www.ukbutterflies.co.uk

Climbed up to the Primrose Hill community wood on Sunday, which is on the slopes behind our house on the outskirts of Bath.

Saw plenty of Common Blues males and females:



Also, my first Large Skipper of the year:


Also seen, peacock, speckled wood, brimstone (m+f), whites.

Thought I saw a Dingy Skipper on the way down the hill, which would have been a first, but it turned out to be a Mother Shipton - still, a nice consolation.


Simon

Great shots!

Martin.

Cool shots. Like the female common blue, very nice. Also like the mother shiption too.

I think your female common blue is a brown argus! Good shots!

I thought that was a brown argus too, now you mention it. Does'nt Female common blue have slight blue patches?

Oh dear - I thought I had this one licked.

My rule is bluish tinge = female blue. No blue = brown argus. So with this one, I thought the bluish tinge on the body (it looks bluish on my computer monitor - maybe that's the problem) meant this had to be a female blue.

Are you sure its a brown argus?

At least one male showed some interest in the subject of the photo, but never consumated. Maybe it knew what I didn't!

Simon

...sorry, but I'm not 100% sure. Look at the Brown Argus page on this site and the Common Blue page, makes me think I'm right.

Usually in these situations some qualified expert jumps into help and will be able to count the number of rings on the left, dorsal gubberthump or something or other!

Help someone!

First off - I'm not a qualified expert

But I think this is a Brown Argus. Female Common Blues always (in my experience) have a varying number of blue *scales* on the forewings. The "tinge" is always visible (again, in my experience) depending on the angle of the body and wings.

Cheers,

- Pete

Thanks Pete!

A Brown Argus would be a first for me on this hill side, although I've seen them in the adjacent valley.

I'm happy to take your reading of this as correct. However.... as an observation which I'd appreciate a comment on, I looked at the blues on the species page, and to me, the piccies that are evidently female uppersides are not typical compared to, say, the illustrations in books done by Richard Lewington, which are what I tend to rely on (not having access to the internet at home). I always assumed it was because the more blue that is present, the prettier the photo, and hence the more likely it is to be kept and/or sent in. Hence I put the difference down to the photos not necessarily being representative.

But maybe I've had it wrong and I've not been careful enough, and there are more Brown Argus's around than I suspected (and correspondingly, far fewer female blues). Would you say the ratio of male:female common blue is 1:1?

I'll certainly pop up the hill at the weekend, weather permitting, and try to get some undersides and use Guy's classification scheme. If successful, I'll report back.

Simon

I can only comment from my own experience but it does seem that male common blues usually significantly outnumber females. However, I'm sure your photo is a brown argus; as Chris says, the rings on the left dorsal gubberthump give the game away.

When I lived in Suffolk I saw the number of brown arguses increase dramatically from zero (I lived in East Suffolk) to its being a common heathland and coniferous woodland butterfly. I think it has generally expanded its range. Thus, it is something one should be increasingly aware of.

The ratio of male to female common blues changes through the season. The first blues on the wing are almost invariably males and they set up their territories for up to a week or so before females become very evident. There is then a period during which females become increasingly common, and finally they at least equal male numbers, in my experience. However, ancient males do seem to drag on and are often the last to be seen of a brood, perhaps because they don't have to expend so much energy on eggs and laying, and instead spend their days at the pub enjoying themselves.

Whenever my first sighting of a particular species of blue at a particular site is a female I suspect that she is a vagrant and that it is not (yet) a true breeding colony.

Re the underside brown argus/common blue distinction, a couple of things to note I didn't mention in my last post. Occasionally, common blues lack the cell spot (but brown arguses never have one). This form, icarinus, is something I personally have only ever seen in males. Secondly, the 'colon' spots in Aricia species may be quite oblique, but are always clearly out of line with the arc. I photographed this artaxerxes (allous) yesterday, after my post, and noticed that it had really very oblique spots - but they still show it is Aricia.



Guy

Another thought, if I'm not getting too boring!!

Male blues have different habits from females and may be seen literally miles away from the breeding colony, nectaring or taking minerals. Thus, in some areas you might only see males. I was excited to bits to find a male Osiris blue in my garden yesterday, and even more thrilled when he reappeared today, in the company of a second Osiris blue. But I don't have the necessary foodplant in the garden and it is highly unlikely I shall ever see a female here.

Guy

You're posts are never boring, Guy!!!

Thought something was odd about Brown Argus. I saw one in my local town, on a car last year. It landed for a minute and flew off.Never seen one here before. The oly place I think they could be was on a hill about 5-6 miles away from this location.

Large skipper found at Hazelbury on 26th May. Cool weather meant that they were approachable: