Common Blue
Polyommatus icarus
This record describes Polyommatus icarus (species). Recorded family: Lycaenidae. Recorded order: Lepidoptera.
Identification and Appearance

This is a small, delicate looking butterfly. The male has bright blue upper sides and the female is primarily brown, with a highly variable amount of blue. This species is found in a wide variety of habitats, including unimproved grassland such as roadside verges and waste ground, downland, woodland clearings, heathland and even sand dunes. This species has two broods in the southern counties of England and one brood further north. There may be a third brood in favourable years. Time of emergence is highly variable. In good years, adults may be seen as early as the middle of May on more southerly sites. These peak at the end of May, giving rise to a second generation that emerges in the second half of July, peaking in the middle of August. Colonies in northern England and Scotland typically have a single brood that emerges in June, reaching a peak in July. The main larval foodplant is Common Bird's-foot-trefoil (Lotus corniculatus), but Black Medick (Medicago lupulina), Common Restharrow (Ononis repens), Greater Bird's-foot-trefoil (Lotus pedunculatus) and Lesser Trefoil (Trifolium dubium) are also used. This is the most widespread Lycaenid found in the British Isles and can be found almost anywhere, including The Orkneys. It is absent, however, from the northern Shetlands and the mountainous areas of Wales and Scotland.
Wikipedia reference for Polyommatus icarus: https://en.wikipedia.org/wiki/Polyommatus icarus.
Classification
- Kingdom
- Animalia
- Phylum
- Arthropoda
- Class
- Insecta
- Order
- Lepidoptera (Butterflies and Moths)
- Superfamily
- Papilionoidea
- Family
- Lycaenidae (Gossamer-winged Butterflies)
- Subfamily
- Polyommatinae
- Tribe
- Polyommatini
- Genus
- Polyommatus
Imported taxonomy record. Source availability varies; see the source references and editorial policy below.
Habitat and Range
Habitat
This species is found in a wide variety of habitats, including unimproved grassland such as roadside verges and waste ground, downland, woodland clearings, heathland and even sand dunes.
Seasonal Activity
May to October.
Additional species information
Recorded status
This is the most widespread
About Butterflies and Moths: the wider group
Order-level background for Lepidoptera, the group containing Polyommatus icarus. Species-specific details appear above.
Group overview
Lepidoptera includes approximately 180,000 described species of butterflies and moths. Moths outnumber butterflies roughly 10:1. The monarch butterfly's eastern population has declined by more than 80% since the mid-1990s, and the western population by over 95% since the 1980s. The IUCN lists the migratory monarch as Vulnerable.
Ecological role of the group
Butterflies and moths are essential indicators of ecosystem health. As caterpillars, they are a primary food source for birds - a single nest of blue tit chicks requires ~10,000 caterpillars. Adult moths pollinate many night-blooming plants.
Economic and practical significance of the group
Lepidoptera are critical pollinators. In Europe, grassland butterfly species have declined by almost 50% since the early 1990s. In the UK, three-quarters of butterflies are in decline. In the U.S., five butterfly species have gone extinct since 1950, with 29 listed as endangered.
Recorded sources for this group: IUCN Red List, Xerces Society, USFWS, PNAS, WWF. Imported estimates may describe particular regions or reporting periods.
Photos of Common Blue (10)
Frequently Asked Questions About Common Blue
What is Common Blue?
Common Blue (Polyommatus icarus) is a species in the family Lycaenidae, within the order Lepidoptera.
Where is Common Blue found?
Habitat: This species is found in a wide variety of habitats, including unimproved grassland such as roadside verges and waste ground, downland, woodland clearings, heathland and even sand dunes.
When is Common Blue active?
Common Blue: seasonal activity - May to October..
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