Brown Argus

[ChrisC]

A query to Millerd in the March sightings thread has me wondering about this species. back in 1999/2000 i recorded a brown argus just outside middlesex ( probably a stones throw) into bucks. my memory is a bit hazy on who or where i posted the pic for confirmation but i seem to recall (possibly incorrectly) that no brown Argus colonies in Middlesex existed at that time. (liz might be able to shed some light on the then and current distributiion changes) what i was wondering, has it spread? if so is this spread due to climate? according to Uk butterflies "This species occurs in small, compact colonies, and is not a great wanderer, only travelling a couple of hundred metres, at most, from where it emerged." or are green corridors working around Heathrow? or is it more of a wanderer than first thought. whatever the cause it's a great little butterfly and long may it's spread continue.

(it shocked me when i looked it up that it was over 10 years ago )

Chris

[millerd]

Brown Argus is certainly present at Harmondsworth Moor, and in at least two separate locations in and around Stanwell Moor. In 2009, in one of the latter locations, I saw the last ones in October, probably a third brood. They may be more mobile than we think.

Here's one from last May at Stanwell Moor.

Dave

[ChrisC]

nice shots Dave, more research has found Brown argus at Bedfont lakes in 1997 so my initial information might be wrong to begin with. hopefully someone in the know will put me straight

http://www.ukbms.org/SpeciesListbyYear. ... &year=1997

Chris

[Piers]

Hi Chris,

See this thread: viewtopic.php?f=2&t=3968&p=30788&hilit=+supper#p30788

...which should go some way to address at least part of your question. Please try to look past the 'climate change' hijack (the world's most jumped on band wagon ) but it does discuss this species in particular taking advantage of favourable climatic conditions, temporarily or otherwise.

Felix.

[David M]

That second photo is exceptionally good.

[ChrisC]

Thanks for the link felix. an interesting read.
Chris

[Crispin]

...... no brown Argus colonies in Middlesex existed at that time. (liz might be able to shed some light on the then and current distributiion changes) what i was wondering, has it spread? if so is this spread due to climate? according to Uk butterflies "This species occurs in small, compact colonies, and is not a great wanderer, only travelling a couple of hundred metres, at most, from where it emerged." or are green corridors working around Heathrow? or is it more of a wanderer than first thought. whatever the cause it's a great little butterfly and long may it's spread continue.

Hi Chris
This may answer your observation:
Brown Argus larvae historically used Rock-rose (and still does) but in more recent years it has been found to also use Cranesbill. As a result some parasitoids, such as the ichneumonid wasp Hyposoter notatus, have difficulty locating Brown Argus larvae that feed on Cranesbill and will instead predate Common Blue larvae. Brown Argus has been able to expand its range northwards in Britain during the last 30 years as a result of warmer conditions and the increased use of Cranesbill as a food plant.
Here is a link to the paper:
http://onlinelibrary.wiley.com/doi/10.1 ... 985.x/full
Alternatively:
http://www.nicholas.duke.edu/people/fac ... nsects.pdf

Saw my first female 2011 Orange Tip today.
Many spiders I have yet to identify and I think my list of birds today was 24 species (no House Martins or Swallows yet).

Crispin

[millerd]

That second photo is exceptionally good.

Thank you, Dave. It was a lovely brand new individual.

Dave

[ChrisC]

thanks for the links Crispin, good to hear a fellow spider admirer too
Chris