Stoneflies
| Stoneflies | ||||||||||||
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Nemoura cinerea |
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| Scientific name | ||||||||||||
| Plecoptera | ||||||||||||
| Burmeister , 1839 |
The stone flies (Plecoptera) are an order of the insects and belong to the flying insects (Pterygota). Of the approximately 3500 known species of stonefly, 127 are common in Germany and 514 in Europe. Most species are 3.5 to 30 mm long. The largest species is Diamphipnoa helgae with a body length of about 40 mm and a wingspan of 110 mm.
features
Stoneflies are relatively soft-skinned (not hard sclerotized), elongated insects with usually cylindrical or somewhat flattened body contours. They are usually dark and not very contrasting in color, individual families are straw-colored or yellowish with dark markings, the Chloroperlidae are greenish in color (name!). Strikingly colored animals occur only in the (non-European) family Eustheniidae. The wings are clear or tinted brown, rarely spotted a little dark. In the resting position, they are placed flat on top of each other on the back, often slightly arched and partially rolled around the torso. They are shortened and functionless in many species (often only in the males), the species Andiperla willinki , which lives in glaciers, is wingless. In some species, flying and short-winged males occur side by side.
The head of the stonefly is more or less pronounced stretched forward (prognath), sometimes slightly drooping, often remarkably broad. The animals have long antennae up to about half their length on their heads . The compound eyes are usually large and hemispherical, and almost always three point eyes ( ocelles ) are formed. The mouthparts are chewing-biting, in some families v. a. the mandibles are partially reduced to the subordination Systellognatha.
The 3 chest segments ( thorax ) of the stone flies are approximately the same size, the front chest (prothorax) often flat upwards with a conspicuous edge, sometimes widened. The legs are relatively thin walking legs that come close to the basic plan of the insects, usually the hind legs are longer than the two front pairs of legs. The tripartite tarsi have two claws with a small adhesive pad (empodium) at the top. The front pair of wings is elongated oval, the rear is just as long (or slightly shorter), but much wider due to an extended rear section (anal fan), which is folded in the rest position. The wing veins are always very pronounced, they consist of strong longitudinal veins and, depending on the family, differently pronounced transverse veins. In flight, both pairs of wings work in parallel, but are not coupled to each other. Due to the large anal fan, the flight style is similar to other Paraneoptera such. B. the cockroaches or grasshoppers. Many species are relatively bad flyers.
The abdomen is always elongated. Abdominal and back plates (sternites and tergites) are usually free, sometimes fused in a ring on the posterior segments. Ten abdominal segments can be seen. The rear end is often transformed into very conspicuous and complexly designed mating organs, especially in the males. Sometimes the anterior abdominal segments of the males also show such formations (e.g. family Leuctridae). Long tail threads (cerci) are present depending on the family (e.g. all Systellognatha) or the cerci are strongly shortened and inconspicuous (e.g. Nemouridae, Leuctridae).
Larvae
The larval development of the stonefly can take several years. The larvae live in the water and are very similar to the adults in their physique. They are often flattened and have 6 fully formed legs and 2 pairs of wing systems , which protrude from the thorax at an angle as rigid covers or lie on the upper side parallel to the body. Their mouthparts are more prominent than those of the adults. The two long abdominal appendages (cerci) designed as tail threads are striking. Some genera have prominent gills that are located on the sides of the abdomen, on the hips (coxae), in the neck area or at the tip of the abdomen, but they are not present in all genera and families. The gills are usually simply built and tufted or tubular, movable tracheal gill plates as in the mayflies do not occur. They are often recognizable as rudiments in the imagines, but also functional in at least one species in the imago. The larvae run on the bottom of the water and are generally bad swimmers. When they swim, they wiggle sideways.
From the living also in the aquatic larvae of mayflies they can to the lack of gill filaments and the absence of a third abdomen thread of Terminalfilums be distinguished.
