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Butterfly taxonomy (classification) The skippers The swallowtails The whites The hairstreaks, coppers and blues. Includes the Duke of Burgundy. The nymphalids, fritillaries and browns. Includes the Monarch.
Common Blue male - Shadowbrook Meadows Solihull 21.05.2014
Wingspan
29 - 36mm
Photo © nfreem
Common Blue

Polyommatus icarus
po-lee-oh-MAY-tuss
IK-uh-russ
Number: 61.018
B&F No.: 1574
Family:Lycaenidae (Leach, 1815)
Subfamily:Polyommatinae (Swainson, 1827)
Tribe:Polyommatini (Swainson, 1827)
Genus:Polyommatus (Latreille, 1804)
Subgenus:Polyommatus (Latreille, 1804)
Species:icarus (Rottemburg, 1775)
Subspecies:icarus (Rottemburg, 1775)
 mariscolore (Kane, 1893)
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  Introduction  

Living up to its name, this butterfly is the commonest blue found in the British Isles. While the male has bright blue uppersides, the female is primarily brown, with a highly variable amount of blue. This is the most widespread Lycaenid found in the British Isles and can be found almost anywhere, including Orkney. It is absent, however, from Shetland and the mountainous areas of Wales and Scotland. This butterfly forms reasonably discrete colonies measured in tens or hundreds, with individuals occasionally wandering some distance.

Taxonomy Notes

Oberthür (1910) described the English race of Common Blue as ssp. tutti. In comparison with the continental race, the English race is said to have less rounded forewings that are lengthened, a male underside that is a deeper grey in tint, and uppersides that have a more transparent blue and pink sheen. Females are generally blue with orange marginal lunules punctuated by black, especially on the hindwings, and a tendency for the colour to lighten to white near the apex of the forewings. Oberthür came to his conclusions based on 150 specimens from North Scotland, Rannoch, Cheshire, North Devon, the New Forest, North Kent, Folkestone, Dover, Glengariff and County Kerry in Ireland, and from various collections.

Graves (1930-1) also described f. postclara of ssp. mariscolore that is used to represent the second generation that occurs in some parts of Ireland. In comparison with the first generation, both sexes have more tapered forewings and are slightly smaller. The male upperside is brighter and the underside of a lighter grey. The female upperside is paler at the apex of the forewings and the submedial area of the hindwings. The female underside has less metallic blue-green scaling on the bases of the hindwings.

Polyommatus icarus ssp. icarus

This species was first defined in Rottemburg (1775) as shown here (type locality: Germany). The nominate subspecies is found throughout England, Scotland, Wales, the Isle of Man and the Channel Islands. It may also be found in some parts Ireland, although there is some confusion regarding its status, as discussed under the subspecies mariscolore.


Common Blue male - Chantry Hill, Sussex 6-Aug-2013
Male
Photo © Neil Hulme
Common-Blue- 5D38526 Lincs June 2013
Male Underside
Photo © IainLeach
Common Blue Female - Crawley, Sussex 17-June-05
Female
Photo © Vince Massimo
Common Blue female - Chantry Hill, Sussex 6-Aug-2013
Female Underside
Photo © Neil Hulme

Polyommatus icarus ssp. mariscolore

This subspecies was first defined in Kane (1893) as shown here (type locality: Ireland). However, Kane first hinted that such a subspecies existed in his European Butterflies [Kane (1885)] where he says "Often the females of L.Bellargus [Adonis Blue] and Icarus [Common Blue] are indistinguishable, and a female form of the latter occurs corresponding to v. (female) Ceronus of the former. Occasionally the male of L.Icarus also assumes a more vivid blue, as in Spain, etc., and the blk. ray points extend slightly into the fringe."

In his definition of mariscolore, Kane (1893) refers to South (1887) who makes similar observations with a direct reference to Irish and Scottish specimens: "Male ... Fig.2 shows a male icarus, closely approaching male bellargus in colour; and fig.3 a decidedly violet specimen. These two last are from Ireland, and were kindly sent me, together with others, ... by Mr. Percy Russ, of Culleenamore, Sligo. Several of the males from Sligo exhibit a tendency to the bellargus coloration, but the one figured is the most decided. The only other locality from which I have seen similar examples is the Isle of Hoy, but these are not quite so striking as the Sligo specimens, and the bellargus colour is mostly confined to the inferior wings. In typical icarus the hind margins of all the wings have a linear black border; this in English specimens does not usually attract one's attention, but in Scotch and Irish examples it is sometimes very conspicuous ... In a few of the Sligo specimens there is a distinct row of black spots on the inferior wings internal to the marginal border. Female ... Some female icarus from Pitcaple, Aberdeenshire; and others from Castletown, Co. Cork, Ireland ... are very handsome. The blue, which in these specimens is of a violet tint, suffuses nearly the whole of the wings up to the large and bright orange crescents. These last are almost confluent, and consequently the orange marking appears band-like, as shown in the Scotch example, Pl.II., fig.6 ... Both sexes of Irish and Scotch are uniformly larger than English specimens".

