Swarm of cicadas coming in May

<p>Periodical cicadas, a species of the grasshopper-like insects best known for the scratching, screeching "singing" of the males, will emerge this May, filling forests in more than a dozen states, including Georgia.</p><p>Then, almost as abruptly as they arrived, they'll be gone, back underground for another 17 years.</p><p>"That's their life cycle. That's their genetic blueprint," said Greg Hoover, senior extension entomologist for Penn State University. "Why do certain insects take only one year to develop, and others take two or three? It's just part of their genetic programming."</p><p>There are at least 13 broods of 17-year cicadas, plus another five broods that emerge every 13 years. The last brood to emerge, Brood IX, was seen last spring in parts of West Virginia, Virginia and North Carolina. Two years ago, Brood VIII emerged in parts of western Pennsylvania, eastern Ohio and West Virginia.</p><p>But this year's emergence is Brood X, the so-called "Big Brood," with a range that stretches from Georgia through Tennessee and to isolated pockets of Missouri, north along the Ohio Valley and into Michigan, and east into New Jersey and New York.</p><p>"This is one of those years we kind of dread," said Paris Lambdin, professor of entomology and plant pathology at the University of Tennessee. "We had an emergence a couple years ago around Nashville, but nothing like what we expect this one will be."</p><p>No other periodic cicada covers so much ground. And with hundreds of them per acre in infested areas, no other periodic cicada will make so much noise.</p><p>"In 1987, coming back from the University of Maryland on Interstate 95, when you drove through a wooded area you could hear the insects," Hoover said. "This would have been mid- to late June, with the windows down, and then it would shut down when you got to a field or a nonwooded area. That's how noisy these insects can be."</p><p>In rare years, a 13-year brood can emerge to add its collective voice to that of a 17-year brood.</p><p>"Out in the Midwest is where things get really hairy," Hoover said. "Missouri, Illinois, Indiana have combinations of 17-year-brooded individuals and 13-year-brooded individuals, and they can have overlap."</p><p>There's no question that the class of 2004 will be a nuisance. The cicadas will make plenty of noise, and adults are poor fliers that tend to bump into things.</p><p>But as swarms go, these cicadas aren't that bad. Adults don't feed on leaves, so they won't strip the trees. The only real damage they do is to cut a slit into small twigs, where they'll lay their eggs.</p><p>"The females, once mated, will lay pockets of eggs along twigs that will cause structural weakening of those twigs. The leaves out on the tips of those twigs will become ... brown, of flagged as we call it," Hoover said. "Eventually they may drop off and fall to the ground, the nymphs will drop off and fall to the soil, and that's where this species is for the next 17 years."</p><p>Indigenous only to the central and eastern United States, periodical cicadas then spend the bulk of their lives underground, feeding on the roots of trees and shrubs.</p><p>"They burrow down, down into the soil, attach themselves to the roots of trees, and begin to feed on the roots of trees," Lambdin said, noting that some will dig as far as 10 feet down into the soil. "They do extract the sap from the trees, but not sufficient to damage the tree from our perspective or to kill the tree."</p><p>___</p><p>On the Net:</p><p>HASH(0x28657f8)</p><p>HASH(0x28658a0)</p>

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