"Firefly" is the common name for the nocturnal luminous insects belonging to the beetle family Lampyridae (order Coleoptera). There are over 2000 species of fireflies inhabiting the tropical and temperate regions, with 150 species in the United States. Fireflies range in size from 1/5 of an inch to one inch in length. Most fireflies found in the United States are about an inch or less in length. They have special light organs on the underside of the abdomen. It is reported that some adult fireflies do not eat. Others feed on pollen and nectar. Both male and female are luminous. The rhythmic flashes produced vary by sex and species. It is believed that the flashes are part of a signal system for attracting mates. Some scientists believe the flashing is a warning system to predators. However, frogs eat fireflies in prodigious amounts when available.
During summer months fireflies rest on plants or in trees during the day and fly around between dusk and midnight. It is reported that they prefer damp places. The firefly light is called a "coldlight" because it produces almost no heat. It is produced when oxygen, breathed in through the abdominal trachea combines with a substance called luciferin in the presence of the enzymeluciferase, in special cells called photocytes.
Female fireflies lay their eggs in the soil or on the underside of leaves. Firefly eggs sometimes glow. About four weeks after they are laid, the eggs hatch into larvae. The larvae live in moist soil and are carnivorous. The larvae sometimes glow also, and are commonly known as "glowworms," as are wingless adult females of certain Lampyridae.
After hatching the larvae spend the summer eating and then dig small tunnels in which to overwinter. As the soil warms up in spring they emerge to eat again for a couple of months. The larvae then dig a place in the soil and become pupae. In about ten days they emerge as adult fireflies. Adult fireflies mate, the females lay eggs, and the cycle is repeated.
The animal kingdom is divided into nineteen phyla. Phyla comes from the Greek word for tribe. Fireflies are in the Arthropoda (Are-THROP-oh-duh) phylum. Arthropoda is Greek for joint footed. The Arthropoda phylum is divided into thirteen classes. Fireflies are in the insect class, called Insecta or Hexapoda (Hex APP oh duh), which is Greek for six feet/legs. The insect class is further divided into orders. Fireflies are in the order Coleoptera (Co-lee-OP-tee-rah), or beetles. Fireflies are in the family of beetles called Lampyridae (Lam-PIR-i-dye).
Unfortunately, I have not discovered a reference on the food sources of the various stages of lampyridae. Many sources list slugs, snails and worms as a food source for the larval form but whether adult fireflies even eat is unclear.