Ford (1945) makes an additional observation regarding the wing shape, saying "In Ireland, however, occurs a characteristic and brilliant sub-species which has arisen in isolation there. The specimens are large and tend to have rather pointed wings, while the females are heavily marked with blue, and the orange crescents along the outer margin of their wings are exceptionally well developed". Ford (1945) also claims that "gynandromorphs are very much more frequent in the Irish than the British race".

The distribution of the subspecies mariscolore is a confusing one. In describing mariscolore-like features, both South (1887) and Kane (1893) make reference to both Irish and Scottish specimens. Indeed, Dennis (1977) states that "The most exaggerated development of the subspecies the writer has seen is from Burray and mainland Orkney - extremely large insects ... with large, bright red lunules on the upperside of the female". Thomson (1980) confirms that a race "resembling" mariscolore is found in north and west Scotland but that "subspecific differentiation without a careful analysis of all the factors and characters involved is not considered to be justified". Thomas & Lewington (2010) state that mariscolore is found both in Ireland and in north-western Scotland. When it comes to Ireland, Nash (2012) suggests that both ssp. mariscolore and ssp. icarus are found there. It is certainly true that not all Irish Common Blues conform to the description of mariscolore, which is characterised by the amount of blue in the female, since many individuals are brown with a variable amount of blue. Riley (2007), however, seems to take a different position from all other authorities, stating that mariscolore is "Restricted to Ireland where it is widespread and common" and is the only subspecies found there, but gives no explanation for this position.

The subspecies mariscolore differs from the subspecies icarus as follows:

1. Generally larger in size, especially the female.

2. The upperside of the female has extensive patches of blue, with large and bright orange marginal spots.

Polyommatus icarus ssp. mariscolore (Kane, 1893)

In the first place, the Irish butterfly usually considerably exceeds in size that of England, varying from about 1 inch 2 lines to 1.5 inches in the June emergence; but the individuals of the second emergence are much smaller, and generally conform much more nearly to the usual English type in both sexes, to which, therefore, I need not further refer. Probably referable to var. pusillus, Gerhard (cf. Dale's 'British Butterflies'). Mr. South notes that the Irish and Scotch icarus are similarly characterised by their large size, and the brilliant blue of the female bordered with bright orange marginal ocelli ...

The female offers the most conspicuous divergence from the normal English and Continental type, in which the basal half only is dusted with blue scales (fig.8), the brown of the upper side being widely replaced by a violet or occasionally wholly by the bright blue of L. bellargus. These forms are not uncommon in Ireland, in Galway, Sligo, Donegal, Antrim, Down, Westmeath, Waterford, &c., and are accompanied by a series (often almost confluent) of very bright orange peacock-eye markings on the outer margins of all wings, so that some specimens (if not too brilliant) would pass muster as the var. ceronus of L. bellargus (fig. 12); another most interesting testimony to the genetic affinities of this species. This var. ceronus of icarus occurs in some abundance at Ballynahinch, Connemara, and at Ardrahan and other parts of Galway, as well as in some central and southern localities ...

Taking a general view of the foregoing, we note, firstly, that the Scotch and Irish races are unusually large (Mr. Jenner Weir notes the Orkney insect being "unexpectedly large," 1 inch 5 lines - Ent. xiv. 3), that they vary in parallel directions from the English type, and present as numerous genetic characters linking them to other species as do the latter; and in the female sex have acquired generally a very remarkable one in addition, and instance of gynandrochromism. It may be that the acquisition of more brilliant colours in the female may be of advantage under less sunny skies, where the sun-loving Rhopalocera have less opportunities of selecting their mates, and cannot afford to indulge in long engagements ...

I have not heard that this Irish variety of the female has been recorded as a local form from the Continent; and as it is an important parallel variation to that of L.bellargus and var.syngrapha of L.corydon, think it may receive the varietal name of mariscolore.

[The counties mentioned in this definition are shaded green in the image below.]

