Some beetles glow in the night

A chemical process involving the luciferase enzyme causes beetle bioluminescence. The firefly (family Lampyridae) is regarded as a species of beetle that uses a light organ on its abdomen to send messages to attract mates. Red lights can occasionally be seen coming from a light organ on the head of fireflies. Typically orange-red or yellow-green in color, males, females, and larvae all emit a cold light. In certain species, even the eggs are luminous.

By using two oval light organs on the thorax and a third light organ on the abdomen, tropical beetles (of the family Elateridae) may also generate light. It is believed that light plays a significant influence in their receptive behavior in order to draw in the opposing sex.