Alpine emerald dragonfly
| Alpine emerald dragonfly | ||||||||||||
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Alpine emerald dragonfly ( Somatochlora alpestris ) |
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| Somatochlora alpestris | ||||||||||||
| ( Selys , 1840) |
The alpine emerald dragonfly ( Somatochlora alpestris ) is a species of dragonfly from the family of falcon dragonflies (Corduliidae), which belong to the large dragonflies (Anisoptera).
features
Characteristics of the imago
The dragonflies are medium-sized and reach a wingspan of six to seven centimeters, whereby they appear more robust compared to the similar arctic emerald dragonfly ( Somatochlora arctica ). The abdomen of the males is 32 to 36 millimeters, that of the females 31 to 35 millimeters. The body is greenish-black in color with a bright metallic green thorax and a black abdomen, the eyes are bright green to blue-green. The forehead ( frons ) has a yellow spot on both sides.
The forewings have between the cubital and anal vein two cross wires, the wing triangle is divided. The dull black abdomen of the males has a fine white ring at the end of the second and often also the third segment, in females the ring is more evident on the 2nd segment and there are also indistinct rings at the end of the 3rd and 4th segment. The cerci of the male are double-sided when viewed from the dorsal side and converge to a point at the end and have two ventral teeth at the base. The subgenital plate of the female is massive and triangular when viewed from the side and protrudes from the abdomen, it does not protrude beyond the 9th abdominal segment.
Similar species are the arctic emerald dragonfly ( Somatochlora arctica ), the shiny emerald dragonfly ( Somatochlora metallica ) and the falcon dragonfly ( Cordulia aenea ).
Characteristics of the larvae
The adult larva and the exuvia reach a length of 19 to 22 millimeters. The comparatively short-legged larva is moderately hairy and has neither lateral nor dorsal spines. Compared to the larvae of the Arctic emerald dragonfly , the anal pyramid is more prominent and the surfaces of the Adominal tergite have fine hairs, while longer hairs are only present on the side edges and on the rear edges of the segments on the back. Triangular sclerites are conspicuous on the pleuras of segments 4 to 6 and 8 while these are absent on the 7th segment (antepleurites). The outer, distal, edge of the labial palpus is deeply incised and the teeth are rounded.
Occurrence and habitat
The alpine dragonfly is predominantly arcto-alpine and partly also boreo-alpine and occurs in three separate distribution areas: Northern Europe from Norway to northeast Russia, the Central European Alpine region and adjacent highland regions, and in East Asia from Siberia via the central Amur and Kamchatka to the Northeast. China and North Korea and Japan. In Central Europe, the occurrence of the species is limited to the higher mountain areas with an alpine climate and mainly includes the entire area of the Alps and the Alpine foothills.
In Germany, it is only found locally in the Bavarian Alps and the Bavarian Forest, the Fichtel Mountains, the Ore Mountains with the deepest location at 420 meters, the Vogtland, the Thuringian Forest, the Harz and the Black Forest.
The animals live mainly at small water points in the peat moss - swinging grass in bogs.
Way of life
The flight time differs slightly from region to region. In Germany, Austria and Switzerland the adults are active from June or July to August or September.
The dragonflies can be found almost exclusively in sunny weather. The males patrol individually or in small numbers in search of females over the swinging lawn, the water surface and the shore area of the habitats and occasionally settle briefly on plants.
Reproduction and development
The mating begins in the air, then the mating wheel is deposited on a tree or in the bushes. The females lay their eggs in flight over small pools of water or in the peat moss lawn. The shaking females touch the water with the end of their abdomen and thus strip off the eggs. The larvae hatch in part before the winter or spend the winter in the egg before they hatch in the spring. They live in sometimes tiny water holes like gullies between peat moss and probably need up to three years for their development.
literature
- Gerhard Jurzitza: The Kosmos dragonfly guide . Franckh-Kosmos Verlag, Stuttgart 2000, ISBN 3-440-08402-7 , p. 156.
- Klaus Sternberg (1995): Influence of oviposition date and temperature upon embryonic development in Somatochlora alpestris and S. arctica (Odonata: Corduliidae). - J. Zool. Lond., 235: 163-174.
- Hansruedie Wildermuth: Europe's falcon dragonflies. Westarp Sciences, Hohenwarsleben 2008, ISBN 978-3-89432-896-2 (Neue Brehm-Bücherei Volume 653), pp. 375–384.
- Klaus Sternberg (2000): Somatochlora alpestris - Alpine emerald dragonfly. Pp. 236-250. in: Sternberg / Buchwald (ed.): Die Libellen Baden-Württemberg. Volume 2: Dragonflies (Anisoptera). Ulmer, Stuttgart, ISBN 3-8001-3514-0