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Common Blue ssp. mariscolore - male - Craigavon Lakes, Northern Ireland - 11-Jun-14-10
Male
Photo © Pete Eeles
Common Blue ssp. mariscolore - male - Craigavon Lakes, Northern Ireland - 11-Jun-14-7
Male Underside
Photo © Pete Eeles
Common Blue ssp. mariscolore - female - Craigavon Lakes, Northern Ireland - 11-Jun-14-11
Female
Photo © Pete Eeles
Common Blue ssp. mariscolore - female - Craigavon Lakes, Northern Ireland - 11-Jun-14-13
Female Underside
Photo © Pete Eeles

  Phenology  

This species has 2 broods in the southern counties of England, and 1 brood further north. There may be a 3rd 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.

Polyommatus icarus ssp. icarus


Polyommatus icarus ssp. mariscolore


The chart(s) above have been correlated with the phenology plot below, taken from the UK Butterfly Monitoring Scheme. The blue line gives average counts over the full data set from 1976 to date, and the red line gives the average for the last year.


  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.

  Larval Foodplants  

The primary larval foodplant is Bird's-foot Trefoil (Lotus corniculatus). Black Medick (Medicago lupulina), Common Restharrow (Ononis repens), Greater Bird's-foot Trefoil (Lotus pedunculatus), Lesser Trefoil (Trifolium dubium) and White Clover (Trifolium repens) are also used.

  Nectar Sources  

Adults feed primarily on Bird's-foot Trefoil (Lotus corniculatus), Bugle (Ajuga reptans), Carline Thistle (Carlina vulgaris), Fleabane (Pulicaria dysenterica), Kidney Vetch (Anthyllis vulneraria), Knapweeds (Centaurea spp.), Marjoram (Origanum vulgare), Ragwort (Senecio jacobaea), Thistles (Cirsium spp. and Carduus spp.), Thyme (Thymus polytrichus), Vetches (Vicia spp.) and White Clover (Trifolium repens).

  Imago  

This species is most active in sunshine and is a frequent visitor to flowers. Males are the more active of the two sexes and set up territories which they patrol in search of females. The female is less conspicuous, spending most of her time nectaring, resting and egg-laying. When egg-laying, the female makes slow flights, low over the ground, searching out suitable foodplants on which to lay. When a suitable plant is located, a single egg is laid on the upperside of a young leaf.

In dull weather this species roosts head down on a grass stem. As for similar species, such as the Brown Argus, this species roosts communally at night, with several individuals occasionally found roosting on the same grass stem.

