What's That Buzzing Noise? Cicadas In Bloom

Billions of periodical cicadas, burrowed for nearly two decades a foot below the ground, have begun their take over like a conquering army. As temperatures rise, and the soil warms, people have already begun spotting these creatures as they spring up from their subterranean abodes.

When they take over a given area, they can number in the thousands. Though they're appearing a little later than expected, they are out in force:

They'll cover everything, make an unbelievable amount of noise, and then leave behind their odorous remains.

While entomologists, who study insects for a living, may welcome their arrival, the ascent of the cicadas feels more like an alien occupation. Reports of their emergence are already reported across several states.

“I’ve seen yards where so many are coming up it looks like the grass is moving, almost like it’s water,” said Gene Kritsky, an entomologist with Mt. Saint Joseph University.

But while many people find their presence disconcerting, there’s no reason to be concerned about the cicadas' presence.

The five-eyed, winged, buzzing creatures burst from the depths of the dirt at the roots of trees, and for weeks they dominate their habitats.

“I’ve seen trees, buildings, headstones in cemeteries, just laden with cicadas,” Kritsky said.

Some find the intensity of their distinctive buzz maddening. Others are disturbed by their sheer ubiquity and find the sight of them repugnant.

But while their presence may be disconcerting, there’s no reason to be concerned about the cicadas' presence.

What should people expect?

Various species of cicadas appear annually each summer in many regions across the country. But periodical cicadas appear in 13 and 17 year cycles, and when they arrive, they inundate.

The brood emerging this year has hidden underground since 1999. They will begin popping up in May over a period of two weeks.

People living in eastern Ohio, Virginia, West Virginia, a small portion of Maryland and the southwest corner of Pennsylvania are most likely to encounter these periodical cicadas this season, said Marten Edwards, an entomologist with Muhlenberg College.

Shaded area expected to see periodical cicadas emerge this May.

As the soil temperature rises in the spring, the cicadas come up from the dirt around the bases of trees.

When they spring up, they are mostly white in color.

Then, their bodies grow black, their eyes become bright red and their translucent wings are lined with orange veins.

They're quite large for insects, from an inch-and-a-half to two inches, including the wings.

In the areas where they thrive, expect swarms. Periodical cicadas come out in far larger numbers than the annual species, said Kritsky.

If this sounds like sounds like a horror movie, well, it may feel that way. But for the cicadas, it's more like spring break.

As the males gather into groups known as leks, or “chorusing centers,” usually on trees, they start to “sing,” or produce a powerful and distinctive buzzing sound. This is an essential part of the cicada mating. By snapping a membrane, known as a tymbal, in rapid succession inside their hollow abdomens, the male cicadas produce this noise to attract females.

Watch the video below to get a sense of the sound:

The high volume produced is difficult to believe without hearing it for yourself.

“I have measured chorusing centers around 94 decibels,” Kritsky explained. “To put that in perspective, jets approaching the Pittsburgh International Airport have been measured around 80 decibels.”

Even after their death, cicadas continue to assault the senses. Once they have bred and completed their final stages of life, their bodies cover the ground surrounding the trees. As the bodies decay, the odor produced is repulsive and intense.

Environmental impact

While some compare the coming of the periodical cicadas to plagues of locusts, they are actually a healthy part of a functioning ecosystem. Kritsky pointed to several beneficial effects of the cicadas.

“They’re providing a food source for a whole range of opportunistic predators,” he said.

“Everything feeds on them, from birds, and raccoons, dogs, cats,” he continued. “Anything that can get to them can probably eat them.”

And though the females lay eggs in the trees, sometimes turning leaves brown or breaking small twigs, this process actually promotes healthy growth.

“It’s like a natural pruning,” Kritsky said. Next year, those trees will likely have larger flower sets and produce more fruit.

Still not a fan of cicadas? Think of it this way: They're doing the yard work you probably couldn't be bothered to do.

If you’re planning on planting a relatively young or small tree, it’s possible the cicadas could damage it as they complete their life cycles. So if you happen to live in an area where the periodical cicadas are prevalent, wait until after June before planting, Kritsky warned.

But overall, the cicadas are an ecological boon. The insects' decomposing bodies will return nutrients to the ground which is absorbed by tree roots.

Even if you find the sight or smell of the deceased cicadas unpleasant, then, it’s best to leave them where they fall.

Deforestation and development of land has destroyed a much of the habitats of the periodical cicadas. So for Edwards, the emergence of the cicadas in any given area is an encouraging sign.

“I think it’s really exciting to see them, because it means that environment has been relatively healthy for the last seventeen years,” he explained. “So it’s something to really celebrate.”

Why do periodical cicadas have such odd life cycles?

Experts believe that the long life cycles of the cicadas, much of which is spent underground, may have originally been an adaptation to cope with ice ages.

But as Kritsky explained, experts believe periodical cicadas evolved life cycles of 13 and 17 years – both prime numbers – as a way to outwit potential predators.

Prime numbers, by definition, are only divisible by the number one and themselves. This means that it’s very difficult for other predatory species to evolve similar life cycles that would coincide with the cicadas’ arrival; since no predators are able to rely on cicadas as a consistent and predictable food source, it is safer for them to reproduce.

But “safer” doesn’t mean “safe.” Kritsky explained that the other survival strategy the cicadas developed is pure strength in numbers.

If you see cicadas in your neighborhood, help researchers out by reporting it here.

Kritsky compared it to chocolate falling from the sky. People might stuff themselves chocolate at first, but there's only so much chocolate you can eat.

When the cicadas come out, they overwhelm their predators with their numbers. Predators gorge themselves, but the number of cicadas outpaces the hunger for them. Even as large numbers of cicadas get eaten, there will still be plenty left over to lay eggs for the next generation.

When the eggs hatch, the nymphs crawl into the ground and nestle up to the roots of a tree where they can extract nutrients. They’ll remain there, underground and beneath the frost level, until the next 17-year cycle is complete and they can finally emerge to breed.

What the cicadas mean

Edwards, from Muhlenberg College, points out that historically the emergence and geographical prevalence of cicadas was not well documented. But since they’ve been around since the ice age, he argues that cicadas are an important indicator of changes to the ecosystem.

Aside from that, though, it’s clear Edwards thinks the cicadas are virtually national treasures. And he thinks people should appreciate the privilege of seeing them emerge.

“You’re seeing something that doesn’t happen anywhere else in the world,” he explained. “There’s nowhere else in the world that has these 17-year cicadas, they’re just in the United States east of the Rocky Mountains.”

He acknowledges that some people find them bothersome. In fact, he first began studying the cicadas over a decade ago when an administrator from his college asked if the noise of the cicadas would drown out the graduation day speakers, as it had in previous years.

Edwards found that there wasn’t much information on them, and in the end the ceremony was unaffected by the insects.

But Edwards said he thinks the the ceremony probably would have been better if they had shown up after all.

“It’s really one of the great wonders of nature. It’s up there with the wildebeest in the Serengeti, or the Monarch butterflies in Mexico,” he said.

“If you’re upset about them, I’d recommend trying to develop a positive attitude,” Edwards continued. “They’re not dangerous, and they’re kind of cute, if you look at them with the right type of attitude.

“It’s more productive to marvel at than to be annoyed by.”

All images courtesy of Dr. Gene Kritsky.