This small slender species is perhaps the most commonly encountered and frequently the most numerous damselfly on the Iberian peninsula.

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.

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.

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 of Cornish Nature for the images and excellent, informative text in this article.

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