The Downy Emerald Dragonfly is one of three similar species that are still found in Britain, the other two being Somatochlora metallica, the Brilliant Emerald, and Somatochlora arctica, the Northern Emerald.
Male and female are similar in appearance and colouring, but the female has a fatter, unwaisted body. (An immature male is shown here; at maturity its eyes will become apple green, as indeed also do those of the female.)
When mature, this dragonfly is distinguished by its bright green eyes, very downy green thorax and dark greenish-bronze abdomen. The male has a slightly waisted and club-shaped abdomen. Typical wingspan is 6.8cm and the overall length around 4.8cm.
A fast-flying dragonfly of canals, ponds and lakes with emergent vegetation, the Southern hawker occurs in scattered populations throughout England, Scotland and Wales, but only in the southeast of England is it at all common. There it is still able to find plenty of the kind of habitat it needs: stillwater with mature deciduous trees nearby. In Britain the flight period of the Downy Emerald is from the middle of May until the end of July and occasionally well into August. On the mainland of Europe the Downy Emerald occurs in all central and most northern countries, its range extending from western France across into Asia, although in southern European countries the Downy Emerald is restricted to the cooler mountainous areas.
After emerging from their eggs, larvae or nymphs (sometimes referred to as naiads) of the Downy Emerald live in the water for three years before emerging on plant stems; there they shed their final nymphal skin or shuck (called an exuvia), dry their wings and then take flight. Winged adults feed on smaller insects and can live for about up to two months. The males patrol along lakeside margins until they find and seize a female with which to mate, and then the females deposit their eggs onto the surface of the water in weedy margins.