Researchers: Fireflies are threatened by artificial light and habitat loss


Growing up around Seattle, Ainsley Seago said she had never seen a firefly until she visited Hershey as a teenager.

These days, she watches with amusement as her 10-year-old son, Maxwell, enjoys catching eclairs and releasing them.

“How not to catch them? said Seago, associate curator of invertebrate zoology at the Carnegie Museum of Natural History. “They are magical and look like supernatural luminous creatures that fly.”

What looks like a wonderland of tiny flashing lights are actually mating signals for lightning bolts. Increasingly, these signals are being interfered with by outside sources, helping to cause a decline in firefly populations around the world, scientists say.

1 in 3 species of firefly are threatened with extinction, according to a study conducted by researchers from the Xerces Society, ABQ BioPark and the IUCN Firefly Specialist Group.

The most serious threats to fireflies are habitat loss, overuse of pesticides and light pollution, said Sara Lewis, one of the study’s authors and professor of biology at Tufts University.

Artificial light at night interferes with the courtship rituals of flashing fireflies and glowing fireflies, said Lewis, author of “Silent Sparks: The Wondrous World of Fireflies.”

“Males blink less and females stop responding to male courtship signals,” she said. “The result is lower mating success, fewer eggs laid to start the next generation of fireflies.”

Turning off or obscuring artificial lighting increases the romance of fireflies, as they can see other people’s signals better.

“We’re lucky that light pollution is instantly reversible – just flip the switch,” Lewis said.

Firefly populations are also affected by barren, tightly mown lawns without tall stems of grass for female fireflies to sit on while watching for a potential mate signal, Seago said.

And pesticides used in agricultural fields can cause fireflies to behave abnormally, making them less likely to survive and mate, she said.

firefly festival

Pennsylvania Firefly Festival Inc. is hosting a “Lights Out for Lightning Bugs” Campaign this month to encourage people to watch out for lightning bugs.

The “Lights Out” campaign officially runs June 9-25, but the Kellettville nonprofit in the Allegheny National Forest suggests residents dim their outdoor lights and opt for climate-activated lights. movement throughout the summer, which can help fireflies mate and be successful. reproduce.

The 10th Annual Firefly Festival runs two nights, June 24 and 25, although it is fully booked. The event is limited to 50 people each night so as not to disturb the fireflies or possibly trample them and their habitat, said Peggy Butler, who, with her husband Ken, founded the Firefly Festival organization.

Synchronous fireflies — lightning bolts that flash in harmony — were discovered in Kellettville in 2011, and people wanted to see them, Butler said.

The couple used to hold firefly watch events as a promotion at their Forest County bed and breakfast, and it became so popular that they officially launched the annual event.

“It looks like a light show, with a strobe light effect much like a marquee in a theater with the lights flashing together,” Peggy Butler said. There can be hundreds of fireflies seen from one location, she says.

These days, biology students and university researchers visit and conduct research around the Butler house.

In 2019, Avalon Owens, a researcher at Tufts University, conducted a study in Kellettville that found that light of any color essentially extinguished females’ blinking responses to attract a mate.

firefly tourism

Due to the decline of lightning bugs, people are heading to the forests and the deep country to find firefly activity reminiscent of their youth.

Firefly tourism is taking off with events offered by parks and organizations, including recent outings in Ohiopyle and Butler County, Butler said.

Parks, conservation areas, forests, and even railroad rights-of-way and cemeteries are important as sanctuaries for fireflies, said Lynn Faust, author of “Fireflies, Glow-worms, and Lightning Bugs.”

“Pennsylvania has a great diversity of fireflies with many showy species,” she said.

Butler said she hopes interest in event viewing will increase.

The Firefly Festival event is quite a spectacle, she said.

“Once it came out in the ‘firefly’ community, they wanted to add it to their to-do list,” Butler said.

Mary Ann Thomas is editor of Tribune-Review. You can contact Mary at 724-226-4691, [email protected] or via Twitter .


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