HEADED OUR WAY?
They’ve lived underground for 17 years, waiting. The last time they surfaced was in 2004, the year Lance Armstrong won his sixth consecutive Tour de France and Ken Jennings won a whopping $2.5 million on Jeopardy!, seizing the record for highest-earning American game show contestant of all time.
This spring, a swarm of 17-year cicadas known to entomologists as Brood X, or the Great Eastern Brood, will appear again in 14 states including Virginia. But scientists have observed that Rappahannock County is just barely outside of their distribution range. This year, the largest swarms of these cicadas will cluster around Washington, D.C., and north into Pennsylvania.
“Their geographic distribution across the Eastern U.S. varies quite widely,” said Chris Bergh, an entomologist specializing in tree pests at Virginia Tech.
The Great Eastern Brood is actually one of 14 distinct 17-year cicada broods that surface in di erent years. “A brood is a population that emerges synchronously in a given year,” Bergh explained. “They feed on roots and when that 17 years is up, they move to the soil surface in response to soil temperatures and then emerge. And their emergence tends to be quite synchronous compared to that of many insects, this emergence occurs over a period of maybe a week or so.”
These insects di er from the annual cicadas that Virginians might see — and hear — every year. That species, whose common name is the dog-day cicada, is smaller and shorter-lived than its 17-year cousin.
So what will happen when Brood
X emerges? In early spring, the males will “sing” to attract females. There are three di erent species in Brood X, Magicicada septendecim, Magicicada cassini and Magicicada septendecula. Each di erent species has a slightly di erent song. (According to Bergh, if there are any Brood X cicadas in our area, they’re likely to be Magicicada septendecim.)
A er mating, female cicadas will cut dozens of V-shaped slits in the bark of young trees and lay 10 to 20 eggs in each one. Some females can deposit up to 600 eggs.
Having completed their life cycle in mid-July, both males and females will die within a matter of days. Then, six to 10 weeks later, their eggs will hatch and out will crawl hundreds of nymphs. Juvenile cicadas instinctively burrow into the soil, where they will live for the vast majority of their lives until they surface again in — you guessed it — 17 years.
The longevity of these cicadas makes them the third longest-living insects in the world, following splendour beetles — which can live up to 30 years — and queen termites — which can live for up to 50.
Even though Rappahannock County is not the epicenter of Brood X’s range, Bergh said we could see a couple of stray 17-year cicadas here and there. “In the area of most concern to us here in the mid-Atlantic would extend to around parts of Central Virginia up through Northern Virginia into Pennsylvania, New Jersey, Maryland, [and] Delaware,” he said, adding, “Some areas have one brood and not others.”
Brood II, the swarm most prevalent in Rappahannock and its neighboring counties, emerged and burrowed again in the spring of 2013, to return in 2030.