Polyommatus icarus ssp. icarus


Common Blue female, MRC, 23rd July 2009
Photo © NickB
23-Jul-2009
Common Blue Female - Crawley, Sussex 17-June-05
Photo © Vince Massimo
17-Jun-2005
Common Blue Female - Warlingham, Surrey 21-June-09
Photo © Vince Massimo
21-Jun-2009
Common Blue Male - Crawley, Sussex 18-May-05
Photo © Vince Massimo
18-May-2005
Common Blue Pair (second brood) - Crawley, Sussex 28-July-05
Photo © Vince Massimo
28-Jul-2005
Common Blue - imago - Greenham Common - 30-Jul-05 (2)
Photo © Pete Eeles
26-Jul-2005
Common Blue - imago - Hartslock - 10-May-08 (1)
Photo © Pete Eeles
10-May-2008
Common Blue - imago - Hartslock - 14-May-08 (13)
Photo © Pete Eeles
14-May-2008
Common Blue pair, Totternhoe 28th May 2009
Photo © NickB
28-May-2009
Common Blue - imago - Stockbridge Down - 12-Jul-09 (1)
Photo © Pete Eeles
12-Jul-2009
Common Blue male - John Muir CP, East Lothian, Scotland 15-June-2010
Photo © NickMorgan
Scotland
Common Blues - Greenham Common - 10-8-08
Photo © Gwenhwyfar
10-Aug-2008
Common Blue - Magdalen Hill Down - 6 June 2010
Photo © Clive
06-Jun-2010
Common Blue Female - Chaldon, Surrey 5-Aug-10
Photo © Vince Massimo
05-Aug-2010
Common Blue Female - Addington, Surrey 15-June-10
Photo © Vince Massimo
15-Jun-2010
Common Blue - imago - The Holies - 31-May-10 (1)
Photo © Pete Eeles
31-May-2010
Common Blue Female (Variant) - Chaldon, Surrey 22-Aug-11
Photo © Vince Massimo
22-Aug-2011
Common Blue (m)  Ryton Country Park, Warwickshire  8th August 2009
Photo © millerd
08-Aug-2009
Common Blue Female - Chaldon, Surrey 2-June-12
Photo © Vince Massimo
02-Jun-2012
Common Blue Male - Addington, Surrey 30-May-12
Photo © Vince Massimo
30-May-2012
Common Blue Male - Woldingham, Surrey 1-June-12
Photo © Vince Massimo
01-Jun-2012
Common Blues roosting  Stanwell Moor Middlesex  23rd August 2012
Photo © millerd
23-Aug-2012
Common Blue - imago - Greenham Common - 19-Aug-12
Photo © Pete Eeles
Common Blue pair - Cissbury, Sussex 21-July-2010
Photo © Neil Hulme
21-Jul-2010
Common Blue - imago - Greenham Common - 09-Jun-13
Photo © Pete Eeles
Common Blue - imago - Greenham Common - 10-Jun-13
Photo © Pete Eeles
Common Blue - imago - Greenham Common - 10-Jun-13-12
Photo © Pete Eeles
Common Blue - imago - Greenham Common - 10-Jun-13-15
Photo © Pete Eeles
Common Blue - imago - Greenham Common - 10-Jun-13-18
Photo © Pete Eeles
Common-Blue- 5D38428 Lincs June 2013
Photo © IainLeach
Common-Blue- 5D38526 Lincs June 2013
Photo © IainLeach
Common-Blue- 5D38639 Lincs June 2013
Photo © IainLeach
Common Blue, Male - Oxenbourne Down 26/06/2013
Photo © Pauline
26-Jun-2013
Common Blue, Female, Oxenbourne Down, 26/07/2013
Photo © Pauline
26-Jul-2013
Common Blue male - Chantry Hill, Sussex 6-Aug-2013
Photo © Neil Hulme
06-Aug-2013
Common Blue female - Chantry Hill, Sussex 6-Aug-2013
Photo © Neil Hulme
06-Aug-2013
Paired Common Blues ("Love In The Balance)!" Aston Rowant Nature Reserve (Bald Hill) 28/08/2013
Photo © whisperervan
28-Aug-2013
Common Blue - Larkhill - 02-09-2013
Photo © Wurzel
02-Sep-2013
Common Blue Dew - Larkhill - 04-09-2013
Photo © Wurzel
04-Sep-2013
Common Blue Dew - Larkhill - 04-09-2013
Photo © Wurzel
04-Sep-2013
Common Blue male - Tongham, Surrey 2013
Photo © Mike Young
Common Blue, male, Hanover Point, Isle of Wight, 26th August 2013
Photo © Lee Hurrell
Common Blue's - Bishopstone - East Sussex - 6th-May-2014
Photo © Butterflysaurus rex
Common Blue Male - Rusper Road,Crawley 17th May 2014
Photo © Buchan Boy
17-May-2014
Common Bue male - Shadowbrook Meadows Solihull 21.05.2014
Photo © nfreem
21-May-2014
Common Blue male - Shadowbrook Meadows Solihull 21.05.2014
Photo © nfreem
21-May-2014
Common Blue male Solihull West Midlands 01.06.2014
Photo © nfreem
01-Jun-2014
Common Blue female - Solihull West Midlands 01.06.2014
Photo © nfreem
01-Jun-2014
Common Blue female - Shipton Bellinger - 4th August - 2014
Photo © Maximus
04-Aug-2014

Polyommatus icarus ssp. mariscolore


Common Blue - imago - Boston, Clare - Unknown date [Adrian Riley]
Photo © Adrian Riley
Common Blue - imago - North Bull Island, Dublin, Ireland - 12-Jun-13
Photo © Pete Eeles
ssp.mariscolore distribution uncertain
Common Blue - imago - North Bull Island, Dublin, Ireland - 13-Jun-13
Photo © Pete Eeles
ssp.mariscolore distribution uncertain
Common Blue - female - The Raven, Co. Wexford, Ireland - 12-Aug-13-4
Photo © Pete Eeles
ssp.mariscolore distribution uncertain
12-Aug-2013
Common Blue - imago - Ballyteigue Burrow Nature Reserve, County Wexford, Ireland - 20-Aug-13
Photo © Pete Eeles
ssp.mariscolore distribution uncertain
20-Aug-2013
Common Blue ssp. mariscolore - female - Craigavon Lakes, Northern Ireland - 11-Jun-14-11
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - female - Craigavon Lakes, Northern Ireland - 11-Jun-14-12
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - female - Craigavon Lakes, Northern Ireland - 11-Jun-14-13
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - female - Craigavon Lakes, Northern Ireland - 11-Jun-14-15
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - female - Craigavon Lakes, Northern Ireland - 11-Jun-14-17
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - female - Craigavon Lakes, Northern Ireland - 11-Jun-14
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - female - North Bull Island, Dublin, Ireland - 11-Jun-14
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - male - Craigavon Lakes, Northern Ireland - 11-Jun-14-7
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - male - Craigavon Lakes, Northern Ireland - 11-Jun-14-8
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - male - Craigavon Lakes, Northern Ireland - 11-Jun-14-9
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - male - Craigavon Lakes, Northern Ireland - 11-Jun-14-10
Photo © Pete Eeles
11-Jun-2014
Common Blue ssp. mariscolore - male - Craigavon Lakes, Northern Ireland - 11-Jun-14
Photo © Pete Eeles
11-Jun-2014

