Fireflies, also known as lightning bugs, thrive in the hot weather. There are different species and they produce different light colours and pattern of flashing.
Fireflies light up to attract a mate. To do this, the fireflies contain specialized cells in their abdomen that make light. The cells contain a chemical called luciferin and make an enzyme called luciferase. To make light, the luciferin combines with oxygen to form an inactive molecule called oxyluciferin.
A firefly controls the beginning and end of the chemical reaction, and thus the start and stop of its light emission, by adding oxygen to the other chemicals needed to produce light. This happens in the insect’s light organ.
Unlike a light bulb, which produces a lot of heat in addition to light, a firefly’s light is “cold light” without a lot of energy being lost as heat. This is necessary because if a firefly’s light-producing organ got as hot as a light bulb, the firefly would not survive the experience.
In short, Fireflies light up because of a chemical reaction between an organic compound in the fireflies’ abdomens – called luciferin – and the air. It is their unique love language.