -- while not checking out where they are not. The National Geographic team did both.
Earlier this month, Gerry Bunker was dispatched to find out firsthand if Brood XIII emerged in southern Michigan, as some historic maps indicated. Bunker, 43, of North Chelmsford, Mass., zigzagged west along U.S. Highway 12 from Sturgis, Mich., but did not hear that familiar chorus until he drove down to northwest Indiana. "I came up with a big, fat negative in Michigan," said Bunker, who was using a two-week vacation from his job.
The Detroit Free-Press trumpeted the discrepancy between historic maps showing cicadas in Michigan with a Page 1 headline in late May: "Yes, We Have No Cicadas!" Cicadas could have been in southern Michigan when those maps were made, Cooley said, though there's no way to tell now.
But that's the point of his project -- to provide more accurate data for the future about sites like Moraine Hills State Park near McHenry. There, Cooley got out of his Explorer and heard the faint staccato call of a single cicada. At the base of an oak tree, he found a nymph's molted shell.
"It's a bit of detective work coming to a place like this," he said. "You might look at this and say, 'There's no cicadas here.' But there are, it's just not a roaring population. If there's nothing here in 2024, it means this is the end for this spot. Without the baseline, you can't make a call about something like that."
