I photographed this Dark Green Fritillary (Argynnis aglaja) feeding on common knapweed (Centaurea nigra) at the National Trust managed, Crom Estate in Co. Fermanagh in July. The estate is the most densely wooded part of Northern Ireland, and includes oak, birch, alder and willow, and lake shore scrub with stands of aspen, buckthorn, hazel and spindle. Dark Green Fritillary can be found in grassy woodland clearings, coastal dunes and mountain meadows (it has been observed at altitudes of more than 3,000 m), throughout Europe and Asia to Japan. The caterpillar lives on violets and hibernates, and the adult is on the wing from June to August which coincides with the flowering of the knapweed.
This native perennial is found on low to moderately fertile soils but is absent from very damp or acid sites. Habitats include meadows (where its cousin Centaurea cyanus, the cornflower is now a rarity), pastures, road verges, field borders, waste ground, scrub land and woodland edges. Knapweed seed heads attract goldfinches and other seed feeding birds.