Regional Species


Dark Green Fritillary
Argynnis aglaja

Photograph by Janet Graham (Morfa Harlech)

Regional Species

This fritillary is now a scarce species, having disappeared from most of its former range. Only in a very few places, which remain suitable mainly by chance, is there an adequate supply of violets to support the large caterpillars. Most sites are now coastal, most importantly the four principal sand dune systems (Morfa Dyffryn, Morfa Harlech, Newborough Warren and Aberffraw) but also coastal cliffs and rough areas immediately adjacent. Further inland some colonies persist on bogs and in a few cases on bracken covered hillsides.

The Dark Green Fritillary will utilise a variety of violet species. The sand dune colonies depend on Heath Dog-violet (Viola canina), the wetland colonies on Marsh Violet (Viola palustris), whilst the larvae of colonies on bracken covered hillside feed on Common Dog-violet (Viola riviniana). The butterfly is a powerful flyer and can sometimes be seen in surprising places such as open moorland. This ability to disperse means that if a new area of suitable habitat were to become available it might well be colonised. Whilst the large sand dune populations persist there will always be the possibility of colonisation inland.

This butterfly is not simple to identify, as all the fritillaries resemble each other and this species is notoriously difficult to net, being a fast flyer with exceptionally quick reactions. However, the Dark Green Fritillary is larger than the Small Pearl-bordered Fritillary, which is now the only other species likely to be encountered. Unfortunately, the Silver-washed Fritillary and the High Brown Fritillary, which were still widespread in North Wales comparatively recently, are now presumed extinct. For an accurate determination a close look is, of course, essential and the green markings on the underside of the wings allow a positive identification to be made.