This is our smallest resident butterfly with a wing span that can be a little as 16mm. The sexes are similar in appearance, although the male upperside is almost black with a dusting of blue scales, whereas the female is more dark brown in colour. Both sexes have an underside that is silvery-grey in colour, and not unlike that of the Holly Blue. This butterfly has a large distribition, being found from northern Scotland to the south of England, with colonies also in Wales and Ireland. However, outside of its strongholds in the south of England, colonies are often isolated pockets, typically in coastal locations. Most colonies consist of less than 30 adults, although a few colonies consist of thousands of adults. This butterfly is absent from the western and northern Scottish isles, the Isle of Man and the Channel Islands.
Subspecies: Cupido minimus minimus
The nominate subspecies was first defined in Fuessly (1775) as shown here (type locality: Switzerland). The population in the British Isles is represented by this subspecies.
Adults generally appear in early May in southern sites, reaching a peak at the end of May and start of June. This butterfly has a partial second generation each year, except in northern Scotland.
Subspecies: Cupido minimus minimus
The chart(s) above have been correlated with the phenology plot below, taken from the UK Butterfly Monitoring Scheme. The blue line gives average counts over the full data set from 1976 to date, and the red line gives the average for the last year.
Suitable sites for this species are those that are sheltered and contain a good amount of Kidney Vetch, together with grasses and shrubs which are used for perching and roosting. A wide variety of habitats is used, including unimproved chalk and limestone grassland, abandoned quarries, road and railway embankments and woodland rides and clearings.
The primary larval foodplant is Kidney Vetch (Anthyllis vulneraria).
Adults feed primarily on Bird's-foot Trefoil (Lotus corniculatus), Kidney Vetch (Anthyllis vulneraria) and Vetches (Vicia spp.).
Both sexes spend a large amount of time basking or resting. Males perch on small shrubs or grass stems which they leave when investigating passing insects or when searching out nectar sources. They are not territorial, however, and can often be found in small groups of 2 or 3. Both sexes take nectar from various flowers, with Kidney Vetch, Bird's-foot Trefoil and Horseshoe Vetch being particular favourites. Males will also take salts and minerals from damp mud, animal droppings and carrion.
Virgin females entering the perching sites are quickly mated without any elaborate courtship. Once mated, the female spends most of her time searching out suitable plants on which to lay and, once found, she lays a single egg between 2 florets on the flower head. She then rubs her abdomen over the flower head which is believed to deter other females from laying on the same plant since the larvae are cannibalistic in their first instar.
Subspecies: Cupido minimus minimus
Description to be completed. Click here to see a full list of aberrations for this species.
ab. obsoleta (Tutt.Brit.Butts.1896.p.161.)= simplex Aigner.Rev.Lapek.1900.p.144.
= paucipuncta Courvoisier.Iris 1912.26.p.63.
The spots of the underside almost obsolete.
ab. semiobsoleta (Tutt.Brit.Lep.1908.X.p.110.)
On the underside the spots of the hindwings reduced to vanishing point or entirely absent. The forewings normal or almost so.
Several eggs are occasionally found on the same inflorescence, although these will generally have been laid by different females. The eggs are quite easy to find at suitable sites, and hatch in 1 to 3 weeks depending on temperature.
The newly-hatched larva is less than 1mm in length and immediately burrows into a floret where it feeds on the developing seed. As the larvae grow they start to feed outside the floret with their head buried deep inside, with their back end exposed. The larva hibernates on the ground, often under moss or in a crevice in the soil. The larvae emerge in the spring and, without feeding further, wander off to find a suitable pupation site. There are 3 moults in total.
Small Blue larvae and the ant Lasius niger. Burnmouth, Berwickshire 21st July 2011.
Photo © IAC
The pupa is attached to a grass blade, leaf, or other vegetation, where it is attached to a silk pad by a silk girdle and the cremaster. This stage lasts between 1 and 3 weeks, depending on temperature.
Description to be completed.
Click here to see the distribution of this species overlaid with specific site information. Alternatively, select one of the sites listed below.
|Ardersier, Ardley Quarry, Aston Upthorpe Downs, Ballard Down, Bishops Itchington, Black Rock, Blue Lagoon, Broadcroft Quarry Reserve, Carymoor Environmental Centre, Clubmen's Down, College Lake, Compton Down, Cotley Hill, Dancersend, Dean Hill (West), Devil's Ditch, Dolebury Warren, Draycott Sleights, Dunnet Head, Dunstable Downs, Durlston Country Park, Epsom Downs, Farley Mount Country Park, Feshie Bridge, Fontmell Down, Grangelands, Greenham Common, Gwrelych Valley, Hexton Chalk Pit, Hod Hill, Hog Cliff Bottom, Holtspur Valley Reserves, Howell Hill, Hutchinsons Bank, Jerry's Hole, Kenfig Pool, Kilvey Hill, Larden Chase, Lein of Garmouth, Levin Down, Lummaton Quarry, Lydden Down, Martin Down, Maryport Harbour, Mill Hill, Mumbles Hill, North Bull Island, Old Down, Basingstoke, Old Winchester Hill, Oxwich, Perryfields Quarry, Pewley Downs, Pitstone Hill, Portland Tout Quarry, Prestbury Hill, Raven NNR, Ringstead Bay, Rosslare Harbour, Seaton Cliffs, Seven Barrows, Sewell Cutting, Sovell Down, Springhead, St Bees, St Cyrus, Stoke Camp, Strawberry Banks, Swyncombe Down, Torr Works, Totternhoe Knolls and Quarry, Townsend Quarry, Ufton Fields, Upper Sundon Quarry, Western Heights, Whiteford Burrows, Whiting Ness to Ethie Haven, Winsdon Hill, Workington, Yoesden Bank|
The population trend of this dainty butterfly is considered relatively stable, whereas the distribution trend shows a distinct decline, with the butterfly completely disappearing from some areas. For example, this species is now considered extinct in Northern Ireland with the last sighting in 2001. This species is therefore considered a priority species for conservation efforts.
From The State of Butterflies in Britain and Ireland and the UK Biodiversity Action Plan (UK BAP) (2007 review).
The following links provide additional information on this butterfly.
The species description provided here has been derived from the author's own observations and the information contained in the following works:
- Asher (2001). Asher, J., Warren, M., Fox, R., Harding, P., Jeffcoate, G. and Jeffcoate, S.: The Millennium Atlas of Butterflies in Britain and Ireland. 2001.
- Fox (2006). Fox, R., Asher, J., Brereton, T., Roy, D. and Warren, M.: The State of Butterflies in Britain and Ireland. 2006.
- Frohawk (1914). Frohawk, F.W.: A Natural History of British Butterflies. 1914.
- Howarth (1973). Howarth, T.G.: South's British Butterflies. 1973.
- Nash (2012). Nash, D., Boyd, T. and Hardiman, D.: Ireland's Butterflies: A Review. 2012.
- Riley (2007). Riley, A.M.: British and Irish Butterflies: The Complete Identification, Field and Site Guide to the Species, Subspecies and Forms. 2007.
- South (1906). South, R.: The Butterflies Of The British Isles. 1906.
- Thomas & Lewington (2010). Thomas, J. and Lewington, R.: The Butterflies of Britain and Ireland. Edn.2. 2010.
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