  Aberrations  

Description to be completed.

Unclassified Aberrations


CmnBlue(ab)_LoughDown_Sep98_2
Photo © MikeOxon
scan from negative - original photo 5th September 1998 at Lough Down, Streatley, Berks
CmnBlue(ab)_LoughDown_Sep98_3
Photo © MikeOxon
scan from negative - original photo 5th September 1998 at Lough Down, Streatley, Berks
Common Blue Female (ab.) Chaldon, Surrey 5-Aug-10
Photo © Vince Massimo
05-Aug-2010
Common Blue Female (ab.) Addington, Surrey 30-July-10
Photo © Vince Massimo
30-Jul-2010
Common Blue Female (variant) - Ballard Down, Dorset 25-May-06 (0155)
Photo © Vince Massimo
25-May-2006
Common Blue - imago - Hartslock - 14-May-08 (15)
Photo © Pete Eeles
14-May-2008
Common Blue - imago - Hartslock - 14-May-08 (20)
Photo © Pete Eeles
14-May-2008
Common Blue - imago - Whitecross Green Wood - 03-Jun-04 (4)
Photo © Pete Eeles
03-Jun-2004
Common Blue (female variant) Windover Hill, East Sussex 16th August 2009
Photo © Lee Hurrell
16-Aug-2009
Common Blue Female (variant) Windover Hill, East Sussex 16th August 2009
Photo © Lee Hurrell
16-Aug-2009
Common Blue - aberration - Beenham Village - Jul-02 [Derek Brown]
Photo © Derek Brown
Common Blue - aberration - Devils Dyke, Newmarket - 10-Jun-07 [Nick Ballard]
Photo © Nick Ballard
Common Blue - imago - Sidmouth, Devon - 17-Jul-07 [Adrian Dexter]
Photo © Adrian Dexter
Common Blue Female - Magdalen Hill Down 29-May-2011
Photo © Pippa
Confused for a (very early) Chalkhill Blue. Undersides had no orange colouration at all.
common blue - finemere wood, bucks
Photo © walt_a
common blue - finemere wood, bucks
Photo © walt_a
Common Blue Female (ab.) Chaldon, Surrey 6-June-10
Photo © Vince Massimo
06-Jun-2010
Common Blue (ab) Fackenden Down, Kent 12 June 2010
Photo © Keith Woonton
Common Blue - imago - Watlington Hill - 28-Jul-10 (1)
Photo © Pete Eeles
28-Jul-2010
Common Blue - imago - Denbies Hillside - 13-May-11 (1)
Photo © Pete Eeles
Common Blue (f) very blue individual; Harmondsworth Moor, Middx  11th May 2011
Photo © millerd
11-May-2011
Common Blue - aberration - Greenham Common - 25-May-12
Photo © Pete Eeles
Common Blue Female (ab.) - Chaldon, Surrey 2-June-12
Photo © Vince Massimo
02-Jun-2012
Common Blue (female), referable to ab. supra-caerulea, Oberthür (1896). St Mary’s, Isles of Scilly (26 August 2012)
Photo © Mark Colvin
26-Aug-2012
Common Blue - imago - Greenham Common - 10-Jun-13-17
Photo © Pete Eeles
Common Blue - imago - Greenham Common - 10-Jun-13-19
Photo © Pete Eeles
Common Blue - imago - Greenham Common - 10-Jun-13-20
Photo © Pete Eeles
Common Blue (confirmed male) ab. - Shropshire 24-July-2013
Photo © ChrissyM
24-Jul-2013
Common Blue - ab - Larkhill - 18-09-2013
Photo © Wurzel
18-Sep-2013
Common Blue - Female - Somerset - 27/05/14
Photo © William
27-May-2014
Common Blue female - Solihull West Midlands 01.06.2014
Photo © nfreem
01-Jun-2014
Common Blue, female, 06/06/2014, Bramshott Common
Photo © Pauline
Common Blue (m) ab. Stanwell Moor Middlesex 2nd August 2014
Photo © millerd
02-Aug-2014

  Ovum  

The white bun-shaped eggs are quite visible and can be easily found on good sites. This stage lasts just over a week.


