Cicada chasers: Meet the citizen scientists mapping the bugs of Brood X

To find these cicada superfans, follow the insects' boisterous mating calls. It's "never-ending amazement."

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For Dan Mozgai, a New Jersey marketing professional, the perfect vacation involves insects. Lots and lots of insects. They can't be just any random bugs, though. They have to be periodical cicadas

The critters spend almost their whole lives underground, living on sap from tree roots. Then, in the spring of their 13th or 17th year, depending on the type, they tunnel out, synchronously and in huge numbers, for a short adult mating frenzy set to the sonorous sound track of the males' come-hither calls.

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"They almost have a personality," Dan Mozgai says of periodical cicadas. Here, he holds a Magicicada cassini. 

Dan Mozgai

Mozgai knows the periodical cicadas' siren song well. He's packed up his car at least 10 times and driven nearly 30,000 miles on America's roads, from Maryland to Mississippi, Kansas to Kentucky, to follow it. 

"I'll go anywhere," he says. 

This year, he's leaving home in search of the insects again. The much-publicized emergence of a group of cicadas known as Brood X, which hasn't been seen above ground since 2004, is under way now. Think of it as the Cicada Olympics. Brood X is one of the largest groups of 17-year cicadas, and 15 Eastern US states, as well as Washington, DC, will see throngs of the black-bodied bugs with red eyes. 

Some places -- including Georgia, Indiana, Kentucky, Maryland, New Jersey North Carolina, Pennsylvania, Tennessee, Virginia and DC -- already have. 

Mozgai, 52, is one of the citizen scientists who regularly dedicate their free time to tracking periodical cicadas. They travel the country, snapping copious photos and meticulously recording data on where particular species show up, the time of day they sing, how they react to predators and what kind of foliage females lay their eggs in. Some come from as far as Japan. 

Call them cicada chasers. 

Their mapping efforts help scientists better understand the broods' behavior and relationships to one another, and explore larger questions about biodiversity, ecology and climate change. Because periodical cicadas are sensitive to temperature, patterns of different broods and species reflect climatic shifts. 

"I like contributing to scientific research," Mozgai says. 

The return of the periodical cicadas typically starts around early to mid-May and runs through late June. This year, Mozgai is  heading to western New Jersey and eastern Pennsylvania for an up-close look at his favorite insects crawling out from their subterranean hideouts. 

"There's an awesomeness to it because you're surrounded by thousands, maybe millions of these creatures that weren't there the day before," Mozgai says. "It's like an alien invasion, like being in a movie."  


It's thought that so many periodical cicadas emerge at once so enough can evade predators and live on to mate and start the cycle all over again. Needless to say, not everyone welcomes the idea of millions of bugs descending like a biblical plague. But even those who view the influx as a loud, pesky annoyance would be hard-pressed to deny they're witnessing nature unfold on an awe-inspiring scale.

The cicadas typically begin to come out when soil temperatures 8 inches (20 centimeters) underground reach 64 degrees Fahrenheit (18 degrees Celsius). "That seems to be the trigger that causes them all to emerge over a few days or weeks in one area," says Michigan State University entomologist Gary Parsons. A warm rain often prompts their appearance, but cool weather in parts of the US this year is delaying their appearance in some places. 

When they do arrive, it's a spectacle of sight and sound, one of the wonders of the insect world. 

"It's amazing that they can keep track of such a long period of time so precisely and emerge synchronously at any given location," says Chris Simon, a professor of ecology and evolutionary biology at the University of Connecticut. "They bring out the inner child in many people and recall the excitement of their youth at first seeing them."  

Count Greg Holmes among them. The 59-year-old photojournalist fondly recalls riding his green bike around Joplin, Missouri, as a kid and spotting annual cicadas molting on tree trunks. On warm nights, he'd hear them buzzing and rattling and see their translucent wings backlit by streetlights. They were part of the suburban landscape, as integral to summer as drinking iced lemonade and dashing through sprinklers. 

Those early Midwest moments helped shape Holmes into an adventuresome, nature-loving spirit who can rattle off cicada species effortlessly: Magicicada septendecim. Magicicada cassini. Neocicada hieroglyphica. 

"If you think bugs are icky, there's probably not anything anyone can say to change your mind," Holmes says. "If you're a citizen scientist, the adult form of a little kid who always had microscopes and telescopes and fossils to look at, cicada research is right up your alley."  


Greg Holmes, in Missouri in 2011 tracking Brood XIX, a group of 13-year cicadas. 

