Common Blue

Polyommatus icarus (Rottemburg, 1775)



A common small butterfly. The male upperside is plain blue with a thin black marginal border, and the female is variable from dark brown to almost blue, and with orange submarginal spots. The underside is brownish in the female and more greyish in the male, with orange submarginal spots on both wings, and a series of postdiscal black spots, white bordererd on both wings. The forewing usually has a black spot in the cell, although not always present. Brown females without any blue on the upperside, could be confused with Aricia agestis, which has a displaced postdiscal spot to create the colon. Males could be confused with P. thersites, which has a large silvery-blue patch on forewing upperside.

Habitat Requirements

This species uses a diverse range of habitats.

Larval Foodplants

Mediterranean Kidney Vetch Anthyllis vulneraria subsp. rubriflora, Milk-vetch Astragalus boeticus (pale sulphur yellow/white flowers), Wild Liquorice Astragalus glycyphyllos, Milk-vetch Astragalus hamosus (pale yellow flowers), Montpellier Milk-vetch Astragalus monspessulanus (mauve flowers), Milk-vetch Astragalus pelecinus (lilac/white flowers) Milk-vetch Astragalus sempervirens, (pink/white flowers), Astragalus suberosus, Rush-like Scorpion Vetch Coronilla juncea, Annual Scorpion Vetch Coronilla scorpioides, Scorpion Senna Coronilla valentina subsp. glauca, Goat's-rue Galega officinalis, Common Bird's-foot-trefoil Lotus corniculatus - not on Corfu, Greater Bird's-foot-trefoil Lotus pedunculatus, Black Medick Medicago lupulina, Yellow Sweet Clover Melilotus officinalis, Furrowed Melilot Melilotus sulcatus, Ononis diffusa, Ononis mitissima, Ononis ornithopodioides, Ononis pubescens, Ononis pusilla (small yellow flowers, no red veins) Small Restharrow Ononis reclinata, Spiny Restharrow Ononis spinosa, Ononis variegata, Ononis viscosa, Crown Vetch Securigera varia - not on Corfu, Red Clover Trifolium pratense, Vicia cordata.


Generally speaking the specimens of Common Blue in Corfu appear slightly larger than those found in northern Europe and the colour of the butterfly appears more intense as well. There are some reports of Chapman's Blue Polyommatus thersites on the island but given that about 10 percent of most Common Blue populations host individuals which also lack the diagnostic cell spot, it is difficult to confirm these reports. 

*The information provided in the tables below is based on verified sightings of the Common Blue submitted via this website since 1st January 2021.

First and Last Sightings

Year First Last/latest # Days
2023 22/03/2023 16/11/2023 239 days
2022 19/03/2022 25/12/2022 281 days
2021 24/03/2021 19/11/2021 240 days

Number of Observations

Year Number of observations
2023 1313
2022 781
2021 616
Grand Total 2710

Distribution Map

Distribution maps for this species are currently unavailable.

Flight Times for the Common Blue (2023)

The chart below shows flight data by month for 2023

Flight Times for the Common Blue (All Data)

The chart below shows flight data by month since 1st January 2021


  • Vernacular/Common Name: Common Blue
  • Family: Lycaenidae (Leach, 1815)
  • Sub-family: Polyommatinae (Swainson 1831)
  • Tribe: Polyommatini (Swainson 1831)
  • Sub-tribe: Polyommatina (Swainson 1831)
  • Genus: Polyommatus (Latreille, 1804)
  • Sub-genus: Polyommatus (Latreille, 1804)
  • Species: icarus (Rottemburg, 1775)


For a list of references, please see our bibliography page.