Common blue butterfly, European common blue
The common blue butterfly or European common blue (Polyommatus icarus) is a butterfly in the family Lycaenidae and subfamily Polyommatinae. The butterfly is found throughout the Palearctic and has been introduced to North America. Butterflies in the Polyommatinae are collectively called blues, from the coloring of the wings. Common blue males usually have wings that are blue above with a black-brown border and a white fringe. The females are usually brown above with a blue dusting and orange spots.
The Common blue was elected as the national butterfly of Israel in 2023.
Named in the Classical tradition. In Greek mythology, Icarus was the son of the master craftsman Daedalus, the architect of the labyrinth of Crete.
Polyommatus icarus has a wingspan of 28–36 millimetres (1.1–1.4 in). The dorsal side of the wings is an iridescent lilac blue, bright violet-blue, or almost hyacinth-blue with a thin black border. Females' wings are brown or black-brown with a row of red reddish yellow spots along the edges of the wings (marginal spots) and usually some blue at the base. The extent of blue and brown is extremely variable depending on location. The top of the wings in the female may be mostly blue, especially in Ireland and Scotland, but it always has red spots.The ventral side has a greyish or dust-grey base colour in the males and a more brownish hue in the females. Both sexes have a row of red or orange spots along the edge of the hindwing and extending onto the forewing, though they are generally fainter there, particularly in the males, where they are sometimes missing altogether. There are about a dozen black-centered white spots (ocelli) on the hindwing and nine on the forewing. These usually include one in the middle of the forewing cell, absent in Chapman's and Escher's blues. The fringes on the outer edge of the wings are uniform white, not crossed with black lines as in the chalkhill and Adonis blues (that is, the common blue lacks checkering).
Other similar species are:-
The caterpillar is small, pale green with yellow stripes and, as usual with Lycaenid larvae, rather slug-like.
The common blue butterfly is found in Europe, North Africa, the Canary Islands, and east across the Palearctic to Northern China. Recently it was discovered in Quebec, Canada. It is widespread in the British Isles. Its distribution trend shows a 15% decline since the 1970s.
These butterflies inhabit flowery or grassy places, warm and cool, open or wooded areas and at all altitudes up to high alpine meadows at an elevation of 0–2,700 m (0–9,000 ft) above sea level. It mostly resides on chalk or limestone grassland, but also in smaller numbers in woodland clearings, meadows, heathlands, sand dunes, along railway embankments, and under cliffs.
As a caterpillar, the common blue eats leaves. As an adult butterfly, it feeds on wildflower nectar and excrement. The adult lives 3 weeks.
Males are often very obvious as they defend territories against rivals and seek out the more reclusive females. In the south of Britain there are two broods a year, flying in May and June and again in August and September. Northern England has one brood, flying between June and September. In a year with a long warm season, there is sometimes a partial third brood in the south flying into October.
