Plebejus argus ¦ Silver Studded Blue ¦ euroButterflies

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Plebejus argus

Silver Studded Blue

euroButterflies

by Matt Rowlings

Pelopennesos, Greece, June 2013

Hautes-Pyrenées, France, July 2017

Female

Field notes and information

This species and the idas blue P. idas, pose plenty of identification issues. Both species are widespread and often common. Variation between individuals and colonies is marked in both species, with plenty of overlap possible.

Identification & Similar species: Separation is sure with the one character which is constant - the male foreleg tibia has a hook in the current species which is never present in P. idas. Other characters offer guidance for separating the males. The upperside male black border is fine and the upperside hindwing space 7 largely blue in P. idas the border often much broader and space 7 lacks blue in P. argus.

Very similar also to Reverdin's blue, P. argyrognomon, which is much more local but is widespread. The upperside blue is subtly darker and the orange band on the underside forewing reaches the apex - the latter feature can also be present in some individuals from some populations of P. idas and P. argus.

Distribution & Flight: Widespread and often common across most of Europe from sea level to high alpine levels >2000m. Absent from north Africa, most of the UK and northern Scandinavia. Flies in two broods from May to August.

Habitat & Behaviour: Very diverse habitats - dry heathy locations, grassy flowery places and damp marshes etc. Adults frequently roost communally in grasses with heads facing downwards.

Variation: Extensive local, regional and altitudinal variation in all markings. Perhaps the most distinctive of subspecies is corsicus from Corsica in which underside markings appear to be "washed out".