Silver-studded Blue. Photo: Brian Arnold
A lovely small butterfly which is not very mobile: individuals will only fly a maximum of 50 metres, so colonies tend to be static and well-defined. The Silver-studded is the blue butterfly which has the strongest relationship with ants. The adult butterflies only live 4-5 days. Declining nationally, but doing quite well in Dorset.
Where to see
- Habitat: Found in two types of habitat: mainly heathland, but also limestone (or occasionally chalk) grassland.
- Caterpillar foodplants: On Heathland: Ling, Heathers, Gorse. Both particuarly on the edge of clear ground. On limestone: Bird's-foot Trefoil, Common Rock Rose.
- Best places: Found only in the south and east of Dorset. Heathland colonies: Higher Hyde, Studland, Tadnoll, Avon Heath Country Park, Sopley Common*, Slop Bog, Ferry Road West*. Limestone colonies: Portland Broadcroft, Portland Tout. *Indicates particularly high numbers
Distribution map
Silver-studded Blue was recorded from these 1km squares in Dorset (2015-19).
- Key:
- 1 record
- 2-9 records
- 10+ records
When to see
A single-brooded butterfly, peaking in July.
Sightings by month (last 5 years)*
This year and last*
What to look for
Our second smallest blue butterfly: only the Small Blue is less big. It can be very variable in its markings.
The male upper wings are deep blue with a black outer band and a white fringe, though this can be very narrow or worn off in old age. The black band is wider than on the Common, Holly or Adonis Blue males.
The female upper wings are dark brown also with a variable white fringe and rather sketchy orange markings on the outer edges of the upperside forewing, though clearer ones on the edges of the hindwing.
The most definitive point to look for is on the hind underwing, where there should be a small silver stud within the black mark, which itself is between the orange and white marks towards the edge of the wing – more easily seen in a photograph than explained. This may sometimes be almost absent and is quite hard to see while the butterfly is on the wing, so get some photos and enlarge them later.
Its flight is ground-hugging, slow and fluttery – if it flies strongly away over the hedge, it is not likely to be a SSB!
The female is most easily confused with the Brown Argus, which is the same size, and neither species has a mark on the underside of the upperwing nearer the body than halfway.
This species relies very heavily on two species of black ant. The female butterfly lays her eggs close to a black ants’ nest and, when the little caterpillars hatch, the ants carry them inside the nest and ‘farm’ them by ‘milking’ them for sugars and amino acids, escorting them outside at dusk to feed, allowing them to pupate in the passages of the nest and accompanying the emerging butterflies up to the surface.
Photo gallery
Click thumbnails to view full-size images.
Silver-studded Blues courting - female to the top. Photo: John Woodruff.
Silver-studded Blue male. The male has a particuarly side black edge band. Photo: John Woodruff
Silver-studded Blue male with a narrower black edge band and almost no white fringe. Photo: Brian Arnold.
Silver-studded Blue female, showing the sketchy orange markings on the outer edge, but clearer ones on the hind wings. Photo: John Woodruff
Silver-studded Blue female. Like the Brown Argus, there is no mark on the underside of the forewing nearer the body than halfway. Photo: John Woodruff
Silver-studded Blue.This shot shows the silver studs very clearly. Photo: Mark Pike
BROWN ARGUS male. Compare the prominent orange markings on both forewing and hindwing to the SSB female, whose orange marks are sketchier. Photo: Chris Becker
Chalkhill Blue (to left) and SILVER-STUDDED BLUE to show the size difference. Photo: James Gould.