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When millions of cicadas expire, the nose knows
Right around Memorial Day, millions of cicadas descended on northeast Illinois in earnest, buzzing into open car windows, hitching rides through kitchen doorways, swooping into runners' mouths and generally flying all over the place like drunken bumblebees, only without the sting.
Now, they're starting to die in earnest, creating a gross encounter of a different kind.
They're being scraped off decks, tennis shoes and windshields. Mounds of cicada carcasses, many oozing appalling yellowish goo, are growing around tree trunks. Stroll near a thick enough collection of the recently departed bugs and an odor somewhere between rotting raccoon and cut grass wafts into the sinuses. The ends of tree branches are droopy and brown.
Not to worry, cicada expert Phil Nixon contends. Like the invasion itself, the death of the cicada will cause temporary nuisances that may be a little messy. "What it really comes down to is that nature is recycling," said Nixon, an extension entomologist at the University of Illinois at Urbana-Champaign. "These are the types of things that happen to us after we die. Bacteria and fungi work on us and we become goo, essentially."
But, let's try to look on the bright side, shall we?
"They're organic matter," Nixon said, "and they're not associated with any diseases. So, they would be a good source of nutrients. I suppose you could put them in your garden. But, certainly wherever they happen to fall, they would be a good source of nutrients for whatever is growing there."
The bugs started invading en masse May 27. Over the next three weeks, males generally looked for dates and mates, then expired. Females may stick around until mid- or late-July laying eggs before dying, Nixon said.
But many people are noticing that the decibel level and numbers of the winged, red-eyed, brown insects are declining significantly, prompting the need for extra cleanup duty and making an assault on the olfactory lobes.
Loretta Whitmore of Lake Forest has found a new use for her leaf blower: moving dead cicadas from her driveway. In her back-yard patio, she uses a broom.
"Once they die, I sweep them up, put them in a plastic bag and take them to the garbage can in my garage," she said. "Otherwise they smell."
Clarendon Hills resident Jim Condon dealt with live cicadas, in part, by placing a 4-by-4 piece of plywood at the mouth of the family's fireplace to keep them from entering the house. Now, like Whitmore, he is confronting the odor of the dead bugs, particularly around the mature trees in his back yard.
"The smell is really bad now," he said. "It's like a sweet, sickly, decomposing odor. It kind of hits you when you come outside."
The goo results from the natural deterioration of the bugs, Nixon said.
For trees, the brown leaves and snapped branches are the result of "die-back" caused by females inserting their eggs into the wood, Nixon said.
Anybody expecting to see obese robins, sparrows and other birds that have overindulged on cicadas probably will be surprised, Nixon said. Most of that extra food is going to newborns, which otherwise would have perished, Nixon said.
That population gain will be temporary. Next year, when the cicadas are absent from the food chain, vulnerable birds will die from lack of food, Nixon said.
Susan Harris of Hinsdale has noticed the odor from thick layers of dead cicadas but calls it more subtle than some have described. The bigger issue to her has been keeping two children off the lawn to avoid the dead bodies.
Now that the cicadas are dying in large numbers, her daughter, Lauren, 3, has become brave enough to pick them up and poke at them, which she did the other day with a new friend, Liz, Harris said.
"It was like a science project to them," Harris said. "She's touched their wings and she's very proud of herself."
IN THE WEB EDITION
Relive the cicada invasion of 2007 at Cicada Central at chicagotribune.com/cicada