British Wildlife Wiki

The Small Blue (Cupido minimus) is a butterfly in the family Lycaenidae.

It is found in Europe, Asia Minor, Transcaucasia, Tian-Shan, West Siberia, Central Siberia, South Siberia, Russian Far East, Amur, Mongolia, Magadan and Kamchatka. Recorded larval foodplants are Oxytropis campestris, Astragalus alpinus, Lotus corniculatus, Anthyllis vulneraria,Melilotus, Coronilla, Medicago, Anthyllis vulneraria, Astragalus glycyphyllos and Astragalus cicer

Appearance, behaviour and distribution[]

This is Britain's smallest resident butterfly and despite its common name not particularly blue! The male has some bluish suffusion at the base of its upperwings but is mostly dark brown like the female. The undersides are a silvery grey with small black dots. The male has a bluish tint at the base of its wings similar to the upperside. It has a very patchy distribution across the UK with its strongholds on the chalk and limestone grasslands of southern England such as the Cotswolds and Salisbury Plain. Across the rest of Britain and Ireland it is often associated with coastal habitats with widely scattered colonies in northern England and the far north of Scotland.

Life cycle and food plants[]

The sole larval foodplant is Kidney Vetch Anthyllis vulneraria. Eggs are laid singly on young flower heads and the larvae feed on the flower heads and developing seeds. They are cannibalistic and will eat any smaller larvae they come across. Females will rarely lay eggs on a flower head where one is already present. The fully grown larvae are a pale cream colour and are well camouflaged as they sit on the developing seed heads. In the Autumn they descend and hibernate in crevices in the ground. Pupation occurs the following spring at ground level in the leaf litter. On the continent both larvae and pupae are tended by ants but there is little evidence of this occurring in the UK. In the south of England there are two broods, one on the wing in June and a second in August but further north there is just one brood flying in June.