Don’t you love chasing glowing fireflies? But do you know why they emit light? Fireflies, also known as lightning bugs, are nocturnal, luminous beetles. The name comes from the fact that some species as adults emit flashes of light to attract mates in order to reproduce, using special light-emitting organs in the abdomen. Many species of lampyrid beetles do not glow as adults, but they all glow as larvae. The larvae of fireflies are generally known as glow worms. Glow worms glow to warn predators that they are poisonous and don’t taste very good.