Large Red Damselfly

Pyrrhosoma nymphula (Sulzer, 1776)

Family: Coenagrionidae - Narrow-winged Damselflies

Order: Odonata (Zygoptera) - Damselflies

Class: Insecta

Phylum: Arthropoda

Kingdom: Animalia

Red List status: Least Concern

Total length: 33-36 mm

Abdomen length: 25-30 mm

Hindwing length: 19-24 mm

Larval body length: 13-14 mm

Caudal lamellae length: 4-6 mm

Other common names: Large red damsel

DESCRIPTION

Adult:  Both sexes of this damselfly are distinctive by their red colouration; all but the final abdominal segments are entirely red except for a narrow black 'ring' at the tip, while the final three segments are mostly black dorsally. The thick antehumeral stripes are red in mature individuals, yellow in immatures, and are broken so that they resemble exclamation marks (!). Uniquely among European damselflies, the humeral suture runs through (rather than below) this stripe in Pyrrhosomna species. The first abdominal segment and the base of the thorax are yellow-green. The legs are black. There is a thin red border to the pronotum. Females broadly resemble males, but can be distinguished by the presence of a narrow yellow ring around the tip of each abdominal segment. A thin black line runs down the centre of the abdomen, and a thicker black mark occurs dorsally on each red abdominal segment.

.

Large red damselfly female
Details of the antehumeral stripes

Larva: Short and rather squat in comparison with 'typical' small damselfly larvae. This appearance is due to extended wing sheaths, which reach almost to abdominal section 6. The head is squarish, with a straight line forming its rear margin. Two dark bands are present on the femur. Larvae have broad, strongly pointed lamellae with characteristic dark markings, often taking the form of an 'X'. Colouration is dark, typically brownish, although this may result from staining  In contrast to many species, large red damselfly larvae can typically be identified in all stages of development, not simply the final instar.

Large red damselfly tandem illustrating sex differences in dorsal pattern.

Similar species: Throughout most of Europe, the large red damselfly's colour and early emergence distinguish it from most co-occurring species. Small red damselflies (Ceriagrion species) have reddish-brown legs and pterostigma (the pterostigma is greyish in the large red damselfly). Dragonflies (e.g. Sympetrum species) are more robust, have a characteristic wings-splayed resting posture, hindwings larger than forewings, and eyes that make contact over the top of the head (as opposed to the broadly separated eyes of damselflies). Large red damselflies potentially co-occur with the poorly-known Greek red damsel (P. elisabethae) in parts of the Balkans. This species cannot be distinguished in flight, but captured males can be separated by the dissimilar anal appendages. In P. nymphula, the upper and lower appendages are of equal length, with a hook below the upper appendages extending almost to their tip. In P. elisabethae, the lower appendages are always slightly longer than the upper, and the hook is retracted almost to the base of the upper appendages. Female Greek red damselflies have two prominent ridges to the rear of the pronotum, visible in profile and dorsal view; these are much reduced in large red damselfly females.

The larval caudal lamellae are distinctive and allow reliable differentiation from species in other genera. Where lamellae have been lost (commonly in exuvia), the banding on the legs and, most importantly, the straight rear margin of the head are diagnostic. This latter feature can be used to distinguish the large red and small red damselflies, which (apart from the caudal lamellae) are otherwise similar, as the small red damselfly has a shallowly concave margin to the head. The small red damselfly also has a very much more restricted distribution, being found primarily in highly acidic waters, although where they occur both species are commonly present.

HABITAT

Variable. Animals reach their highest densities in late-successional standing waters with dense vegetation and plentiful debris to act as shelter and foraging habitats for larvae; however populations in eastern Europe exhibit a preference for stream habitats. The species is able to colonise acidic habitats, such as Sphagnum bogs.

 

BEHAVIOUR

Adult males are non-territorial, but can behave aggressively towards other damselflies, behaviour which includes attempts to physically force an opponent into the water or ground. Most aggression is directed towards members of the same species, but small red damselflies (which have a similar appearance) may also be victims.

Larvae are 'cryptic claspers', concealing themselves from predators by remaining fixed to debris and vegetation that acts as camouflage, a strategy which appears to defend them effectively against fish (Corbet & Brooks, 2008). They may also 'play dead' when disturbed in an effort to avoid predation.

Larvae are ambush predators and appear to adopt a conservative feeding strategy, expending little energy in pursuit of prey but limiting their potential food intake. They exhibit a range of territorial behaviours when faced with conspecifics, including jabbing the caudal lamellae at competitors and engaging in 'staring contests' until one animal withdraws.

Diet: Dragonflies are typically opportunistic predators at all stages of the life cycle, and P. nymphula is known to eat a wide variety of prey items in the larval stages. Prey items include crustaceans as small as 0.8 mm, and animals prey on progressively larger organisms as they develop, including worms, larger crustaceans and a range of insect larvae, although predation on members of the same species is rare.

Breeding behaviour: Male large red damselflies identify suitable females visually, based on the colour of the abdomen (Corbet & Brooks, 1980). This species oviposits in tandem, selecting suitable oviposition sites by the shape of plant leaf margins (Corbet & Brooks, 2008). Males guard the females by adopting an upright 'sentinel' position to keep watch for predators while eggs are being deposited. Groups of tandem pairs will often oviposit in the same location, attracted to the presence of ovipositing pairs already at the site.

Emergence: From as early as the beginning of April to mid-August, occasionally to late August. Most emergences take place in early- and mid-May, and animals emerge low down on bankside and emergent vegetation. Emergence is often synchronised so that large numbers of new adults take to the wing at once.

Flight season: From April until August, with a peak between May and June. Southern populations may be on the wing up to several weeks earlier. In Germany, the flight season begins as much as a month earlier than it did in the 1980s due to rising temperatures; this effect is stronger for P. nymphula than for other northern European species (Corbet & Brooks, 2008).

 

BIOLOGY

The large red damselfly is highly efficient at extracting energy from its diet, absorbing almost 90% of available energy from food items (Lawton, 1971).

Although dragonflies are primarily visual animals, P. nymphula has been found to respond to chemical traces left by predators, foraging less when chemical signals of a predatory dragonfly larva is detected (Corbet & Brooks, 2008).

Life cycle: The large red damselfly is semivoltine, taking two years to complete larval development, developing to a late larval stage in its first year and overwintering prior to emergence. This long developmental period is associated with a low rate of larval survival; as few as 0.2% of larvae may complete development in fish-free ponds (Lawton, 1970). Maturation takes 9-15 days to complete, and adults may live for a further 40 days or more (with males exhibiting greater average lifespans than females).

 

TAXONOMY

Several forms have been distinguished based on female patterning, but variation in this species is poorly-known. The typical form, described above includes populations known as typica and intermedia; others are characterised by females with less (form fulvipes) or more (form melanotum) black dorsal patterning. fulvipes form females also exhibit a black hind margin to the pronotum, while melanotum females have yellow (never red in mature specimens) antehumeral stripes and may altogether lack red colouration on most of the abdomen.

 

STATUS

Common throughout much of its range, but localised in much of the south.

 

REFERENCES

 

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

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

Lawton, J.H. 1970 A population study on larvae of the damselfly Pyrrhosoma nymphula (Sulzer) (Odonata: Zygoptera) Hydrobiologia 36: 33-52

Lawton, J.H. 1971 Ecological energetics studies on larvae of the damselfly Pyrrhosoma nymphula (Sulzer) (Odonata: Zygoptera) Journal of Animal Ecology 40: 385-423

Pyrrhosoma nymphula male, Buckinghamshire, UK. Note the position of the antehumeral stripe, crossing the humeral suture.

Male large red damselfly. Epping Forest, Essex, UK.

RANGE

Throughout Europe east to Finland in the north and the Urals in the south. The species has not been recorded from Ukraine, and only in isolated areas of Romania, but is likely to be widespread in this region. It is absent from northern Scandinavia and much of southern Iberia, although isolated populations occur in Morocco. 

Range        Description        Habitat        Behaviour        Biology        Taxonomy        Status        References