A Signal System 200 Million Years in the Making
Fireflies are not flies. They are beetles, members of the family Lampyridae, and their light is one of the most efficient chemical reactions in biology. The bioluminescence is produced when an enzyme called luciferase catalyses the oxidation of a compound called luciferin, releasing energy almost entirely as light, with almost no heat lost. Evolution has had roughly 200 million years to refine this system. A single flash lasts between 0.3 and 0.5 seconds depending on species, and the interval between flashes is species-specific, functioning as a species-recognition code. Males flash from the air. Females respond from the ground. Without the right answer, there is no mating.
