As the 17-year periodic cicadas begin to emerge, most people find the noise the insects make annoying, but entomologists say it's a love call.

NASHVILLE, Tenn. — As 17-year periodic cicadas scratch and buzz in 13 states, entomologists remind us that brash noise is really an insect love song.

"It's the men's glee club serenading the ladies," said Dr. Frank Hale, with the University of Tennessee Extension in Nashville. The current emergence is Brood XIV and it stretches over 13 states from Georgia to Massachusetts. The periodic cicadas are a phenomenon of the hardwood forests of the eastern U.S.

While cicadas get turned on by the sound they emit from two drumlike membranes on the abdomen, humans find it shrill, loud and annoying.

But listen carefully, advises Greg Hoover, an entomologist at Pennsylvania State University in State College. You'll hear different songs because there are three different species in Brood XIV.

The female cicadas' response to this courting is subtle. A demure flick of wings indicates a female is ready to mate, Hoover said.

Beyond the noise, people can be unsettled by the 1Z\x-inch bugs' red eyes, their clumsy flight and what Hoover calls their tendency to assume anything upright is a landing spot.

But cicadas can't bite or sting even when they light on you, he assures.

Periodic cicadas — the insects people sometimes call 'locusts' — are unique to eastern North America.

"The (American) colonists thought they were witnessing a locust plague," Hoover explained.

Locusts, however, are more like grasshoppers, which eat grasses and crops, Hoover said. Cicadas suck nutrients from trees, but usually do little damage.

Brood XIV is expected to appear in at least parts of Georgia, Kentucky, Indiana, Massachusetts, Maryland, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia.