Banded Demoiselle

 

Calopteryx splendens (Harris, 1782)

Family: Calopterygidae - Demoiselles

Order: Odonata (Zygoptera) - Damselflies

Class: Insecta

Phylum: Arthropoda

Kingdom: Animalia

Red List status: Least Concern

Total length: 45-48 mm

Abdomen length: 33-41 mm

Hindwing length: 27-36 mm

Larval body length: 18-24 mm

Caudal lamellae length: 9-14 mm

 

DESCRIPTION

Adult: A distinctive large, long-legged, metallic damselfly with broad wings lacking an elongated ‘stem’. Males are characterised by a blue-green body, metallic blue wing venation and a wide, dark band across each wing; this band is only rarely absent, although its extent varies with age (being less extensive in immature specimens) and geographical region. The underside of the male abdomen has a bright yellow to white ‘tail light’ (eighth abdominal segment). Females are green to bronze, typically with clear metallic-veined wings. Males lack a pterostigma; in females a white pseudopterostigma is present, distinguishable from a true pterostigma by the presence of veins running across the cell. Occasional females exhibit male wing patterning, but can be distinguished by the presence of the pseudopterostigma.

Male banded demoiselle.

Larva: Larval demoiselles are larger and more slender than other damselfly larvae, with long, spider-like legs. The antennae are long, with the first segment comprising over 50% of antennal length. A deep groove runs along the centre of the frontal portion of the labium. As in all damselfly larvae, three caudal lamellae are present; these are narrow, and the central lamella is shorter than the outer two. Two pale vertical bands are typically present on the lamellae.

Similar species: Metallic species of Lestes have narrower, unmarked wings with an elongate stem, and less extensive venation. Other co-occurring damselflies lack metallic colouration. Similarly-sized metallic dragonflies (Cordulidae) have more robust bodies, unbanded wings with dark pterostigma, and have hindwings that are larger than the forewings (equal size in damselflies).

Among European demoiselles, C. splendens only commonly co-occurs with the beautiful demoiselle (C. virgo). This species is larger and darker than C. splendens, with wings that are broader and almost entirely dark blue in males. C. virgo males have a reddish, rather than a white or yellow, tail-light. Females can most reliably be distinguished by association with males of a particular species, but may be larger and with darker brown wings than in C. splendens. In contrast with western demoiselle (C. xanthostoma), the bands on the male wing do not extend to the wing tip in the banded demoiselle.  C. splendens has black legs; those of glittering demoiselle (C. exul) are dark brown. Male copper demoiselle (C. haemorrhoidalis) are much redder in colour; females have a banded tip to the hindwing and pale lines across the thorax.

Other damselfly larvae are typically smaller and squatter, with shorter legs and antennae. C. virgo larvae favour faster-flowing waters with a rockier substrate. Where both species occur together the beautiful demoiselle can be distinguished by the possession of a distinct, pointed ‘tooth’ projecting like a horn behind each eye (present but rounded and indistinct in C. splendens). Additionally, this species has only a single pale band marking the lamellae rather than two, and the first antennal segment is equal in length to the rest of the antenna (longer in C. splendens).

HABITAT

A species of flowing waters, being the most common riverine odonate in Europe. Adults prefer small streams and rivers with partial vegetation cover, avoiding both deep shade and open water. The banded demoiselle is widespread wherever waterways occur, but is absent from high mountains, cold torrents and often from larger rivers. Males may wander far from suitable habitat. Populations may also occur in lakes adjacent to rivers. The species appears to prefer areas with tall riverside vegetation and few bankside trees (Ward & Mill, 2005).

Reproductive habitat: Banded demoiselles breed only in slow-flowing rivers and streams. The larval habitat is characterised by accumulated mud and silt, often associated with emergent and overhanging vegetation.

 

BEHAVIOUR

These damselflies fly slowly with a distinctive, butterfly-like motion. Individuals gather in large numbers along the edges of water ways, and commonly roost communally. Males defend small territories near potential oviposition sites, such as submerged vegetation, and may hold a single territory for ten days or more. Males exhibit several forms of aggressive display and chase behaviour (Corbet & Brooks, 2008).

Larvae use their long caudal lamellae in displays of aggression or defence, using them to jab competitors or potential predators.

Breeding behaviour:, Males court females with fluttering aerial displays that highlight their coloured wings and tail-lights. Individuals intermittently land on the water surface during courtship dances. Animals without territories may secure females without courtship, and appear to exhibit several strategies for doing so - for instance by grabbing or pursuing passing females (they have even been known to pursue females underwater). An individual may adopt a different strategy on separate occasions.

Following copulation, which lasts up to five minutes (a long period for an odonate), a male will guard the ovipositing female without making contact with her. Females lay eggs directly into emergent vegetation

Emergence: The peak period for larval emergence takes place between late May and early June, but larvae may emerge at any point between early May and the end of September.

Flight season: May to August in northern areas; from late April to October in southern parts of the range.

 

BIOLOGY

Life cycle: Once laid, eggs take around 14 days to hatch. Larvae take two years to complete development. Adults can be extremely long-lived for odonates, surviving up to 80 days following emergence in captivity.

 

TAXONOMY

Numerous subspecies have been erected to describe regional variation in C. splendens, but the extent of hybridisation and within-population variation renders the validity of these uncertain (Dijkstra & Lewington, 2006). These divisions are based on the extent and colouration of the wing band in different regions. C. s. intermedia in Turkey is further distinguished by the proportion of androchrome females (those with male wing patterning), with some populations having only androchrome females. The western (C. xanthostoma) and glittering (C. exul) demoiselles are sometimes considered the most distinctive subspecies of C. splendens rather than full species.

 

STATUS

The banded demoiselle is widespread, often very numerous and with an extensive range, justifying its conservation status as Least Concern. Nevertheless, it may be vulnerable to pollution of waterways and to habitat loss, and trends in overall population size are unknown. In some areas, habitat restoration and population monitoring of this species are underway (Clausnitzer, 2007).

 

REFERENCES

 

British Dragonfly Society Calopteryx splendens – Banded Demoiselle

Cham, S. 2009 Field Guide to the larvae and exuviae of British Dragonflies Volume 2: Damselflies (Zygoptera) The British Dragonfly Society: 76 pp.

Corbet, P. and Brooks, S. 2008 Dragonflies New Naturalist Series 106, Harper-Collins, London: 456pp

Clausnitzer, V. 2007. Calopteryx splendens. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2

Dijkstra, K-D.B. and Lewington, R. 2006 Field Guide to the Dragonflies of Britain and Europe British Wildlife Publishing: 320 pp

Ward, L. and Mill, P.J. 2005 Habitat factors influencing the presence of adult Calopteryx splendens (Odonata: Zygoptera). European Journal of Entomology 102: 47-51

Male Calopteryx splendens. Note the dark band, not extending to the wing tip, the broad wing bases and the dense, metallic venation to the wingd.

Banded demoiselle female, Buckinghamshire, UK

RANGE

From southern France through temperate Europe and Asia east to northwest China and Lake Baikal, Siberia. The species is absent from northern England, Scotland, and areas of Scandinavia at similar latitudes. It is absent from the northern Alps and the Carpathian Mountains. Calopteryx splendens is abundant throughout most of its range, but occurs as an uncommon resident in Sicily.

Range        Description        Habitat        Behaviour        Biology        Taxonomy        Status        References