Blue Form of Common Blue

[Devon Dave]

It was a cool cloudy morning yesterday with little sun until the afternoon but I did spot this Common Blue snuggled up in the grass of a local meadow.Obviously a female, but a very blue one and I hazarded a guess at being the Blue form of the species. Any thoughts welcome, and sorry about all the blades of grass obscuring the view of her.

[millerd]

Hi Dave,

Common Blue females display a huge variety in colouration, ranging from those that are nearly as brown as a Brown Argus to some that are even bluer than your striking example. Consequently, there is nothing that can be strictly classified as a definitive "blue" form: the majority of females will have some blue on them. A browse through the examples in the species album linked below will demonstrate what I mean about variety!
https://ukbutterflies.co.uk/album.php?id=304
Here's the link to the "aberrations", with more extreme examples shown. There are some very blue females here.
https://ukbutterflies.co.uk/album.php?id=305

Cheers,

Dave

[Chris L]

Wow ! That is a very striking shade of blue. All of the colours on the butterfly look like they have been done with wax crayons. Well, they do to me at any rate. I am glad that I have been made aware of this phenomenon. It would have baffled me had I encountered one out in the field. Even worse if I had encountered one in the field and not got a photo.

Thank you Dave and Dave.

[Devon Dave]

Dear Otep she was really a lovely deep blue and very striking,and thanks to Dave for your information, all noted with great interest.
I wonder what the true Blue form actually looks like and how it is distinguished.Or is the "Blue Form" of the species just a general name for any like mine.
Good Hunting yourselves, the season is upon us, just need some stable weather now.

[millerd]

I've always loved the variety female Common Blues provide (though I don't recall ever seeing one sporting quite such a deep shade of blue as Devon Dave's).

Here is a recent selection from Mill Hill in Sussex (18th May)...

...plus one seen today (20th) on my local patch near Heathrow.

They are always worth looking for and make a very rewarding study - the modern equivalent of the obsessions of Victorian butterfly collectors I suppose.

Dave

[zigzag_wanderer]

Fantastic pictures on this page I have to say.

As a linked aside (and one I appreciate should possibly be housed under separate cover), presumably Brown Argus males were blue at one stage in their development history as they split off from (I assume) a common ancestor of themselves and Common Blue ?

If so I wonder what caused the move to a more uniform brown between sexes.

The alternative of course is that they split off before the blue scale evolution in a common ancestor of all the other blues, but that seems more unlikely.

I find all this stuff fascinating. Even Dave's comment on the Victorian collectors makes me ponder what very subtle changes to female (or even male) Common Blue blueness has occurred since then.

(Apologies if Brown Argus lack of blueness has been regularly featured during the ongoing evolution of UKB itself !).

[millerd]

Here's another lovely new example seen on my local patch today...

Common Blues and Brown Argus are in two entirely different genera, so if they evolved from a common ancestor it is likely to have happened a long time ago. Paradoxically, there are European species in the Common Blue's genus (Polyommatus) which are completely brown (including the males), and at least one species in the Brown Argus' genus (Aricia) which is blue...

Dave

[zigzag_wanderer]

Ah...thanks for that Dave. I must admit my knowledge of butterfly Latin names is shockingly poor. I know slightly more about moth taxonomy because there's so many of the blighters that you have to learn some basic groups to have any chance of IDing them. But I'm still only on common name terms with the UK butterflies for the simple (and admittedly lazy) reason that there's only a comparatively limited number of species to ID.

It does leave me a bit exposed when asking questions like this on here though

Barring the obvious upperwing colour and size differences they do look very similar (to me) though, which is my only excuse.

Fascinating to learn about the European differences in these two genera. But foreign butterfly species represent a whole separate mountain of my ignorance. Or, as one of my teachers used to more kindly put it, "a development opportunity".

