The annual early June light show is on display at Congaree National Park, as hundreds of fireflies mysteriously synchronize their flashes in the floodplain forest.
Retired ranger Fran Rametta, who first publicized the phenomenon at the park several years ago, went out to the park Monday night with his wife, Elizabeth, to see if the synchronization had begun. “Elizabeth said it was the best she’s ever seen,” Rametta said. “There were at least 100 synchronized just a little ways down the boardwalk. It was absolutely amazing.”
The mass synchronization has been documented at only a few places, including Congaree and Great Smoky Mountains National Park. Each year, thousands of people flock to the Great Smoky display in Elkmont, Tenn. Congaree gets less attention, but Rametta said there were eight cars in the parking lot Monday night.
While the Congaree visitor center is closed at night, the park is open. If you want to view the firefly show, park at the visitor center and walk on the boardwalk. If you head out to the park at night, remember to take a flashlight and bug repellent, and stay on the boardwalk. To prevent light pollution that bothers the wildlife, it’s best to cover flashlights with a piece of red cellophane or keep them off unless absolutely necessary.
Rametta only went a short distance Monday before spotting a large group of fireflies glowing on and off simultaneously, but he suspects there were other spots along the boardwalk with similar displays.
Of the 170 species of fireflies in North America, only the Photinus carolinus is known to put on the synchronized display. Scientists aren’t sure of the biological reason for the display, but it likely has something to do with the mating process. The production of light is a form of bioluminescence in which the fireflies, which actually are beetles, combine the chemical luciferin and oxygen with the enzyme luciferase in their abdomens.
In general, firefly populations in the Southeast have been reduced in recent decades with the expansion of housing developments into former forest areas. Clemson University researchers staged the annual census of their Vanishing Firefly Project last weekend, allowing the public to register the numbers of the beetles they spot in their yard or neighborhood. Six of the 11 early reporters inside the I-26, I-20 and I-77 beltway found no fireflies that night, and none of the other five reporters found more than 30.
Fireflies are more common in rural areas and around natural wetlands, and they are common at Congaree National Park in the summer months. The synchronization, however, generally lasts only a couple of weeks.