They spin silken webs on the walls and ceilings of the caves. The light that the larvae produce attracts other small insects, which are trapped in the web and eaten by the larvae. The most common light-producing insect is the firefly. Firefly adults glow or flash their light while flying around at night. Firefly larvae, often called glowworms, flash their light on the ground.
Fireflies have light-producing chemicals in special organs inside their abdomens.
The light produced by fireflies has been called perfect light. This is because in the production of light, no energy is wasted as heat. A light bulb does not produce perfect light like fireflies. If you have ever touched a light bulb after it has been on for a while, you know that the light bulb gets very hot and you have to be careful not to burn yourself. Fireflies use their light to attract mates.