Den almindelige rygsvømmer (Notonecta glauca) er et 15-16 millimeter langt næbmundet insekt. Den findes oftest i stillestående ferskvand, hvor den kan ses svømme med ryggen nedad. Rygsvømmeren ses ofte hænge i overfladehinden med for- og mellemben og med bagkropsspidsen i kontakt med luften. Den lever af bl.a. vandkalvelarver, haletudser og fiskeyngel.
Den typiske form har lyse halvdækvinger. Kroppen er bådformet og øjnene er store og sorte. Snabelen er kort og kraftig, og dens stik kan være meget smertefuldt.
Den almindelige rygsvømmer (Notonecta glauca) er et 15-16 millimeter langt næbmundet insekt. Den findes oftest i stillestående ferskvand, hvor den kan ses svømme med ryggen nedad. Rygsvømmeren ses ofte hænge i overfladehinden med for- og mellemben og med bagkropsspidsen i kontakt med luften. Den lever af bl.a. vandkalvelarver, haletudser og fiskeyngel.
Der Gemeine Rückenschwimmer (Notonecta glauca) ist eine Wasserwanze (Nepomorpha) aus der Familie der Rückenschwimmer (Notonectidae). Das besondere Kennzeichen dieser Art wie auch der weiteren Vertreter der Rückenschwimmer ist, dass sie stets mit der Bauchseite nach oben schwimmen. Diese auffällige Schwimmposition resultiert aus dem bauchseits am Hinterleib mitgeführten Luftvorrat.
Die Wanzen erreichen Körperlängen zwischen 13,5 und 16 Millimetern. Die Bauchseite ist flach. Die Rückenseite ist bootsförmig gewölbt und die Flügel sind dachförmig gestellt. Das Schildchen (Scutellum) der Tiere ist schwarz gefärbt, sein Seitenrand ist länger als die Clavusnaht. Die Zipfel der Membran sind etwa gleich lang. Die Vorderecken des Halsschildes (Pronotum) sind stumpf und gerundet. Sein Hinterrand ist gerade. Die Halbdecken (Hemielytren) sind gelbgrau, gelbweiß, gelbrot oder grünweiß gefärbt und oft schwarz oder braun gefleckt. Der Rücken des Hinterleibes ist einfarbig schwarz oder braun gefärbt – im Gegensatz zur ähnlichen Notonecta maculata, welche vorn und hinten je eine gelbrote Querbinde auf dem Abdomen tragen. Die Hinterbeine sind durch Schwimmhaare, die sich beim Schwimmen automatisch auffächern, gekennzeichnet. Die Insekten schwimmen in Rückenlage, da der größte Teil der Atemluft auf der Unterseite des Hinterleibes in zwei, jederseits mit dichten Haarreihen besetzten Luftrinnen gehalten wird.
Die Art kommt in ganz Europa, östlich bis in den Osten Sibiriens und über Zentralasien nach China vor. Sie kommt in den Alpen bis etwa 1.800 Meter über Seehöhe vor, ist die häufigste Art ihrer Gattung in Mitteleuropa und ist überall häufig zu finden. Gemeine Rückenschwimmer leben in nahezu allen stehenden und langsam fließenden Gewässern und besiedeln auch stark eutrophierte Gewässer. In sauren Moorgewässern und in Brackwasser sind sie seltener.
Die Imagines ernähren sich wie alle Arten ihrer Familie räuberisch von im Wasser lebenden oder ins Wasser gefallenen Kleintieren, wie Insekten und Kaulquappen und sind gute Schwimmer. Die Art entwickelt sich in einer Generation pro Jahr und überwintert als Imago. Die Paarung findet in der Regel nach der Überwinterung statt, kann aber auch schon im Herbst erfolgen. Die Weibchen stechen ihre etwa 200 Eier zwischen Februar und April mit ihrem kurzen Legebohrer (Ovipositor) in Pflanzenmaterial ein. Die Elterngeneration stirbt bis Mai, die Imagines der neuen Generation sind nach fünf Häutungen ab Ende Juli und Anfang August voll entwickelt. Gerade im Herbst sieht man Rückenschwimmer auch des Öfteren fliegen. Da sie gute Flieger sind, legen sie auch große Distanzen zurück und können so leicht neue Gewässer besiedeln.
