Golden-ringed dragonfly  (Cordulegaster boltonii)

This species is not threatened in much of its range. It is not listed under any conservation designations (3).

The golden-ringed dragonfly is one of Britain’s largest dragonflies, and is the only member of the genusCordulegaster in the country (3). Both the thorax and abdomen are black with bright yellow bands (3), the legs are black with yellow bases (2) and the abdomen is swollen towards the tip (3). The large green eyes meet in a point at the top of the head. Females can be identified by the presence of a long pointed ovipositor at the tip of the abdomen (3). As with other dragonflies, the large wings are held outstretched when at rest, not folded back over the body as in damselflies (4). The large aquatic larva is hairy, and spends most of its life partially buried in the sediment with just the eyes and tip of the abdomen visible. The short head has prominent eyes, and in common with other dragonfly larvae it is armed with fearsome mouthparts (2).

Common in southern, western and northern England, Wales and Scotland. It becomes rare or even absent in parts of eastern England, the Midlands, eastern Scotland and Ireland. Elsewhere this species is found in central and northern Europe (3) and extends through Asia Minor to India (4).

This dragonfly is found in heathland and moorland habitats. The larvae inhabit small streams that are typically less than 2m wide and overhung with vegetation. They are not found in still water (3).

Larvae live partially buried in the sediment, waiting for suitable prey to pass by, which they then ambush. Their development can take as long as 2-5 years, being slower in colder waters (5). They undergo several moults during their development, which allows them to grow (3). These aggressive ambush predators feed on insect larvae, snails, tadpoles and even small fish (3).

When fully developed and metamorphosis has taken place, the larva crawls up bankside vegetation and the adult stage emerges, leaving the shed ‘skin’ of the larval form, known as an ‘exuvia’, behind on the vegetation (3). Emergence usually takes place at night in order to reduce the high risk of predation (3). Occasionally, larvae may crawl quite a distance away from the water before selecting an emergence site, and may even climb trees (2). The newly emerged adults, or ‘tenerals’ do not become sexually mature for around ten days (3). Like the larvae, the adults are also highly efficient and fearsome predators, feeding on large insects such as damselflies, other dragonflies, wasps, beetles and bumblebees. They are fast, agile and powerful flyers (4) and can be seen on the wing from late May to September (3).

Although adult males do not defend exclusive territories, they do react aggressively towards other males that they encounter. They patrol lengths of breeding streams at just a few centimetres above the water (3). When a female is encountered the male will grab her thorax from above with his legs (2) and then manoeuvre so that the he holds her behind her head with claspers located at the tip of his abdomen. At this point the pair is said to be ‘in tandem’ and the male will fly with the female in this position to perch amongst vegetation, where copulation takes place (3).

Females lay their eggs alone, typically in the morning (3). The eggs are laid into the sediment of the stream, and the female hovers vertically over the water thrusting her ovipositor downwards into the sediment with a stabbing motion (5) that has been likened to the action of a pneumatic drill (3). The eggs hatch after a few weeks (3).

This species is not threatened.

Conservation action has not been targeted at this widespread species.

For more on dragonflies and their conservation see: The British Dragonfly Society:
http://www.dragonflysoc.org.uk/

• Abdomen: in arthropods (crustaceans, insects and arachnids) the abdomen is the hind region of the body, which is usually segmented to a degree (but not visibly in most spiders). In crustacea (e.g. crabs) some of the limbs attach to the abdomen; in insects the limbs are attached to the thorax (the part of the body nearest to the head) and not the abdomen. In vertebrates the abdomen is the part of the body that contains the internal organs (except the heart and lungs).
• Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
• Larva; larvae: stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
• Larval: of the stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
• Metamorphosis: an abrupt physical change from the larval to the adult form.
• Ovipositor: egg-laying organ in female insects consisting of outgrowths of the abdomen (the hind region of the body in insects). The stinging organ and poison sac of worker bees and non-reproductive female wasps is a modified ovipositor.
• Thorax: part of the body located near the head in animals. In insects, the three segments between the head and the abdomen, each of which has a pair of legs.

1. National Biodiversity Network Species Dictionary (September 2003): http://www.nhm.ac.uk/nbn/
2. McGeeney, A. (1986) A complete guide to British dragonflies. Jonathan Cape Ltd, London.
3. Brooks, S. (1997) Field guide to the dragonflies and damselflies of Great Britain and Ireland. British Wildlife Publishing, Hook.
4. Silverside, A.J. (2003). Biodiversity reference- University of Paisley. Golden-ringed dragonfly (December 2003): http://www-biol.paisley.ac.uk/bioref/Animalia_inverts/Cordulegaster_boltonii.html
5. Centre for Ecology and Hydrology- Atlas of the dragonflies of Britain and Ireland (December 2003): www.brc.ac.uk/brc_spp_acc/dragon/NBNSYS0000005621.htm