How Does a Firefly Make Its Light?
A firefly produces its light through a chemical process that takes place in an organ near the tip of its abdomen. The cold light is made from certain chemicals in the insect’s body. When these chemicals mix together with oxygen in the air, the bug lights up. This type of light production is called bioluminescence. Fireflies are born knowing how to glow as larvae.
Researchers believe bioluminescence serves a different purpose for larvae than it does for adult fireflies. Firefly larvae contain chemicals that are toxic to other creatures. It is a warning light that alerts anyone or anything on the hunt for a snack they may be better off looking elsewhere.
When it comes to adult fireflies, researchers believe bioluminescence serves two purposes: to attract a mate and to attract prey.
Fireflies use their flashing lights as a mating signal. The male flies about at night, flashing his light. The female usually waits on the ground for the male’s signal. When she sees the light, she answers him by flashing her own light. The fireflies flash their lights on and off until they meet.
For a long time it was a mystery as to how some firefly species manage such a high flash rate, considering the relatively slow speed of the muscles that control oxygen transport. Researchers fairly recently learned that nitric oxide gas plays a critical role in firefly flash control.