Stonefly nymphs are found in cool, fast-moving waters with a high oxygen content. Like the mayfly, they are intolerant of habitat disturbances and are excellent indicators of water quality. About 550 species are found in North America. The name Plecoptera refers to the adult s ability to fold its wings over its back. The detritivores use fungi and bacteria associated with decomposing leaves as part of their protein source.
Nymphs crawl from the water onto a partially submerged rock or log to emerge into adults.
Adults emerge at all times of the year and usually live from 1 to 4 weeks. Males often drum with their abdomen to attract females. Life cycles may range from 1 to 3 years although the average is one year. The Megaloptera are among the largest of the aquatic insect larvae and are active, ferocious predators. Most are found along the bottom of streams and rivers, although they may also be found in ponds or lakes.