'Alien buzz' kicks off cicada mating season

"An alien buzz; it's a pretty cool sound," said Apex resident Brad Bergeson.

That "alien buzz" is so loud that it's sometimes hard for Katie Henry, of Holly Springs, to talk above the noise.

"It sounds like close encounters," she said. "We thought it was the nuclear power plant."

She called Progress Energy, the utility that runs the Shearon Harris nuclear plant in western Wake County. The company said she wasn't the first to call about the noise.

"She said, 'You are not going to believe me, but it is the cicadas,'" Henry said.

This special kind of cicada stays underground for 13 years and then rises above ground in order to mate.

"They come out in mass, all at once," said Clyde Sorenson, professor of entomology at North Carolina State University. "This is a really cool natural phenomenon and the only place it happens is in eastern North America."

Sorenson said there can be as many as a million per acre, so it's no wonder the buzz can be deafening.

The male cicadas produce the sound with their bodies, flexing little plates on the sides of their abdomens that are covered in ridges of exoskeleton, Sorenson said. 

The buzz is a mating call.

"It is all about sex, they just want to find females," he said.

Cicadas only live about three or four weeks above ground. Their eggs hatch in the trees and their offspring make their way back to the dirt.

"They go back into the ground for 13 more years," Sorenson said. 

WRAL received many reports from visitors about the buzz. Some people said they had called 911. 

But Sorenson said he expects the insects to die off by the end of May. And, he added, cicadas don't bite and aren't dangerous to people.

In fact, Sorenson said, people ate them hundreds of years ago.