Wingspan: 21–27 mm
Flight period: in two generations; from May to June and from July to August
Caterpillar host plants: species from the legume family (f. Fabaceae)
The Argus blue (Plebejus argus) is a small butterfly, and its wingspan places it among the mid-sized representatives of its family. The upperside of the male's wings is violet-blue with a pronounced, broad black border that blends into the blue of the wings, and at the edge there is a band of snow-white fringes. Its underside is gray with a light blue sheen near the body. It is adorned with prominent white-edged black spots, along the edge there is a series of orange spots. These are bordered on the inner side by black semicircular spots, on the outer side they touch oval black spots, which in the center are usually metallic blue. The orange spots are pronounced on the hindwings of the male, while on the forewings they fade towards the apex. The male is also characterized by a small thorn at the tip of the foreleg, which males of other species in this genus do not have.
The female is brown on the upperside, with a series of orange semicircular patches along the wing edges, which are noticeable on the hindwings but faded on the forewings. The pattern on the underside of her wings is similar to that of the male, but on a gray-brown background. Additionally, the orange patches along the outer edge of the underside of the wings are pronounced on the forewings as well in the female.
This is a distinctly myrmecophilous species, as the larvae of the Argus blue, with the odor they emit, attract certain ant species; these caterpillars are carried into ant nests and cared for until they pupate. The Argus blue is a common blue butterfly in our country. In summer we will be able to observe adults on almost every flowering meadow, as it lives in both moist and dry meadows, and it occurs from the sea almost to the forest edge.
