www.ukbutterflies.co.uk

Taken in the Dordogne three weeks ago. I wasn't able to get upper wing, unfortunately, as it flew off too fast to follow, but I know it is a male as I could see it was blue as it flew.

Thanks
Trik

PS : The reason I am asking is that there was a confirmed female Escher's in the vicinity.

I guess it's possible, but my limited experience of Escher's is of an underside forewing with orange lunules, which this specimen lacks.

I think it might take a Padfield or a Gibbons to comment definitively on this.

I had noted the lack of orange lunules on the underside of the forewing, although you mention upperside hindwing, David? There is no checkering on the fringes, so not Adonis. I believe that Common Blues can lack the cell spot although I did not see any definite Common Blues in the area, so with the presence of the female Escher's, that was my best guess. We tried to net it, but it was off like a shot and not seen again.

Trik

Sorry Trik, that was a typo. I meant underside forewing, and must resolve to be more careful when posting!! (I have corrected my earlier faux pas).

I think it is Escher's. Obviously an upperside would have been nice, as undersides of blues can be incredibly variable, but Escher's is the obvious choice here. The only other option is Chapman's, which typically has much better developed oranged and less heavy branding - this doesn't feel like Chapman's to me.

Guy

Thank you, Padfield. I will call it Escher's unless/until I hear to the contrary. We did find another blue at the same site which was initially thought to be a Chapman's, but there turned out to be a very tiny dot in the cell of only one forewing. I suggested it might just have been loss of scales or some such, but no one was convinced!

Thanks again
Trik

Chapman's/common blue is usually easy without regard to the cell spot, from the upperside or underside. If you have any pictures, feel free to post them.

I think those species that lack a cell spot have lost it in more recent evolutionary history, rather than those that have it having gained it. A spot may appear atavistically in pretty well any species and may similarly be absent in any species that is supposed to have one. Tim Cowles recently sent me photos of an Adonis blue lacking the cell spot on both sides. For this reason, although it is a handy thing to look for, the presence or absence of a cell spot can never be considered definitive in itself.

Guy

Trik,
Here is an Escher's Blue I saw last year in the Sierra Nevada. Looks pretty close to your butterfly.
Nick

I do find identifying the non-UK blues tricky (no pun on my user name intended!). The Turquoise Blue is OK, and probably Reverdin's, but the others... Re cell spot v. no cell spot, I have a shot of an Adonis female taken in the UK that seems to have a double cell spot, like a figure of eight.

Thanks for your shot of an Escher's, Nick.

Trik