Greg Holmes

Holmes -- a fan of roadside attractions who writes a lively travel blog under the name Ace Jackalope -- drives around the country with a magnetic GPS puck stuck to the roof of his Toyota Avalon and a notebook computer, customized with a little numerical keyboard, adhered to the steering wheel. This year, he's road-tripping from his home in Hutchinson, Kansas, to a cicada hot spot in Maryland. 

"As you're driving along, when you hear a particular species, there's a numerical code you punch in," he explains. "Because the GPS is hooked up to the computer, it makes a record of where exactly that was." 

With three 17-year species making up Brood X, Holmes is entering nine codes -- one for no activity, one for light activity and one for heavy activity. He'll get out his camera and ponder how to best capture the little winged creatures. Sometimes he'll just stop and catch his breath.  

It's "never-ending amazement," he says of his cicada adventures. "It doesn't get old."


When Brood X last emerged, George W. Bush was president, the final episode of Friends had just aired, and Mark Zuckerberg had launched Thefacebook, Facebook's precursor, only months before.    

"Those who weren't alive 17 years ago or who were too young at the time and can't remember ... are in for quite an experience," says Gene Kritsky, dean of behavioral and natural sciences at Cincinnati's Mount St. Joseph University and a recognized cicada expert. 

This year, Brood X will emerge in Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and Washington, DC.  

Brood X cicada emergence in photos: How it looks as trillions of bugs appear

See all photos

Once the 17-year cicadas crawl out after years underground, they climb up the nearest vertical surface. They shed their exoskeletons and inflate their wings. Then the mating frenzy begins. It's impossible to miss once the males start emitting their high-pitched mating song via sound-producing structures called tymbals on either side of their abdomen. The noise can surpass 90 decibels, about the same level as a motorcycle 25 feet (about 8 meters) away


The insects don't bite, sting or carry diseases, and while females can damage young trees by laying so many eggs in their branches, the egg-laying also naturally prunes trees, resulting in more flowers and fruit in the years that follow. Periodical cicadas aerate large amounts of soil when they emerge en masse, and when they die, their decaying bodies enrich the ground with nutrients. 

To track cicada distributions over time, researchers need detailed, high-quality data. Holmes, Mozgai and their fellow citizen scientists play a key role in gathering such vital information because periodical cicada populations cover enormous areas of the country and the bugs only appear above ground for limited stretches of time, years apart. 

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Scientist Chris Simon, husband Steve Chiswell and young friend Dylan Kennan scour for Brood X cicadas remaining in the soil after the 2017 four-year-early emergence in Washington, DC. 

Corinne Siboni

Cicada chasers, Simon says, help fill in the center of the distribution of broods so scientists and their mapping teams can concentrate on the edges. Amateurs have even tipped off scientists to unknown populations. 

Mozgai first became interested in periodical cicadas in the mid-'90s, when he started making random websites to teach himself how to code. When Brood II emerged in his hometown of Metuchen, New Jersey, he set up a simple site to share his photos. There weren't many cicada websites back then, and people interested in the phenomenon reached out to him. His interest in cicadas grew. 

Now he's a go-to expert who runs Cicada Mania, an extensive online resource for all things cicada. He's administrator for a Facebook cicada discussion and study group with more than 700 members, and he knows fellow cicada enthusiasts around the country. 

When Mozgai's in active cicada-chasing mode, he'll spend up to seven hours a day focused on the insects. He's even created his own app to collect data on the creatures.  

"They almost have a personality," he says. "Because they're a bit bigger, you can see their whole face. When they first emerge, they're very timid, so you can pick them up and interact with them."  

Mozgai also credits the cicadas with getting him to parts of the country he might not visit otherwise. Because of them, he's been to Graceland in Memphis and to Metropolis, Illinois, a small town dedicated to all things Superman. 

But the cicada-curious needn't be as committed to cicadas as Mozgai to get in on the tracking. A free app, called Cicada Safari and available for iOS and Android, lets anyone with a smartphone record sightings by uploading photos and short videos. The app -- developed by Kritsky and others at Mount St. Joseph University -- automatically attaches the date, time and geographical coordinates of each observation for real-time and future study. 

Cicada Safari users submitted nearly 8,000 photos and videos in 2020.

"Not only did [the app] map Brood IX, but it also verified the off-cycle emergence of four other periodical cicada broods," Kritsky says. "That had never been observed before." 

This year, Cicada Safari's developers hope to see the app go huge for Brood X, with at least 50,000 observations. "This is the big one," Kritsky says. "A generational event."  

Who knows? A whole new brood of cicada chasers could emerge. 

cicada in the grass

A newly emerged cicada in Louisville, Kentucky. After coming above ground, the periodical cicadas shed their larval skin, inflate their wings and begin to mate, making considerable noise in the process.

Erin Carson/CNET