Der Gemeine Rückenschwimmer (Notonecta glauca) ist eine Wasserwanze (Nepomorpha) aus der Familie der Rückenschwimmer (Notonectidae). Das besondere Kennzeichen dieser Art wie auch der weiteren Vertreter der Rückenschwimmer ist, dass sie stets mit der Bauchseite nach oben schwimmen. Diese auffällige Schwimmposition resultiert aus dem bauchseits am Hinterleib mitgeführten Luftvorrat.
Notonecta glauca (common backswimmer) is a species of aquatic insect, and a type of backswimmer. This species is found in large parts of Europe, North Africa, and east through Asia to Siberia and China.[1] In much of its range it is the most common backswimmer species.[2] It is also the most widespread and abundant of the four British backswimmers.[3] Notonecta glauca are Hemiptera (true bug) predators,[2] that are approximately 13–16 mm in length.[4] Females have a larger body size compared to males.[2] These water insects swim and rest on their back (hence their common name "backswimmer" or "water boatman") and are found under the water surface.[5] Notonecta glauca supports itself under the water surface by using their front legs and mid legs and the back end of its abdomen and rest them on the water surface;[6] They are able to stay under the water surface by water tension, also known as the air-water interface (surface tension).[7] They use the hind legs as oars; these legs are fringed with hair and, when at rest, are extended laterally like a pair of sculls in a boat.[8] Notonecta glauca will either wait for its prey to pass by or will swim and actively hunt its prey. When the weather is warm, usually in the late summer and autumn, they will fly between ponds.[9][10] Notonecta glauca reproduce in the spring.[2]
There has been a great deal of research on the eye of N. glauca. These insects use their eyes for both day and night vision, which is used for prey capture and flight when searching for new habitats.[5] Notonecta glauca, like other insects, have a compound eye. Specifically, their eye is an acone-type with corneal structure, which helps them create a sharp image when both in the water and in the air.[11][12][13] The acone is the site of the pupil. Immonen et al. (2014), found that backswimmers are able to see in both day and night light conditions because of:
They also found that the green-sensitive peripheral photoreceptors function in a similar way as nocturnal Phasmatodea (or stick insects). To protect their eye from direct sunlight during the day, the pigment cell's diaphragm are condensed, and during the night they open fully to allow as much light in as possible.[5] Notonecta glauca have two photoreceptor subsystems:
The first subsystem is sensitive to green light, one of the colours in the visible spectrum. This sensitivity helps the backswimmer see in dimmer light or at night. The second subsystem allows the backswimmer to see in bright light and when in flight.[5] Notonecta glauca pupil (acone) take a different amount of time to adjust to light. It takes the N. glauca approximately 40 minutes for the pupil to adjust to daylight and approximately 50 minutes to adjust to the light at night.[14]
Although N. glauca live in the water, they breathe atmosphere air and do not have gills. When these insects are diving or resting under the water surface, they create a film of air that surrounds their body.[15] This air film is also known as a superhydrophobic coating or surface, and it prevents the insect from becoming wet.[4] It also reduces the drag (physics) that is created when diving.[16][17] To be able to create this air film around it, N. glauca is covered in hairy structures, except on its head and legs.[15] There are two types of hairs and air retention is maximized by having both types: setae and microtrichia.[15] The most important part in creating an air film is the density of the hairs.[4] Notonecta glauca has dense microtrichia and their air film can last up to 120 days.[4] The air film cannot last forever because as an insect respires (breathes), the oxygen partial pressure will decrease and nitrogen partial pressure will increase, causing the air bubble to decrease in size.[4]
Notonecta glauca is used as a model organism for friction reduction and air retention.[15] Possible applications for this include reduction of drag in ships.
Notonecta glauca can discriminate between prey and non-prey, like other backswimmers, by surface waves.[18] Lang (1979), completed an experiment that showed that waves that were created by other backswimmers swimming, emerging, turning and paddling were of a lower frequency (below 40 Hz) compared to waves created by their prey items, who had a frequency between 70–140 Hz. Larval backswimmers were found to create different waves that differed from adult backswimmers, but their frequency were similar to that of adult swimming produced waves (up to 70 Hz).
