Image Credit: Tim Wynkoop - www.wynkoop.smugmug.com
Image Credit: Kenneth O.
The Giant Stonefly is a delicate and useful insect for anglers and biologists alike.
Giant Stoneflies are a narrow-bodied insect that are identifiable by their highly veined wings. These wings are very long and crossover the body when folded at rest, covering the Stonefly's whole body, and even extending out beyond it. Their eyes are found on either side of the head. Giant Stoneflies have long, thin antennae protruding out in front of their eyes. Bodies may appear to be black, brown or gray. An orange or red color may appear on or around the neck collar (thorax).
Eggs are laid and hatching takes place in water, where young Giant Stoneflies spend the earliest phases of life. Offspring are called naiads, and these juveniles are incredibly sensitive to pollution, dying off quickly in unclean waters. Because of this clear response to dirty water, biologists and anglers use the presence of adult Giant Stoneflies as a mark, or indicator, of clean water in that area. Naiads look more like crayfish or small crustaceans than winged insects. Only the naiads eat, and they prefer to feed on algae and other plant material underwater. They in turn are eaten by frogs and fish. Adult Giant Stoneflies do not eat at all. Though they fly, they are often spotted on the ground or resting on nearby rocks or branches. Birds and spiders prey on them.
Look for Giant Stoneflies in areas near freshwater streams, creeks, or rivers. They, in general, can be attracted to artificial light after sunset in the late spring and early summer months of the year.
Scientific Name: Pteronarcys species
Other Name(s): Salmonfly
Size (Adult; Length): 40mm to 84mm (1.56in to 3.28in)
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.