Editing Plecoptera (section)

==Description and ecology==
[[File:SteinfliegenLarve2.JPG|left|thumb|[[nymph (biology)|Nymph]] of a golden stonefly, Plecoptera, Perlidae]] 
[[File:Stonefly - dinotoperla.jpg|thumb|left|''[[Dinotoperla]]'' [[imago]] (adult)<br />([[Gripopterygidae]]: [[Dinotoperlinae]])]]

Stoneflies have a generalized anatomy, with few specialized features compared to other insects. They have simple [[insect mouthparts|mouthparts]] with chewing [[mandible (arthropod)|mandibles]], long, multiple-segmented [[antenna (biology)|antennae]], large [[compound eye]]s, and two or three [[ocelli]]. The legs are robust, with each ending in two claws. The [[abdomen]] is relatively soft, and may include remnants of the nymphal gills even in the adult. Both [[Nymph (biology)|nymph]]s and adults have long, paired [[cercus|cerci]] projecting from the tip of their abdomens.<ref name=IIBD>{{cite book |author= Hoell, H.V. |author2= Doyen, J.T. |author3= Purcell, A.H. |name-list-style=amp |year=1998 |title=Introduction to Insect Biology and Diversity |edition=2nd |publisher= Oxford University Press |pages= 383–386|isbn= 978-0-19-510033-4}}</ref>

The name "Plecoptera" literally means "[[braid]]ed-wings", from the [[Ancient Greek]] ''plekein'' (πλέκειν, "to braid") and ''pteryx'' (πτέρυξ, "wing").<ref>{{cite book |author=S. C. Woodhouse |year=1910 |title=English-Greek Dictionary - a Vocabulary of the Attic Language |publisher=George Routledge & Sons |location=London |url=https://www.lib.uchicago.edu/efts/Woodhouse/}}</ref> This refers to the complex venation of their two pairs of [[insect wings|wings]], which are [[biological membrane|membranous]] and fold flat over their backs. Stoneflies are generally not strong fliers, and some species are entirely wingless.

A few wingless species, such as the [[Lake Tahoe benthic stonefly]] (''[[Capnia lacustra|"Capnia" lacustra]]''{{#tag:ref|The genus ''[[Capnia]]'' is not [[monophyletic]] and this species is suspected to belong elsewhere.<ref>{{cite web |author=C. Riley Nelson |work=[[Tree of Life Web Project]] |url=http://tolweb.org/Capniidae/13943/1996.01.01 |title=Capniidae. Winter Stoneflies |date=January 1, 1996 |access-date=July 31, 2008}}</ref>|group=Note}}) or ''[[Baikaloperla]]'', are the only known insects, perhaps with the exception of ''[[Halobates]]'', that are exclusively aquatic from birth to death.<ref>{{cite book |author=E. M. Holst |year=2000 |chapter=Lake Tahoe benthic stonefly (''Capnia lacustra'') |editor1=D. D. Murhy |editor2=C. M. Knopp |url=http://www.fs.fed.us/psw/publications/documents/gtr-175/ |title=Lake Tahoe Watershed Assessment |pages=O–118 – O–120 |publisher=[[United States Department of Agriculture]] |chapter-url=http://www.fs.fed.us/psw/publications/documents/gtr-175/gtr-175-appendixO.pdf |format=[[PDF]]}}</ref> Some [[true water bug]]s (Nepomorpha) may also be fully aquatic for their entire lives, but can leave the water to travel.

The nymphs (technically, "naiads") are aquatic and live in the [[benthic zone]] of well-oxygenated lakes and streams. A few species found in New Zealand and nearby islands have terrestrial nymphs, but even these inhabit only very moist environments. The nymphs physically resemble wingless adults, but often have external gills, which may be present on almost any part of the body. Nymphs can acquire oxygen via diffusing through the exoskeleton, or through gills located on behind the head, on the thorax, or around the anus.<ref>{{Cite web|title = ENT 425 {{!}} General Entomology {{!}} Resource Library {{!}} Compendium [plecoptera]|url = https://www.cals.ncsu.edu/course/ent425/library/compendium/plecoptera.html|website = www.cals.ncsu.edu|access-date = 2016-02-23}}</ref> Due to their nymph's requirement for well oxygenated water, the species is very sensitive to water pollution. This makes them important indicators for water quality.<ref>{{Cite web|title = Plecoptera - Stoneflies -- Discover Life|url = http://www.discoverlife.org/mp/20q?search=Plecoptera|website = www.discoverlife.org|access-date = 2016-02-23}}</ref> Most species are herbivorous as nymphs, feeding on submerged leaves and benthic algae, but many are hunters of other aquatic arthropods.<ref name="IIBD" />
{{Further|Mesoleuctra}}