Crowds of eco-tourists from around the world will gather in two remote Appalachian forests in Tennessee and Pennsylvania in coming weeks to see spectacular light shows created by a rare species of firefly that can synchronize its flashes.
The phenomenon is created by swarms of fireflies that are able to illuminate at the exact same instant, stay lit for 10 seconds, go dark for about a minute, then shine bright again.
"You're standing in a dark forest and suddenly there is a brilliance of little lights everywhere," said Tara Cornelisse, a senior scientist with the Center for Biological Diversity in Portland, Oregon.
Scientists are not certain why some species blink in sync but theorize that it helps attract reproductive partners during the weeks-long mating season.
"It's like the Milky Way flashes on and then off. You hear people gasp ‘Ohhhh!’” said Cornelisse, 37, who traveled to the Pennsylvania Firefly Festival in the Allegheny National Forest to see the phenomenon three years ago.
Synchronous fireflies are found only in a handful of places worldwide. In the United States, as well as Allegheny, they light up the night in Tennessee's Great Smoky Mountains National Park and Oak Ridge Wildlife Management Area, South Carolina's Congaree National Park, and around Arizona's Cajon Bonito Creek, according to Firefly.org. Other synchronous firefly species are found in Southeast Asia in mangrove forests.
Fireflies live for two years underground as larvae, feasting on worms and snails, said Sara Lewis, author of "Silent Sparks: The Wondrous World of Fireflies."
The creatures emerge as adults to spend a few weeks blinking to attract a partner, mating and laying eggs before they die, said Lewis, professor of evolutionary and behavioral ecology at Tufts University in Massachusetts.
Researchers studying fireflies that synchronize their luminosity "know very little about why they developed this behavior that makes them an eco-tourist attraction," Lewis said.
Loss of fireflies
To witness the Smoky Mountain spectacle from May 30 to June 6, the national park ran a lottery for 1,800 parking spots that drew more than 28,000 applications, said park spokeswoman Dana Soehn. Tourists from over 40 states and as far away as Taiwan won the spots near the park's entrance in Townsend, Tennessee, home to 445 people, sawmills and a handful of inexpensive restaurants and motels.
Tickets sold out in 12 hours for this year's light show in the Allegheny forest on June 22, said festival organizer Peggy Butler. The event by the town of Tionesta, home to fewer than 500 people, has ballooned in recent years, prompting organizers to charge tour and parking fees to try to limit the crowd to 800.
Many visitors who flock to the firefly events are from Asia, organizers said.
"They want to see the fireflies they remember but don't see any more in places like China and Japan, where human impact and human encroachment on the environment has led to the loss of the firefly," Butler said.
"People are very curious about the environment now, climate change, the nature world in general. Fireflies are an indicator species, indicating that the habitat is clean, free from pesticide pollution. But they are disappearing across the world," she said.
There are 2,000 different species of fireflies worldwide, blinking yellow, green, blue, in sync or not. In Asia, synchronous males remain stationary in mangrove trees, timing their flashes to attract flying females.
"The situation is pretty much reversed in North America, where it's the males who are flying around flashing and the females are sitting on the ground," Lewis said.
The downside to firefly tourism is the likelihood that without crowd controls and limits, humans will destroy the very attraction that drew them there in the first place.
"There is a danger in just the presence of those people," Lewis said. "You could actually wipe out the population that is so attractive."