Ischnura elegans

 
 
Common Name:
Beautiful Demoiselle
Odonata
Order:
Odonata
Suborder:
Zygoptera
Family:
Coenagrionidae
Genus:
Ischnura
Species:
I. elegans
The Name
Ischnura elegans (Vander Linden, 1820), the Blue-tailed Damselfly, is a European damselfly. The name Bluetails comes from the bright blue (or rather cyan) "tail-light" , which is placed at 8th of 9th abdominal segment. Males in most species have this "tail-light" , while not all female forms have. 

The related but uncommon Scarce Blue-tailed Damselfly superficially resembles this species but has a different position for the tail spot. At a glance could be confused with the two Red-eyed Damselfly species Erythromma najas and E. viridulum but are smaller, less robust looking insects and do not have red eyes.

 

The Characteristics
Length around 29-34mm; Wingspan around 35-40mm; Hindwing around 14-21mm.

Adult male Blue-tailed Damselflies have a head and thorax patterned with blue and black. They have a largely black abdomen with very narrow pale markings where each segment joins the next. Segment eight (S8), however, is entirely pale blue.

Female Blue-tailed Damselflies come in a variety of colour forms, with the colour darkening as the damselfly ages. The thoracic markings and the tail spot are violet in the immature form violacea, but salmon pink thorax and blue spot in the form "rufescens". When mature the female may be blue (like the male) in the form "typica", olive green thorax and brown spot in the form "infuscans" or pale brown thorax and brown spot in the form "infuscans-obseleta". Male and female both have bi-coloured pterostigma on the front wings. 

Larvaes are aquatic, and prey on small aquatic insects or other aquatic larvae. The adult damselflies prey on small flying insects, caught using their legs like a basket to scoop the prey up while flying, or insects taken from leaves.

At rest, the wings of most damselfly species are held back together, unlike dragonflies, which rest with their wings out flat.

Found in most types of water including brackish or polluted water where it may be the only species present. 
 

 

The Reproduction and Development
Adults mature rapidly in this species. Both sexes stay close to breeding sites. Mating is prolonged, often lasting 3-6 hours. Catch prey in flight or by gleaning insects off leaves and spider webs. Eggs are laid within plant tissue. Female oviposits alone often laying late in day when male activity much reduced. 

Larvaes occur amongst aquatic vegetation. Feed on micro-crustaceans and insect larvae. Most larvae emerge within one year, but small proportion wait a further year. Emergence on vertical stems of low growing plants close to water's edge. Often emerges in inverted position.

Flight period can be extended from March to October, depending on different locations.
 
 
 

 

The Distribution
Distribution throughout Europe to southern Fennoscandia, Middle East and Asia to China.
 
The Protection Status
Common
 

References:
http://en.wikipedia.org/wiki/Blue-tailed_Damselfly
http://www.dragonflysoc.org.uk/isele.html
http://www.habitas.org.uk/dragonflyireland/5600d.htm
The Species on Stamps

 
Alderney
1994.05.05
Netherlands
2005.03.22
Alderney
2010.02.25

 
 

 


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