Get out the ear plugs—the 17-year periodical cicadas are getting their buzz on.
It has not been confirmed how cicadas “know” to emerge every 17 years.
The last time the 17-year periodical cicadas showed up—in 2004—Nancy Hinkle drove through the north Georgia mountains, collecting a few of the insects and taking photos.
“I’d stop my car every once in a while and listen,” recalls the good-humored entomology professor at the University of Georgia. “I’d just look up into the trees and see them flying from one to another and kind of bouncing off limbs periodically. They are not elegant fliers.”
From around mid-April to late May, Brood X, a.k.a. “The Great Eastern Brood” of periodical cicadas, will emerge from the warming soil to settle in oaks, hickories and other deciduous trees in the mountainous areas from Tennessee to West Virginia. With their red and black bodies, orange wings and devil-red eyes—characteristics that distinguish them from the larger, green-bodied ones that come out every summer and fall—the visual effect is unmistakable, and a bit jarring.
But it’s the rattling buzz or collective hiss that most observers notice first.
“People have some amazing descriptions of them,” says Hinkle. “One of them said it sounded like there was a UFO down in the woods. Several people thought somebody was running a machine down in the woods all day, maybe a lawnmower.”
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The mature nymphs of the periodic (17-year) cicada (Magicicada sp.) burrow up out of the ground before climbing onto a tree trunk or other object to begin metamorphosing into an adult.
It’s the males, of course, that make all the racket. Rapidly flexing their near-hollow abdomens in a sort of chest-beating display of ardor, they broadcast the alien tone through sound-amplifying membranes, called tymbals, to attract the females. After mating, the lady bug inserts her egg-laying device under the bark in the tender tip of a branch. Within a few weeks, the grain-of-rice-sized nymphs hatch and fall into the soil, where they feed underground on the roots for the next 17 years. They don’t stray far, so if the tree dies, they do too.
“Every time we denude a forest, there go all the periodical cicadas from that area,” says Hinkle.
It’s difficult to assess exactly where the highest concentrations live in the Blue Ridge region, simply because they so seldom appear.
“There really are only a half-dozen people in the whole United States that are actually working on periodical cicadas,” Hinkle says. “It’s hard to have a career when you can only do something every 17 years.”
So what exactly prompts these unusual bugs to come out of hiding?
“No one has actually confirmed how they know that,” Hinkle admits. “The prevalent theory is that somehow they can calculate when the trees lose their leaves and they know that’s been a year. Somehow, way down underground, the nymphs are able to count that, so they know when 17 years have passed. But that is the great mystery.”
Most people take the rare invasion in stride but, if it really bugs you, Hinkle jokingly suggests “a vacation west of the Mississippi River because there will not be any of them there.”
Better yet, she says, “For people who are just squeamish: Get over it. This is a wonderful natural phenomenon, especially if you have children. This is a great opportunity to introduce them to the marvels of nature. Nothing compares to it.”
And when engaged couples call her department and ask if their outdoor May weddings will be upstaged by the sound of periodical cicadas, she encourages them to go for it anyway.
“I think that’s the most romantic thing in the world. Think about it. You’re getting married with the song of cicadas all around you. Every 17 years, when you celebrate your anniversary, they are there to remind you of your perpetual love.”
The Truth about Periodical Cicadas
These noisy bugs often get a bad rap, says Dr. Nancy Hinkle, professor of entomology at the University of Georgia. Here are some little-known truths—and a few benefits of having them around:
- Cicadas are harmless to humans; they cannot bite or sting.
- “The main misconception is that they are locusts,” says Hinkle. “They aren’t.” (Locusts are detrimental to crops; not so with cicadas.) They’re also not katydids, which sing at night. Cicadas buzz during the day.
- Periodical cicadas serve as nature’s pruners, removing tree limbs before ice and snow can weigh them down and break them off.
- “They provide food for virtually every animal in the forest, so it’s not surprising that bird and wildlife populations often burgeon the year following a cicada emergence,” says Hinkle, noting that it’s okay for cats and dogs to eat them.
- Humans can munch on them too. “They’re kind of like shrimp,” Hinkle notes. No, she hasn’t cooked them herself, she says, laughing. “But there are recipes on the internet if you want to try them.”
The story above first appeared in our May/June 2021 issue. For more like it subscribe today or log in with your active BRC+ Membership. Thank you for your support!