At exactly 9:27 p.m., when dusk slips into darkness in the Great Smoky Mountains National Park, the "light show" begins. It's June, and for two weeks in Elkmont, Tennessee, the fireflies pool their efforts. Instead of scattershot blips of light in the summer sky, the fireflies—thousands of them—pulse together in eerie, quiet harmony. It's as if the trees were strung up with Christmas lights: bright for three seconds, dark for six, and then bright again, over and over. It continues this way for hours.
As a child, Lynn Faust would huddle with her family on the cabin porch to watch the spectacle. They'd sit, mesmerized by the "drumbeat with no sound." And though they'd appreciated the show for generations, Faust never thought the event was newsworthy. "I'd assumed there was only one kind of firefly and thought they did a nice show in the Smokies," she says.
The natural world has long enchanted Faust. In college, she majored in forensic anthropology and minored in forestry. In her twenties, she circumnavigated the globe for three years, visiting islands you could only get to by boat, learning about cultures before they disappeared, pursuing underwater photography. Today, in her 60s, she's a naturalist who writes scientific papers and field guides about fireflies. But she wasn't always obsessed with the insect. In fact, her academic interest began only in the '90s, when she read an article by Steven Strogatz, a Cornell mathematician, in which he marveled at a species of Southeast Asian firefly that synchronized its flashes. Highlighting how rare this phenomenon was, Strogatz noted that there were no synchronous fireflies in the Western Hemisphere.
This struck Faust as odd. It contradicted the light shows she had seen growing up. As she dug deeper, Faust found that while there had been more than 100 years of colloquial accounts of North American fireflies flashing in sync, scientists discounted those reports, attributing them to lore or optical illusion. Faust knew the truth: that her Tennessee fireflies were every bit as special as the species in Asia. But how could she prove it?
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Fireflies—or lightning bugs—may be the closest thing nature has to a magic trick: lighting the world from the inside out. Technically, they are bioluminescent beetles. Their glow comes from an internal chemical reaction that combines oxygen and calcium with a series of enzymes, including a key light-producing one called luciferin. The bugs flash for lots of reasons: to communicate, to attract mates, to scare off predators. But for creatures so striking, they're also common. There are roughly 2,000 species worldwide and 125 or more in North America alone, where catching them is a childhood rite of passage.
More than 20 years ago, Faust wrote a letter to Strogatz after reading his article. He connected her with Jonathan Copeland, a biologist and professor at Georgia Southern University who was studying firefly behavior in Malaysia and Indonesia. Copeland was skeptical of Faust's tale. Reports of synchrony had crossed his desk before but had never panned out. "The dogma said they do not synchronize in North America," he says.
Still, he indulged Faust, asking her to describe what she'd witnessed by drawing a "musical score." As a child, Copeland, a tuba player, dreamed of playing with the Boston Symphony. Ever since, music dominated his approach to the natural world. In grad school, he'd studied and documented the rhythmic lunge and strike patterns of praying mantises. He took a similar slant on firefly behavior and found that if people charted the synchronic rhythms they were witnessing, he could separate a bogus account from a real one. Putting pencil to paper, Faust was nervous. "To look at it scientifically is very different from sitting in your rocking chair with a blanket and enjoying it," she says. "I didn't want to sound like a complete idiot."
When her note arrived, "it looked like synchrony on paper," says Copeland. In June 1993, he was intrigued enough to make the eight-hour drive to Elkmont. He pulled into the cabin's driveway as dusk fell, no trace of the insects to be seen, and promptly fell asleep—only to wake up to flashes of light all around him. "It was completely obvious—no doubt about it!" he remembers. He rushed to find a pay phone to call his colleague Andy Moiseff. "It must have been about midnight," he says. "I said, 'Andy, Andy, you've got to see this, they're flashing synchronously!' Andy laughed and said, 'Prove it,' like any good scientist." The following summer, that's exactly what Copeland, Faust, and Moiseff, a professor of physiology at the University of Connecticut, set out to do. It was an unlikely partnership, but the trio made a formidable team. Copeland is a neuroethologist—he studies the neural basis for animal behavior. Faust, an unflappable outdoorswoman and keen observer, knows the area and its wildlife like home. And Moiseff is a computer whiz, with a proclivity for dreaming up theories and building devices to test them.
