The Red-eyed Damselfly – Erythromma najas, is a common sight in the region. One of two very similar red-eyed damselfly species, positive identification needs care.
|Coenagrionidae||Blue or red Damselflies|
The male’s distinctive red eyes, dark abdomen with its prominent blue ‘tail-light’ on segments 9 and 10, make it easy to separate from all other damselflies except the Small Red-eyed Damselfly – Erythromma viridulum. The upper surface of the thorax is black and there is no shoulder stripe.
The female is green and black without a tail-light and has duller brownish red eyes. Shoulder stripe is narrow and incomplete.
Stronger flier, with proportionately larger wings than other blue damselflies.
The most similar species is the Small Red-eyed Damselfly – Erythromma viridulum, and the differences are summarised below:
|Feature||Red-Eyed Damselfly – |
|Small Red-Eyed Damselfly – |
|Abdomen||Features a grey pruinescence||Glossy black, no pruinescence|
|Segments||1, 9 & 10 blue, the rest are black||2, 3 & 8 also (mostly) blue. 10 features a black ‘X’ marking seen from above|
|Wings||Wings extend to S8||Wings extend to S7|
|Legs||All black||Black with subtle blue stripe|
|Eyes||Blood red||Paler red, tomato-like|
|Flight period||May – September||July – September|
For other blue damselflies in the region, the obvious distinction is the red eyes of the male, and the generally dark abdomen in both the male and the female. Other things to look out for are noted below.
Similar to the Small Red-eyed Damselfly – Erythromma viridulum, and favours still waters, large ponds, lakes, gravel pits and slow rivers, especially where there is floating vegetation – they are often seen on water lilies or floating mats of algae.
Common throughout the county, particularly along the River Great Ouse. They are abundant at Felmersham NR.
Visible from May to September, peaking in June.