Adult Cicadas rest on a plant, Monday, May 17, 2021, at Woodend Sanctuary and Mansion, in Chevy Chase, Md. (AP Photo/Carolyn…
Adult cicadas rest on a plant, May 17, 2021, at Woodend Sanctuary and Mansion, in Chevy Chase, Md.

ALEXANDRIA, VIRGINIA - Billions, perhaps even trillions, of cicadas are emerging from the soil over a six-week period in more than a dozen U.S. states. The Washington region, including Northern Virginia, is a hot spot for the plentiful but short-lived thumb-sized insect that some find fascinating and others unnerving.

Entomologist Floyd Shockley searched a wooded area in Alexandria, Virginia, for the harmless insects, which slowly climb out of the ground every 17 years from under the deciduous trees on which they feed.

An adult cicada climbs up a bush at a forested park in Alexandria, Virginia. Scientists say billions, perhaps even trillions of the insects, may emerge during the next several weeks. (Deborah Block/VOA)

"There's a couple of adults over here," Shockley said as he gently picked up a black creature with translucent wings and prominent red eyes. Shockley is the collections manager at the Smithsonian National Museum of Natural History in Washington. Today, he is collecting specimens for research.

More than 3,000 kinds of cicadas can be found worldwide. While many appear annually, some U.S. varieties spring from the ground either every 17 or 13 years. The cicadas currently blanketing the Washington area are known as Brood X (10).

"It's an amazing phenomenon," Shockley said.

Two-year-old Robert Cody in Alexandria can't get enough of the cicadas, even when they fly and land on him. "The cicadas are my friends. They tickle my ears, and their eyes look like fire," he said.

Some people are wary of the bugs, like Jeremy Buchanan in Herndon, Virginia, who likes to take a run after work. "When I run by some trees, they sometimes drop on my head," he said.

"There's no reason for people to be afraid of them," explained Gene Kritsky, a cicada expert at Mount St. Joseph University in Cincinnati, Ohio. "They don't bite or sting or spread diseases on crops."

Kritsky came up with the idea of a phone app and website called Cicada Safari that citizen scientists can use to post their cicada photos and the location where they were taken.

Male cicadas court the females with a mating call. A chorus of cicadas can be louder than being near an airport where jets are landing. (Video courtesy Gene Kritsky, Mount St. Joseph University, Cincinnati, Ohio)

The Brood X cicadas came into being in 2004. After 17 years underground, they emerged when soil temperatures reached 18 degrees Celsius. Light brown male nymphs emerge first, shedding their exoskeletons and unfurling their wings as they climb up nearby trees. Within a week, the females follow suit.

"They come out for one reason, and that is to mate and keep the population going," explained Stuart McKamey, a leading cicada expert with the U.S. Department of Agriculture's Systematic Entomology Laboratory.

"The secret is to come out in great numbers to overwhelm their predators, which include birds, mammals and reptiles," added Kritsky. "Even if a million of them are eaten, there's still many more left."

A Brood X cicada tracker map on CicadaSafari.com shows locations in the US where the bugs are appearing after 17 years of being underground. (Courtesy Cicada Safari/Gene Kritsky, Mount St. Joseph University, Cincinnati, Ohio)

Since the protein-rich cicadas aren't poisonous, adventurous humans can eat them as well. A cookbook called Cicada-Licious includes recipes for cicada pizza, tacos and cookies.

Brian Schwatken in Arlington, Virginia, fried some cicada nymphs with butter, garlic and onions. "They are tender, have kind of a nutty taste and are really good," he said.

The males court the females with a screaming high-pitched mating call that resembles the droning sound of a UFO in an old movie, Shockley said. A chorus of cicadas can be louder than the sounds near an airport when jets are landing, Kritsky added.

The females don't fall for just any male. He must win her over by showcasing his different tones and rhythms. If she's interested in him, she clicks her wings, McKamey said.

Adult cicadas die soon after mating and fertilize the soil.

Brian Schwatken in Arlington, Virginia, fries cicadas with butter, garlic and onions. 'They are tender and have a nutty taste,' he said. (Courtesy Brian Schwatken)

The females lay their eggs on small branches. After they hatch in about six weeks, tiny white nymphs fall from the trees and burrow into the soil, repeating the 17-year natural wonder all over again.

Kritsky said it's a "big mystery" how the cicadas time the 17-year cycle. Underground, they feed on the sap of deciduous tree roots, stopping during the winter and beginning again in the spring. It could be the insects detect the trees' seasonal changes, Shockley said.