After 17 Years Underground, the Cicada Brood XIV Is Coming

The first recorded American sighting of the cicada brood now known as Brood XIV was made by William Bradford, the governor of the Plymouth Colony, in 1634—and he was impressed by what he beheld. “There was such a quantity of a great sort of flies like for bigness to wasps or bumblebees,” he wrote in his journal, “and soon made such a constant yelling noise…as ready to deaf the hearers.”

Bradford and the rest of the colonists were not deafened for long. As it has done every 17 years since, Brood XIV died off just six or so weeks after it emerged, but not before laying billions of eggs that would make their appearance as adults another 17 years later—and so on down the centuries. In late April of this year, the brood began making its second 21st century appearance, when the first of the invaders appeared in Tennessee and North Carolina, preparatory to a 15-state sweep that will also include Alabama, Arkansas, Georgia, Indiana, Illinois, Kentucky, Louisiana, Maryland, Missouri, Mississippi, Oklahoma, South Carolina, and Virginia—before they vanish again in mid- to late-June. [time-brightcove not-tgx=”true”]

There’s no overstating just how many of the bugs there will be. On average, about 1.5 million cicadas occupy every acre of tree-covered land during an emergence, according to Gene Kritsky, professor emeritus of biology at Mount St. Joseph University in Cincinnati, Ohio, and author of The Pilgrims’ Promise: The 2025 Emergence of the Periodical Cicada Brood XIV. The southeast U.S. alone covers 371 million acres—which makes for some formidable math. Here’s what else you need to know about the upcoming visitation.

Brood XIV is not alone

If you’re a cicada fancier, you could be forgiven for being confused about the insects’ 17-year cycle, because cicadas can appear at much shorter intervals—even annually. That’s because there are actually 15 different broods at large, 12 of them observing a 17-year schedule and three making their appearance every 13 years—and the broods’ emergences are staggered. It was in 1902 that entomologist Charles Marlatt developed the nomenclature scheme used to identify different appearances, with the 17-year cicada variety designated Broods I through XVII, and their 13-year cousins Broods XVIII through XXX.

Distinguishing one 17- or 13-year brood from another is not hard, because each one has a different geographical footprint, with little overlap among them. “They don’t occur uniformly over all parts [of the U.S.],” says Kritsky. “They do occur in certain areas, in certain pockets.”

Entomologists had another way too to determine that each brood is unique to its own turf. During the adults’ six weeks of life, the females will make small cuts in the ends of tree branches and deposit their eggs there. The eggs incubate for six to 10 weeks before hatching into nymphs, which fall to the ground, burrow beneath the surface, and clamp their mouth parts onto a rootlet, from which they will feed for their long subterranean stay. When they emerge, they evacuate the underground en masse.

“When you go into an area where they’re emerging and you dig into the ground, you don’t find anything there. They’re all out,” says John Cooley, professor of ecology and evolutionary biology at the University of Connecticut, Hartford. “If you go back to that same spot in a year, when they’re not emerging, and you dig, you’re going to find them underground.”

Are cicadas pests?

That depends on your tolerance for the sight and sound of zillions of winged bugs appearing at once, settling in trees, getting crunched underfoot, and often splooching against your windshield. But apart from that—not really.

“They don’t swarm,” says Kritsky. “That’s a misuse of the word. Swarms are usually directed, coordinated movements of individual [insects] in a particular area. They’re lousy flyers. They’re flying around, but they’re really not doing much, just going from tree to tree. They don’t carry disease. They don’t bite. They won’t carry away your pets.”

“In pediatric journals you read about people being harmed by cicadas,” says Cooley. “But it was always something stupid, like riding down the road on a motorcycle without a helmet and one hits them in the eye.”

Cicadas also don’t attack crops or gardens or plants—partly because their mouths are adapted only for sucking, not biting or chewing. To the extent that they do any harm to vegetation, it’s mostly to young trees, whose branches may weaken and break due to the cuts the females make to deposit their eggs. If you have young trees or maturing orchards, both Kritsky and Cooley say, it pays to cover them with avian netting—which is used as protection against birds and can be found in hardware and garden stores.

Whatever you do, don’t even think about using pesticides to rid your yard or field of cicadas. “You can’t spray enough insecticide to deal with this,” says Cooley. “And if you try to spray that much, you’re going to kill everything in sight.

So if they don’t do any harm, do they do any good?

Yes. A lot, actually. Cicadas benefit the environment in a number of ways. First, in emerging from the ground they leave open tunnels about as big around as a pinky, which can persist until December. That aerates the soil and provides entry points for rainwater, which nourishes tree roots. They also serve as a ready food source for birds and other predators such as cats, dogs, chipmunks, and squirrels. The bugs are harmless if eaten by pets, though Cooley warns that dogs—being dogs—may gorge on them beyond what’s best for them, with all that roughage resulting in a constipated canine. Either way, most cicada predators enjoy the feast.

“The pulse of nutrition allows for more offspring,” says Kritsky. “I’ve also heard reports that the body weight of male turkeys taken during hunting season was larger in areas where cicadas emerged than in areas where there weren’t cicadas.” Even the damage cicadas do to tree branches pays some dividends, serving as a healthy, natural pruning. “It looks unsightly this year, says Kritsky, “but the reports are that the flower sets for those trees the next year will be even greater.”

Finally, death becomes cicadas, with their uncounted little bodies providing nutrients for the soil and trees. “Below ground they’re collecting nitrogen, phosphorus, and other nutrients,” says Cooley. “Then they come above ground and they’re recycling the nutrients.” The downside to so much decomposition? “They stink to high heaven,” says Kritsky. “Its a sense memory—if you’ve never smelled it, look for it this year.”

How are cicadas faring in a warming world?

Cicadas are “insects of climate,” as Kritsky calls them. The genus to which they belong emerged about 3.9 million years ago, and the insects moved alternately north and south in response to the advance and retreat of glaciers. Today they are responding to the climate again, changing the timing of their emergence, which usually begins when the soil temperature reaches 64°F. Those warmer conditions are occurring earlier and earlier each year. “Before 1940 here in Cincinnati,” Kritsky says, “the average date of emergence was May 28 or 29. Right now they’re emerging two to two and a half weeks earlier.”

Increasingly, the appearance of cicada broods is being tracked by citizen scientists armed with mobile phones and the Cicada Safari app, which Kritsky and Mount St. Joseph University created. In the 1840s, Maryland physician Gideon Smith took a shine to cicada tracking and began crowd-sourcing sightings, writing to newspapers and asking locals to contact him with reports of the emergence of new cicada swarms. Things moved slowly in that analog era, but they’ve picked up considerably today. People who download Cicada Safari are asked to send pictures of the cicadas they spot to the site; once the images are confirmed, they add to the real-time growth of a map of cicada emergence.

“Back in 2021, when Brood X emerged,” Kritsky says, “we received over half a million photographs. We verified them to produce the most granular, widespread map of that brood.”

However many cicadas emerge this year, they will be parlaying their 17 years in the nymph state and their six weeks in the adult state to do just one principal thing: mate and ensure the appearance of the next brood, in 2042. “Their function,” says Cooley, “is to make more of themselves. And this is how they do it.”