Also called lightning bugs, total about 1 900 species. Most species produce a cool, chemical light in the abdomen through a process called bioluminescence. The fireflies produce this light to find one another during mating. Each species uses a special pattern of flashes to identify each other. Some adult fireflies do not feed at all while others eat pollen or nectar. The larvae prey on snails and insects. The glowing larvae and the flightless females of some species are often called glow worms.