 |
 |
 |
|
| UK Status |
|
|
|
| Resident |
A species which is continually Resident in the UK with stable breeding populations. |
|
|
| Migrant |
A species which occurs as a Migrant in the UK. It may be able to breed here although they are usually unable to survive our winter months. Migrants are normally reported in the UK every year. |
|
|
| Rare Migrant |
A species which occurs as a Rare Migrant in the UK. It may able to breed here although they are usually unable to survive our winter months. Rare Migrants may not be seen for many years. |
|
|
| Extinct |
A species which is Extinct in the UK, usually as a result of habitat loss. |
|
|
| Introduction |
A species which ocurs in the UK as an accidental introduction. |
|
|
 |
|
|
|
|
|
Description
The silver-studded Blue is a stunning little butterfly which sometimes occurs in large numbers within compact colonies. Individuals rarely fly any distance from their colony.
Males are usually seen basking or flying low over vegetation on the search for newly emerged females. There is one brood each year.
The female will lay her eggs singly on the larval foodplant or on other vegetation nearby. They prefer to lay their eggs close to the ground in sheltered spots where the slightly higher average tempereature (micoclimate) helps in the development of the young larva within the egg. The larva is fully developed within the egg but does not emerge until the following spring.
When the larva does emerge, it first feeds on the young tender shoots and buds of the foodplant. As the larvae grow they will feed on less tender leaves and are often attended by ants. It is thought that the ants provide some protection from predators and in return the larva exudes sweet secretions from a gland near its rear end. The larval stage occurs over 4 instars before pupation takes place in a silk lined chamber just below the ground surface where again it is often tended by ants.
Ants continue to attend even when the adult butterfly begins to emerge from the pupa.
Habitat
The Silver-studded Blue prefers lowland heathland or calcareous (limestone or chalk) grassland as its main habitat but also occurs on a peatland site in Wales.
As with the Large Blue the Silver-studded Blue has an important relationship with ants in this case with the genus Lasius which requires open ground (bare soil or short vegetation) which provide relatively warmer microclimates at ground level compared to the surrounding area. This requirement becomes increasingly important towards the northern limit of the species range where it prefers sheltered areas or those that are south-facing.
Sites where the habitat has been grazed following recent disturbance such as quarrying or heathland fires tend to hold the stongest populations with ideal conditions for breeding occuring after 4 years of regrowth of the larval foodplant.
Many sites are managed in a way to replicate these processes. Domestic animals may be used to graze the vegetation folowing mechanical cutting or controlled burning. If management is not sustained the habitat quickly becomes unsuitable often within 10 years. As a result most populations of the Silver-studded Blue exist as metapopulations. Occasional dispersals of adults allowing suitable habitat nearby to be colonised.
It is also important for the Silver-studded Blue to have areas of long grass and/or low shrubs which offers protection against stong winds as they tend to roost communally at night and during poor weather.
Larval Food Plants
On acid heathland the larvae feed on Heather Crossed-leaved Heath Bell Heather and Gorse while on calcareous grassland Common Rockrose Common Birds-foot-trefoil and Horseshoe Vetch are used.
British Subspecies
The following sub-species of the Silver-studded Blue occur in the UK.
 Silver-studded Blue - Plebeius argus argus (Linnaeus, 1758) - Occurs in southern and eastern England. It is the most widespread of the sub-species occuring throughout the species range.
Silver-studded Blue - Plebeius argus caernensis (Thompson, 1937) - Occurs in Limestone areas of north Wales only, centred on Great Ormes Head. Known as the Western Silver-studded Blue, this sub species is smaller than ssp. argus. The female also tends to have more blue colouration to the uppersides of her wings.
Silver-studded Blue - Plebeius argus cretaceus (Tutt, 1909) - Occurs in Dorset only - restricted to quarry sites on Portland Bill. Colonies also exisited in Kent, Surrey and Essex but these are now extinct. Known as the Southern Silver-studded Blue, this subspecies differs from the ssp. argus by its larger size and the reuced with of the dark margings to the upper wings. The male is also brighter blue in colour.
Silver-studded Blue - Plebeius argus masseyi (Tutt, 1909) - Occurs in Shropshire at the Butterfly Conservation Reserve at Prees Heath only - other colonies in Lancashire and Westmoreland are now extinct. Known as the Northern Silver-studded Blue, ssp. masseyi differs from ssp. argus by the much narrower dark border to the upper surfaces of the wings which reveal clear marginal spots on the rear wings of the males. The male undersides tend to be chalky grey in colour. Females tend to have a flush of blue colouration across much of the upper surface of the hind wings.
