Coenagrion lunulatum (Charpentier, 1840)
Family: Coenagrionidae

Discovered only in 1981, this damselfly is present in Ireland but absent from Britain. Approximately 35 colonies are known from Northern Ireland, the majority in Counties Fermanagh and Tyrone. New sites continue to be found, but it has also apparently disappeared from several of its recorded sites.

In brief

• Recorded from all six counties, with the majority of records from Armagh, Fermanagh, and Tyrone. It is only known from single sites in Antrim and Londonderry

• Colonies exist on small mesotrophic lakes and cutover bogs

• Adults have been recorded between mid-May and late July but the best time to see them is between early June and the beginning of July

• It is in decline with the UK population restricted to Northern Ireland, and stronghold of the Irish population being Northern Ireland

• The Irish damselfly is uncommon in most of Western Europe

• The species is threatened by loss of habitat and change in nutrient status of lakes, specifically enrichment, to which this species appears particularly sensitive

• Following the discovery in Sligo 1981, the first Northern Ireland population was found in 1984 at Watson’s Lough, County Fermanagh

• A photograph of an adult taken at Brackagh Bog, County Armagh exists, that confirms the species was present at this site in 1976.

Species description
The adults are slender insects, about 30mm in length. Males and females differ in appearance. The males are blue and black above with distinctive black markings on the second abdominal segment. The underside of the head and thorax is bright green on mature individuals. Females are mainly black with blue and green markings and much less distinctive and conspicuous than the males.

Life cycle
The Irish Damselfly has an annual life cycle. Most of it is spent as an aquatic larva. Adults are present in early summer (May to July) but each lives for just a few weeks. Females lay their eggs into the submerged stems of aquatic plants, particularly pondweeds Potamogeton. These hatch in a few weeks and the larvae grow through a series of moults until they are fully grown in the spring of the following year. The larvae climb out of the water up a plant stem and the new adult emerges directly from the larval skin. Adults remain close to the pond for a few days as they mature, before returning to the water’s edge to breed. Males perch on floating leaves or on emergent stems looking for females. Both larvae and adults are predatory, feeding on small invertebrates and insects.

Similar species
There are four superficially similar damselfly species in Ireland. The Irish damselfly is smallest and darkest of these, having more black on abdomen than others. The males can be distinguished by the pattern of black markings on the abdomen. A diagnostic feature of the male Irish damselfly is the bright green colour of the underside of the head. Females, which can exist in one of a number of colour forms, are more difficult to identify and best identified by association with the males. Identification of the larvae is also difficult, requiring examination under a microscope.

How to see this species
The species is found at scattered wetland sites in Northern Ireland, such as Montiaghs Moss in County Antrim and Lough Alaban in County Fermanagh. The latter possesses a very strong colony, best visited in late June or early July. The Montiaghs Moss colony is smaller and adults are most reliably seen from mid-May to mid-June. As many of the sites are only accessible through private land, relevant access permissions should always be sought prior to visiting any sites.

Current status
There is a minimum of 35 colonies of the Irish damselfly in Northern Ireland out of an Irish total of about 80 (year 2000 figures). The number of colonies continues to grow with increased recording, but it is unlikely that there is a significant number of undiscovered colonies in Northern Ireland. It appears to have disappeared from some of its Northern Ireland sites including Crab Lough near Kilrea (its only Londonderry site), Watson’s Lough in Fermanagh and Brackagh Moss in County Armagh.

Why is this species a priority in Northern Ireland?

• Northern Ireland holds the entire UK population and a significant proportion of the Irish population (c. 40 per cent). There is evidence of decline, estimated at 10% per decade.

Threats/Causes of decline
Enrichment of lakes is thought to be the main threat. This reduces species diversity of damselflies and dragonflies, leading to dominance by a few species. Reclamation of land around lakes reduces the amount of feeding and resting habitat for the adults.

Conservation of this species

Current action

• A number of the known colonies are covered by ASSI designation, e.g. Montiaghs Moss.

• Recent management at the Montiaghs Moss has created new pools that are suitable for the Irish damselfly and other aquatic insects.

Proposed objectives/actions

• Maintain the range of the species

• Maintain the number of viable populations at the current level.

What you can do
If you see the species, report any sightings to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU, Tel: 028 9039 5256, cedar.info [at] nmni.com or to the Irish Dragonfly Recorder, Mr Robert Thompson, 8 Weavers Court, Banbridge, County Down BT32 4RP, rst1@bann8.fsnet.co.uk.

Further information

Links
DragonflyIreland

http://www.ehsni.gov.uk/area_interest_sitesview?SiteNo=ASSI109

Literature
Brooks, S. and Lewington, R. (2002). Field guide to the Dragonflies and Damselflies of Great Britain and Ireland. Second revised Edition. British Wildlife Publishing, Hook.

Cotton, D.C.F. (1982). Coenagrion lunulatum (Charpentier) (Odonata: Coenagrionidae) new to the British Isles. Entomologist’s Gazette 33: 213-214.

Nelson, B. (1985). Coenagrion lunulatum (Charpentier) (Odonata) new to Fermanagh (H33). Irish Naturalists' Journal 21: 503-504.

Nelson, B. (1999). The status and habitat of the Irish damselfly Coenagrion lunulatum (Charpentier)(Odonata) in Northern Ireland. Entomologists’ Monthly Magazine 135: 59-68.

Nelson, B. and Thompson, R. (2004). The Natural History of Ireland’s Dragonflies. MAGNI Publication No 013. NMGNI, Belfast.

Text written by:
Dr Brian Nelson, Curator of Freshwater Invertebrates, Ulster Museum

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