Common Blue Egg freshly laid - Collard Hill, Somerset 2-June-2011
Photo © jamesweightman
03-Jun-2011
Common Blue Egg side view (laid on Rest Harrow) - Collard Down 2-June-2011 (Image taken 8-June-2011)
Photo © jamesweightman
Common Blue - ovum - Godlingstone Hill - Sep-90 [Tim Norriss]
Photo © Tim Norriss
Common Blue - ovum - Unknown location - 2004 (2) [REARED] [Reg Fry]
Photo © Reg Fry
Common Blue - ovum - Unknown location - 2004 [REARED] [Reg Fry]
Photo © Reg Fry
Common Blue (egg) - Stanwell Moor, Middlesex 1-Oct-2009
Photo © millerd
Common Blue (egg) - Stanwell Moor, Middlesex 1-Oct-2009
Photo © millerd
Common Blue - ovum - Greenham Common - 18-May-11 (1)
Photo © Pete Eeles
Common Blue - ovum - Greenham Common - 18-May-11 (2)
Photo © Pete Eeles
Common Blue - ovum - Greenham Common - 18-May-11 (3)
Photo © Pete Eeles
Common Blue Ova - Somerset - 22/08/13
Photo © William
22-Aug-2013
Common Blue Ovum - Somerset - 29/08/13
Photo © William
29-Aug-2013
Common Blue ovum - Found near Stafford - Summer 2013.
Photo © Tony Moore
15-Aug-2013

  Larva  

The larva emerges after a week or two. On emerging from the egg the larva moves to the underside of the leaf, where it feeds, by day, on the lower surface without breaking through the upper leaf surface. This leaves characteristic blotches on the foodplant that can give away the presence of a larva. More mature larvae feed more extensively on the leaves. Those larvae that overwinter do so in leaf litter at the base of the foodplant, changing from green to olive, resuming their green colouring in the spring.

Like many other species of blue, the larva is attractive to ants, although only in its last instar. There are 4 moults in total. If the larva does not overwinter, then this stage lasts around 6 weeks.


Common Blue Larva with eggshell Larva emerged 12-6-11 from egg laid 2-6-11
Photo © jamesweightman
12-Jun-2011
Common Blue - larva - Stockbridge Down - Jul-99 [Tim Norriss]
Photo © Tim Norriss
Common Blue - larva - Thatcham - 05-May-10 (1) {REARED}
Photo © Pete Eeles
04-May-2010
Common Blue - larva - Thatcham - 05-May-10 (2) {REARED}
Photo © Pete Eeles
04-May-2010
Common Blue - larva - Thatcham - 20-Apr-10 (1) {REARED}
Photo © Pete Eeles
20-Apr-2010
Common Blue Larva (1 day old with empty egg) - Caterham, Surrey 12-Aug-11
Photo © Vince Massimo
12-Aug-2011
Common Blue Larva (3 days old) - Caterham, Surrey 14-Aug-11
Photo © Vince Massimo
14-Aug-2011
Common Blue Larva (17 days old) - Caterham, Surrey 28-Aug-11
Photo © Vince Massimo
28-Aug-2011
Common Blue Larva (21 days old) - Caterham, Surrey 1-Sept-11
Photo © Vince Massimo
01-Sep-2011
Common Blue Larva (34 days old) - Caterham, Surrey 14-Sept-11
Photo © Vince Massimo
14-Sep-2011
Common Blue Larva (post hibernation) - Caterham, Surrey 4-April-12
Photo © Vince Massimo
04-Apr-2012
Common Blue Larva (final instar) - Caterham, Surrey 24-May-12
Photo © Vince Massimo
24-May-2012
Common Blue Larva - Somerset - 27/08/13
Photo © William
27-Aug-2013
Common Blue Larva - Somerset - Freshly Hatched - 28/08/13
Photo © William
28-Aug-2013
Common Blue Larva - Shedding Skin - Somerset - 31/08/13
Photo © William
31-Aug-2013

  Pupa  

The pupa is formed on the ground or, occasionally, at the base of the foodplant, under a few silk strands. The pupa is attractive to ants which may bury it in earth. This stage lasts around 2 weeks.


