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Green-eyed Hawker (Aeshna isoceles)


Green-eyed Hawker (Aeshna isoceles)
Photo Information
Copyright: Hans Hendriks (hansh) Gold Star Critiquer/Gold Note Writer [C: 277 W: 1 N: 741] (2762)
Genre: Animals
Medium: Color
Date Taken: 2011-05-14
Categories: Insects
Camera: Canon 7D, Sigma 150mm f2.8 macro
Exposure: f/4.5, 1/320 seconds
Details: Tripod: Yes
More Photo Info: [view]
Photo Version: Original Version
Date Submitted: 2011-07-29 12:06
Viewed: 3544
Points: 2
[Note Guidelines] Photographer's Note
I made this crop to show the details of the chest and the way the light has been captured by the wings.

A. isoceles is one of only two brown hawkers found in Europe, the other is A. grandis. Both have a brown thorax and abdomen but A. isoceles has green eyes and clear wings and a diagnostic yellow triangular mark on the second abdominal segment. The hindwings have a amber patch at their base. In contrast A. grandis has yellowish wings and blueish eyes. The green eye of A. isoceles stand out even in flight and in practice it is not difficult to tell these two dragonflies apart. In addition to the morphological differences A. isoceles is on the wing much earlier in the year than A. grandis.

A. isoceles is found in central Europe and around the Mediterranean and, the lowlands of North Africa. It is more common in eastern Europe than the south western Europe; it occurs in Spain and Portugal but is local.

It is found wet areas, ponds, ditches and marshes, with dense vegetation and, in studies carried out in England, was found to be associated with Water-soldier (Stratiotes aloides).

It is one of the earliest Aeshna dragonflies to be on the wing with a flight period from May to August. Adults do not spend as much time on the wing as other Aeshnas. Males will fly around over a stretch of water defending a territory and if the pond is small the male will hover over the centre of the pond. Unlike other aeshnas, where the adults seem to be continuously on the wing beating up and down their territory, male A. isoceles come to rest on vegetation from time to time. Females oviposit onto plants and the eggs hatch in about 2 weeks. Larval development takes 2 years.

This species was first described as Libellula quadrifasciata, var. 36. isoceles by Muller in 1764. It has since been called Aeshna rufescens and Aeshna chysophthalmus and more recently Anaciaeschna isosceles. It is by this last name that it is referred to in many books. It has since been included into the genus Aeshna and in many books is called Aeshna isosceles: however the original specific name was isoceles. Dijkstra and Lewington (2006) and Boudot JP., et al.. (2009) both call it Aeshna isoceles whereas Askew, R.R. (2004),and earlier books, refer to it as Aeshna isosceles.

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Critiques [Translate]

hallo Hans
Leuk weer een foto te zien van je
deze is wel super mooi scherp veel details goed licht en super kleuren
Bedankt groetjes lou
sorry ik ben door mijn Smile,s

  • Great 
  • fapple (38)
  • [2012-02-02 14:37]

Hans,
Superb colours and the composition is also very appealing with nice syncopation of the vegetation. Useful note too.
Best wishes
Andrew

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