Are fireflies lights flickering out? What experts say.

For many Americans, fireflies (or lightning bugs, depending on where you live) are an iconic sign of summer, lighting up warm evenings with their twinkling glow.

Fireflies are little beetles in the family Lampyridae. There are more than 175 species of fireflies in the United States, with several at risk of extinction, according to the Xerces Society, an international nonprofit organization dedicated to protecting invertebrates and their habitats. In a 2021 study, 18 firefly species in North America (about 14%) were considered threatened, including those classified as critically endangered, endangered or vulnerable.

"While a few generalist firefly species may be doing okay, there is a scientific consensus that overall we are seeing a global decline in fireflies," Scott Hoffman Black, the executive director of the Xerces Society, said in an email.

Here's a closer look at what fireflies really are and how you can help keep their flickering lights shining.

Where fireflies flicker across America

The firefly population has slowly been declining for decades, according to AFP.

"Many of us grew up with the ubiquitous shinning lights of fireflies in our yards, meadows, stream sides and parks," said Black. "Unfortunately, across the U.S., we are seeing far fewer fireflies in our landscapes. Firefly populations are declining because of the combination of habitat loss, light pollution, insecticide use and climate change."

The map below tracks firefly observations across North America using three data sources: Reports from Firefly Atlas volunteers, records from the Global Biodiversity Information Facility (GBIF) and museum and observation data gathered by the Xerces Society:

Unable to view our graphics? Click here to see them.

The secret behind fireflies' glow

A firefly's glow helps it communicate with other fireflies, especially when searching for a mate. The light is produced by specialized organs beneath the abdomen that take in oxygen.

When oxygen mixes with two chemicals called luciferin and luciferase, it produces light with almost no heat, making fireflies one of nature's most efficient light sources. Every firefly species uses a distinct blinking pattern to communicate, according to Insider Science.

Scientists think fireflies originally evolved their glow as a warning to predators, but today they mostly use their flashes to find mates. Each species has its own flashing pattern. In many cases, males blink about every five seconds while searching for females and females respond with flashes of their own about every two seconds.

What's causing the decline of of fireflies?

Fireflies are facing growing challenges from habitat loss, pesticide use, climate change and light pollution. The insects depend on moist environments and vegetation to survive and artificial lighting can make it harder for them to spot the flashes they use to attract mates.

Although this is likely an underestimate, due to insufficient data on more than half of North America's firefly species, at least 18 species are officially listed by the International Union for Conservation of Nature as threatened with extinction.

Can firefly populations recover?

There is still hope for the firefly populations.

"I believe that we can restore populations of fireflies and other insect groups like bees and butterflies," Black said. "We understand the causes and know the solutions – it is a matter of acting to protect and restore habitat for these important animals."

Helping fireflies thrive in your yard and garden

The good news is that helping fireflies doesn't require major changes, and small efforts can have a big impact on their populations over time.

• Only leave on lights that are needed for safety and where possible all lights should be on motion detectors.
• Do not use insecticides – unless there is an real economic or human health need.
• Most landscapes do not need pesticides to thrive, so put away the chemicals.
• Larval fireflies spend their time underground or under damp logs and leaf litter. Leave some messiness in your garden and leave the leaves, as decaying leaves are great habitat for fireflies.

Consider that fireflies need: Darkness, moisture, shelter and food. Even though we tend to think of fireflies primarily in the summer, their adult stage is just one small part of their life cycle. At any time of year, there may be eggs, larvae, or pupae present, according to the Xerces Society.

Fireflies go through four life stages – egg, larva, pupa and adult – in a process called complete metamorphosis. Depending on the species, that journey can take just a few months or stretch over several years. Along the way, the insects can look and behave very differently at each stage. There are three main types of fireflies:

• Daytime dark fireflies: Active only during the day and they don't produce light.
• Glowworm fireflies: Flightless females that produce long-lasting glows.
• Flashing fireflies: Also known as lightning bugs, they are best known for their bright flashes.

This article originally appeared on USA TODAY: Are fireflies lights flickering out? What experts say.

Reporting by Janet Loehrke, USA TODAY / USA TODAY

USA TODAY Network via Reuters Connect

Copyright Reuters or USA Today Network via Reuters Connect

This story was originally published July 5, 2026 at 6:09 AM.