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Flora & Fauna (media)
Silver-studded Blue (Plebejus argus)    Linnaeus (1758)    Hairstreaks and Blues (Lycaenidae)    SSBL    24864
Argusblåfugl (dk)   Esmaltada Espinosa (es)   Ljungblåvinge (se)      Synonyms: Bredrandet Blåfugl (dk) Allmän Blåvinge (se)
Subspecies
argus
corsicus
Bellier (1862).
Measurements:
WS: 23-27mm
Generations:
1
Flight period:
JFMAMJJASOND 
SE
Identification:
In Nordic region most similar to idas (Foranderlig Blåfugl).

Male violet-blue above with broad white margin and broad black rim diffuse and ill-defined toward the center (contrary to well-limited on idas). The distal part of the ribbons is black. The female above is brown with orange angled spots along the submarginal edge. However, in the northern Nordic region the female shows more blue above, like idas, why the two can be impossible to separate there.

Below the male is paler than the female, and shows more bluish cast toward the body than male idas. Both sexes show a well-marked row of orange submarginal spots and 3-6 bluish glittering spots within the orange spots distally. Proximally the orange spots are flanked by white wedges.

Argus has a amber-colored tag on the foreleg that idas lacks, but it can only be seen with magnification, why it is normally not useful as a field mark.

The black spots within the white wedges mentioned are supposed to be smaller and more irregular than on idas (comparing photos I don't think this is a reliable separation marker).
Life stages:
Distribution:
Europe, Turkey through temp Asia.
Habitat:
Behavior:
Dry sandy soils, coastal dunes with vegetation, heaths, dry forest clearings.
Status:
Scarce in Denmark. Coastal. Mostly Jylland and adjacent small islands. Also N Sjælland, Møn, Falster and Bornholm. Common in Sweden and Finland.
Host plants:
Hedelyng (Calluna vulgaris) [Heather ~ Brecina ~ Ljung]
Klokkelyng (Erica tetralix) [Cross-leaved Heath ~ Brezo de Turbera ~ Klockljung]
Almindelig Kællingetand (Lotus corniculatus) [Bird's-foot Trefoil ~ Loto Corniculado ~ Käringtand]
Mose-Bølle (Vaccinium uliginosum) [Bog Blueberry ~ Arándano Negro ~ Odon]
Rundbælg (Anthyllis vulneraria) [Common Kidneyvetch ~ Vulneraria ~ Getväppling]

Sweden:
Bakke-Soløje (Helianthemum nummularium ssp. obscurum) [Common Rock-rose ~ Mirasol ~ Solvända]
Comment:
Very small individuals have been seen.
Collective night roost.
Ant symbiosis.
Silver-studded Blue 931    (1 photos)
2022-07-12    Horna Grushåla (Åhus), Sweden

Imago ♂
Silver-studded and Idas are very similar underneath, but in general Silver-studded shows more turquoise-blue to the base of the underside and body, why I'm confident to call this one an SS.



Silver-studded Blue 932    (1 photos)
2022-07-12    Horna Grushåla (Åhus), Sweden

Imago ♂
Silver-studded and Idas are very similar underneath, but in general Silver-studded shows more turquoise-blue to the base of the underside and body, why I'm confident to call this one an SS.



Silver-studded Blue 933    (2 photos)
2022-07-12    Horna Grushåla (Åhus), Sweden

Imago ♂

A straight forward individual with broad and ill-defined black border.

According to Norden Fjärilar, Bo Söderström, the black spots on the underside of the hindwing are generally smaller and not so round on Silver-studded, which is certainly not the case here, where they look large and round. Apparently nobody else mentions this as a useful field character, and I start to think that it is only of supporting quality rather than something to rely on.




Silver-studded Blue 934    (2 photos)
2022-07-12    Horna Grushåla (Åhus), Sweden

Imago ♂




Silver-studded Blue 935    (1 photos)
2022-07-12    Horna Grushåla (Åhus), Sweden

Imago ♂

The black front edge of the frontwing is supposed to fade away on this species compared to Idas, which seems to be supported on this individual.




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