Common Blue - pupa - Stockbridge Down - Jul-99 [REARED] [Tim Norriss]
Photo © Tim Norriss
Common Blue - pupa - Thatcham - 03-Jun-10 (1) {REARED}
Photo © Pete Eeles
03-Jun-2010
Common Blue - pupa - Thatcham - 03-Jun-10 (2) {REARED}
Photo © Pete Eeles
03-Jun-2010
Common Blue - pupa - Thatcham - 03-Jun-10 (3) {REARED}
Photo © Pete Eeles
03-Jun-2010
Common Blue pupal cell - Caterham, Surrey 29-May-12
Photo © Vince Massimo
29-May-2012
Common Blue Pupa (11 days before hatching) - Caterham, Surrey 3-June-12
Photo © Vince Massimo
03-Jun-2012
Common Blue Pupa (3 days before hatching) - Caterham, Surrey 11-June-12
Photo © Vince Massimo
11-Jun-2012
Common Blue Pupa (2 days before hatching) - Caterham, Surrey 12-June-12
Photo © Vince Massimo
12-Jun-2012
Common Blue Pupa (1 day before hatching) - Caterham, Surrey 13-June-12
Photo © Vince Massimo
13-Jun-2012
Common Blue pupa (6 days old) - Caterham, Surrey 3-June-12
Photo © Vince Massimo
03-Jun-2012
Common Blue Pupa (6 days before hatching) - Caterham, Surrey 8-June-12
Photo © Vince Massimo
08-Jun-2012
Common Blue Pupa (4 days before hatching) - Caterham, Surrey 10-June-12
Photo © Vince Massimo
10-Jun-2012
Common Blue Pupa (3 days before hatching) - Caterham, Surrey 11-June-12
Photo © Vince Massimo
11-Jun-2012
Common Blue Pupa (2 days before hatching) - Caterham, Surrey 12-June-12
Photo © Vince Massimo
12-Jun-2012
Common Blue Pupa (1 day before hatching) - Caterham, Surrey 13-June-12
Photo © Vince Massimo
13-Jun-2012

  Similar Species  

Adonis Blue

The male Adonis Blue is often mistaken for a male Common Blue. However, the two can be distinguished by looking at the white fringes of the wings. Only on the Adonis Blue are the fringes intersected by black bands. This diagnostic can also be used to distinguish the two species based on their undersides.


Adonis Blue male (left) and Common Blue male (right)

Brown Argus

Of the two sexes, it is the female Common Blue that causes most confusion with the Brown Argus. The blue present in a female Common Blue is highly variable, with individuals ranging from almost completely blue through to completely brown. It is this latter colouring that causes the most confusion. Even so, the Brown Argus has no blue scales, but may give off a blue sheen from the wings and the hairs found on the thorax and abdomen. Another diagnostic is that the Brown Argus normally has a prominent dark spot in the centre of the forewings.


Brown Argus (left) and female Common Blue (right)

Differentiating Brown Argus and Common Blue from their undersides is even more problematic, and we need to resort to the pattern of spots. Here we have two distinguishing features. The first is that the Common Blue has a spot on the underside of the forewing that is absent in the Brown Argus. The second is that two of the spots on the leading edge of the hindwing are relatively-close in the Brown Argus, almost forming a "figure of eight", but are more spaced apart in the Common Blue. This diagnostic is particularly useful if the underside of the forewing isn't visible.


Brown Argus (left) and Common Blue (right)

Chalkhill Blue

Description to be completed.

Holly Blue

Description to be completed.

Northern Brown Argus

Of the two sexes, it is the female Common Blue that causes most confusion with the Northern Brown Argus. The blue present in a female Common Blue is highly variable, with individuals ranging from almost completely blue through to completely brown. It is this latter colouring that causes the most confusion. Even so, the Northern Brown Argus has no blue scales, but may give off a blue sheen from the wings and the hairs found on the thorax and abdomen. Another diagnostic is that the Northern Brown Argus normally has a prominent dark spot in the centre of the forewings and, in the case of the artaxercxes subspecies of Northern Brown Argus, it a distinctive white dot. Any identification challenges are usually, therefore, with respect to the salmacis subspecies of Northern Brown Argus that does not have this white spot.


Common Blue female (left) and Northern Brown Argus ssp. salmacis (right)

Differentiating Common Blue and Northern Brown Argus from their undersides is even more problematic, and we need to resort to the pattern of spots. Here we have two distinguishing features. The first is that the Common Blue has a spot on the underside of the forewing that is absent in the Northern Brown Argus. The second is that two of the spots on the leading edge of the hindwing are relatively-close in the Northern Brown Argus, almost forming a "figure of eight", but are more spaced apart in the Common Blue. This diagnostic is particularly useful if the underside of the forewing isn't visible.


