Firefly Facts & Information

What You Can Do

Homeowners can take measures to attract more fireflies, also called lightning bugs, by reducing or eliminating unneeded lighting on their property since light can interfere with fireflies’ luminous signals and make it harder for them to locate mates in the area. Fireflies also determine the time of night they’ll flash by the intensity of ambient light. This is why you don’t see many fireflies flashing on clear nights with a full moon.

Where do fireflies live?

There are about 2,000 known species of fireflies worldwide, but only about 200 species are found in the U.S. Lightning bugs live in a variety of warm environments, as well as in more temperate regions. Fireflies are a familiar sight on summer evenings, and they don't sting, bite, or carry diseases. Fireflies are not truly flies but are beetles.

What is the life cycle of a firefly?

Fireflies go through four developmental stages: eggs, larvae, pupae and adults. Their preferred habitats are areas that contain ponds, streams, marshes or rivers, especially if those aquatic environments are surrounded by tall grass that grows where forests and fields are close to water. Eggs laid by female Photinus pyralis - one of the most populous and wide spread firefly species in the U.S. - hatch from the egg stage about 4 weeks after eggs are laid, and develop into the larval stage, which lasts 1-2 years. Adult Phontinus pyralis live only about 30 days.

Eggs, pupae and most adults of many kinds of fireflies do not feed; however, firefly larvae consume small animals such as other insects, snails and earthworms. Some species of female fireflies feed on males of the species by attracting the males with their flashing light pattern, then killing and eating the unsuspecting males.

Firefly Reproduction and Mating Signals

The typical evening for lightning bugs begins around sunset when males start to fly low to the ground using their flashing signals to attract mates or prey. The females remain on the ground and attract the males with a specific flash of their own. After mating, the female will lay up to 500 eggs in damp soil.

At night, these lightning bugs crawl to the tops of blades of grass and fly into tree branches to signal for mates. Long grass provides concealment for fireflies and allows them a better vantage point for signaling at night.

Some species, especially the genera Photinus, Photuris, and Pyractomena, are distinguished by the unique courtship flash patterns emitted by flying males in search of females.

In general, females of the Photinus genus do not fly but do give a flash response to males of their own species. Also, some species of firefly larvae produce light to warn potential predators that they taste bad. The bad taste of fireflies is the result of the steroid-like chemicals known as lucibufagins that make fireflies distasteful to spiders and birds.

Not all firefly adults flash and many species do not use light as an adult mating signal. Instead, these “dark” fireflies use airborne smells such as pheromones to communicate.

What makes fireflies glow?

Fireflies produce a chemical reaction inside their bodies that allows them to light up. When oxygen combines with calcium, adenosine triphosphate (ATP) and the chemical luciferin in the presence of luciferase, a bioluminescent enzyme, light is produced.