Keeled skimmer

The keeled skimmer, Orthetrum coerulescens, is a species of dragonfly belonging to the family Libellulidae. [1]

Keeled skimmer
Male
Female
Porto Covo, Portugal

Least Concern  (IUCN 3.1)
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Class:
Insecta
Order:
Odonata
Suborder:
Anisoptera
Family:
Libellulidae
Genus:
Orthetrum
Species:
O. coerulescens
Binomial name
Orthetrum coerulescens
(Fabricius, 1798)
Synonyms

Distribution

The keeled skimmer is common in central and southern Europe, marginally entering into Russia, [2] and in North Africa. It is locally common in western Britain and Ireland.[3]

This species is present in Afghanistan; Albania; Algeria; Armenia; Austria; Azerbaijan; Bosnia and Herzegovina; Bulgaria; Croatia; Cyprus; Czech Republic; Denmark; Finland; France; Georgia; Greece; Hungary; Iran, Islamic Republic of; Iraq; Ireland; Italy; Lebanon; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Montenegro; Morocco; Netherlands; Norway; Poland; Portugal; Romania; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Syrian Arab Republic; Tunisia; Turkey; Ukraine; United Kingdom. [2]

Habitat

The typical habitats ofOrthetrum coerulescens are pools and streams in acidic heath land, where it is often seen alongside golden-ringed dragonflies.

Pools and streams in wet heathland sites are favoured. wet heathland sites are favoured.

Description

Orthetrum coerulescens can reach a body length of 40–44 millimetres (1.6–1.7 in).[3] These dragonflies have a thorax with pale yellow ante-humeral stripes. In the males the color of these stripes fades with age. The abdomen is rather slim and shows an evident dorsal keel. Males have blue-grey eyes and a blue pruinescence on the abdomen, developed with age. Young males are yellow-brown. On the contrary some (androchrome) females at the end of the reproductive cycle assume the bluish color of the male. In the female the abdomen is yellowish-brown, with a thin median black line and small transverse lines to the connections of the various segments. The hyaline wings have yellow costa and a long yellow-brown pterostigma (about 4 mm). They are usually hold well forward at rest. [3]

This species resembles the black-tailed skimmer [3] but is smaller and slimmer and the male has no black tip. Females and immature males lack the black abdominal pattern.

Biology and behaviour
Mating weel

Adults fly (in the UK) from June to September. [3] Its flight is quite skittish, with frequent hovering, and it lands often. It can fly quite a distance from water, despite its seemingly weak flight. When it perches, the wings are held forward. This species breed mainly in peat bogs. The mating lasts between 5 and 120 seconds. The mating wheel usually lands, but not always. After copulation and a short rest period on the side of the male, the female flies, followed by the male to the water and lays the eggs in flight by touching the surface of the water. The larvae develop in running water but also in stagnant waters (ponds, peat bogs, etc.). After five to six weeks, the larvae hatch. Their development cycle is estimated in two years.

gollark: Basically! There's actual competition.
gollark: I don't trust governments to not do bad things given control of banks and stuff.
gollark: Like, I don't know, internal training sales manager.
gollark: I'm sure you could come up with much worse ones.
gollark: Those are all pretty useful jobs.

See also
  • List of British dragonflies

Bibliography
  • Robert, Paul-A. (1959): Die Libellen (Odonaten) - Autorisierte Übersetzung von Otto Paul Wenger [S. 300ff], Kümmerly & Frey, Geographischer Verlag, Bern.
  • Dreyer, W. (1986): Die Libellen – Das umfassende Handbuch zur Biologie und Ökologie aller mitteleuropäischen Arten mit Bestimmungsschlüsseln für Imagines und Larven [S. 88], Gerstenberg Verlag, Hildesheim, ISBN 3-8067-2022-3
  • Sternberg, K. & R. Buchwald (2000): Orthetrum coerulescens (Fabricius, 1798) – Kleiner Blaupfeil. S. 506–523. In: Sternberg, K. & R. Buchwald (Hrsg.): Die Libellen Baden-Württembergs. Band 2: Großlibellen (Anisoptera). Ulmer, Stuttgart, ISBN 3-8001-3514-0

References
  1. BioLib
  2. Clausnitzer, V. (2009). "Orthetrum coerulescens". IUCN Red List of Threatened Species. 2009: e.T158682A5249638. doi:10.2305/IUCN.UK.2009-2.RLTS.T158682A5249638.en.
  3. "Keeled Skimmer". British Dragonfly Society. Retrieved 28 September 2011.


This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.