The Brood X bugs, red-eyed cousins of the larger annual black-eyed late-summer "Dog Day" green cicadas, will begin emerging from their underground holes in western North Carolina later this month. They don't devour vegetation the way locusts do, and they don't bite or sting. But they sure do sing.
Like many human adolescents, periodical cicadas spend umpteen years in their dirty rooms, indulging in sweet stuff and oblivious to much of the world outside themselves. Then, suddenly, as if a hormone switch were flipped, they emerge with a single-minded commitment to find favor with whatever peer they deem sexually appealing.
The bug nymphs live all that time on tender hardwood tree roots until they finally get the hots. Well, it's more like the "warms," because their signal to go forth and mate is a rise in the soil temperature to 64 degrees Fahrenheit.
Once in heat, millions of them push their way to the surface and climb onto new branch growth on nearby trees and shrubs, according to entomologist Stephen Bambara, who works with the N.C. State Cooperative Extension Service in Raleigh.
The males get together in choruses and harmonize in a unique doo-wop that strikes humans as a decidedly un-sexy metallic screeching. But cicada females respond to it with abandon, making clicking sounds and wing flips -- their version of an air kiss and a toss of the hair.
After 13 or 17 years of underground obscurity, periodical cicadas emerge to a multi-week Mardi Gras, a party thrown by nature solely to ensure that what goes around comes around, generation after generation. Like most such reveries, it's noisy, it's not pretty, and many participants meet violent fates from predators. But in this case, it gets the job done, according to Bambara, because the weird life cycle itself offers a form of protection for the species.
"Cicadas go 13 or 17 years between life cycles because it's to their advantage," said Bambara. "It throws possible predators off track. Seventeen years is a long time to wait between meals if that were your prey. So I think that's where they got their niche. A lot of them are consumed and die when they come out. But their sheer numbers also help ensure their survival. Even if a lot of them get eaten, a lot of others are still left to reproduce."
Birds are periodical cicadas' main predators, he said, plus other omnivorous ground-dwelling animals such as opossums, skunks, raccoons and foxes. Fish, too, eat cicadas that fall into the water.