Large pincer level
| Large pincer level | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Great dragonfly ( Onychogomphus uncatus ), male |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Onychogomphus uncatus | ||||||||||||
| ( Charpentier , 1840) |
The great dragonfly ( Onychogomphus uncatus ) is a dragonfly from the family of the river damsel (Gomphidae). The Mediterranean species inhabits southwest Europe and the North African coastal regions. In Germany and in Switzerland , the Large pliers dragonfly was also disseminated to 1970 and is regarded within both countries now considered extinct.
features
The great dragonfly reaches a body length of 50 to 53 and a wingspan of 60 to 68 millimeters. The basic coloration of the species is composed of black and yellow drawing elements , as with all pincer dragonflies ( Onychogomphus ) and can also be very variable. The coloring also depends on the area. In the wooded Cevennes in the south of France, for example, specimens of the species are clearly darker in color than is the case in the gravel steppe Crau, which is also located in southern France , where the dragonflies then appear much lighter.
The eyes of mature adults (adult animals) are blue or grayish In contrast, the eyes of younger adults are still gray. There is a yellow stripe or spot between the eyes.
The thorax (chest section) has several black stripes, including two in the shoulder area. The smaller and inner one merges into a transverse line at the rear and thus completely frames this area, while the larger and outer one of the two strips ends at the back and does not collide with the transverse line. The flanks of the thorax have two more continuous and extensive and partially convoluted ligaments.
The predominantly black abdomen (abdomen) has a yellow triangle per segment on the dorsal side.
Sexual dimorphism
Like other dragonflies, the great dragonfly has a conspicuous sexual dimorphism (difference between the sexes), which in this species is particularly recognizable by the characteristics of the abdomen. In the female, this is slightly wider in the middle and is usually provided with larger yellow triangles on the dorsal side than in the male. The color of the female's abdomen can also vary widely.
Unlike the female, and as with all species of the genus, the male of the great dragonfly has an abdomen that is not centrally widespread at the back and the pincer-shaped cerci (abdominal appendages) at the end of it , which are longer than the tenth abdominal segment. The male's cerci are bright lemon yellow in color.
Similar species
Species similar to the dragonfly are particularly represented in the genus of the dragonfly ( Onychogomphus ), to which the species itself belongs. As with all pincer dragonflies, the great pincer dragonfly can also be confused with other dragonfly species from the family of the river damsel (Gomphidae).
Confusion with the small pincer level
--Kleine_Zangenlibelle-Maennchen.jpg)
Most likely, the great pincer dragonfly can be confused with the slightly smaller little pincer dragonfly ( O. forcipatus ) belonging to the same genus and its subspecies, the western pincer dragonfly ( O. f. Unguiculatus ). However, unlike the large tongued dragonfly, the small tongued dragonfly has green eyes and a yellow spot in between, but between which there are again two light stripes.
In addition, in contrast to the large bubble level, the outer of the two stripes on the shoulder side of the thorax is connected to the rear transverse line, which completely surrounds the yellow shoulder mark on the small pincer level. The cerci of the little dragonfly are also brown and not yellow. Furthermore, the lower pliers of the small pliers level have an extension at the tip, which is not the case with the large pliers level.
Confusion with other river maids
Confusion with other species of the river maiden family is also possible. In contrast to the other species of the family, however, the pincer levels do not have parallel-edged and thinner lines on the thorax and also differ in the pincer-shaped cerci of the male.
The similarly similar wedge cubs ( Gomphus ) differ from the great dragonfly by the predominantly uninterrupted, thin and yellow center lines on the dorsal side of the abdomen and the missing triangular spots there.
The distantly similar green mermaid ( Ophiogomphus cecilia ) differs from the great dragonfly in particular in the green color that gives it its name, which is particularly pronounced on the head and thorax (with the exception of younger females) and in the less pronounced pattern on the dorsal side of the thorax .
Occurrence
The great dragonfly lives in western parts of the Mediterranean area . Its distribution area includes the Iberian Peninsula in southwest Europe , the south and west of France as the main distribution area of the species, and northeast Italy . The distribution area ends north at the height of Rome . The species is also represented in North Africa , where it occurs in Egypt , Algeria , Tunisia and Morocco . The great dragonfly has been detected at heights of up to 1,000 meters above sea level.
habitat
The great dragonfly has comparatively high demands on its habitat and lives mainly in clean and fast-flowing streams, but also main and tributaries of rivers with this characteristic. Rivers whose subsoil is not relocated during floods and are slightly shaded and have a high oxygen content are particularly popular.
frequency
Due to their demands on their habitats, the great dragonfly has a different frequency, which varies depending on the area. In the western Mediterranean area it is not uncommon in places.
