Iberian Bluetail - Ischnura graellsii - Cola azul ibérico

Iberian Bluetail – Ischnura graellsii – Cola azul ibérico

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  • Family: Coenagrionidae
  • Scientific: Ischnura graellsii (Rambur, 1842)
  • English: Iberian Bluetail
  • Spanish: Cola azul ibérico

The Iberian Bluetail – Ischnura graellsii – Cola azul ibérico is a small slender damselfly species. It is possibly the most commonly encountered and frequently the most numerous damselfly on the Iberian peninsula.

Iberian Bluetail - Ischnura graellsii - Cola azul ibérico
Immature female Iberian Bluetail with “pinched” blue marking on segment 8 of the abdomen similar to that of a female Island Bluetail
  • Total length: 26 to 31mm
  • Hind Wing length: 13 to 19mm
  • Flight period in Iberia: early June to early November
  • Habitat: Any wetland habitat with plentiful emergent vegetation including rivers, ditches and pools. Can sometimes be numerous around coastal lagoons & saltmarshes.
  • Distribution: The Mediterranean regions of Morocco, Algeria & Tunisia, Portugal & most of Spain
  • Similar species: Very similar to the Common Bluetail (Ischnura elegans) and the Scarce Bluetail (Ischnura pumilio) both of which occur on the Iberian peninsula.
Iberian Bluetail - Ischnura graellsii - Cola azul ibérico
Mature female Iberian Bluetail, eating prey, with the same colour markings as a male.

Mature male Iberian Blue-tails have blue eyes, a black & blue thorax, and a generally black abdomen setting off the characteristic blue “tail light” on segment 8. On both males and females this blue segment sometimes has black markings within it, breaking up the blue, giving variations that are not uncommon in large populations in southern Portugal and Andalucia.

Iberian Bluetail - Ischnura graellsii - Cola azul ibérico
An Iberian Bluetail male not quite matured, the thorax will soon change to blue

Immature females are variable in colour with a lilac/purple, orange or pink thorax and sometimes have a “pinched” blue marking on segment 8 of the abdomen, similar to that of a female Island Bluetail (Ischnura genei) which is currently not known from the Iberian peninsula. Mature females can be green, or blue on the thorax, with identical markings to a mature male. Unlike many other small species of this size the female I.graellsii oviposits alone.

Where the Common Bluetail (Ischnura elegans) also occurs great care should be taken when identifying the insect at hand. Colour markings are not sufficient to separate the two species, so close scrutiny of the pronotum from the side is needed. Male I.graellsii lack the upright projection at the rear of the pronotum which is clearly visible in male I.elegans. When looking from above this projection will be visible as a well defined median lobe which I.graellsii, in common with other Bluetail species, lacks.

Iberian Bluetail - Ischnura graellsii - Cola azul ibérico
Two images showing different species of Ischnura, with and without the upright projection at the rear of the pronotum. The left hand image: Immature female Iberian Bluetail with no upright projection at the rear of the pronotum. Ischnura graellsii. The right hand image: Male Common Bluetail with upright projection at the rear of the pronotum. Ischnura elegans
Credits

Thanks to Steve Jones for the images and excellent, informative text in this article.

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