Summer of the Cicada
For 17 years they've been out of sight, out of mind. Now they will be in your face. Get set for Brood X
Telltale holes, each about the size of a dime, recently started appearing in the soft spring earth beneath big trees on the University of Maryland campus in College Park. Entomologist Mike Raupp can hardly contain his excitement. In a few weeks, the massive cicada community known as Brood X will suddenly emerge from the ground after lurking underfoot for 17 years. Billions of the large, red-eyed bugs will fly clumsily around 15 eastern states in a brief mating frenzy, shrieking in a daytime din that can rival a jet engine. "This is just going to be a wicked cool biological event," says Raupp. He's already gotten out his frying pan and dug up some immature ones to show students that the critters make good eatin', too.
Ann Weinberg, a telecommunications consultant in Arlington, Va., isn't so thrilled. The first Brood X invasion she experienced, in 1987, left her shell-shocked. "Number one, they're so big. Number two, there are so many of them, millions of them, that it's like a Hitchcock movie, The Birds. Number three, they tend to fly right into you." Weinberg is glad she telecommutes so she can hide indoors until they disappear.
Fast life. That won't take long. While Brood X spends nearly two decades underground, sucking sap from tree roots, a cicada's life in the world above lasts just weeks. When the dirt warms up in late spring, the soft-bodied nymphs, or immature cicadas, climb the nearest vertical object, which they hope is a tree. There they cling until they are ready to split their amber- colored shells and emerge as winged adults. The males sing to attract mates, which lay ricelike eggs inside a tree branch. The adults die, and soon the hatched young fall to the ground, burrowing in to await 2021 and their own summer of love.
Nearly every year in early summer, one of many tribes of 17- and 13-year cicadas pops up somewhere on the East Coast, weeks before the "dog-day" cicadas, which have shorter sojourns underground and emerge in smaller numbers. But among "periodical" cicadas, Brood X has gained special notoriety. It's the 17-year brood with the greatest numbers and the largest geographic range, hitting many major cities. Accounts of Brood X date all the way back to 1715, says cicada expert Gene Kritsky of the College of Mount St. Joseph in Cincinnati.
By coming out all at once, in a staggering swarm, Brood X overwhelms birds and other predators, so each individual bug has a good chance of surviving to mate. And since they pop up so infrequently, few predators have evolved to depend on the insects as a routine food source. But no one is sure how periodical cicadas keep track of time. They may have a way to count seasonal changes in their tree-sap diet; a few years ago, scientists found that cicadas came up early if the tree they fed on was artificially forced through more than one flowering cycle in a year.
Plenty more puzzles remain for scientists to study when this year's emergence begins. Kritsky, whose new book, Periodical Cicadas: The Plague and the Puzzle, is out next month, wants to figure out how different broods are related and whether they interact underground. Others are gearing up to study mating habits and long-term effects on trees.
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