Small Blue Lycaenidae

Cupido minimus (Fuessly, 1775)

Description: Wingspan 18-27mm. This is the smallest N. Irish butterfly and is distinctive for this reason alone. The sexes are similar. The upperside is dark smoky grey with white fringing hairs. The underside is silvery grey with numerous small black dots. Sexes differ little in size. Males show a blue suffusion at base of wings on both sides.

Similar Species: None in N. Ireland.

Key Identification Features:

Sets:  male upperside male underside

Flight Period: Single brooded. In Fermanagh it has been recorded between the end of May and mid July.

Status: This is the rarest N. Irish butterfly now confined to just one colony in the Monawilkin area of west Fermanagh. Other populations existed on Islandmagee and the north shore of Belfast Lough in south Antrim but these died out in the late 19th Century. A second Fermanagh colony was lost in the 1970s.

Ecology: A colonial species found in calcareous and dune grassland. In N. Ireland the only colony is found on lightly grazed, short limestone grassland. Adults fly low over the habitat. Males gather in tall vegetation waiting for females. Once mated females avoid males and remain close to feeding and egg-laying sites. Females lay on the flowerheads of Kidney Vetch Anthyllis vulneraria. The larvae feed internally on the flower and developing seedhead except when nearly fully-grown. The full-grown larva overwinters.

World Distribution: Central and southern Europe except most of Iberia; absent from most of northern Europe; eastwards through Eurasia as far as Mongolia.

Bradley & Fletcher number: 1569 Agassiz number: 61.010

Additional information:

UK Butterflies account


 Thompson, R. S. & Nelson, B., 2003 (Oct 2). [In] The Butterflies and Moths of Northern Ireland