Temporal range: Permian–Recent
|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 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.
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.
All species of Plecoptera are intolerant of water pollution, and their presence in a stream or still water is usually an indicator of good or excellent water quality.
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) 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 swift 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 phylogenywith 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")
Orthoptera is an order of insects that comprises the grasshoppers, locusts and crickets, including closely related insects such as the bush crickets or katydids and wētā. The order is subdivided into two suborders: Caelifera – grasshoppers, locusts and close relatives; and Ensifera – crickets and close relatives.
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 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.
Mayflies are aquatic insects belonging to the order Ephemeroptera. This order is part of an ancient group of insects termed the Palaeoptera, which also contains dragonflies and damselflies. Over 3,000 species of mayfly are known worldwide, grouped into over 400 genera in 42 families.
The Gerridae are a family of insects in the order Hemiptera, commonly known as water striders, water skeeters, water scooters, water bugs, pond skaters, water skippers, Jesus bugs, or water skimmers. Consistent with the classification of the Gerridae as true bugs, gerrids have mouthparts evolved for piercing and sucking, and distinguish themselves by having the unusual ability to walk on water, making them pleuston (surface-living) animals. They are anatomically built to transfer their weight to be able to run on top of the water's surface. As a result, one could likely find water striders present in any pond, river, or lake. Over 1,700 species of gerrids have been described, 10% of them being marine.
The caddisflies, or order Trichoptera, are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the basis of the adult mouthparts. Integripalpian larvae construct a portable casing to protect themselves as they move around looking for food, while Annulipalpian larvae make themselves a fixed retreat in which they remain, waiting for food to come to them. The affinities of the small third suborder Spicipalpia are unclear, and molecular analysis suggests it may not be monophyletic. Also called sedge-flies or rail-flies, the adults are small moth-like insects with two pairs of hairy membranous wings. They are closely related to the Lepidoptera which have scales on their wings; the two orders together form the superorder Amphiesmenoptera.
Hemimetabolism or hemimetaboly, also called incomplete metamorphosis and paurometabolism, is the mode of development of certain insects that includes three distinct stages: the egg, nymph, and the adult stage, or imago. These groups go through gradual changes; there is no pupal stage. The nymph often has a thin exoskeleton and resembles the adult stage but lacks wings and functional reproductive organs. The hemimetabolous insects differ from ametabolous taxa in that the one and only adult instar undergoes no further moulting.
Cicadomorpha is an infraorder of the insect order Hemiptera which contains the cicadas, leafhoppers, treehoppers, and spittlebugs. There are approximately 35,000 described species worldwide. Distributed worldwide, all members of this group are plant-feeders, and many produce either audible sounds or substrate vibrations as a form of communication. The earliest fossils of cicadomorphs first appear during the Late Permian.
The Peltoperlidae, also known as roach-like stoneflies or roachflies, are a family of stoneflies.
Pteronarcys californica is a species of insect in the family Pteronarcyidae, the giant stoneflies and salmonflies. It is known commonly as the giant salmonfly.
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).
Chloroperlidae are a family of stoneflies, commonly known as green stoneflies, with more than 200 species and 22 genera. They appear green to yellow in colour, and are popularly used among fisherman as bait for trout fishing. Green stoneflies live in the benthic zone of the cold streams and rivers of five continents and four zoogeographical regions, emerging from the water to live in the riparian zone as adults. They are sensitive to pollutants, making them an indicator species for determining the quality of water bodies. Chloroperlidae are hemimetabolous, having no pupal stage, but instead hatch from eggs as nymphs and mature directly into adults. They are omnivorous, feeding on small organisms and plant particles, and become more carnivorous as they mature. The classification of Chloroperlidae is contested, with some believing that they should be considered as members of different orders, as opposed to the order Plecoptera that they currently belong to.
Eustheniidae is a family of insects in the order Plecoptera, the stoneflies. They are native to Australia, New Zealand, and Chile.
Capnura is a genus of small winter stoneflies in the family Capniidae. There are about seven described species in Capnura.
Arsapnia is a genus of small winter stoneflies in the family Capniidae. There are about eight described species in Arsapnia.
Eurekapnia is a genus of small winter stoneflies in the family Capniidae. There is one described species in Eurekapnia, E. maculata.
Sierracapnia is a genus of small winter stoneflies in the family Capniidae. There are about seven described species in Sierracapnia.
Zwicknia is a genus of small winter stoneflies in the family Capniidae. There are about 11 described species in Zwicknia.
Bolshecapnia is a genus of small winter stoneflies in the family Capniidae. There are at least four described species in Bolshecapnia.
Aquatic macroinvertebrates are insects in their nymph and larval stages, snails, worms, crayfish, and clams that spend at least part of their lives in water. They play a large role in freshwater ecosystems by recycling nutrients as well as providing food to higher trophic levels.
Capnia lacustra, also known as the Lake Tahoe benthic stonefly, is a species of insect in the family Capniidae. It was first described by S.G. Jewett in 1965. It belongs to the family Capniidae and is the only stonefly known to spend its entire adult life underwater.