Get It Growing: Keep firefly light from going out forever

Many people think back on their childhood summers and recall evenings spent chasing fireflies across a field, perhaps catching the insects in jars to admire their fascinating blinking patterns up close.
But across the United States, fireflies — known in some parts as lightning bugs — are an increasingly rare sight. While scientists have pointed to several reasons for the decline, habitat loss is widely considered to be a primary driver.
“Oftentimes, fireflies only have one generation a year, and if they lose that habitat, then we lose their population in that area,” said LSU AgCenter entomologist Aaron Ashbrook.
Not only are more and more kids missing out on the joy of watching glowing fireflies dance across the night sky. There also are ecologically concerning consequences of firefly population loss.
“The presence of fireflies indicates that there is a good and balanced habitat nearby,” Ashbrook said. “When we’re not seeing fireflies, that would indicate there might be some issues that need to be corrected.”
There are numerous firefly species, and some are pollinators.
So fireflies aren’t just entertaining. They’re much more valuable to the ecosystem than you may have realized. So what can you do to help them out?
Providing habitat is a good first step. Depending on their species, fireflies may prefer open fields or forested areas. In general, however, firefly larvae are drawn to damp environments such as leaf litter and rotten logs.
As long as they are not contributing to problems with insect pests, Ashbrook suggests keeping piles of leaves and old logs in your yard rather than disposing of them.
“It provides habitat for larvae as well as slugs and snails, which the larvae prefer to feed upon,” he said.
Light pollution, or excessive artificial outdoor lighting, also harms fireflies. They rely on bioluminescence, a chemical reaction that generates light, to defend themselves and reproduce.
“They use flashing signals to attract mates,” Ashbrook said. “If there’s excess light, it can interfere with their ability to lure in a mate and reproduce.”
To ensure it’s dark enough for fireflies to see one another’s signals, Ashbrook recommends limiting the use of outdoor lights. Timers and sensors make it easy to turn lights on only when they’re needed. You also can change bulbs in outdoor light fixtures to amber or orange shades, which are less disruptive to fireflies.