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Dragonflies of Irish Bogs

Imagine you're on a bog in early summer. It is a warm still day. You hear a loud rustling of wings coming from the edge of a pond. Looking around for the source you see a large blue-spotted insect slowly weaving through the upright stems of the aquatic plants - a dragonfly. Then above the pond you see two more dragonflies. This time stocky brown insects which appear to be fighting in mid air. They engage briefly before one hurriedly departs, leaving the apparent victor behind, now perched on a stout stem. On closer inspection you see some smaller more delicate insects close to the edge of the pond - damselflies. These are flying more sedately than the dragonflies, and the sunlight picks out the fiery red colour of the body.

	A female Four-spotted Chaser Libellula quadrimaculata. Photo: Brian Nelson
	A male Northern Emerald Somatochlora arctica. Photo: Brian Nelson
	An immature male Black Darter Sympetrum danae. Photo: Brian Nelson

It comes as a surprise to many people that the scene described is not uncommon in Ireland. It is probably true that dragonflies can be seen on any body of still water below 300m. Adult dragonflies are insects of summer living for a few weeks. Most of the insect's lifecycle is spent as an aquatic larva and this can last as long as four years. So it is the conditions the larva need which determine where the species will be found. Bogs and fens are amongst the best places for these insects in Ireland, supporting both large numbers of species including some of the rarest Irish species and large populations of individual species. This is because the conditions found on our surviving bogs and fens satisfy many of the ecological requirements of dragonflies including sheltered ponds with water unaffected by enrichment in which the larvae will live, with few if any fish, these being significant predators of dragonfly larvae. Adult dragonflies require good feeding areas so sites with additional habitats such as woodland, scrub or unimproved grassland and wetland vegetation close to breeding sites will support the strongest dragonfly populations.

The Black Darter Sympetrum danae is one species which is very typical of bogs. It breeds in shallow acid pools and small lakes, on raised and blanket bogs. Black Darters can be seen from mid July well into October. Newly emerged adults are a beautiful golden-yellow which match the colour of Bog Asphodel flowers. With time the male becomes all black but females retain the yellow colour. Other dragonflies common on bogs include the Large Red Damselfly Pyrrhosoma nymphula (instantly recognised as it is the only red damselfly in Ireland), the Four-spotted Chaser Libellula quadrimaculata and Common Hawker Aeshna juncea which is one of the largest Irish species. These four species are the characteristic dragonflies of our intact bogs. On hand cutover bogs, the network of flooded peat cuttings created provide some of the best dragonfly habitat in Ireland. The pools on these sites are more productive than those on intact bog and additional species can coexist with the bogland species. The fauna resembles that found in natural fens. Typical species in these sites include the Hairy Dragonfly Brachytron pratense, Ruddy Darter Sympetrum sanguineum and Variable Damselfly Coenagrion pulchellum. On a few sites the rare Irish Damselfly Coenagrion lunulatum can be seen.

	Dragonfly Habitat: flushes and wet heath vegetation on the western edge of the Mourne Mountains Co. Down. Photo: Brian Nelson
	A male Large Red Damselfly Pyrrhosoma nymphula the only red species found in Ireland. Photo: Brian Nelson
	A male Common Hawker Aeshna juncea. Photo: Brian Nelson

With the loss of intact and cutover bogs and fens, our dragonfly species are undoubtedly in decline. Two species in particular are of concern. The Irish Damselfly is a very local species found on mesotrophic lakes, fens and cutover bogs. Some 30 colonies are known most in Armagh, Fermanagh, Monaghan and Tyrone. Although this species was only found in Ireland 20 years ago, already some colonies appear to have been lost. Eutrophication of sites is believed to have been the main factor but one Longford site has apparently totally disappeared. The status of our rarest Irish dragonfly the Northern Emerald Somatochlora arctica is also of concern as it is apparently confined to the Killarney National Park. Here it breeds in shallow pools in bogs. However it is an elusive insect which has been rarely seen and the number of known breeding sites is worryingly small. The Northern Emerald is threatened by habitat change and also by longer-term climate change as it is, like many of our bog dwelling insects, a northern, cold-adapted species. We still have much to learn about our dragonflies.

The number of dragonfly species recorded in each 10km square of the Irish grid.

Dragonfly Ireland
DragonflyIreland is a four year project organised by the Ulster Museum and supported by Dúchas and the Environment and Heritage Service (N. Ireland) which aims to record the distribution of the Irish dragonflies and document important sites and habitats. Anyone can participate in DragonflyIreland and if you would like details please use the contact address below. Information on the project can be found on the DragonflyIreland website which describes all the Irish species and gives lots of other information about these fabulous insects.

Further Information
Brian Nelson
DragonflyIreland
Ulster Museum
Botanic Gardens
Belfast, N. Ireland BT9 5AB +44 28 90383145
email: brian.nelson.um@nics.gov.uk

Field Guides
Field Guide to the Dragonflies and Damselflies of Great Britain and Ireland by Steve Brooks, published by British Wildlife Publishing, Lower Barn, Rooks Farm, Rotherwick, Hook, Hampshire RG27 9BG (ST£18.95).

Guide to the Dragonflies of Ireland published by the Ulster Museum. Available from the Ulster Museum Shop, Botanic Gardens, Belfast BT9 5AB at ST£2.95 plus p&p. (Tel: Belfast 90383047)

- Brian Nelson