An onslaught of insects that could number more than a million per acre are now fighting their way to the surface of yards and fields throughout the region before exploding onto the local scene in mid-May.

Three species of the magicicada, a 17-year cicada, will not be harmful to humans, but will sing their tiny little hearts out for three to four weeks as they try to attract a mate in Western Pennsylvania, Ohio and West Virginia, said Jack Layne, a biology professor at Slippery Rock University.

The bugs live underground for 17 years, surviving on roots and other plant matter, until their biological clocks tell them it's time to procreate.

The cicada nymphs crawl up to and through the surface of the earth and make a beeline for the nearest tree.

They climb up the tree and hang there vertically until their bodies send fluid into their folded wings.

Once the cicadas molt and their wings unfold, they begin calling loudly to attract a female, Layne said.

They don't search for food or eat at this stage, aside from sucking a small amount of tree sap from their host tree.

“It will be late May into June when you will hear them calling,” Layne said.

The world's longest-living insect, the cicadas are more than an inch long and sport bright red eyes.

They inflict no damage on humans or plants, but the small slits the female carves into bark to lay her eggs can potentially damage very young trees.

Layne said after mating and laying eggs in the tree, both male and female go into a stage called “senescence,” which means they have done their genetic duty and are ready to die.

At this stage, Layne said they lose some coordination and vitality, which makes their trajectory unpredictable as they endure the throes of death.

“They might fly into you on occasion,” Layne said calmly, “or you might go out and see a bunch of them on the sidewalks just kind of flopping around.”

The professor doesn't seem the least bit creeped out by the encroaching creepy crawlies.

“That's what brooms are for,” Layne said.

He was working at SRU the last time the magicicadas made an appearance — in 2002.

“People should sit back and watch the show because it is impressive,” Layne said. “They will be quite noisy as the days move into afternoon and early evening.”

He said if anything, the cicadas are a benefit to the area, as birds, squirrels, raccoons, skunks and other animals will feed on the bugs.

They also will provide nutrients to area ponds, which will see a rise in algae levels and a subsequent increase in the animals that feed on the algae.

“They'll produce a surge in ecological activity,” Layne said. “It's almost like fertilizer for the pond.”

Mary Reefer, a Penn State master gardener who lives in Franklin Township, is another science-minded expert who looks forward to the event.

“I think they're fascinating,” Reefer said. “They're very pretty with their red eyes.”

Reefer said according to her informal research, the bugs will be louder in southern Butler County than in the northern portion.

She said once the nymphs molt, they leave their exoskeleton on the tree they choose.

Reefer agreed that the bugs will not harm plants or flowers and do not sting, bite or eat.

“They're just going to make a lot of noise for about a month and then they'll die,” she said.

Reefer said the magicicadas emerged the year the original colonists came to America from England, and they thought the barrage of bugs represented the plague of locusts mentioned in the Bible.

“They probably thought it was the end of the world,” Reefer said.

She said the 17-year cicadas, which are not locusts as they are frequently called, only occur in the northeast area of the United States.

“They're not found anywhere else in the world,” she said. “Each of the 33 broods come out at different times than they come out here.”

Reefer said there is no way to keep the critters away, so residents should just try to endure the inevitable cycle.

“Enjoy the cacophony,” she said.