Lampyridae

Most adult fireflies are nocturnal; males commonly fly and emit species-specific light patterns while females respond with matching flashes (or remain glowing) to coordinate mating. Some species use chemical defenses and mimicry—certain females (e.g., Photuris) imitate the flashes of other species to lure and prey on males.

After mating, females lay eggs in moist soil, leaf litter or moss; eggs hatch into larval fireflies (glow-worms). Larvae are often predatory (feeding on snails, slugs, earthworms and other invertebrates), may spend months or years growing through multiple instars, then pupate and emerge as short-lived adults primarily focused on reproduction.

Bioluminescence is produced by a luciferin–luciferase reaction (with ATP and oxygen) in ventral light organs, producing nearly 100% efficient “cold light.” Flash timing, frequency and color (green to yellow to orange) are species-specific signals; many adults do not feed or have reduced mouthparts, while larvae are ecologically important predators.

Firefly bioluminescence has deep evolutionary roots; light signals evolved for intraspecific communication and, in some taxa, aposematic advertising of chemical defenses. They feature widely in human culture and scientific research—the luciferase system is a foundational tool in molecular biology.

Many firefly species are declining locally from habitat loss, pesticide use, light pollution (which interferes with flash signaling), and environmental change. Conservation actions focus on protecting moist habitats (wetlands, woodlands, meadows), reducing night lighting, limiting harmful pesticides, and supporting citizen-science monitoring programs.