English name:
Silver-studded Blue
Full scientific name:
Plebejus argus (Linnaeus, 1758)
Croatian name:
Trnonogi plavac
Flight Period and Life Cycle
2 broods per year. Overwinters as caterpillar.
Distribution in Croatia
The entire territory. Check the included map.
External Morphology Characteristics
In males, the upper side of both wings is blue with a wide dark border on both wings. Females are very similar to Plebejus argyrognomon and Plebejus idas. Males are easier to determine. Moreover, the details how to determine species are below:
(1) Plebejus argus male has the widest dark border of the upper side of the wings. Plebejus argyrognomon male has the narrowest dark border.
(2) Plebejus argus male has a small spine on the front pair of legs. The spine is visible with a magnifying glass only.
(3) In most male individuals of Plebejus argyrognomon, there are dark spots in the marginal zone on the upper side of the hindwing.
(4) In both sexes of Plebejus argyrognomon, there are prominent orange spots in marginal zones on the underside of the forewing. The same is true for some individuals of Plebejus argus and Plebejus idas females.
(5) In the marginal zones of the hindwing, a series of silvery-blue-orange spots are visible depending on the viewing angle. In all three species they are visible at least in S1-S4 zones. In Plebejus idas male, there are silvery-blue-orange spots in zones S5, S6 and sometimes in S7 too. In Plebejus argus male, silvery-blue-orange spots are missing in S5-S7 zones. Furthermore, in Plebejus argyrognomon male, silvery blue orange spots are missing in S6 and S7 zones.
(6) In Plebejus idas male, in zones S2 and S3, the inner black edge of the orange spots has a sharp end.
(7) Plebejus argus female has the series of orange spots in the submarginal zone of the upper side of both wings. Additionally, they are more far away from the margin compared to Plebejus idas and Plebejus argyrognomon species.
(8) Most individuals of Plebejus idas females have more bluish upper side of both wings.
Behavior
It often rests on blades of grass. Sometimes males are grouped together.
Caterpillar Host Plants
Families Fabaceae, Ericaceae and Cistaceae.
Habitat
From rocky terrains to warm meadows at edges of woodland and bushes. Elevations: 0-1500m.
Gallery
