St Nicks

Centre for nature and green living

July 2016: Spotlight on.. Dragonflies

Azure Damselfly (male)

Azure Damselfly (male)

The dragonfly is one of the truly charismatic insects – colourful, darting, elusive, captivating and possessing amazing aerobatic skills. Almost any water body will attract them – ponds, lakes, streams, rivers, rock pools, estuaries, peat bogs, waterfalls, puddles. Their evocative family names beautifully describe their brief lives: skimmers, darters, hawkers, chasers.

Most adult dragonflies live for only a few weeks, but to get there takes up to two years as underwater larvae (five in the case of the Golden-Ringed Dragonfly), during which time these fierce predatory creatures feed on tadpoles, small fish and other larvae (including their own kind), shedding their skins up to 15 times as they grow. Finally they are ready to climb out of the water and up a stem, struggling to emerge from their final larval skin before taking to the sky, utterly transformed into beautiful adult dragonflies or damselflies.

Life is more dangerous for them out of the water. When they first emerge their bodies are soft and their wings look glassy and vulnerable. At this stage they are described as teneral, a condition lasting a week or two. So, as soon as they can, newly-emerged dragonflies fly high and away from the bustle and danger of the lake or river to harden up in a quiet place where they will be undisturbed. Dragonfly and damselfly sightings at St Nicks are frequently out on the reserve as well as at the Environment Centre pond and along the becks.

The order Odonata includes both Anisoptera (dragonflies) and Zygoptera (damselflies) but both come under the umbrella of the name dragonfly. The world contains some 5,300 species of Odonata but only 38 of these breed in Britain and Ireland. As a general rule (sometimes broken) dragonflies rest or perch with their two pairs of wings wide open while damselflies fold their wings along their abdomens or hold them partially open.

Clockwise from top left: Common Darter (head); Common Darter (male); Large Red Damselfly; Southern Hawker

Clockwise from top left: Common Darter (head); Common Darter (male); Large Red Damselfly; Southern Hawker

When you see a dragonfly or damselfly at rest the huge eyes in relation to the rest of the body are immediately obvious, surrounding or dominating the head. In dragonflies the eyes wrap around the top and side of the head, while damselfly eyes are like large dumbells at each side of the head. These are compound eyes and can see forward, sideways, backwards, upwards and downwards. Each eye contains up to 20,000 tiny lenses, many of which can be seen in the close-up picture of the head of a Common Darter dragonfly shown above.

Common Darters mating

Common Darters mating

Easily the most frequent species seen at St Nicks are the Azure Damselfly (May to early July) and Common Darter Dragonfly (mid-June to late September). Azure males are a gleaming bright blue colour, while Common Darter males are an attractive red (females are pale yellow-green). The picture on the right shows Common Darters mating in typical ‘wheel’ position. Mating can take up to half-an-hour. The females of both species lay their eggs in tandem with the male, who grasps and supports her as she dips her ovipositor into the water to place individual eggs on submerged plant material. Azure damselfly eggs hatch in a few weeks and the larvae take one year (in the south) or two years (in the north) to mature, going through 10 moults. After emergence it can be up to two weeks before Azure adults are ready to mate, and after mating they live for only about a week longer. Common Darter eggs hatch in a few days, or if late in the season it will be the following spring. Their larvae usually take a year to mature, and the adults are around for longer, sometimes being seen as late as November.

The range of dragonflies seen at St Nicks is not large. Of the damselflies the first to appear is usually the Large Red, followed by Azure, Common Blue, Blue-tailed and Emerald. In 2015 we also saw Banded Demoiselle and, with some surprise, a single Beautiful Demoiselle which is a southern and western species in the UK, breeding on fast sandy-bottomed acidic rivers and streams – which we definitely don’t have at St Nicks! There are a few scattered colonies in the North York Moors National Park and in the Vale of Pickering.

Dragonflies seen at St Nicks include Common Darter, Migrant Hawker, Southern Hawker, Brown Hawker, Broad-bodied Chaser, and Emperor.

All the photos above were taken at St Nicks.

26 July 2016 | Categories: Spotlight on... | Tags: common darter, damselflies, dragonflies, Large Red Damselfly, Southern Hawker