The Plecoptera are 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 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. The modern diversity, however, apparently is of Mesozoic origin.
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.
Stoneflies have a generalized anatomy, with few specialized features compared to other insects. They have simple mouthparts with chewing mandibles, long, multiple-segmented antennae, large compound eyes, 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 nymphs and adults have long, paired cerci projecting from the tip of their abdomens.
The name "Plecoptera" literally means "braided-wings", from the Ancient Greek plekein (πλέκειν, "to braid") and pteryx (πτέρυξ, "wing"). This refers to the complex venation of their two pairs of 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 Lake Tahoe benthic stonefly ("Capnia" lacustra[Note 1]) or Baikaloperla, are the only known insects, perhaps with the exception of Halobates, that are exclusively aquatic from birth to death. Some 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. 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. Most species are herbivorous as nymphs, feeding on submerged leaves and benthic algae, but many are hunters of other aquatic arthropods.
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 swifting moving currents. 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.
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. 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. Adults are not strong fliers and generally stay near the stream or lake they hatched from.
Traditionally, the stoneflies were divided into two suborders, the "Antarctoperlaria" (or "Archiperlaria") and the Arctoperlaria. However, the former simply consists of the two most 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).
The Arctoperlaria, though, have been divided into two infraorders, the Euholognatha (or Filipalpia) and the Systellognatha (also called Setipalpia or Subulipalpia). This corresponds to the phylogeny 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.
Basal lineages ("Antarctoperlaria")
Arctoperlaria is a suborder of stoneflies.Capniidae
The Capniidae, the small winter stoneflies, are a family of insects in the stonefly order (Plecoptera). It constitutes one of the largest stonefly families, containing some 300 species distributed throughout the holarctic. Their closest relatives are the rolled-winged stoneflies (Leuctridae).Many species are endemic to small ranges, perhaps due to the family's tendency to evolve tolerance for cold (isolating populations in mountain valleys) and winglessness (inhibiting dispersal). Indeed, some wingless Capniidae – e.g. the Lake Tahoe benthic stonefly ("Capnia" lacustra, Capnia is not monophyletic and this species is suspected to belong elsewhere) or Baikaloperla spp. – spend their entire lifecycles under water and do not disperse from their native lakes at all.Chloroperlidae
The Chloroperlidae are a family of stoneflies, commonly known as green stoneflies, with more than 180 species in 15 genera. They appear green to yellow in color.Eumetabola
Eumetabola is an unranked category of Neoptera. Two large unities known as the Paurometabola and Eumetabola are probably from the adelphotaxa of the Neoptera after exclusion of the Plecoptera. The monophyly of these unities appears to be weakly justified.Eusthenia
Eusthenia is a genus of insect in the family Eustheniidae containing a number of species of stonefly most native to Tasmania. It contains the following species: E. brachyptera is considered a subspecies of E. venosa and Eusthenia extensa or Eusthenia purpurescens are considered E. costalis.
Eusthenia costalis TAS
Eusthenia lacustris TAS
Eusthenia nothofagi (Otway stonefly) VIC
Eusthenia reticulata TAS
Eusthenia spectabilis TAS
Eusthenia venosa ACT NSW VICEustheniidae
Eustheniidae is a family of insects in the order Plecoptera, the stoneflies. They are native to Australia, New Zealand, and Chile.The nymphs live in lakes and in swift-flowing rivers and streams, where they cling to rocks. They are carnivorous. They take two to three years to develop into adults.Genera include:
Cosmioperla McLellan, 1996
Eusthenia Westwood, 1832
Neuroperla Illies, 1960
Neuroperlopsis Illies, 1960
Stenoperla McLachlan, 1867
Thaumatoperla Tillyard, 1921
† Boreoperlidium Sinitshenkova, 2013
† Stenoperlidium Tillyard, 1935Leuctridae
The Leuctridae are a family of stoneflies. They are known commonly as rolled-winged stoneflies and needleflies. This family contains at least 390 species.Nemouridae
The Nemouridae are a family of stoneflies containing more than 700 described species, occurring primarily in the Holarctic region. Members of this family are commonly known as spring stoneflies or brown stoneflies. Fly fishermen often refer to these insects as tiny winter blacks.
Although these insects use a wide range of flowing-water habitats, they tend to be most prevalent in smaller streams. The nymphs are distinctive, being broad-bodied and bristly with divergent wing pads.Neoptera
Neoptera (from New Latin neo "new" and ptera "wing") is a classification group that includes most parts of the winged insects, specifically those that can flex their wings over their abdomens. This is in contrast with the more basal orders of winged insects (the "Palaeoptera" assemblage), which are unable to flex their wings in this way.Nymph (biology)
In biology, a nymph is the immature form of some invertebrates, particularly insects, which undergoes gradual metamorphosis (hemimetabolism) before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult, except for a lack of wings (in winged species). In addition, while a nymph moults it never enters a pupal stage. Instead, the final moult results in an adult insect. Nymphs undergo multiple stages of development called instars.
