Walking in a forest on the trail of synchronous fireflies
KELLETTVILLE, PA. » Picture a moonless June evening, shortly after midnight, deep in a northwestern Pennsylvania forest. Wild sounds echo gently. Stars glow far above through the canopy of trees. Otherwise it is dark — so very dark.
But wait. There — right there, to the left — a single tiny light flickers on. And then another. And another. In moments they are switching on and off in stunning synchronicity, as if, deep in the woods, you have come upon a magical summertime Christmas tree. It’s a show of light and nature, biology and dreaminess. It’s everything the glowing screen in your pocket is not.
This is what it’s like to walk smack into a pack of synchronous fireflies — “lightning bugs,” as many of us called them in childhood. But these possess the unique capability of flashing in glorious, almost otherworldly unison.
The display happens every year in North America as spring ebbs into summer. It sweeps north as temperatures warm, up from Tennessee’s Smoky Mountains to, on this night, the thick woods of the 500,000-acre Allegheny National Forest, 100
miles from Pittsburgh.
Of hundreds of types of fireflies, these are perhaps the most remarkable. What they do, in a world of mass-produced experiences, is organic and natural and utterly unplugged.
People come from around the world for this. Peggy and Ken Butler organize an annual Pennsylvania Firefly Festival here, offering an intricate, quiet and fleeting experience where science and poetry live side by side.
Visitors come to see the “Chinese lantern” fireflies that seem to float through the air by Tionesta Creek. But they come, most of all, for the synchronous fireflies that put on their choreographed light show for two weeks in late June in the forest around the Butlers’
Black Caddis Ranch.
“It’s so hard to put into words,” Peggy Butler says. “A lot of people tell us they’re here for a bucket list item. They’re trying to find some missing piece of something.”
How do the fireflies do it? And why?
The first question has an answer. As for the second, firefly experts only have theories.
Synchronous males can see each other light up, and they can reset their internal pacemakers in real time to sync with male counterparts flying nearby, according to researchers.
Females wait below, in brush near the ground. The males light up to attract them, as with most firefly species.