Beautiful demoiselle
Calopteryx virgo
— Where the name comes from
Calopteryx is “beautiful-winged”, from kalós and ptéryx, and it is one of the few times a naturalist confined himself to saying that the animal was beautiful. Virgo, the maiden, continues in the same key. The English name demoiselle distinguishes the damselflies from true dragonflies: they are slighter, they hold their wings closed above the body when they settle, and they fly as though fluttering.
— Facts
- Group
- Insects · Insecta
- Order
- Dragonflies
- Habitat
- Clean, shaded, fast-flowing streams and rivers
- Range
- Europe and western Asia
- Size
- 4.5–5 cm long
- Diet
- Small insects caught in flight
- Lifespan
- 2 years as a nymph, a few weeks as an adult
— Characteristics
- 01
The male’s wings are wholly blue-black; the female’s bronze.
- 02
The flight is slow and fluttering, almost like a butterfly’s.
- 03
The nymph lives two years among submerged roots.
— What sets it apart
The male holds a stretch of stream and defends it, but courtship is not a battle: when a female arrives he performs a display flight in which he opens and closes his wings, showing the metallic blue against the shade of the bank, and then leads her to the spot where she can lay. The quality of that spot is what she judges. The colour of the wings is not pigment but structure, as in the feathers of iridescent beetles, and its intensity changes with the angle: as he moves, the male modulates its brilliance — a signal that switches on and off at will.