Hemocyanin in larvae
As a big surprise, the blue blood pigment hemocyanin was found in larvae of the stonefly Perla marginata in 2004 . a. was known from crustaceans . Until then, it had been assumed that the breathing of stoneflies, like all insects in general, was based exclusively on tracheal breathing . In later studies, hemocyanin was found to be more common in insects (but only hemimetabolic). The blood pigment was found in numerous other stonefly larvae, but is obviously not also biologically active in all of them. Although hemocyanin has been shown to play a role in oxygen transport in stonefly larvae, the further biological relevance of this discovery is still unclear.
Ecology and way of life
The larvae of the stonefly are aquatic (aquatic), as a major exception there are a few species in South America whose larvae live in damp habitats on land. They show a pronounced preference for cold, usually oxygen-rich waters, with flowing waters being populated with considerably more species than stagnant waters. Accordingly, they are more species-rich in northern and temperate latitudes than in the permanently warm tropics. But even in tropical latitudes there are quite a number of species in suitable habitats, e. B. in fast flowing streams in the Amazon rainforest. In some species, the larvae can hatch from the egg at water temperatures of 2 ° C and develop into an imago. The maximum tolerated water temperature, even for species adapted to warmer waters, is around 25 ° C. Many species develop over winter and hatch in early spring (winter species). Summer species that develop in the summer half-year often have a diapause in the warmest time of midsummer .
The larvae usually develop very slowly and with numerous moults (usually around 10 to 25, number varies depending on living conditions). In Central Europe, the generation time is usually one year (univoltin), some large species take several years to develop (e.g. Dinocras three years). As a rule, the animals leave the water for their imaginal molt; For this purpose, winter species often choose the hollow space under the ice cover of the water after freezing, but they cannot fly off in this cold environment, but leave the bank continuously. Depending on the type, the slippage takes place synchronously over a short period of time or over a long period of time. The males usually hatch a little earlier than the females, although the times overlap strongly. Depending on the hatching rhythm, the adults can only be observed for a short period of a few weeks or for many months. With some genera (e.g. Protonemura or Leuctra ) numerous species follow one another in a very short flight period from early spring to autumn.
The larval stage is important as the essential growth stage for occurrence and habitat choice, while the adults have a relatively short lifespan and are focused on reproduction and spread at this stage. However, food is also consumed in the imaginal stage. Some species can more than double their body weight after hatching before oviposition. Even in groups with greatly reduced mouthparts (most of the Systellognatha), food is consumed more frequently than previously thought. As food z. B. algae coatings on tree bark, decomposed wood and other relatively soft substrates. The lifespan of the adults is a few days to a few weeks. The mating takes place on the ground, whereby the sexes can find and recognize each other through substrate sound. To do this, the male drums his abdomen with a species-specific rhythm on the surface, the female answers as well. Depending on the species, the eggs are laid as a compact egg mass on the surface of the water a few days after mating or only after a certain maturation phase. The egg mass quickly dissolves into individual eggs in the water. In some species (e.g. the Capniidae family) the larvae hatch immediately after they have laid their eggs (ovoviviparia). Very few genera reproduce parthenogenetically.
The spread of the adults through flight is limited by the low efficiency of the flight style and the low tendency to fly. In a study in England, 90% of adults (regardless of gender) stayed within 60 meters of larval water, regardless of whether the catchment area was wooded or open, and regardless of how steep the adjacent slopes were. In general, very little is known about the dispersion caused by flight in stone flies.
The larvae of the stone flies have different diets depending on their relationship. Many of the smaller species feed on dead organic matter such as B. Fall foliage. Many species also graze the organic coating ( biofilm ) of algae and microorganisms on stones and other hard substrates. B. the species of the genus Brachyptera (Fam. Taeniopterygidae) predominantly of it. Many of the large species are predators, especially the Perlidae and Perlodidae in Europe. The diet can be quite variable depending on the stage and habitat. Relatively small and soft-skinned prey organisms such as mayfly and mosquito larvae are primarily captured. The larvae mostly live on hard substrates such as stones, gravel or dead wood. Some specialized species live deeply buried in the sand, these are usually very pale in color with few bristles (e.g. genera Isoptena , Paraperla , Isocapnia ). The larvae are mainly found in little polluted streams and are not infrequently indicator species ( bioindicators ) for good water quality . In contrast, many species are exceptionally resistant to acidification by sulfur dioxide.