This is the case, for example, in Orthoptera (crickets and grasshoppers), Hemiptera (cicadas, shield bugs, etc.), mayflies, termites, cockroaches, mantises, stoneflies and Odonata (dragonflies and damselflies).Nymphs of aquatic insects, as in the Odonata, Ephemeroptera, and Plecoptera, are also called naiads, an Ancient Greek name for mythological water nymphs. In older literature, these were sometimes referred to as the heterometabolous insects, as their adult and immature stages live in different environments (terrestrial vs. aquatic).Orthopterida
The Orthopterida is a superorder of the Polyneoptera that represents the extant orders Orthoptera (grasshoppers, crickets, and katydids), and Phasmatodea (stick insects and leaf insects). The Orthopterida also includes the extinct orders Titanoptera and Caloneurodea. There is general consensus of monophyly in this superorder, based on reduction of the second valvulae, an ovipositor derived from the gonoplac, and an enlarged precostal region on the forewing.
The two other superorders of the Polyneoptera are the Plecopterida, which represents the orders Plecoptera (stoneflies), Emboidea (Embioptera/Embiidina; webspinners), and Zoraptera (angel insects), and the Dictyoptera, which represents Blattodea (cockroaches & termites), and Mantodea (mantids). Two other orders, the Notoptera (ice-crawlers and gladiators) and Dermaptera (earwigs) are also placed in the Polyneoptera but outside the superorders discussed above.Peltoperlidae
The Peltoperlidae, also known as roach-like stoneflies or roachflies, are a family of stoneflies.
The family Peltoperlidae comprises 11 genera and 46 known species. Species are semivoltine, meaning their lifecycles last 1 to 2 years. Adults of the family usually emerge in late spring or early summer, April through June. Larvae are flattened and brown in color, and they are roach-like in appearance because of the expanded thoracic plates covering the bases of their legs, heads, and abdomens. Tapering gills occur on the thorax at the bases of the legs. These tracheal gills are multifunctional and key to many biological processes. No dense tufts or branching gills are found on their thoraces or abdomens, unlike other Plecoptera families. The larvae also possess broad, chisel-like mandibles. Adults have two ocelli in addition to its two compound eyes. Male epiprocts are sclerotized and rod-like in shape, and both genders lack cross-veins in the anal lobe of the forewings.Peltoperlidae are generally lotic erosional and depositional. These habitats are flowing streams marked by sediments, vascular plants, and detritus. Roach-like stoneflies are generally found in leaf litter and debris piles trapped in either riffles or pools.
This family is considered to be clingers-sprawlers; they attach to surface in erosional habitats or rest loosely on the top surfaces of substrates, respectively. The body of this stonefly is flattened and streamlined to aid in minimizing water resistance in a flowing stream.
The Peltoperlidae are classified as in the feeding group shredders-detritivores. They chew and mine through leaf litter in their habitats. They are a significant contributor to leaf breakdown in streams. This family is very sensitive to disturbances in environmental conditions. They are intolerant to loss of coarse particulate organic matter for food and habitat. Given this low tolerance, Peltoperlids make potential bioindicators.Perlidae
The Perlidae are a family of stoneflies, with more than 50 genera and 1,100 described species. The majority of the Perlidae are found in eastern North America, but they occur worldwide except for Antarctica and parts of Africa. Their lifecycles range between one and three years. They adults emerge in the summer; they are very active and known to be attracted to light sources. They are usually very sensitive to changes in environment.Perlidae are usually lotic and lentic erosional. They are found in cool, clear medium-sized to large streams and sometimes in larger, warm rivers that carry silt. They are crawlers and can move quickly. In still water, no water moves over their gills, so they move their bodies up and down to keep oxygen flowing over them.
They are engulfer-predators. They consume all types of invertebrates. Very young larvae are collector-gatherers.Perlodidae
The Perlodidae, also known as the perlodid stoneflies, stripetails, or springflies, are a family of stoneflies.Plecoptera (moth)
Plecoptera is a genus of moths of the family Erebidae. It was described by Achille Guenée in 1852.Plecoptera quaesita
Plecoptera quaesita is a species of moth of the family Noctuidae. It is found in India, Sri Lanka, Burma, Andamans, Borneo, Northern Moluccas and Australia.Pteronarcyidae
The Pteronarcyidae, also known as giant stoneflies or salmonflies, are a family of the order Plecoptera.Pterygota
The Pterygota are a subclass of insects that includes the winged insects. It also includes insect orders that are secondarily wingless (that is, insect groups whose ancestors once had wings but that have lost them as a result of subsequent evolution).The pterygotan group comprises almost all insects. The insect orders not included are the Archaeognatha (jumping bristletails) and the Zygentoma (silverfishes and firebrats), two primitively wingless insect orders. Also not included are the three orders no longer considered to be insects: Protura, Collembola, and Diplura.Taeniopterygidae
Taeniopterygidae are a family of stone flies with about 110 described extant species. They are commonly called willowflies or winter stoneflies and have a holarctic distribution. Adults are usually smaller than 15 mm.
Extant Plecoptera families