The Pteronarcyidae, also known as giant

stoneflies Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the mo ...

or salmonflies, are a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of the order

Plecoptera Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the mo ...

Natural history

Two

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

of Pteronarcyidae are found; ''Pteronarcys'' is found in all of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, while ''Pteronarcella'' is found only in the west. The two genera comprise 10 distinct

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

, two of which are ''Pteronarcella''. Lifespans range from one to four years. The name "salmonflies" comes from their role in the diets of salmon, and they play an important role in fly fishing. Adults emerge from April to June. The giant stoneflies are very sensitive to stress.

Habit and habitat

They live in a

lotic River ecosystems are flowing waters that drain the landscape, and include the Biotic component, biotic (living) interactions amongst plants, animals and micro-organisms, as well as abiotic (nonliving) physical and chemical interactions of its man ...

-erosional habitat.

Larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e of giant stoneflies live in cool streams of small to medium size, in leaf and woody debris packs. They prefer swift

riffle A riffle is a shallow landform in a flowing channel. Colloquially, it is a shallow place in a river where water flows quickly past rocks. However, in geology a riffle has specific characteristics. Topographic, sedimentary and hydraulic indica ...

s between cobbles and boulders. Although the Pteronarcyidae are primarily shredders-detritivores, some facultative scrapers occur. They chew and mine through leaf litter. They are intolerant to loss of coarse particulate organic matter that is their food and habitat.

Movement and other biology

They are classified as crawlers. The larvae move very slowly and pretend to be dead when disturbed. They move their abdomens from side to side when under respiratory duress.

Evolutionary history

A fossil genus, '' Pteroliriope'' is known from the Middle Jurassic of

Daohugou The Haifanggou Formation (), also known as the Jiulongshan Formation (), is a fossil-bearing rock deposit located near Daohugou () village of Ningcheng County, in Inner Mongolia, northeastern China. The formation consists of coarse conglomerates ...

, China.

References

* Voshell, J.R. ''A Guide to Common Freshwater Invertebrates of North America.'' McDonald and Woodward. Blacksburg, Va. 2002. * Merritt and Cummins. ''An Introduction to the Aquatic insects of North America 3rd ed.'' Kendall Hunt. Dubuque, Iowa. 1996. {{Authority control Plecoptera families Insects of North America