Brown Argus
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Gosfield
f. snelleni. Male. 20 May 2014
Brown Argus
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Great Yeldham
Male. 24 May 2011
Brown Argus
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Bison Hill, Beds
Male. 9 June 2013
Brown Argus
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Great Yeldham
Male. 7 July 2011
Brown Argus
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Great Yeldham
19 July 2010
Brown Argus
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Great Yeldham
Female. f. snelleni. 21 July 2014
Brown Argus
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Great Yeldham
Female. f. snelleni. 21 July 2014
Brown Argus
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Great Yeldham
Female. f. snelleni. 21 July 2014
Brown Argus
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Great Yeldham
Female. 27 July 2013
Brown Argus
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Great Yeldham
Female. 27 July 2013
Brown Argus
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Great Yeldham
Female. 27 July 2013
Brown Argus
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Great Yeldham
Male. 2 August 2013
Brown Argus
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Great Yeldham
Male. 2 August 2013
Brown Argus
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Great Yeldham
Female. 14 August 2013
Brown Argus
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Aston Rowant
Female. 26 Aug 2012
Brown Argus
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Devil's Dyke
Male. 15 Sept 2012

Brown Argus underside
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Brown Argus.

Brown Argus underside, missing a spot.
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Brown Argus (missing a spot).

Common Blue underside
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Common Blue.

The Brown Argus, Aricia agestis

The Brown Argus was one of our more common butterflies in 2010, becomming scarcer in 2011 and 2012. In Great Yeldham the adults can be seen feeding on Thistle, Knapweed and Water Mint flowers.

It has two broods per year, flying in May to June, and early July to September. Overwinters as a caterpillar.

Brown Argus in flight are usually more busy and erratic than Common Blue, quite close to the ground and not far above the foliage. Often, briefly, in little groups of two or three together.

Female Common Blues can be similar to Brown Argus, but are not usually quite so uniformly dark brown.

The undersides of the forewings of the Brown Argus lack a spot on the forewing between the main central spot and the wing-base.

On the undersides of the leading edge of the underwing, the second and third spots outwards are close together if not above each other (like a colon) in the Brown Argus, but further apart in the Common Blue. If in doubt double check with the lack of extra spot on the fore-wing.

Brown Argus are usually noticably smaller than Common Blues but this character cannot be relied upon as is shown by an extra small Common Blue female in South's plate 106.

The illustrations in South's 'Butterflies of the British Isles' are not particularly clear by modern standards. They are all of pinned specimens, but by their number of examples give a good indication of the amount of variation to be expected in the spotting of the undersides of the blue butterflies.

The larval foodplants are usually given as Rock Rose, a plant of chalky downs. Butterflies of Essex notes that in this county, where we lack Rock Rose, the main foodplants are Storksbill and Cranesbill. Long Stalked Cranesbill, Geranium columbianum is scattered in the grass all over the paddock at Roseland House.

Internal links: Home . Butterfly list . Main gallery . Aston Rowant

External links to the Brown Argus pages at: British Butterflies by Steven Cheshire . Peter Eele's UK Butterflies website
Search menu at Cockayne database for forms and aberrations

Adults in flight: MOST SEEN on ANY ONE DAY in early, mid and late month thirds.
Brown Argus sightings at Roseland House, Great Yeldham.
March April May June July August Sept
2011 0 0 0 0 0 0 0 1 2 2 1 1 1 0 2 2 4 2 1 0 0
2012 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 1 0 0 0
2013 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 6 3 2 0 0
2014 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 3 0 0 0 0 0

Adults in flight: AVERAGE SIGHTINGS PER COUNTING DAY in early, mid and late month thirds.
Brown Argus sightings at Roseland House, Great Yeldham.         All species
March April May June July August Sept
2011 0 0 0 0 0 0 0 0.3 0.4 1.0 0.4 0.1 0.1 0 1.3 1.0 0.5 0.2 0.1 0 0
2012 0 0 0 0 0 0 0 0 0.1 0 0 0 0 0 0 0 0.1 0.2 0 0 0
2013 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.2 0.8 1.3 0.9 0.1 0 0
2014 0 0 0 0 0 0 0 0 0 0 0 0 0 0.3 1.0 1.0 0 0 0 0 0

Weather notes:
2011. July - early August very wet.
2012. April - mid July very wet. August to mid September dry.
2013. Winter wet, March and early April, very cold. The rest of the spring was mostly cold. July, mostly very warm. August, warm.
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20 May 2013