Cretan bluet  (Coenagrion intermedium)

This Cretan damselfly is typical of the Coenagrion genus, commonly known as ‘northern bluets', in which males possess vibrant blue-and-black colouration (4). Northern bluet females usually come in two colour forms, either sharing the male's same blue-and-black colouration (known as homeochromatic morph), or being different, typically brown to olive-coloured (known as heterochromatic morph), and therefore easily distinguishable from the male (2). Known females of this restricted species are all heterochromatic and have the dorsal part of the abdomen largely black with a small blue-green area on the anterior part of each segment. They are easily distinguishable from the males, which are predominantly blue with black areas.

Endemic to the Greek island of Crete (1) (2) (3).

Found only in and around rivers, with larvae having been collected from between floating tree roots (1).

Although not investigated, the larval period is thought to last around one year or less in the Cretan bluet, by extrapolation of what occurs in the closest relative species from the Mediterranean area. The flight period runs from the last third of April to mid-August. Adults feed on small flying insects. Males are unlikely to defend territories. Oviposition is done in tandem with the male. Females lay their eggs in floating herbs, small roots along the river edge and rotten wood in the water, using their ovipositor to cut a slit in the substrate (3).

The Cretan bluet seems to be presently widespread and abundant in its restricted area, but is likely to become vulnerable in the near future due to water use, global warming and dryness (1) (2) (3).

There are currently no conservation initiatives targeting this species.

Authenticated (18/12/2006) by Jean-Pierre Boudot, CNRS, Université Henri Poincaré Nancy I, France.