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The Firefly Firework Lottery

Tuesday, May 10, 2016 - 05:41 PM

For two weeks every spring, thousands of people in the southern Appalachian region make a pilgrimage to the woods to see the mating rituals of a very small beetle with an astounding ability.

Photinus Carolinus is just one of at least 19 species of fireflies that can be found in the Great Smoky Mountians. What makes them special, however, is their remarkable ability to synchronize their flashing abdomens, a phenomenon you may recall from our Emergence episode.

Originally, we had said that this breathtaking event was confined to Southeast Asia and so we were obviously thrilled to find that the United States also boasts a synchronous firefly show.  “I took this job around the time the fireflies began to mate last year, and it’s completely unimaginable,” Stephanie Sutton told me over the phone. Sutton is the Chief of Resource Education at the Great Smoky Mountains National Park, home to hundreds of thousands of the small invertebrates.  According to Sutton, the best places to see these tiny beasts of wonder is “low to midlevel elevation in rich, alluvial forests.” (Think forests that lie in a floodplain.)

“These beetles hang out in the ground for most of their lives as larva, and only live for 21 days once they mature into adults,” says Sutton.  It is during their brief adulthood that the males perform their coordinated fireworks display, as they take to the sky and light up in the hopes of attracting one of the females watching from the ground below. The latest theory according to Becky Nichols, the park's entomologist, is that the females, who will blink twice in a row in response to the males, need a significant amount of light input before they will respond. When the males blink all together, the females will know it's the right species, and will blink back.

Photinus Carolinus was known to scientists as early as the sixties, though not much attention was given to the phenomenon. It wasn't until the 1990s that devoted study of the species began, when a local Knoxville resident happened to mention to Dr. Jonathan Copeland of Georgia Southern University, that she had been watching the annual event for nearly 40 years. Dr. Copeland found this a “big surprise,” according to Sutton and began to study the fireflies in the Great Smoky Mountains. "It's one thing for a bunch of locals to say they see this synchronized flashing, but it's another thing to prove it mathematically," Becky Nichols told me. (If you're interested in the findings of Copeland's study, you can read the original published paper here.)

Today, the park hosts so many visitors that they have to apply to a lottery in order to get a seat at the coveted event. Over 20,000 people applied for this year’s viewing, though only 1,800 passes are granted.  “For years the park didn’t actively manage the event,” Sutton told me. “But it became unmanageable and started impacting the resources.” Because the viewing happens at night, guests are required to put red cellophane or  red balloons over their flashlights, helping to eliminate light pollution but making it trickier to see where one is walking. “Native plants were being trampled in the dark, not to mention the fireflies that were on the ground.” Now the park hands out red cellophane to visitors and erects barricades to prevent people from wandering off the viewing area.

While nothing can compensate for the real thing, for those of us not living on the alluvial soils of the Appalachian Mountains, there are videos of the lightshow on YouTube. We recommend this one (at 40 seconds in they begin to blink in tandem) and this one, which has more information on Photinus Carolinus and the specific event in the Great Smoky Mountains. 


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Comments [12]

Ni ute crowe from great smoky mointains

Please do not spread the knowledge of this. It has come to the point that locals like me that have been quietly enjoying this phenomenon for decades are not allowed into the woods to see it. The govt. now blocks all roads and trails into the woods and closes off all of the camp sites close enough to hike in. It is a very sad evolution of events for those of us that have been respectfully and quietly respecting the mating ritual for our entire lives.

Apr. 19 2018 10:27 PM
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Mar. 27 2018 03:41 AM
Gina from Tacoma, WA

A friend and I traveled from WA to The Great Smokies two years ago to see the synchronized fireflies. We were super lucky and won a spot in the lottery. And we made it onto the local news!

I grew up on the west coast, so I hadn't ever seen a firefly in person. Seeing the flash all in unison was kind of an indescribable experience. Go if you can!

Jan. 19 2018 05:03 PM
Dr. John D. Fowler

I've seen this once near my ranch in central Texas, I thought it was moving up from Mexico. It was about 20 years ago.

Jan. 10 2018 01:21 PM
William P Gloege Gloege from Santa Maria, CA

Dear Radio Lab,

I've got the answer to fire flies blinking together: They have eyes. They see the other guys blinking.

Not wanting to be odd by out-of-sync blinking, they blink in sync.

Mystery solved.

Thanks for great show.

Jan. 07 2018 07:06 PM
Sam from West Virginia

I've been a fan of fireflies for 70 years. Have seen synchronized flashing only once, in central WV about 1971 or 1972.

Jan. 07 2018 01:18 PM
John Olander from Park Hill Library Denver Colorado USA

Fascinating. I have seen many fireflies in my life, but nothing like this.
Yet, I am profoundly moved and aware by the synchronicity of the Universe.

Jan. 06 2018 04:50 PM
Bryan Smith from Sacramento, calif.

When I was a very small boy, I used to collect the bugs in a glass jar in Bluefied W.V. I was fascinated by them, and they were magical to me. That was in 1966. I still have relatives there, and they light up everytime I come to visit.

Feb. 10 2017 11:33 AM
Joe thacker from Columbia sc

Congaree national park in SC also is lucky enough to win the firefly synchronization lottery. More can be found at

May. 20 2016 06:25 PM
D Schutz from Leander, TX

We live in 7 acres in Leander, just outside Austin, TX, and we have been enjoying the fireflies lightshow every evening right outside our kitchen door! No lottery tickets required. Our house is built on the higher elevation alongside a wooded ravine and those woods have been coming alive every night with the insects' lights for the last 10 days or so.

May. 15 2016 01:26 PM
Brad Stevenson from Ashtabula, Ohio

I watched the synchronized fireflies in Ohio years ago. Glad I wasn't imagining it.

May. 14 2016 01:54 PM

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