How You Can Help Scientists Study a Summertime Favorite: the Firefly

Almost a decade ago, staff at the Audubon Center and Sanctuary at Francis Beidler Forest were lingering in the parking lot to debrief the night’s “Wine and Warblers” event. It was almost time to head home when the fireflies appeared. Instead of leaving, the group stood for another 45 minutes, amazed by the light show. From this spectacle, an idea was hatched.

Today hundreds of people head to the South Carolina center every year for “Firefly Nights.” Visitors walk a boardwalk through the old-growth forest—also refuge to more than 150 bird species, from Wood Storks to the striking yellow “swamp candle,” or Prothonotary Warbler—to see several types of lightning bugs, including a species that blinks in synchrony. Eager attendees share nostalgia, as well as a worry.
 
“I can’t tell you how many people come that are like, ‘I grew up seeing fireflies, and I don’t see as many now,’ ” says Matt Johnson, the center’s director.

Candace Fallon, a conservation biologist at the Xerces Society for Invertebrate Conservation, had long heard similar concerns. But when she checked the literature in 2018, she found little to no information on firefly trends. In fact, there was no comprehensive population data for any of the 179 known firefly species in the United States.

Fallon and a team at the International Union for Conservation of Nature set out to determine how American fireflies are faring. In 2021 they published their findings, the first list of conservation statuses for U.S. fireflies. Of the 132 species they reviewed, more than half lacked enough data to conclude anything for certain. But among the species whose status was clear, the scientists found 20 to be threatened or near threatened.

Fireflies, which are actually bioluminescent beetles, face many of the same threats as birds. Habitat loss—especially of wetlands, given the insects' preference for moist areas—is a major issue. (Indeed, the most threatened fireflies are the species that depend on only one type of landscape, such as the critically endangered Bethany Beach firefly, which primarily occupies freshwater wetlands between sand dunes along a 20-mile stretch of the Delaware coast.) Rising seas and extreme weather events drown coastal birds' nests as well as firefly habitat, while pesticides kill insect prey that both fireflies and birds rely on—and likely fireflies themselves. Light pollution, which can disorient nocturnal migratory birds and contribute to fatal building collisions, also disrupts lightning bugs’ ability to communicate: Flashing in a brightly lit environment is like trying to yell across a crowd.

To help fill critical knowledge gaps, researchers are turning to community science. The Fireflyers International Network collects data on iNaturalist from all over the world, and in 2022 Fallon and the Xerces Society launched the Firefly Atlas, where U.S. participants can share incidental observations and even conduct field surveys. These crowdsourced records can illuminate how species are trending in the face of threats.

In some parts of the country, community scientists are logging the first records of fireflies. In the West, the flashing beetles are such a rare sight that some people believe they are imaginary. “It’s like: unicorns, dragons, fireflies,” says Christy Bills, an entomologist at the Natural History Museum of Utah. Western fireflies have always been harder to find: They appear late at night, in small numbers, and in marshy areas where people don’t often hang out. So Bills and her partners at Brigham Young University started the Western Firefly Project to focus attention on them. Today its participants have spotted fireflies in 27 of 29 counties in Utah, where previously there had been only a few documented sightings—and in Idaho, Wyoming, and Montana, so exciting to Bills that she likens the discoveries to finding gold.

If you’d like to join the effort, or just enjoy the radiance, you likely won’t have to travel far. Fireflies live in every state except Hawaii. For most of their lifespan (around two years), they exist as larvae, snuffling around in leaf litter. Their glitzier adult phase only lasts about a month; its timing depends on location but tends to occur in late spring and summer.

To determine when your local fireflies come out, check the species lists and sightings recorded near you on Firefly Atlas and iNaturalist. Then get outside. If you can find a dark, damp area that’s not degraded, “chances are you’re probably gonna see something,” Fallon says. Fireflies don't like wind, rain, or cold, so go on a fair night. And leave the jars at home. “It’s one of the few bugs I ask people not to catch,” Bills says. “Just enjoy watching them.”

While some firefly populations are indeed declining, Fallon believes the sense of loss might have as much to do with us as the bugs. “We don’t spend as much time outside without lights,” she says. “It’s really easy to not even notice the fireflies around you.”

Those who take the time to look into the dark may find it deeply rewarding—which explains why Beidler’s firefly events typically sell out within days. “I wish that I could tell everybody, ‘Come see this with me,’ ” Bills says. “It feels like stars have fallen down into this meadow and are twinkling just for you.”

This story originally ran in the Summer 2025 issue as “Night Lights.” To receive our print magazine, become a member by making a donation today.