Situation and Southwest Europe and North Africa
The great dragonfly is fairly common on the Iberian Peninsula. In its main distribution area in France it occurs again more frequently in the south of France , where in the past 630 larvae of the species were found on one square meter. In North Africa, the great dragonfly is rarer in Morocco and Algeria than in Egypt and Tunisia.
Situation in Germany and Switzerland
In Germany , the great dragonfly once occurred on the Upper Rhine and in Switzerland there also below Lake Constance and was widespread there until 1970. The species was once quite abundant within these areas. In 1979 only a single female was found in Switzerland, making the species extinct there. The last records of the great dragonfly in Germany were made in 1991 and 2000. The construction of power plants on and promotion of the navigability of the river, which were driven forward between 1960 and 1967, is held responsible for the disappearance of the species on the Upper Rhine .
Protection status
The IUCN assesses the degree of endangerment of the great dragonfly according to the frequency in the respective areas. In the distribution areas of the countries in the western Mediterranean area, it is classified in the "LC" ( least condern ) category due to its relative frequency there and enjoys no protection. In Germany and Switzerland, the species has been considered extinct since its disappearance in these countries and is accordingly in the Red List of Threatened Species Animals, Plants and Fungi in Germany in the category "0" ( extinct ) and equally in the Red List of Switzerland in the category "RE" ( Regionally Extinct ), in Austria it was not proven. The IUCN does not record the global population of the Great Dragonfly.
Way of life
.jpg)
Like all dragonflies, the great dragonfly is takactive and usually lingers in areas exposed to the sun. The males of the species stay mainly in the bank area of the running waters on stones or on sandy banks, while the females prefer resting places in light vegetation close to the ground.
As with many dragonflies, the males of the great dragonfly are territorial and drive away rivals by briefly flying up from their perch and chasing them away in flight.
Catching prey
The great dragonfly shares its predatory way of life with other representatives of the order and hunts various flying insects as a stalker . As soon as one of these gets close enough to the dragonfly in flight, it flies up and tries to grab the prey in flight accordingly. If the hunt is successful, the dragonfly lands on a suitable surface again and consumes the prey.
Life cycle
The life cycle of the great dragonfly is divided into several phases and also depends on the season.
Phenology of the adults
The phenology (time of activity) and thus the flight time of the adults is between the months of May and mid-September, with the peak of this period occurring between the beginning of June and mid-August. In southern Europe in particular, the flight time usually takes place over a longer period of time.
Mating and laying eggs
As with prey and rival conspecifics, a resting male flies up when a female is flying by and tries to grab it in flight. The female is ready to mate, mating takes place in the form of typical dragonflies mating wheel . Mating can take 2.5 to 3.5 times and is therefore comparatively long compared to other dragonflies. The sexual partners stay close to the ground near the banks of the waters and remain almost motionless, making them difficult to spot.
The female lays her eggs alone, which means that the tandem position that occurs in other dragonflies does not occur in the great dragonfly . Egg-laying takes place between 9:40 a.m. and 5:00 p.m. First, it squeezes out a lump of egg at a standstill, with which it then flies to the nearest body of water and seeks the closest proximity to the water surface. Directly above the water it then goes into a shaking flight (flying on the spot) and then flies with the head pointing upstream about five to ten centimeters above the water surface. At an interval of one second each, the eggs are deposited in lumps, each containing 12 eggs. In total, a female can shed up to 450 eggs in 12 seconds, which corresponds to a rate of 38 eggs per second.
Hatching and development of the larvae
Three to four weeks after laying eggs hatch the aquatic (water-living) living larvae , which need 40 to 60 minutes for the slip. Many of the larvae fall victim to various predators (predators), such as fish , which explains the high number of eggs laid. The greatest natural enemy of the larval form of the great pincer dragonfly is that of the two-striped spring damsel ( Cordulegaster boltonii ), which also belongs to the dragonflies . The larvae of the great dragonfly, in turn, live like all dragonflies and, like their adults, are also predatory. In contrast to the adult dragonflies, the larvae hunt at night and lurk buried in the sand for prey. These are captured with the help of the trap mask typical of dragonfly larvae . The prey spectrum of the larvae consists mainly of larvae of mosquitoes , annelid worms , water isopods , leeches , river fleas and young fish.
