thumb|Male underside, [[Munich]]
The small blue (Cupido minimus) is a Palearctic butterfly in the family Lycaenidae. Despite its common name, it is not particularly blue. The male has some bluish suffusion at the base of its upper wings but is mostly dark brown like the female. The species can live in colonies of up to several hundred and in its caterpillar stage is cannibalistic.
Description
thumb|[[Paratype of subspecies pilyachuch from Kamchatka, in the Natural History Museum, London ]]
Small blue males are dark brown with a scattering of bright blue scales that speckle their wings. Females lack this blue speckling. Both males and females exhibit the characteristic silver underside with black spots. The male has a bluish tint at the base of its wings similar to the upper side.
Geographic range
C. minimus is found in Europe, Asia Minor, Transcaucasia, Tian-Shan, western Siberia, central Siberia, southern Siberia, the Russian Far East, Amur, Mongolia, Magadan and Kamchatka.
UK and Ireland
The small blue is the smallest butterfly species found in the United Kingdom. It has a very patchy distribution across the UK, with strongholds in the chalk and limestone grasslands of southern England, such as the Cotswolds and Salisbury Plain. Elsewhere in Great Britain and Ireland, it is often found in coastal habitats, with widely scattered colonies in northern England and the far north of Scotland.
Larvae
First instar
First-instar larvae are typically very pale blue, almost white, with a black head. When the caterpillar first emerges from the egg, it is about .80mm long and will grow to 1.3 mm by the end of the first instar. They have several small hairs along the length of their bodies. Once hatched, the larvae will eat through the calyx of the plant as well as the young green legumes on which they are typically laid. First instar larvae are also cannibalistic, and will feed on any smaller larvae that cross its path.