Butterflies of the World - Lifecycle, Ecology, Taxonomy, Conservation, Photography, Butterfly Holidays, Photo Galleries, Book Reviews and more.........
Text and photographs protected by Copyright © Adrian Hoskins 2007, and must not be published in part or in whole elsewhere without prior written permission from the author.
Butterflies of Britain & Europe
 
Small Blue
Cupido minimus FUESSLY, 1775
Family - LYCAENIDAE
subfamily - POLYOMMATINAE
 
 introduction | habitats | lifecycle | adult behaviour
 
Small Blue Cupido minimus, male, Martin Down, Hampshire, England
 
Introduction
 
The Small Blue, also known as the Little Blue, is the smallest butterfly found in the UK, and one of the smallest in Europe. It is a widespread and common species in continental Europe, where it occurs from the Cantabrian mountains of northern Spain, eastward across Europe, and thence across temperate Asia to Mongolia and Amur.
 
On the continent there are 3 other members of the genus Cupido, with which the Small Blue can be confused. The males of C. osiris, which occur in the same habitats as minimus, have deep blue uppersides, but the females are dark grey, peppered with greyish-blue scales like those of both sexes of minimus. The other 2 species, lorquinii and carswelli, occur only in southern Spain, where minimus is absent.
 
Small Blue Cupido minimus, female, Martin Down, Hampshire, England
 
Habitats
 
The butterfly is widely distributed over much of southern England, but very localised, and confined to lightly grazed or ungrazed chalk or limestone grassland habitats where the foodplants grow in profusion.
 
Most colonies comprise of only a few dozen insects, although there are a small number of sites where populations may run into a few hundreds. There are also small colonies in Wales, Scotland, and Ireland, scattered mainly around coastal areas.
 
Typical sites include old chalk or limestone quarries, south facing grassland slopes, cliffs, and road / rail embankments. In Europe the butterflies also breed in limestone gorges, sub-alpine meadows, and in grassland / woodland mosaics.
 
All sites are characterised by the presence of flowering kidney vetch Anthyllis vulneraria, growing amongst sparse fine grasses, often at the edge of paths, or on eroding banks.
There also need to be tall grasses or bushes growing nearby, where the adult butterflies can find shelter during periods of inclement weather.
 
Small Blue Cupido minimus, female, Martin Down, Hampshire, England
 
Lifecycle
 
The adults emerge in late May and June, and there is often a partial 2nd brood, which emerges in late July and early August.
 
The butterflies lay their pale greyish-blue eggs singly on the flowers of kidney vetch, at the base of the calyx. Sometimes several eggs can be found on a flower head, but these are laid singly by different females, or by the same female on subsequent visits. The eggs hatch in about 10 days.
 
The caterpillar rests on the calyx tube, facing downwards, and makes a hole at the base, through which it feeds on the tissue of the developing seed. The fully grown larva leaves the foodplant and settles into a crevice in the ground, where it spends the winter. Most larvae pupate the following May, and produce butterflies in June, but some larvae remain in diapause for up to 15 months, emerging in August of the following year.
 
The larvae and pupae are both attended by ants of various species, including Lasius niger and Myrmica rubra.
 
The slightly hairy chrysalis, which is greyish, spotted with black, is formed at ground level, hidden in a crevice, or amongst leaf litter. The pupal stage lasts about 2 weeks.
 
Small Blue Cupido minimus, male, Portsdown Hill, Hampshire, England
 
Adult behaviour

 

The butterflies are usually found in small groups of a dozen or so, although at some sites I have found up to 200 at roost on grasses in sheltered depressions.

 

The males spend most of their time basking with wings half-open, on grass blades or on the foliage of bramble and other low plants, where they await passing butterflies. They will intercept Brown Argus or other Small Blues, but ignore larger species.

 

Small Blue Cupido minimus, male, Martin Down NNR, Hampshire, England

 

Periodically several butterflies will erupt into flight, and during male-male encounters a very brief sortie takes place, after which each male returns to another perching place. When virgin females are intercepted copulation takes place almost instantaneously, but when gravid females are intercepted they immediately settle deep amongst grasses, where they hide until the male flies away.

 

Copulated pairs can often be found sitting amongst lush foliage in depressions or ditches close to the breeding sites.

 

The adults nectar mainly on leguminous plants including kidney vetch, bird's foot trefoil, black medick and horseshoe vetch, but will also imbibe dissolved minerals from animal dung - I once found a group of over 50 Small Blues feeding at a very dry cowpat in the French Alps, and have often found singletons or small groups on animal faeces in the UK.

 

Small Blue Cupido minimus, male, Portsdown Hill, Hampshire, England

 

Small Blue Cupido minimus, male, Portsdown Hill, Hampshire, England
 
 
                                                       
Almost every British and European species of butterfly is declining rapidly in numbers, due in most cases to loss or degradation of habitats.
 
You can help to reverse the decline by supporting conservation organisations which purchase and manage habitats as nature reserves, and which lobby government at local, national and international levels, often very successfully, to bring about changes in farming, forestry and urban development policies.
 
Please contact the conservation organisations for advice on how you can help protect British and European butterflies and their habitats. You may be able to offer practical help e.g. by monitoring butterfly populations or helping to manage nature reserves. Donations to these organisations enable them to employ ecologists and biologists. Even if you are unable to provide such help, merely having your name on the membership list can be a powerful tool for conservation organisations wishing to demonstrate the levels of support they have for their policies.

 

 
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