The larva takes two to four, but mostly three years to develop into an imago and goes through 13 larval stages. It reaches a maximum length of 26 millimeters. The larva of the great dragonfly resembles that of the green mermaid ( Ophiogomphus cecilia ), which also has thorns on the lateral sides. Unlike the larva of the great dragonfly, however, that of the green mermaid only has such thorns on the eighth and ninth segments.
Hatching of the adults
In the period from mid-May onwards, the fully developed larvae, which previously leave the water, hatch, then the adults close above the water surface and mostly on the surface of stones. In this species, hatching takes 40 to 60 minutes. When hatching, both sexes are equally represented, but the females move away from the water according to their preferred habitat, while the males mostly stay there.
Maturation and life expectancy of the adults
The adults need 14 days to mature after hatching. The maximum lifespan of the adults of the dragonfly, which is usually short, is four to six weeks.
Conduct towards humans
Unlike the closely related little dragonfly ( Onychogomphus forcipatus ), the great dragonfly shows no great shyness towards humans and remains even when a person feeds the dragonfly. It is assumed that this behavior is related to the need for warmth of the species that is higher than that of the small pincer dragonfly, or that the dragonfly does not want to leave a suitable place to linger and thus also to sunbathe if possible.
Systematics
The Big pliers dragonfly received from her Erstbeschreiber Toussaint de Charpentier in the first description in 1840 already its Today's designation Onychogomphus uncatus , but at the same time of selbigem author also synonymous Aeshna uncata . In addition, it now has other synonyms . These are:
- Aeschna unguiculata Boyer de Fonscolombe , 1838
- Aeshna unguiculata Boyer de Fonscolombe , 1838
- Onychogomphus occitanicus Rambur , 1842
gallery
Dorsal view of a male
Frontal view of a male
Lateral view of a male
Rear view of a male
Male sitting in the vegetation
Lateral view of a female
Rear view of a female
Frontal detailed view of a large bubble level
Lateral detail view of a large bubble level
Lateral view of an exuvia
_male_(20007648039).jpg)
Individual evidence
- ↑ a b c d e f g h i j k l m n o p q r Onychogomphus uncatus (Charpentier, 1840) at Libellen.tv, accessed on April 16, 2020.
- ↑ a b c d e f g h i j k l m n o p q r s t u v w x Onychogomphus uncatus (Charpentier, 1840) from Libellenschutz, accessed on April 16, 2020.
- ↑ a b c d e f g h i j k l m n o p q r s t u v w x y Onychogomphus uncatus (Charpentier, 1840) at waldschrat-online.de, accessed on April 16, 2020.
- ↑ a b c d e f g h i j k Onychogomphus uncatus (Charpentier, 1840) at LibellenWissen.de, accessed on April 16, 2020.
- ↑ a b Onychogomphus uncatus (Charpentier, 1840) at the University of Ulm, accessed on April 17, 2020.
- ↑ a b c d Heiko Bellmann: Der Kosmos Libellenführer Kosmos Naturführer, Kosmos (Franckh-Kosmos), 3rd edition, 2013, p. 230, ISBN 978-3-440-13516-7 .
- ↑ a b Onychogomphus uncatus (Charpentier, 1840) at Global Biodiversity Information Facility , accessed on April 17, 2020.
literature
- Heiko Bellmann: Der Kosmos Libellenführer Kosmos Naturführer, Kosmos (Franckh-Kosmos), 3rd edition, 2013, p. 230, ISBN 978-3-440-13516-7 .
- Frank Suhling: Interspecific competition and habitat selection by the riverine dragonfly Onychogomphus uncatus , Freshwater Biology 35, 2nd edition, 1996, pp. 209-217.
Web links
- Onychogomphus uncatus (Charpentier, 1840) in Fauna Europaea
- Onychogomphus uncatus (Charpentier, 1840) at the Global Biodiversity Information Facility
- Onychogomphus uncatus (Charpentier, 1840) with dragonfly protection
- Onychogomphus uncatus (Charpentier, 1840) at Libellen.tv
- Onychogomphus uncatus (Charpentier, 1840) at waldschrat-online.de
- Onychogomphus uncatus (Charpentier, 1840) at LibellenWissen.de
- Onychogomphus uncatus (Charpentier, 1840) at the University of Ulm