Plecoptera

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For the genus of moths, see Plecoptera (moth).

Plecoptera
Temporal range: 299–0 
Ma
 Permian–Recent
Eusthenia sp.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
(unranked): Dicondylia
Subclass: Pterygota
Infraclass: Neoptera
Cohort: Polyneoptera
Order: Plecoptera
Burmeister, 1839
Suborders

mostly Arctoperlaria: see text

Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide,[1] with new species still being discovered. Stoneflies are found worldwide, except Antarctica.[2] Stoneflies are believed to be one of the most primitive groups of Neoptera, with close relatives identified from the Carboniferous and Lower Permian geological periods, while true stoneflies are known from fossils only a bit younger. Their modern diversity, however, apparently is of Mesozoic origin.[3]

Plecoptera are found in both the

Southern and Northern Hemispheres, and the populations are quite distinct, although the evolutionary evidence suggests species may have crossed the equator on a number of occasions before once again becoming geographically isolated.[3][4]

All species of Plecoptera are intolerant of water pollution, and the presence of their nymphs in a stream or still water is usually an indicator of good or excellent water quality.[5]

Description and ecology

Nymph of a golden stonefly, Plecoptera, Perlidae
Dinotoperla imago (adult)
(Gripopterygidae: Dinotoperlinae)

Stoneflies have a generalized anatomy, with few specialized features compared to other insects. They have simple

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 nymphs and adults have long, paired cerci projecting from the tip of their abdomens.[6]

The name "Plecoptera" literally means "

wings, which are 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

true water bugs
(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.[10] 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.[11] Most species are herbivorous as nymphs, feeding on submerged leaves and benthic algae, but many are hunters of other aquatic arthropods.[6]

Further information: Mesoleuctra

Life cycle

The female can lay up to one thousand eggs. It will fly over the water and drop the eggs in the water. It also may hang on a rock or branch. Eggs are covered in a sticky coating which allows them to adhere to rocks without being swept away by swift currents.[12] The eggs typically take two to three weeks to hatch, but some species undergo diapause, with the eggs remaining dormant throughout a dry season, and hatching only when conditions are suitable.[6]

The insects remain in the nymphal form for one to four years, depending on species, and undergo from 12 to 36 molts before emerging and becoming terrestrial as adults.[13] Before becoming adults, nymphs will leave the water, attach to a fixed surface and molt one last time.

The adults generally only survive for a few weeks, and emerge only during specific times of the year when resources are optimal. Some do not feed at all, but those that do are herbivorous.[6] Adults are not strong fliers and generally stay near the stream or lake they hatched from.[12]

Systematics

Traditionally, the stoneflies were divided into two

basal superfamilies of stoneflies, which do not seem to be each other's closest relatives. Thus, the "Antarctoperlaria" are not considered a natural group (despite some claims to the contrary).[14]

The Arctoperlaria, though, have been divided into two

phylogeny[15] with one exception: the Scopuridae must be considered a basal family in the Arctoperlaria, not assignable to any of the infraorders. Alternatively, the Scopuridae were placed in an unranked clade
"Holognatha" together with the Euholognatha (meaning roughly "advanced Holognatha"), but the Scopuridae do not appear significantly closer to the Euholognatha than to the Systellognatha.

In addition, not adopting the clades Antarctoperlaria and Holognatha allows for a systematic layout of the Plecoptera that adequately reproduces phylogeny, while retaining the traditional ranked taxa.[3][16]

Euholognatha
)
Systellognatha
)

Basal lineages ("Antarctoperlaria")

Suborder Arctoperlaria

Notes

  1. monophyletic and this species is suspected to belong elsewhere.[8]

References

  1. ISBN 978-1-4020-8258-0
    .
  2. ^ Brittain, 1987
  3. ^
    PMID 10761594
    .
  4. ISBN 978-0-900386-28-2
    .
  5. ^ Nelson, Riley. "Clean water has bugs in it, says BYU Biology Professor Riley Nelson". Archived from the original on 6 September 2015. Retrieved 16 May 2013.
  6. ^
    ISBN 978-0-19-510033-4
    .
  7. ^ S. C. Woodhouse (1910). English-Greek Dictionary - a Vocabulary of the Attic Language. London: George Routledge & Sons.
  8. ^ C. Riley Nelson (January 1, 1996). "Capniidae. Winter Stoneflies". Tree of Life Web Project. Retrieved July 31, 2008.
  9. PDF). United States Department of Agriculture
    . pp. O–118 – O–120.
  10. ^ "ENT 425 | General Entomology | Resource Library | Compendium [plecoptera]". www.cals.ncsu.edu. Retrieved 2016-02-23.
  11. ^ "Plecoptera - Stoneflies -- Discover Life". www.discoverlife.org. Retrieved 2016-02-23.
  12. ^ a b "ENT 425 | General Entomology | Resource Library | Compendium [plecoptera]". www.cals.ncsu.edu. Retrieved 2016-04-12.
  13. ^ "Order Plecoptera - Stoneflies - BugGuide.Net". bugguide.net. Retrieved 2016-04-12.
  14. ^ C. Riley Nelson (January 1, 1996). "Plecoptera. Stoneflies". Tree of Life Web Project. Retrieved July 31, 2008.
  15. S2CID 80621609
    .
  16. ^ Nelson (1996b)

External links

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