Common Blue (left) and Northern Brown Argus (right)

Silver-studded Blue

Description to be completed.

  Videos  

Video © John Chapple
Common Blue.

  Sites  

Click here to see the distribution of this species overlaid with specific site information. Alternatively, select one of the sites listed below.

Sites
Aberffraw Dunes, Airhouse Quarry, Aldbury Nowers, Alemoor West Loch and Meadow SSSI, Allan Water Hillhead SSSI, Arlington Reservoir, Arnside Knott, Arthur's Seat, Ashampstead Common, Aspal Close, Aston Rowant NNR, Attenborough Nature Reserve, Badbury Rings, Banstead Downs, Banstead Woods, Barkbooth Lot, Beachy Head, Bedfont Lakes Country Park LNR, Berwick Hills Allotments, Bishop Middleham Quarry, Bryncelyn Hall, Burnmouth Coast SSSI, Butchershole Bottom, Coldingham Bay, Cuerden Valley Park, Darlands Banks LNR, Denbies Hillside, Devil's Ditch, Dowlaw Dean, Dunhog Moss SSSI, Durlston Country Park, Durlston NNR, Ellerburn Bank, Fermyn Wood, Fleam Dyke, Forest Farm Meadows, Gait Barrows, Glenarm, Glenkinnon Burn SSSI, Gordon Moss SSSI, Greenham Common, Greenlaw Dean, Gwrelych Valley, Hangingshaw Burn, Hareheugh Craigs SSSI, Hartwoodmyres, Higher Hyde, Horsenden Hill, Hounslow Heath LNR, Howardian Local Nature Reserve, Hutton Roof Crags, Hyde, Invermoriston, Kinghorn Loch Path, Lauder Burn, Laughton Common Wood, Lavernock, Leighton Moss, Lindean Reservoir SSSI, Linn Dean, Loch Ard Forest, Mansmead wood, Mayford Pond, Meldon Hills, Mill Hill, Millenium Arboretum, Moss Field, Mount Caburn, Mynydd Marian, Nupend Wood, Old Down, Basingstoke, Over Cutting, Pulborough Brooks (RSPB), Redscar and Tunbrook Woods, Rookery, Roughlee, Ryton Woods Meadows, Shankend, Smardale Gill, St Abbs Head, St. Abbs Head to Fast Castle SSSI, Staines Moor, Stockbridge Down, Strumpshaw Fen, The Bell, Thornielee Forest, Thurlbear Quarrylands, Tophill Low, Totternhoe Knolls and Quarry, Whitbarrow Scar, Whitecross Green Wood, Whitlaw Mosses NNR, Whixall Moss, Willesley Wood, Windover Hill, Yair Hill Forest, Yoesden Bank

  Conservation Status  

Despite a general decline in distribution, this butterfly remains widespread and is not currently a species of conservation concern.

UK BAP StatusDistribution TrendPopulation Trend
Not ListedStableDecrease

From The State of Butterflies in Britain and Ireland and the UK Biodiversity Action Plan (UK BAP) (2007 review).


  Links  

The following links provide additional information on this butterfly.

  References  

The species description provided here references the following publications:

ReferenceDetails
Dennis (1977) Dennis, R.L.H.: The British Butterflies - Their Origin and Establishment. 1977.
Ford (1945) Ford, E.B.: Butterflies. Edn.1. 1945.
Graves (1930-1) Graves, P.P.: Notes on Collecting in Ireland. Entomologist's Record and Journal of Variation. 1930.
Kane (1885) Kane, W.F. de Vismes: European Butterflies. 1885.
Kane (1893) Kane, W.F. de Vismes: A catalogue of the Lepidoptera of Ireland. The Entomologist. 1893.
Nash (2012) Nash, D., Boyd, T. and Hardiman, D.: Ireland's Butterflies: A Review. 2012.
Oberthür (1910) Oberthür, C.: Etudes de Lépidoptérologie comparée. 1910.
Riley (2007) Riley, A.M.: British and Irish Butterflies: The Complete Identification, Field and Site Guide to the Species, Subspecies and Forms. 2007.
Rottemburg (1775) von Rottemburg, S.A.: Der Naturforscher. 1775.
South (1887) South, R.: Notes on the Genus Lycaena. The Entomologist. 1887.
Thomas & Lewington (2010) Thomas, J. and Lewington, R.: The Butterflies of Britain and Ireland. Edn.2. 2010.
Thomson (1980) Thomson, G.: The Butterflies of Scotland. 1980.

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