Stars on earth: These rare fireflies dazzle SC forest each year. Are they in danger?
Deep in the pitch-black woodlands of Congaree National Park lives a mysterious insect that draws thousands of onlookers each year.
The forest is dead quiet at night, aside from the chirping of crickets and the occasional hoot of a distant owl. On winding wooden boardwalks and roped-off trails, families with children, groups of friends, and elderly couples feel their way through the darkness to catch a glimpse of the rare sight. Thousands of fireflies flash in unison underneath the forest canopy as they search for a mate in the warm summer night.
“We are looking at the firefly’s final blaze of glory,” said Jonathan Manchester, chief of visitor services at Congaree National Park in central South Carolina, just outside of Columbia.
The rare species of firefly responsible for the dazzling light show thrives in Congaree’s unique hardwood swamps. But coming changes to how the United States protects its natural landscapes raise questions about the future of the beloved natural phenomenon.
The mysteries of light
Once a locally held secret, Congaree’s special fireflies have exploded in popularity over the years. Visitors now need to enter a lottery weeks in advance for a chance at one of only 1,160 available passes for the annual firefly event.
The strobing light show occurs at the end of the firefly’s life cycle. Male fireflies flash and sparkle as female watch coyly from the underbrush, before signaling to a male to come on down.
The light is a form of communication, just like birds communicate through song and bees communicate through dance.
There are thousands of species of fireflies worldwide, but only three species of synchronous fireflies have been spotted in North America. Scientists still don’t understand why these species evolved the ability to flash in unision, or how female fireflies select a mate.
“It’s still one of those mysteries,” Manchester said.
Why flashy insects flock to Congaree
The wet, swampy woodlands these rare lightning bugs call home is one of the last standing patches of a type of forest that used to span 30 million acres across the southeastern United States. It’s a relic from pre-colonial America that’s remained intact through centuries of logging and clear cutting.
Called old-growth bottomland hardwood forests, these woodlands are found in low-lying lands that flood frequently. It’s a dream home for the fireflies: the wet, fertile soils provide plenty of food for the firefly larvae, while the thick carpet of plants and leaves that cover the ground help protect the larvae from hungry birds and larger insects.
Logging and development has steadily chipped away at these habitats. The hardwood trees that make up the forest are prime building material, resistant to rot and insects. The rich, fertile soils make perfect grounds for growing crops. Urban and suburban development have also diminished the spread of the forests.
Congaree National Park is the largest intact stretch of old-growth bottomland hardwood forest in the country, Manchester said, with 11,000 acres of forest that escaped the logging boom of the late 19th and early 20th century America.
Is this rare phenomenon at stake?
Between various threats to the environment, such as climate change, logging, and wildfires, firefly enthusiasts may be wondering if this natural wonder will still be around by the time their lottery number comes up.
The good news is, there’s no cause to worry — for now.
The rare synchronous fireflies are not considered an endangered species by any national or international agency. Although Congaree isn’t immune from the impacts of climate change, the fireflies themselves continue to put on their twinkling light shows every year and haven’t shown any indication that they’re in decline.
The biggest threats to these special bugs are light pollution and bug spray. That’s why park rangers ask visitors to only use red flashlights at night and avoid dousing themselves in clouds of insect repellent on the trails. To protect themselves from becoming mosquito food, park visitors can apply bug spray in their cars or opt for lotions and wipes instead of aerosol sprays.
As long as park visitors respect the fireflies, and their habitat is preserved, the little bugs will likely continue drawing crowds of visitors each summer. However, new policy directives from the Trump administration raise questions about the future of park preservation.
As a federally recognized national park, Congaree is currently protected from any logging activity. While the Trump administration recently ordered to expand timber production in U.S. national forests, those orders don’t apply to national parks, which are a distinct category from national forests and have far more restrictions on their use.
A recent federal budget proposal, however, would slash the National Park Service’s budget by nearly 25%, USA Today reported. It also suggests that parks that “receive small numbers of mostly local visitors” should be transferred to state control. Congaree received just over 242,000 visitors last year, and is ranked number 51 out of 63, according to NPS visitation data.
It’s unclear how the budget cuts could impact Congaree, but preserving the forest comes at a cost. For example, the park conducts routine prescribed burns to reduce the risk of disastrous wildfires, like the ones that scorched South Carolina in March.
Under current protections, Congaree’s swampy woodlands are safe for now, but park rangers can’t say what the future will hold. For the time being, Manchester said, Congaree hasn’t made any plans to halt the firefly event in the coming years.
“We’re still moving ahead as we normally move ahead,” the park ranger said.
This story was originally published May 18, 2025 at 9:22 PM.
