the Teachable Moment
How Do Fireflies Light Up?
Fireflies, or lightning bugs, create light from a chemical reaction. The last two or three abdominal segments comprise the light-producing organ that contains an enzyme, called luciferase, which causes the bugs to glow. Lucifer comes from the Latin lucis, meaning light, and ferre, meaning to carry. Luciferase is literally the enzyme that carries light.
Light-producing fireflies flash in a pattern and color that is unique to their species. Each species can be recognized by the length, number, and rhythm of their flashes; the interval of time between their flashes; the color of light they produce; their preferred flight patterns; and the time of night when they typically flash. Luciferase is a valuable enzyme for biomedical research and has been used to help identify food contamination by bacteria. Luciferase is in high demand by laboratories, and scientists successfully cloned the luciferase gene in 1985, enabling the production of synthetic luciferase and making the harvest of live fireflies for profit entirely unnecessary. Unfortunately, rather than produce and sell the synthetic version, some chemical companies still extract luciferase from live fireflies, almost exterminating the firefly population in some areas.