No.038 · Butterflies, moths and other insects · Uncommon
Beautiful demoiselle
Calopteryx virgo
A big damselfly of fast, clean streams. The male's body and wings shine metallic blue-purple, and the wings flutter like a butterfly's.
When to look
June to August, mostly at day.
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Time of day
- Dawn
- Day
- Dusk
- Night
- Best time
- Sunny days from June to the end of August (New Forest National Park Authority), beside clean, fast, gravelly streams. Across Britain the flight season is roughly May–August.
- Where in the game
- the New Forest (stream)
- Size
- Length about 45 mm
- Lifespan
- Adults live a few weeks in summer; the larvae live in the stream
- Population
- Widespread across Wales and south-west England, with scattered populations in northern England and western Scotland (British Dragonfly Society); common along most New Forest streams (New Forest National Park Authority)
- Status
- Common and widespread on New Forest streams; very sensitive to pollution (New Forest National Park Authority)
Diet
Small flying insects, caught on the wing.
Habitat
Fast-flowing, clean streams and small rivers with gravel or sand beds and bankside plants.
Breeding
Females lay eggs into plant stems in the stream; the aquatic larvae develop in the stream.
Field signs
- Fluttering, butterfly-like flight low over the stream
- Male's iridescent blue-green body and dark wings
- Females with brown-green body and translucent wings
- Males perched on riverside plants
Did you know?
- Its flight is more like a butterfly's than most damselflies, fluttering on broad wings (British Dragonfly Society).
- The male's metallic wings look black until the sun catches the blue.
- It is very sensitive to pollution, breeding only in clean, fast-flowing streams with stony or gravelly bottoms (New Forest National Park Authority).
Moments worth waiting for
- Male display
A male flashes his blue wings over a riffle, guarding his patch of stream from rivals.
Photo tip
Wade no further than the bank. In midday sun, find a shaded stream bank where males perch on rushes. Use a 100 mm macro or 300 mm lens and shoot from a low crouch; approach in slow steps.
Be a good naturalist
Do not net or handle them; the wings are fragile. Stay on the bank so you don't trample breeding vegetation, and keep clear of gravel beds where larvae live. Do not disturb the streambed.
The law
No specific legal protection, but clean streams are protected as habitat.