Systematics
The stone flies are made up of 2 suborders, the second of which can be divided into two kinship groups (clades). The current system (based on Zwick) replaces older systems that were primarily set up on the basis of European representatives and had to be modified to take account of the other fauna regions. The system shown corresponds to that shown online in the Plecoptera Species File.
Antarctoperlaria
The representatives of the Antarctoperlaria (synonyms: Archiperlaria, Gondwanoperlaria) live only in the southern hemisphere, especially in Australia , New Zealand , Chile and Argentina . Autapomorphies, which establish a monophyly, are a prothorax muscle and floriform chloride cells.
Arctoperlaria
Monophyly confirmed by substrate noise generation when finding a partner. The Arctoperlaria are divided into two groups:
Euholognatha
In these animals, the labial palpus is thread-shaped and does not taper towards the tip. With the exception of the wingless (East Asian) Scopuridae, all representatives of the superfamily Nemouroidea are assigned. These correspond to the "Filipalpia" of the older European systems. This subheading includes the families Capniidae, Leuctridae, Nemouridae and Taeniopterygidae with Perlodes microcephala, which are distributed throughout the northern hemisphere ( Holarctic ) .
Systellognatha
The Systellognatha include two superfamilies, Perloidea (synonyms are "Setipalpia" and "Subulipalpia") and Pteronarcyoidea. The three families of the second superfamily live in North America ( Nearktis ) and East Asia ( Orientalis ) and have no European representatives. The most important characteristic of the perloidea is a button on the mouth parts (labial palpus) that tapers like a bristle. This subheading includes, for example, the representatives of the globally distributed Perlidae, the Holarctic - East Asian Perlodidae and the Palearctic Chloroperlidae.
External system
The stoneflies belong to a group of morphologically primitive insect orders that are known as Polyneoptera (also: Orthopteroidea). Whether the Polyneoptera are a monophyletic taxon or are paraphyletic with respect to the other Neoptera (the holometabola and the Paraneoptera) is a matter of debate in science. Within the Polyneoptera, various hypotheses have been put forward about the sister group of the stonefly, without a consensus yet having been reached. Hennig contrasts the Plecoptera as the most primitive Neoptera with all the others (referred to by him as "Paurometabola"). Other scientists have a variety of other placements, e.g. B. proposed as a sister group of the tares spinner, this is disputed by others. Molecular analyzes have not yet been able to elucidate the relationships; the results are unstable and fluctuating depending on the model used and the taxa analyzed.
Fossil occurrences
Traditionally, the Protoperlaria found in the Upper Carboniferous (Pennsylvania) were considered to be the main group representatives of the stone flies. According to recent research, these are probably not closely related to the stone flies, they may belong to the root group of the cricket cockroaches . In 2011, however, a fossil stonefly from the Carboniferous was described for the first time, which already corresponds to the recent order in many features. Most descriptions of fossil stoneflies ( imagines , exuvia and nymphs ) refer to inclusions in the Eocene Baltic amber with representatives from five families: Nemouridae, Perlidae, Perlodidae, Taeniopterygidae and Leuctridae. A member of the Perlidae family has also been found in the somewhat younger Dominican amber , which was particularly surprising because no recent representatives of the stonefly are known from the Antilles (origin of the Dominican amber).
Individual evidence
- ↑ Romolo Fochetti, José Manuel Tierno de Figueroa (2008): Global diversity of stone flies (Plecoptera; Insecta) in fresh water. Hydrobiologia 595: 365-377. doi : 10.1007 / 978-1-4020-8259-7_39
- ↑ http://www.freshwaterecology.info
- ↑ James H. Marden & Michael A. Thomas (2003): Rowing locomotion by a stonefly that possesses the ancestral pterygote condition of co-occurring wings and abdominal gills. Biological Journal of the Linnean Society 79: 341-349.
