# Banded demoiselle (Calopteryx splendens) > A metallic blue-green damselfly (male) with a distinctive dark band across each wing; found along slow-flowing rivers and streams across Europe and western Asia. Source: https://insectscanner.com/species/banded-demoiselle/ (updated 2026-10-10) ## Is it dangerous? **Non-toxic.** Banded demoiselles do not sting. They can nibble with mouthparts if handled but are harmless to people. No venom or significant medical risk; wash hands if you have handled aquatic plants or water to avoid minor contamination. **Pets:** Not dangerous to pets. They are small and would only be eaten accidentally; they do not carry diseases of concern to pets. ## Quick facts - Scientific name: Calopteryx splendens - Also called: Banded agrion - Order: Odonata (Dragonflies and damselflies) - Family: Calopterygidae (Broad-winged damselflies) - Size: Body length 45-48 mm, wingspan about 60-70 mm - Colours: Metallic blue-green, Dark wing band (blackish), Olive-brown (female), Pale wing patch (female) - Habitat: Slow-flowing rivers, streams, canals and their vegetated margins; prefers waters with submerged and marginal plants. - Range: Widespread across Europe and into western Asia; absent from the far north and some Mediterranean islands where conditions are unsuitable. - Active: Spring and summer, typically April to September depending on latitude; adults are diurnal and most active in sunny weather. - Lifespan: Adults usually live a few weeks; larvae take one to two years to develop and overwinter in the water. - Effect on plants: Harmless - Pest: no ## Overview Calopteryx splendens is a large, colourful damselfly in the family Calopterygidae. Males are metallic blue-green with a broad, dark band across the middle of each wing; females are metallic green and have translucent greenish wings without a dark band. They live and breed along slow-flowing rivers, streams and canals with plenty of aquatic vegetation. Adults are aerial predators of small flying insects; larvae are aquatic predators that live among submerged plants and sediments. They are common in much of Europe and parts of western Asia and are active in the warmer months. ## How to identify it Male banded demoiselles have a glossy metallic blue-green or turquoise body with a distinct broad, opaque dark band across the centre of each wing. The wing band usually leaves the wing bases and tips clear. Females are metallic green to bronze-green with translucent greenish-tinted wings that lack the dark band and carry a small white spot (pseudopterostigma) near each wingtip. Both sexes have long, broad wings compared with narrow-winged damselflies, and the body is relatively robust for a damselfly. - Males: metallic blue-green body with a broad, continuous dark band across the middle of each wing, leaving clearer tips. - Females: metallic green body with translucent greenish wings, no dark band, and a small white spot near each wingtip. - Broad wings held closed above the body at rest (typical damselfly posture) and larger, more robust form compared with narrow-winged damselflies. ## Lookalikes - **Beautiful demoiselle** (Calopteryx virgo): Male C. virgo usually has darker, more extensive wing coloration often covering most of the wing and a darker, bluer body; habitat often in shadier, faster-flowing streams. C. splendens usually has clearer wing tips and a slightly different wing band shape. - **Western demoiselle** (Calopteryx xanthostoma): Closely related; the male wing band extends right to the wingtip, whereas in C. splendens the tip is usually clear. Found mainly in Iberia, southern France and Italy. - **Emerald damselfly** (Lestes sponsa): Lestes spp. are slimmer, have clear wings and a different resting posture (often partly open); they lack the broad dark wing band of Calopteryx. ## Life cycle - **Egg:** Females lay eggs in or on aquatic plants and submerged stems; eggs develop over days to weeks depending on temperature. - **Nymph (nymph):** Aquatic nymphs live among submerged vegetation and detritus for many months, preying on other small aquatic invertebrates; they usually overwinter as larvae. - **Adult (imago):** Emergence from the final larval moult produces the winged adult. Adults fly, feed, defend territories, and mate; they live for several weeks to a few months. ## Diet and predators - Young eat: Small aquatic invertebrates such as insect larvae, crustaceans and other microfauna. - Adults eat: Small flying insects: midges, mosquitos, mayflies and other soft-bodied insects caught in flight. - Predators of the young: Fish, aquatic beetles, larger aquatic predators and some amphibians. - Predators of adults: Birds, spiders, larger dragonflies and other aerial predators; they may also be preyed on by bats at dusk. ## Effect on plants and gardens Larvae live among submerged and marginal plants but do not damage vegetation in a way that concerns gardeners; adults perch on stems and hunt near vegetation. ## Where and when to find it Adults: perching on emergent stems, low vegetation and overhanging branches beside slow rivers and streams. Larvae: among submerged plants and detritus in the same water bodies. - Best time: Best from late spring to late summer, during warm sunny weather and mid-morning to late afternoon when they are active. - Tips: Approach slowly and photograph from the bank or a hide; use a telephoto lens or macro to capture wing band details. Watching territorial males along stretches of stream is a reliable way to find them. ## Fun facts - Males perform conspicuous aerial displays and territory patrols to attract females and chase rivals. - The wing band is used in courtship and male-male interactions; its size and darkness can affect success in contests. - Larvae can spend a year or more underwater before emerging as adults. ## Frequently asked questions ### Are banded demoiselles harmful to people? No. They do not sting and are harmless. They are beneficial predators of nuisance insects like midges. ### Do banded demoiselles bite? They have mouthparts capable of a small nip, but they do not bite people as a defensive behaviour and bites are extremely rare and harmless. ### Why are banded demoiselles in my garden? If you have slow-flowing water, ponds or streams with plants nearby, the habitat is suitable for breeding and hunting, so adults will visit and perch on vegetation. ### How can I encourage banded demoiselles? Provide or restore slow-flowing water with areas of submerged and marginal plants, maintain unpolluted water, and leave vegetation along banks for perching and emergence. ### How do I tell a male from a female? Males are metallic blue-green with a solid dark wing band; females are metallic green with translucent greenish wings and a small white spot near each wingtip. ### When can I see banded demoiselles? Look on warm, sunny days from late spring to late summer (roughly April to September in much of Europe), especially near suitable water bodies. --- More about this species: [iNaturalist](https://www.inaturalist.org/taxa/51824), [Wikipedia](https://en.wikipedia.org/wiki/Banded_demoiselle). Identify insects and spiders from a photo with the Insect Scanner iPhone app: https://apps.apple.com/app/id1543946563?pt=126685406&ct=web-markdown&mt=8 Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.