Some adult fireflies consume flower pollen, dew droplets and nectar. Some adult fireflies eat nothing. During their larval stage, fireflies are carnivorous insects that either feed on decomposing bodies or hunt ants, snails, earthworms and other arthropods found in the soil.
The larvae immobilize their prey by injecting it with an anesthetic digestive fluid before starting to feed on it with their strong jaws. After one or two years when pupation occurs, fireflies turn from carnivorous to herbivorous. It is not uncommon for adult fireflies of many of the nearly 2,000 species, especially wingless female fireflies, to not eat at all.