Adonis Blue (Polyommatus bellargus)
Species

Male. Taken at Lardon Chase, Berks, on August 18th 2013.
(1/500th sec at f13. Approx 3x lifesize)

Male underside. Taken at Aston Rowant NNR, Oxon., on August 29th 2016.
(1/200th sec at f13. Approx 3x lifesize)

Female. Taken at Lardon Chase, Bucks on August 20th 2011.
(1/125th sec at f13. Approx 3x lifesize)

Female underside. Taken at Lardon Chase, Berks, on August 26th 2012.
(1/125th sec at f14. Approx 3x lifesize)

Mating pair. Taken at Aston Rowant NNR, Oxon, on August 29th 2016.
(1/200th sec at f13. Approx 3x lifesize)

© David Hastings

Description

Wing span: 30 - 40 mm
 
This butterfly is found on chalk and limestone grassland where the turf is short. The sexes are strongly dimorphic; the males are a brilliant blue, and the females are chocolate brown. There are 109 named aberrations known to occur in Britain. Occasionally hybridisation occurs with the Chalkhill Blue.
 
This species is restricted to the south and east of England.
 
There are two broods each year. The first adult emergence is in the second half of May, peaking at the end of May and beginning of June. The second adult emergence is in the second half of August, peaking at the end of August and beginning of September. The larva is the over-wintering stage. Larvae are often attended by a species of red ant (Myrmica sabuleti) or a black ant (Lasius alienus).
 
The larval foodplant is Horseshoe Vetch. Adults feed primarily on Marjoram and Ragwort.
 
The female Adonis Blue can easily be mistaken for a female Chalkhill Blue. One guideline is that the pale scales on the hindwings, between the red dots and the white fringe, are blue in a female Adonis Blue and white in a female Chalkhill Blue.
 
This species is listed as Near Threatened in the latest Red List of British Butterflies (PDF).
 

Sightings

29-Aug-2016:Aston Rowant NNR, Oxon(7m,1f)
29-May-2016:Pewsey Down, Wilts(8m)

29-Aug-2015:Lardon Chase, Berks(1m)
22-Aug-2015:Aston Rowant NNR, Oxon(3m)
22-Aug-2015:Yeosden Bank, Bucks(2m,1f)
26-Jul-2015:Bansko meadows, Bulgaria
23-Jul-2015:nr Novo Hodzhovo, Bulgaria
20-Jul-2015:Kresna Gorge, Bulgaria
30-May-2015:Aston Rowant NNR, Oxon(7m)

23-Aug-2014:Aston Rowant NNR, Oxon(5m,1f)
16-Aug-2014:Aston Upthorpe Downs, Oxon(1)
01-Jun-2014:Lardon Chase, Berks(2m)

31-Aug-2013:Aston Rowant NNR, Oxon(16m,1f)
18-Aug-2013:Lardon Chase, Berks(28m,2f)
09-Jun-2013:Cotley Hill, Wilts(6m)