Beautiful Demoiselle (Calopteryx virgo) is a fairly widespread damselfly on flowing waters in Monmouthshire; it prefers faster-flowing rivers than its relative Banded Demoiselle (C. splendens).

The oldest record in our data set is from Devauden, near Chepstow, on an unspecified date in 1961 (observer P. C. Webb).

Current distribution in the county: what we know

There are post-2019 records from many areas of the county: the lower stretches of the Rhymney and Ebbw rivers in the west, several rivers and streams around Newport and in Torfaen, the Usk valley and the Sor and Olway Brooks in the centre of the county, rivers such as the Gavenny, Trothy and Monnow in the north of the county, and the Angidy river in the east. In the northwest uplands it has only been recorded recently at Blaenavon and on one stretch of the Sirhowy. It also occurs on many stretches of the Monmouthshire and Brecon canal, and a population is present on at least one reen on the Gwent Levels, near Duffryn, although other records on the Levels are probably of wandering individuals.

Current distribution in the county: what we don’t know

There are many rivers and streams throughout the county which are suitable breeding habitat for Beautiful Demoiselle. As with many other species, the low level of recording in the north and east of the county is likely to be the reason for the lack of recent records, rather than because the species is not present there. It can be expected on many stretches of the Trothy and its tributaries, for example, around the streams that flow into the Wye, and on the upper stretches of any streams which run south towards the Gwent Levels. There are older records in some of these areas.

It is surprising that in the west, Beautiful Demoiselle has been recorded (not just recently, but also in previous decades) almost solely on the southern stretches of the such rivers as the Rhymney, Ebbw, Sirhowy and not more widely further north. Further recording here will determine if there are overlooked populations or if it is genuinely absent here.

While Beautiful Demoiselle is found on the Usk, the lack of records from the Wye is not surprising given that this is a slow-flowing river by the time it reaches Monmouthshire.

Distribution elsewhere

Beautiful Demoiselle is a common and widespread damselfly throughout Wales. In England it is common and widespread in the southwest, parts of the southeast, the west Midlands and Cumbria, with small isolated populations elsewhere; in Scotland, there is a population centred on Argyll and the southwestern highlands. Elsewhere in Europe, it is found from Ireland and Portugal east to western Russia, north to northern areas of Sweden and Finland, and south to Italy and Greece, though it is missing from much of Spain; outside of Europe, there are also populations in Morocco and Turkey.