Species account

Large Redeye (Erythromma najas)    (Hansemann, 1823)
   Pond Damselflies (Coenagrionidae) [Dragonflies]    LARE    24791
Rødøjet Vandnymfe (dk)   Större Rödögonflickslända (se)  
Synonyms (common):
Red-eyed Damselfly (us)
Synonyms (scientific):
Agrion analis Vander Linden, 1825
Agrion chloridion Charpentier, 1825
Erythromma humerale Selys, 1887
Erythromma nigrithorax Förster, 1902
Erythromma bipunctatum Schimer, 1913
Erythromma immaculatum Schimer, 1913
Erythromma puellaris Schimer, 1913
Erythromma baicalense Belyshev, 1964
Measurements:
To 30-36mm Ab 25-30mm Hw 19-24mm
Generations:
Flight period:
JFMAMJJASOND 
SE
EU
Identification:
Similar species:
Life stages:
The mating takes place on floating water plants or in shore-close vegetation, and lasts ? minutes. In tandem the female inserts the eggs into water plants from the surface or up to half a meter below it (up to half an hour). Sometimes the male detach when she seeks deeper down to follow a good stem for egg-insertion. The eggs hatch after 4-5 weeks and the larvae live in-between water plants and develop during 1-2 years. The imago-transformation also takes place on floating plants or in vegetation close to the water.
Distribution:
Large part of Europe; absent Iberian peninsula and northern part of British isles and northern part of Scandinavian peninsula. Also Russia and Ukraine and patchily eastward through temperate Asia to E China and Japan. In Denmark seen in all regions.
Habitat:
Behavior:
Host plants:
Tusindblad (Myriophyllum)
Hornblad (Ceratophyllum)
Gul Åkande (Nuphar)
Vandaks (Potamogeton)
Endemic:
Comment:
Large Redeye 721    (1 photos)
2022-06-05    Søholt Storskov (Maribo), Denmark

Imago Male
Typical male.



Large Redeye 1574    (1 photos)
2023-06-07    Hästenäs Kyrkskog (Östergötland), Sweden

Imago Male




Large Redeye 1576    (1 photos)
2023-06-07    Valdemarsvik (Östergötland), Sweden

Imago Male
Young.



Large Redeye 2050    (1 photos)
2023-07-27    Skær Sø (Egtved), Denmark

Imago Male
Young



Large Redeye 2976    (2 photos)
2024-08-04    Amager Fælled, Denmark Map

Imago Male
DLK. Two animals.
The same kanal but apparently the two erythromma species fly in separate parts, at least at this time of the year.



Large Redeye 2975    (2 photos)
2024-08-15    Amager Fælled, Denmark Map

Imago Male
DLK. Two animals.
The main flight period is over, but you still find the larger of the two erythromma species flying - close to the smaller viridulum [Lille Rødøjet Vandnymfe], why details should be checked before naming them.

Notice the bluish marking low on S8 that superficially resembles a miniature version of the one seen on viridulum, but is still too insignificant; also the short greenish shoulder proximally on first animal is a feature of the young najas.



Large Redeye 3172    (2 photos)
2025-05-17    Holmegaards Mose, Denmark

Imago Male
Young.



Large Redeye 3173    (1 photos)
2025-05-17    Holmegaards Mose, Denmark

Imago Male
Young.



Large Redeye 3331    (3 photos)
2025-05-23    Lergravene (St. Magleby), Denmark

Imago Male
An unusual observation of this species on Amager - away from Kalvebod Fælled and particularly Amager Fælled.

Partly obscured, but the thorax without any sign of a shoulder stripe and the blue S10 without a dark X marking, eliminate viridulum [Lille Rødøjet Vandnymfe].



Large Redeye 3326    (1 photos)
2025-07-23    Amager Fælled, Denmark

Imago Male
DLK-nord.
The species is starting to show up in-between the vast majority of viridulum animals. Here with a good amount of parasitic mites on the abdomen.

I've noticed online that some people seem to get the separation of the two species wrong because they see the blue tap on S8 sticking up on the side. But that is not enough to call it a viridulum. On viridulum the black gap between the blue on S9 and S8 is narrow and deep, with the blue on S8 reaching well into the upper part of the segment. Of course the pattern on top of S10 is always a good way to separate the two males, with viridulum, even when young, showing the dark x on top of the segment.



Large Redeye 1575    (1 photos)
2023-06-07    Valdemarsvik (Östergötland), Sweden

Imago Female
Young.



Large Redeye 2781    (2 photos)
2024-05-09    Amager Fælled, Denmark

Imago Female
DLK-vest. Teneral.
No shoulder stripes on young individuals. Overall greenish look a good feature compared to similar-looking species, like ischnura species for example. My first this year, and only this one of the species this day.



Large Redeye 2733    (2 photos)
2024-06-04    Amager Fælled, Denmark

Imago Female
DLK øst.
Nice with a female without being attached to a male!

The shoulder line formed as an exclamation mark and the limited blue in between segments and at wing bases are good character compare to the smaller cousin [viridulum] - which is not on the wings yet, though! With mites as often seen on this species.
Large Redeye 3132    (3 photos)
2025-05-02    Amager Fælled, Denmark

Imago Female
Den landskabelige kanal - vest.
First appearance this year. 2 females. And a week earlier than last year.



Large Redeye 722    (1 photos)
2022-06-05    Søholt Storskov (Maribo), Denmark

Imago Male & Female
As you normally see the species, close to the water surface. Here several egg-laying tandems and a few unattached males.