Blue damselfly (Ischnura elegans) ranks among the most common and most widespread equal-winged damselflies in Europe and in our country. It is typically 30 to 34 mm long, and the wingspan measures about 3.5 cm.
We will easily recognise the males of damselflies by the distinctive two-coloured pterostigmas (the inner half is dark gray, the outer half whitish) on the front pair of wings. If we view the male from above, we also notice a bright blue segment at the end of the abdomen, which stands out distinctly from the bronze-black dorsal side. For the blue damselfly, it is characteristic that it has a blue eighth abdominal segment. When viewed from the side, it shows turquoise-blue thorax and the ventral side of the initial and terminal parts of the abdomen, while the remaining abdominal segments are greenish-yellow.
In females, things are more complex, as we know three color forms of adult females. Some are more or less the same coloured as males, in the other two forms the blue colour does not express. The sides and the ventral side of the latter are pale green to yellow-brown in colour.
The blue damselfly inhabits especially standing waters, but can also be found in watercourses. It prefers bodies of water with low and dense aquatic vegetation. Particularly nutrient-rich, highly productive (eutrophic) waters can host very large populations of this species, as the males are not territorial and they feel comfortable in the company of others.
Adults can be observed flying from late April to late September.
