- Fireflies flash signals to find a mate. While the female sits on the ground, males flash different signals ranging from single flashes to continuous glows to pulsed flashes, or "flash trains." Females are attracted to males that flash the fastest. After mating, females lay spherical eggs either singly or in groups, about 500 per year. Most species of fireflies bury their eggs in damp soil for protection and incubation.
- Firefly eggs, which glow slightly, hatch in about four weeks. The flightless larvae are carnivorous grubs, eating other insects foraged from nearby. Most larvae live in rotting wood or forest litter. Some Asian species lay eggs in water, and their larvae have gills and live underwater until they pupate. The larvae of a few tropical firefly species hatch from eggs laid in trees, where the larvae live after hatching and hang under leaves to pupate.
Larvae have flattened, spindle-shaped bodies made of protective shieldlike segments that shed several times during the larval stage. Some species have wingless females that look similar to larvae. Many larvae (and the wingless females) produce light and are often called glowworms in the United States. - Larvae shed their skin several times before they are ready to pupate. Most species pupate in spring and emerge in the summer. The firefly larvae climb through tunnels in the soil or forest debris to find empty spaces or small chambers in which to pupate. They secrete a silky strand to make a cocoon. Inside the cocoon, the larval body becomes soft and breaks down, reforming to grow the legs, wings, abdominal structure and antennae of an adult firefly. Fireflies go through what's known as "complete" metamorphosis, meaning that the adults look nothing like the larvae.
- Adult fireflies live between five and 30 days, with an entire life span of only three to four months, depending upon the species. They are approximately a half-inch long with black heads, a red section behind the head (prothorax) and dark brown wing covers (elytra) with yellow edges. According to Animal Diversity, "Their most notable feature is the underside of the abdomen with the last number of segments colored greenish-yellow, forming a 'tail light' capable of producing flashes of light." While other insects glow, none produces light using the same abdominal structure as fireflies.
- The reaction of luciferin and the enzyme luciferase with oxygen in the firefly's abdomen produces the taillight. This is a cool chemical reaction, as the light produces no heat. The energy for the light comes from the same thing as your own energy, the enzyme ATP (adenosine triphosphate). Between 90 and 98 percent of the energy actually produces light, with only 3 percent lost as heat. That is much more efficient than a typical light bulb, which releases about 97 percent of its energy as heat.
Mating and Reproduction
Larvae
Pupae
Adult
Light Production
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