Hawk dragonflies

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Hawk dragonflies
Arctic emerald dragonfly (Somatochlora arctica)

Arctic emerald dragonfly ( Somatochlora arctica )

Systematics
Class : Insects (Insecta)
Subclass : Flying insects (Pterygota)
Order : Dragonflies (Odonata)
Subordination : Dragonflies (Anisoptera)
Superfamily : Libelluloidea
Family : Hawk dragonflies
Scientific name
Corduliidae
WF Kirby , 1890
Genera

The falcon dragonflies ( Corduliidae) are a family of dragonflies (Odonata). Seven species of this group live in Germany. The family is named after the falcon dragonfly ( Cordulia aenea ). Their scientific generic name Cordulia means something like "the club" (Greek: kordyleia), which refers to the shape of the abdomen of the male.

features

The falcon dragonflies are medium-sized representatives of the large dragonflies (Anisoptera); their closest relatives are the dragonflies (Libellulidae). Most species have relatively long legs and are metallic-green in color (sometimes copper-colored when old; some also dark and dull), with the bodies of the emerald dragonflies (genus Somatochlora ) in particular showing a shimmering green. The eyes are often colored in bright shades of green. The ovipositor of the females is reduced to a simple valve. The eggs are released into the water individually ( Somatochlora ), in lumps ( Cordulia ) or in spawning strings ( Epitheca ). The stocky looking larvae wear a helmet mask and are partly equipped with particularly long legs and conspicuous thorns on the abdomen.

Way of life

The falcon dragonflies owe their German name to the rapid flight of their male adults , during which they often change direction. This is reminiscent of the flight of a hawk . The males are also noticeable for their persistent and agile flight activities. However, the females are shy and often hide in the bank vegetation.

The mating of the animals begins in flight, but ends sitting. The female is not accompanied by the male to lay eggs. It usually flies close to the water surface and dips its abdomen briefly into the water several times; some species also lay their eggs in the bank mud.

The larvae mainly stay on the bottom of the water and are very slow to move. Often they can also be found in the mud. They usually develop over two to three years, and some species have twelve or more larval stages known.

Falcon dragonflies have very narrowly defined habitat requirements. Some species specialize in dystrophic bog waters, others prefer near-natural, herbaceous waters in floodplains and lowlands.

Fossil record

The fossil record of corduliidae whole is very sparse, and due to the systematic discussion, the assignment is difficult. One of the oldest known falcon dragonflies is the Eocordulia cretacea , which was described in Mongolia in 1986 and comes from the Lower Cretaceous ; however, the assignment is questioned. An in Bernstein entrapped wing from the early Eozän France has similarities with those of various corduliidae genera ( Dorocordulia , Williamsonia , Hemicordulia ) which further finds from the Eozän, Oligozän and Miozän be the genera Croatocordulia , Stenogomphus , Miocordulia , Cordulia , Epitheca and Epophthalmia assigned, however, are also controversial. Molecordulia karinae from the Paleocene of Denmark, which was described in 2005 and is around 65 million years old, is now the oldest fossil find that was definitely assigned to the falcon dragonflies .

Genera and species

Shiny emerald dragonfly ( Somatochlora metallica ),
male on patrol flight

There are currently 39 genera of falcon dragonflies. 11 species from a total of 5 genera are native to Europe, with the species of the emerald dragonflies ( Somatochlora ) predominating with 7 species. The remaining 4 genera are only represented by one species each.

literature

  • Heiko Bellmann : Observe dragonflies - determine . Naturbuch Verlag, Augsburg 1993, ISBN 3-89440-107-9 .
  • Klaus Honomichl, Heiko Bellmann: Biology and ecology of insects . CD-ROM. Gustav Fischer Verlag, Stuttgart 1994, ISBN 3-8274-0760-5 .
  • Gerhard Jurzitza: The Kosmos dragonfly guide . Franckh-Kosmos Verlags GmbH & Co., Stuttgart 2000, ISBN 3-440-08402-7 .
  • Klaus Sternberg, Rainer Buchwald: Dragonflies in Baden-Württemberg. Volume 2: Dragonflies . Eugen Ulmer Verlag, 2000, ISBN 3-8001-3514-0 .
  • Hansruedi Wildermuth: Europe's falcon dragonflies . Die Libellen Europa, Volume 5. Die Neue Brehm-Bücherei 653. Westarp Wissenschaften, Hohenwarsleben 2008, ISBN 3-89432-896-7 .

Web links

Commons : Corduliidae  - Collection of images, videos and audio files

Individual evidence

  1. ↑ The Libelluloidea - a young family group. In: Hansruedie Wildermuth: The falcon dragonflies in Europe. , Pp. 27-29.
  2. ^ Martin Schorr, Martin Lindeboom, Dennis Paulson: World Odonata List. Update from February 10, 2010 ( download )
  3. ^ Hansruedie Wildermuth: The falcon dragonflies in Europe. Neue Brehm-Bücherei Volume 653, Westarp Sciences Hohenwarsleben 2008; P. 14. ISBN 978-3-89432-896-2 .