For many Americans, fireflies (or lightning bugs, depending on where you live) are a symbol of summer, lighting up warm nights with their twinkling lights.
Fireflies are small beetles of the family Ceramicidae. The United States is home to more than 175 species of fireflies, some of which are at risk of extinction, according to the Xerces Society, an international nonprofit organization dedicated to protecting invertebrates and their habitats. In 2021, 18 firefly species (approximately 14%) in North America are considered threatened with extinction, including those classified as endangered, endangered, or endangered.
“While some species of common fireflies may be doing well, there is overall scientific consensus that we are seeing a global decline in fireflies,” Scott Hoffman Black, executive director of the Xerces Society, said in an email.
Here, let’s take a closer look at what fireflies are and how you can make their flickering lights shine.
Places where fireflies dance across America
According to AFP, the firefly population has been slowly declining for decades.
“Many of us grew up seeing the glowing lights of fireflies everywhere: in gardens, meadows, along rivers, in parks,” Black said. “Unfortunately, fireflies are much less common in our landscapes across the United States. A combination of habitat loss, light pollution, pesticide use, and climate change are causing firefly populations to decline.”
The map below tracks firefly sightings across North America using three data sources. Reports from Firefly Atlas volunteers, records from the Global Biodiversity Information Facility (GBIF), and museum and observational data collected by the Xerces Society.
If you can’t see the graphic, click here to view it.
The secret of firefly light
Fireflies’ lights help them communicate with other fireflies, especially when searching for mates. Light is produced by special organs under the abdomen that take in oxygen.
When oxygen is mixed with two chemicals called luciferin and luciferase, light is produced using little heat, making fireflies one of nature’s most efficient light sources. According to Insider Science, all firefly species use unique blinking patterns to communicate.
Scientists believe that fireflies originally evolved their light as a warning to predators, but now their light is primarily used to find mates. Each species has its own flashing pattern. Males often blink about every 5 seconds while searching for females, and females respond with their own blinks about every 2 seconds.
What is the cause of the decline in fireflies?
Fireflies face serious challenges including habitat loss, pesticide use, climate change, and light pollution. This insect relies on moist environments and plants to survive, and artificial lighting makes it difficult for it to find the flash it uses to attract mates.
Although this is likely an underestimate, there is insufficient data for more than half of North America’s firefly species, with at least 18 species officially listed as endangered by the International Union for Conservation of Nature.
Will the firefly population recover?
There is still hope for the firefly population.
“We believe we can restore populations of fireflies and other insect groups such as bees and butterflies,” Black said. “We understand the causes and we know the solutions. The key is to act to protect and restore the habitat of these important animals.”
Help fireflies thrive in your yard or garden
The good news is that big changes aren’t needed to help fireflies, and small efforts can have a big impact on firefly populations over time.
- For your safety, you should only turn on the lights you need, and if possible, place all lights on motion detectors.
- Pesticides should not be used unless there is a real economic or human health need.
- Most landscapes don’t need pesticides to thrive, so put away the chemicals.
- Firefly larvae spend their time underground and under damp logs and fallen leaves. Decaying leaves are a great habitat for fireflies, so leave them in your garden with some dirt.
Consider that fireflies need darkness, moisture, shelter, and food. Although we tend to think of fireflies primarily in the summer, the adult stage of a firefly is only a small part of its life cycle. According to the Xerces Society, eggs, larvae, or pupae can be present at any time of the year.
Fireflies go through four life stages: egg, larva, pupa, and adult in a process called complete metamorphosis. Depending on the species, the journey can take months or even years. During the process, insects look and behave very differently at each stage. There are three main types of fireflies.
- Dark fireflies during the day: They are active only during the day and do not emit light.
- Glowworm firefly: A flightless female with a long-lasting glow.
- Flashing fireflies: Also known as lightning bugs, they are best known for their bright flashes of light.