- ↑ Silke Hagner-Holler, Axel Schoen, Wolfgang Erker, James H. Marden, Rainer Rupprecht, Heinz Decker, Thorsten Burmester (2004): A respiratory hemocyanin from an insect. Proceedings of the National Academy of Sciences USA 101 no. 3: 871-874. doi : 10.1073 / pnas.0305872101
- ^ Christian Pick, Marco Schneuer, Thorsten Burmester (2009): The occurrence of hemocyanin in Hexapoda. Federation of European Biochemical Societies (FEBS) Journal 276 (7): 1930-1941. doi : 10.1111 / j.1742-4658.2009.06918.x
- ↑ Amore, V., Belardinelli, M., Guerra, L., Buonocore, F., Fausto, AM, Ubero-Pascal, N., Fochetti, R. (2009): Do all stoneflies nymphs have respiratory proteins? Further data on the presence of hemocyanin in the larval stages of plecoptera species. Insect Molecular Biology 18: 203-211. doi : 10.1111 / j.1365-2583.2008.00859.x
- ↑ Alejandro Palma & Ricardo Figueroa (2008): Latitudinal diversity of Plecoptera (Insecta) on local and global scales. Illiesia 4 (8): 81-90.
- ↑ José Manuel Tierno de Figueroa & Antonino Sánchez-Ortega (1999): Imaginal Feeding of Certain Systellognathan Stonefly Species (Insecta: Plecoptera). Annals of the Entomological Society of America 92 (2): 218-221.
- ↑ KW Stewart, SW Szczytko, M. Maketon (1988): Drumming as a behavioral line of evidence for delineating species in the genera Isoperla, Pteronarcys and Taeniopteryx (Plecoptera). Annals of the Entomological Society of America 81: 689-699
- ^ I. Petersen, Z. Masters, AG Hildrew, SJ Ormerod (2004): Dispersal of adult aquatic insects in catchments of differing land use. Journal of Applied Ecology 41 (5): 934 - 950. doi : 10.1111 / j.0021-8901.2004.00942.x
- ↑ http://plecoptera.speciesfile.org/HomePage.aspx
- ^ Peter Zwick (2009): The Plecoptera - who are they? The problematic placement of stoneflies in the phylogenetic system of insects. Aquatic Insects Volume 31, Supplement 1, 2009. Special Issue: Proceedings of the 12th International Conference on Ephemeroptera and the 16th International Symposium on Plecoptera, Stuttgart, 2008: 181-194 doi : 10.1080 / 01650420802666827
- ↑ z. BMD Terry & MF Whiting (2005): Mantophasmatodea and phylogeny of the lower neopterous insects. Cladistics 21: 240-257. doi : 10.1111 / j.1096-0031.2005.00062.x
- ↑ Olivier Béthoux, Yingying Cui, Boris Kondratieff, Bill Stark, Dong Ren (2011): At last, a Pennsylvanian stem-stonefly (Plecoptera) discovered. BMC Evolutionary Biology 11: 248 doi : 10.1186 / 1471-2148-11-248 open access.
- ↑ George O. Poinar, Jr .: Life in Amber . 350 pp., 147 figs., 10 plates, Stanford University Press, Stanford (Cal.) 1992. ISBN 0-8047-2001-0
- ↑ Wolfgang Weitschat and Wilfried Wichard: Atlas of plants and animals in Baltic amber , 256 p., Numerous. Fig., Pfeil-Verlag, Munich 1998. ISBN 3-931516-45-8
literature
- Bernhard Klausnitzer: Plecoptera, stone flies. In Westheide, Rieger (Hrsg.): Special zoology part 1: single-cell and invertebrate animals. Gustav Fischer Verlag, Stuttgart, Jena 1997; Pages 635-636.
- Peter Zwick: Plecoptera (Perlaria, bank flies). Handbook of Zoology, A Natural History of the Tribes of the Animal Kingdom. Delivery 26. Verlag Walter de Gruyter; Edition: 2nd edition 1980. ISBN 3110081415 .
