Emerald Damselfly
Lestes sponsa
Tap image to enlarge · Wikimedia Commons
Overview
The Emerald Damselfly is distinctive in that it rests with its wings held partially open away from the body — unlike most damselflies which rest with wings folded over the back. It prefers dense rush and grass stands at dune slack margins and can often be found some distance from open water. The metallic green-bronze colour is beautiful. It's expanded dramatically across the Sefton Coast since 1990 — one of several Odonata species that have benefited from the dune slack habitat.
At a Glance
| Order | Odonata |
| Family | Lestidae |
| Habitat | Rush-bordered dune slack pool · Boggy dune slack · Pond with tall emergent vegetation |
| Diet | Small flying insects |
| UK population | Common in England; has expanded range significantly |
| Sefton Coast | Established across the Sefton Coast dune slack system since the 1990s; significantly expanded range |
| Conservation | UK Green List |
Where to See It
Dune slack pools with emergent Rush and grass at Ainsdale NNR. Typically rests away from the water's edge.
Identification
Metallic green-bronze damselfly. Unique resting posture — wings held open at 45–60 degrees (not closed over back like other damsels). Pale blue pruinescence on abdomen tip and thorax of mature males. Blue eyes.
Viewing & Photography Tips
Check rush beds around dune slack margins at Ainsdale in August. The open wing posture at rest is unmistakeable once you know it.
Conservation Status
UK Green List
This species has a favourable conservation status in the UK and remains an important part of Sefton Coast biodiversity.
Frequently Asked Questions
Why does the Emerald Damselfly hold its wings open at rest?
The Lestidae (Spread-winged Damselflies) hold their wings partially open at rest — this is the family characteristic that separates them from all other damselflies. The biological reason is not fully understood but may relate to thermoregulation — the open wing position may allow more efficient warming in cool conditions, or may be a display signal.
Related Species
Plan your visit to the Sefton Coast
Marshside RSPB, Formby pinewoods, Ainsdale NNR — practical guides to getting there, what to bring, and the best spots for each season.