Stoneflies are about 3,500 species of small insects that can be found worldwide except for Antarctica. They have compound eyes, mandibles used for chewing, long segmented antennae, legs with claws, and a long soft body. Stoneflies are not strong fliers and usually live near running water such as rivers or streams. They are intolerant of polluted water and if present they are usually an indication of good water quality. Females only mate once whereas males will mate multiple times, but both will die shortly after mating. Once their eggs hatch, the nymphs live one to four years and will molt 12 to 33 times before emerging as terrestrial adults that only survive for a few weeks. Both larvae and adults feed on algae, rotting wood and plants, although some species are omnivorous.