The Pteronarcyidae, also known as giant
stoneflies or salmonflies, are a
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of the order
Plecoptera.
Natural history
Two
genera of Pteronarcyidae are found; ''Pteronarcys'' is found in all of
North America, 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-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.
...
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, 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