Thursday, December 12, 2013
Seth Borenstein / The Associated Press
WASHINGTON — Any day now, billions of cicadas with bulging red eyes will crawl out of the earth after 17 years underground and overrun the East Coast. The insects will arrive in such numbers that people from North Carolina to Connecticut will be outnumbered roughly 600-to-1. Maybe more.
Red-eyed "magicicadas" are seen only in the eastern half of the United States, nowhere else in the world.
AP/University of Connecticut
Scientists even have a horror-movie name for the infestation: Brood II. But as ominous as that sounds, the insects are harmless. They won't hurt you or other animals. At worst, they might damage a few saplings or young shrubs. Mostly they will blanket certain pockets of the region, though lots of people won't ever see them.
"It's not like these hordes of cicadas suck blood or zombify people," said May Berenbaum, a University of Illinois entomologist.
They're looking for just one thing: sex. And they've been waiting quite a long time.
Since 1996, this group of 1-inch bugs, in wingless nymph form, has been a few feet underground, sucking on tree roots and biding their time. They will emerge only when the ground temperature reaches precisely 64 degrees. After a few weeks up in the trees, they will die and their offspring will go underground, not to return until 2030.
"It's just an amazing accomplishment," Berenbaum says. "How can anyone not be impressed?"
And they will make a big racket, too. The noise that all the male cicadas make when they sing for sex can drown out your own thoughts, and maybe even rival a rock concert. In 2004, Gene Kritsky, an entomologist at the College of Mount St. Joseph in Cincinnati, measured cicadas at 94 decibels, saying it was so loud "you don't hear planes flying overhead."
There are ordinary cicadas that come out every year around the world, but these are different. They're called magicicadas -- as in magic -- and are red-eyed. And these magicicadas are seen only in the eastern half of the United States, nowhere else in the world.
There are 15 U.S. broods that emerge every 13 or 17 years, so that nearly every year, some place is overrun. Last year it was a small area, mostly around the Blue Ridge Mountains of Virginia, West Virginia and Tennessee. Next year, two places get hit: Iowa into Illinois and Missouri, and Louisiana and Mississippi. And it's possible to live in these locations and actually never see them.
The website Cicada Mania doesn't list Maine as one of the states expecting to see great numbers.
This year's invasion is one of the bigger ones. Several experts said they really don't have a handle on how many cicadas are lurking underground, but that 30 billion seems like a good estimate. At the Smithsonian Institution, researcher Gary Hevel thinks it may be more like 1 trillion.
Even if it's merely 30 billion, if they were lined up head to tail, they'd reach the moon and back.
"There will be some places where it's wall-to-wall cicadas," said University of Maryland entomologist Mike Raupp.
Strength in numbers is the key to cicada survival: There are so many of them that the birds can't possibly eat them all, and those that are left over are free to multiply, Raupp said.
The males come out first, as nymphs, which are essentially wingless and silent juveniles. They climb onto tree branches and molt one last time, becoming adult winged cicadas. As they perch on tree branches they sing, individually or in a chorus. When a female comes close, the males change their song, they do a dance and mate, Raupp explained.
The males keep mating, and eventually the female lays 600 or so eggs on the tip of a branch. The offspring then dive-bomb out of the trees, bounce off the ground and eventually burrow into the earth, he said.
"It's a treacherous, precarious life," Raupp said. "But somehow they make it work."