Here’s a full scientific and natural history overview of the Beautiful Demoiselle (Calopteryx virgo), one of Europe’s most elegant damselflies, known for its metallic shimmer and graceful flight over clear forest streams.
🩵 Beautiful Demoiselle (Calopteryx virgo)
Taxonomy
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Insecta
- Order: Odonata (Dragonflies and Damselflies)
- Family: Calopterygidae (Broad-winged damselflies)
- Genus: Calopteryx
- Species: C. virgo
General Description
The Beautiful Demoiselle is a large, broad-winged damselfly with a metallic, iridescent body that glows in sunlight. It is one of Europe’s most striking Odonates, often seen fluttering like a butterfly along forested streams and rivers.
- Body length: 45–49 mm
- Wingspan: 60–70 mm
- Male: Metallic blue or blue-green body, with deeply colored, dark blue wings.
- Female: Metallic green or bronze body, with translucent greenish-brown wings that have a white pseudostigma (spot near the tip).
- Both sexes exhibit a beautiful metallic sheen that changes hue depending on light and angle.
Distribution
The Beautiful Demoiselle is widely distributed across:
- Europe: From Ireland and Portugal eastward through Central and Northern Europe to the Balkans and the Ural Mountains.
- Asia: Extends into western Siberia, the Caucasus, and parts of the Middle East.
- Prefers temperate regions and is more common in western and northern Europe than its close relative, the Banded Demoiselle (Calopteryx splendens).
Habitat
- Found along clean, fast-flowing rivers and streams, especially those with gravel or rocky beds and wooded banks.
- Favors shaded, unpolluted watercourses in hilly or forested areas.
- Avoids still or stagnant water.
- Presence is a good indicator of high water quality.
Behavior and Ecology
- Flight period: May to September (varies with climate).
- Activity: Diurnal; males are territorial and defend stretches of streamside vegetation.
- Flight: Fluttering and butterfly-like, often hovering gracefully above the water.
- Resting: Commonly seen perched on leaves or twigs near water.
- Diet:
- Adults feed on small flying insects, such as midges and mosquitoes.
- Larvae (naiads) are aquatic predators, feeding on insect larvae, worms, and small crustaceans.
Reproduction
- Courtship: One of the most elaborate among damselflies:
- The male displays his metallic body and flutters around the female in a characteristic “butterfly dance.”
- If accepted, the pair forms the tandem position for mating.
- Egg-laying (oviposition):
- The female inserts eggs into submerged plant stems or soft vegetation just below the water surface.
- She often remains underwater for several minutes while doing so.
- Larval stage:
- Lasts up to two years, depending on temperature and conditions.
- Larvae live among submerged plants and stones, emerging in late spring or early summer to transform into adults.
Conservation Status
- IUCN Red List: 🟢 Least Concern
- Population trend: Stable across most of its range.
- Threats:
- Water pollution, siltation, and loss of clean streams.
- Deforestation and removal of riparian vegetation.
- Acts as a bioindicator species—its presence signals good freshwater ecosystem health.
Identification Tips
Feature | Male | Female |
---|---|---|
Body color | Metallic blue or blue-green | Metallic green or bronze |
Wing color | Uniform dark blue | Greenish-brown, translucent |
Wing spot (pseudostigma) | Absent | Present (white or yellowish) |
Behavior | Territorial, aggressive displays | Quieter, spends more time resting |
Ecological Role
- Controls populations of small flying insects.
- Serves as prey for birds, spiders, and amphibians.
- Its aquatic larvae help maintain balance in stream ecosystems by preying on smaller invertebrates.
Interesting Facts
- The metallic blue and green coloration is not due to pigment, but structural iridescence, caused by light scattering from microscopic scales.
- Males often return to the same perch or territory day after day.
- Females can remain underwater for up to an hour while laying eggs—breathing through stored air around their bodies.
- The species’ presence is often used by ecologists to monitor water quality in conservation projects.
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