Mind you I was looking closely at the Painted Lady I spotted in the late afternoon sun on Thursday thinking its hind wings definitely had a bit of a Silver-washed Fritillary look and sheen to them....and even I know they're in different genera, although I have just triple checked before hitting submit

[Testudo Man]

Good thread, with some lovely examples of females posted.
I do like to see if i can find some nice colour variants each season myself.
I also refer to some of these as "blue form", but as Dave/Millerd has suggested, they all "come under the same roof" really, with just so many colour variations seen. The OP's blue example looks above average for sure an it would seem that this last Saturday, i may have found one to equal Devon Dave's .
Whilst his images are not as clear as we could have wished for, you can still see she is a real blue beauty.
I managed to get some "clearer" images myself, an it would seem our 2 females are quite similar in colour/appearance?
As with all things such at this, camera/lens/settings/equipment/light/sun/cloud/angles/time of day, etc. etc. do play a part in how the colour of the butterfly appears...but we all know that when we see a super blue looking female out in the field, its a kinda special moment...makes it all worth while, with the hours an hours of trundling up an down those hillsides

Anyway, my possible matching blue female. 2 camera setups used for each image...I think at least half an hour between shooting times, an conditions were not the same. Im pretty sure both my images are of the same female. Images are not cropped. Cheers Paul.

Camera 1.

Camera 2.

[millerd]

That's another gorgeous turquoise-blue female, TM, whichever way you look at it! I'm on the lookout for one like that, as the females are currently emerging on my local patch, and every one is different and all are little gems. At the risk of monopolising the thread, here are three more...

Here's one seen yesterday (22nd), which is as nearly typical if there could be such a thing.

I then followed this with two more today, one in the morning and one in the afternoon, both completely different.

Cheers,

Dave

[millerd]

Lots more variety today (26th) - the cloudy but warm and bright conditions prompted them to bask, and the strong wind kept them in sheltered spots.

Dave

[Jack Harrison]

I am sure someone will have done a study of the genetics of Common Blue.

Common Blue females seem to have the entire range of colours from no blue at all to extensive amounts.
However, compare say, Silver Washed Fritillary. Females are either 'normal' or valesina with nothing in between.

If it hasn't already been done, then breeding from blue Common Blues would be a very good project for a young lepidopterist.
I say 'young' as it might take a long time for the results to become clear!

Jack

[IacobnDG]

It is at least partially developmentally plastic in some populations, this great paper was written on that a few years ago:
Kertész, K., Piszter, G., Horváth, Z. E., Bálint, Z., & Biró, L. P. (2017). Changes in structural and pigmentary colours in response to cold stress in Polyommatus icarus butterflies. Scientific Reports, 7(1), 1–12. https://doi.org/10.1038/s41598-017-01273-7

In Ireland most of our females have around this level of blue suffusion, but the orange lunules tend to be more pronounced, eg
https://www.ukbutterflies.co.uk/phpBB/d ... &mode=view
https://www.ukbutterflies.co.uk/phpBB/d ... &mode=view
This must be a genetic difference, but I don't think any work has been done on it.

[Testudo Man]

That's another gorgeous turquoise-blue female, TM, whichever way you look at it! I'm on the lookout for one like that, as the females are currently emerging on my local patch, and every one is different and all are little gems. At the risk of monopolising the thread, here are three more...

Here's one seen yesterday (22nd), which is as nearly typical if there could be such a thing.CB1 220522.JPGI then followed this with two more today, one in the morning and one in the afternoon, both completely different.CB1 230522.JPGCB2 230522.JPG

Cheers,

Dave

Thanks for that Dave, yes that female was a little beauty.
Monopolize away ...you can never see enough of these female Common Blues.

[Testudo Man]

It is at least partially developmentally plastic in some populations, this great paper was written on that a few years ago:
Kertész, K., Piszter, G., Horváth, Z. E., Bálint, Z., & Biró, L. P. (2017). Changes in structural and pigmentary colours in response to cold stress in Polyommatus icarus butterflies. Scientific Reports, 7(1), 1–12. https://doi.org/10.1038/s41598-017-01273-7

In Ireland most of our females have around this level of blue suffusion, but the orange lunules tend to be more pronounced, eg
https://www.ukbutterflies.co.uk/phpBB/d ... &mode=view
https://www.ukbutterflies.co.uk/phpBB/d ... &mode=view
This must be a genetic difference, but I don't think any work has been done on it.

Thanks for those fascinating links, i confess to only really "skim reading" them so far, but as i said, fascinating stuff.

[millerd]

Monopolize away ...you can never see enough of these female Common Blues.

I tend to agree - here are a few more, all from the same site... Considering all these individuals will have been subjected to the same weather conditions throughout their pupation period, it's hard to see how temperature extremes could be the reason for their wide variety of colouration.

21st May

3rd June

3rd June

1st June

1st June

21st May

Dave