Where were you seventeen years ago? We ask because this is a story about an event that takes place only every seventeen years in southwestern Virginia. No invitations go out. There are no RSVPs, but somehow, everyone will be there-- or forget about finding a mate.
To some, the sound of Cicadas is like big party. The females sporting their shiny six legs and gossamer wings, like nominees at an academy awards ceremony. The males, literally rocking their wings, providing the music for this Cicada Dance. “Only the males make the sound” says Doug Pfieffer, an entomologist at Virginia Tech. “They have a little white membrane just behind the wings called the 'Timble' that vibrates and creates the singing sound. Once they start singing both sexes will begin to congregate.”
In some places, it’s like a Cicada rave going full tilt with thousands, even hundreds of thousands of the critters moving closer and closer together until the ground itself looks like it’s moving to the beat and here’s the reason they do that. “It’s an evolutionary device to reduce predation, mainly by birds. Birds are the most important predators of Cicadas.
And with so many Cicadas in one place, says Pfieffer, the birds can’t eat them all, and that’s actually a survival of the species trick, called, ‘predator satiation.’
“The predators just can't keep up with them so the impact of the predators on the population is minimized that way. We have this evolutionary synchronization that is a very interesting.”
For the past 17 years this particular Brood of Cicadas, Brood 9, has been living underground, molting, taking nutrients from the earth and leading sedentary and solitary lives.
Entomologist Eric Day is Manager of Virginia Tech’s Insect ID Lab. He explains what is about to happen in southwestern Virginia: “Their last molt (while underground) was about four years ago. So, they're in their final molt (now). They are not hibernating. They're feeding a little bit. And they're all starting to work their way up to the soil surface.”
Even as you’re reading this, they are climbing up through the earth. “And right now, there still would be technically in the immature stage or the nymph stage. And then what'll happen is when you get into the middle of May, when they start emerging, once we get that 64-degree temperature in the soil, they emerge. They will, they will crawl up the sides, the trunks of trees or any sort of upright structure they can find, whatever's nearby.”
In some parts of this region, you may not see any Cicadas, but where they congregate, you won’t be able to miss them, as they seem to multiply right before your eyes. But as Day points out, that’s an illusion. When they arrive above ground, they cast off their last of their outer skins. “They leave these husks which are actually the cast-off skin of the Cicada, on the tree trunk. And sometimes you can just see hundreds on an individual tree and then the adults will merge out of there. If you can get out there at night or keep an eye on it, you'll see these white cicadas coming out.”
Scientists and tourists come to this region just to watch this unusual, and long-awaited event. But as Day points out, for some people it can be a nuisance. “When you have high numbers in your yard, you can't hear yourself think.”
They can also be a hindrance to farmers, stunting the growth of fruit trees this time of year. “We often get calls on Cicada emergence years where people say, 'I'm having an outdoor event or an outdoor wedding and what's up with these cicadas?'”
This year with ‘stay at home’ orders in effect, he points out “there won’t be many outdoor activities’ to be overwhelmed by swarms of Cicadas.
Cicadas don’t bite or sting. They don’t carry disease. And because they rely on their sheer numbers for defense, they haven’t had to develop toxins to dissuade predators, which means, Cicadas are safe to eat for humans. “It’s best to get them when they newly emerged” says Pfeiffer. “Just think of them as a land shrimp.”
But you’ll have to work fast. Just about a month after this brood of 17-year cicadas emerges, they’ll be gone, their offspring heading underground for another 17, leaving only their transparent husks to be scattered by the wind.
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Gene Kritsky, Ph.D., Dean of Behavioral and Natural Sciences at Mount St. Joseph University in Cincinnati, who has studied cicadas throughout his academic career, worked in partnership with the Center for IT Engagement (cITe) at Mount St. Joseph University to create the Cicada Safari app. It allows users to search, photograph, video and help map the cicadas. The University also maintains a cicada website showing where the cicadas will emerge this year.
https://apps.apple.com/us/app/cicada-safari/id1446471492