Water depth can affect how N. glauca pick which prey they eat. Males and females both spend a lot of time on the surface of the water where they encounter mosquito (Culex) larvae. They feed on this prey because there is a decrease in travel cost (having to dive for them) and Culex gives a higher energy rate.[19]
Mature females, however, will also dive to the bottom of the pond to feed on isopods (Asellus), but only in shallow waters.[19] Reaching Asellus requires a higher travel cost of energy. This behaviour is not consistent with the optimal foraging theory.[19] It is possible, however, that because mature females are larger than males and immature females, they have a reduced buoyancy and therefore require less energy to capture Asellus.[20] Also, mature females have a larger abdominal size, which could support a larger air bubble and allow them to remain submerged for longer.[19] However, if the water depth increases, mature females will switch and spend more time at the surface and not feed on Asellus, as the deep water increases the amount of energy needed for diving and staying submerged.[19]
The oxygen concentration in the body of water can affect the choice of prey N. glauca pick, as Cockrell (1984) found that when oxygen was at a high dissolved level, N. glauca will spend more time submerged and attacking Asellus.[21]
Notonecta glauca (common backswimmer) is a species of aquatic insect, and a type of backswimmer. This species is found in large parts of Europe, North Africa, and east through Asia to Siberia and China. In much of its range it is the most common backswimmer species. It is also the most widespread and abundant of the four British backswimmers. Notonecta glauca are Hemiptera (true bug) predators, that are approximately 13–16 mm in length. Females have a larger body size compared to males. These water insects swim and rest on their back (hence their common name "backswimmer" or "water boatman") and are found under the water surface. Notonecta glauca supports itself under the water surface by using their front legs and mid legs and the back end of its abdomen and rest them on the water surface; They are able to stay under the water surface by water tension, also known as the air-water interface (surface tension). They use the hind legs as oars; these legs are fringed with hair and, when at rest, are extended laterally like a pair of sculls in a boat. Notonecta glauca will either wait for its prey to pass by or will swim and actively hunt its prey. When the weather is warm, usually in the late summer and autumn, they will fly between ponds. Notonecta glauca reproduce in the spring.
Harilik selgsõudur (Notonecta glauca) lutikaliste alamseltsi kuuluv putukaliik.
Putukat on ka Eestis.[1]
Harilik selgsõudur (Notonecta glauca) lutikaliste alamseltsi kuuluv putukaliik.
Putukat on ka Eestis.
Notonecte glauque, Abeille d'eau
Notonecta glauca, la notonecte glauque ou abeille d'eau[1], est une espèce d'insectes aquatiques de la famille des Notonectidae, dont elle est le représentant le plus abondant (49 %).
Il s'agit de l'un des insectes les plus communs de la faune aquatique de France métropolitaine. Elle se trouve d'ailleurs dans toute l'Europe (excepté la Scandinavie), dans le Caucase, l'Afrique septentrionale et en Amérique du Nord.
Notonecta glauca fait partie des hémiptères prédateurs (disposant d'un appareil buccal de type piqueur-suceur), et mesure environ entre 13 et 16 mm de longueur.
Il existe chez cette espèce un dimorphisme sexuel à l'avantage des femelles.
Ces insectes d'eau nagent et se reposent sur leur dos (d'où leur nom tiré du grec ancien νῶτος, nôtos « dos » et νηκτός, nêktos « nageant ») et évoluent sous la surface de l'eau. Ils sont en effet capables, en tirant parti du phénomène de tension superficielle, de plaquer le bas de leur abdomen et leurs pattes avant sous la surface, alors que leurs pattes arrière rament comme des pagaies. Notonecta glauca va aussi bien attendre à l'affût que sa proie passe à proximité que nager pour la chasser énergiquement[2].
Quand le temps est assez chaud, généralement à la fin de l'été et en automne, les notonectes peuvent voler d'un étang ou d'une mare à l'autre, pour se reproduire ou pour coloniser de nouveaux habitats.
Notonecta glauca se reproduit au printemps et en été. Le jour ou la nuit, le mâle émet un chant qui évoque celui du grillon. Ce chant est émis sous l'eau, mais si l'on y prête attention, il peut être entendu à plusieurs mètres par l'oreille humaine.
Notonecte glauque, Abeille d'eau
Notonecta glauca, la notonecte glauque ou abeille d'eau, est une espèce d'insectes aquatiques de la famille des Notonectidae, dont elle est le représentant le plus abondant (49 %).
Notonecta glauca Linnaeus, 1758 è un insetto della famiglia Notonectidae.
È il più diffuso ed abbondante dei quattro Notonectidae britannici[1].
Notonecta glauca Linnaeus, 1758 è un insetto della famiglia Notonectidae.
È il più diffuso ed abbondante dei quattro Notonectidae britannici.
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