|
|
|
| Stock Photography Library |
| We have 58 photographs of the Silver-studded Blue in the British Butterflies photo library |
|
BB703 - Silver-studded Blue
DSC_4072.JPG
|
 |
|
BB702 - Silver-studded Blue
DSC_4059.JPG
|
|
|
BB701 - Silver-studded Blue
DSC_4049.JPG
|
|
|
BB700 - Silver-studded Blue
DSC_4043.JPG
|
|
|
BB699 - Silver-studded Blue
DSC_4034.JPG
|
|
|
BB698 - Silver-studded Blue
DSC_4030.JPG
|
|
|
BB697 - Silver-studded Blue
DSC_4025.JPG
|
|
|
BB696 - Silver-studded Blue
DSC_4020.JPG
|
|
|
|
|
|
|
|
| Distribution |
|
 |
| During the last century it is thought that the Silver-studded Blue undergone a severe decline in its range by an estimated at 80%. It is extinct in Scotland and northern England and absent throughout the majority of central eastern and south-eastern England. It is widespread on the heaths of Dorset and Hampshire with strong populations occuring in North Wales. |
|
 |
|
| Where to see the Silver-studded Blue |
Cornwall: St Day nr Redruth
Dorset: Higher Hyde, Studland, Tadnoll, Portland Broadcroft Quarry, Portland Perryfields,
Portland Tout, Avon Heath CP North, Avon Heath CP South, Sopley Common
Merseyside: Thurstaston Common SSSI (introduced in 1994 - present on SE part of reserve)
Norfolk: Buxton Heath and Kelling Heath (re-introduced)
Shropshire: Prees Heath BC Reserve
Suffolk: RSPB Minsmere and Westleton Heath.
A new colony of Silver-studded Blues was discovered in 2006 on the RSPB’s Minsmere reserve. Over 3000 individuals were recorded following the conversion of the land from arable fields to grassland and heathland since the 1990's. Another good site is the English Nature managed site at Sunnyside Farm Stoborough Heath Ridge near Wareham. |
|
| Population Trends |
| species status |
the Silver-studded Blue is a resident species in Britain |
| population trend1 |
(1995-2004)  down by -72% |
(1976-2004) down by -1% |
|
|
1Fox, R., Asher. J., Brereton. T., Roy, D & Warren, M.
(2006) The State of Butterflies in Britain & Ireland, Pices, Oxford. |
| UK Biodiversity Action Plan (BAP) Status |
| UK BAP status2 |
priority species (link) |
|
|
| 2 For more information about the UK Biodiversity Action Plan (BAP) species status, visit www.ukbap.org.uk. |
| IUCN Category Status |
| IUCN category3 |
 vulnerable4 |
|
|
3 Fox, R., Warren, M & Brereton, T.
(2007) New Red List of British Butterflies. Butterfly Conservation, Wareham.
4 More information about IUCN categories available here. |
| Find Out More Online* |
| More information about the Silver-studded Blue can be found on Peter Eeles excellent UK Butterflies web site. |
|
|
|
|
Aberrations and Forms |
|
|
| We currently know of 33 named aberrant forms of the Silver-studded Blue. More information about aberrants can be found here. |
 ab. anterocroceus - Tutt (1909) |
|
| ab. argyrotoxus - Bergstrasser (1779) |
|
| ab. basijuncta - Tutt (1909) |
|
| ab. bina - Rostagno (1906) |
|
| ab. caeca - Grund (1908) |
|
| ab. costajuncta - Tutt (1909) |
|
| ab. croceolunulatus - Tutt (1909) |
|
| ab. croceovirgatus - Tutt (1909) |
|
| ab. cuneata - Tutt (1909) |
|
| ab. disco-anteriora - Tutt (1909) |
|
| ab. disco-lunulata - Tutt (1909) |
|
| ab. flavescens - Tutt (1909) |
|
| ab. fulvescens - Tutt (1909) |
|
| ab. furvescens - Wykes (1945) |
|
| ab. fuscescens - Lempke (1955) |
|
| ab. infraobscura - Lempke (1955) |
|
| ab. juncta - Tutt (1909) |
|
| ab. leodorus - Gerhard (1853) |
|
| ab. magnipuncta - Tutt (1909) |
|
| ab. minor - Tutt (1909) |
|
| ab. nigrescens - Tutt (1909) |
|
| ab. obscura - Grund (1908) |
|
| ab. pallida - Tutt (1909) |
|
| ab. posterocroceus - Tutt (1909) |
|
| ab. privata - Courvoisier (1910) |
|
| ab. purpurascens - Tutt (1909) |
|
| ab. radiata - Oberthür (1896) |
|
| ab. rufescens - Tutt (1909) |
|
| ab. transversa - Wykes (1945) |
|
| ab. tribasijuncta - Courvoisier (1912) |
|
| ab. ultranubila - Wykes (1945) |
|
| ab. unipuncta - Mousley (1902) |
|
| ab. violascens - Tutt (1909) |
|
|
|
|
|
|
|
|
| References |
| The information on this web site comes from a variety of freely available resources including books, academic reports and web sites alongside my own personal observations of butterflies. The species descriptions are currently in the process of being edited (spring 2009) to include new data, recent personal observations and referencing following a major update to the site.
A complete list of references mentioned in the text on this web site is available here. |
| * External Links Disclaimer |
| This web site includes links to information provided by external web sites which are not in any way under the control of www.britishbutterflies.co.uk. We cannot, therefore, be held responsible for the content of external web pages. |
|
|
|
|
26-31mm
