www.ukbutterflies.co.uk

http://www.facebook.com/photo.php?fbid= ... =1&theater
This Facebook link shows a Swallowtail pair; I saw that the male was more yellow than the female. She is much lighter in colour.
And I got to thinking of my own shots from Strumpshaw, and elsewhere, over the last few years. Re-examining them, I saw this accounted for,one morning, when all the individuals I saw were much yellower than others I had taken. I had taken it that the WB on the camera had adjusted the colours, but the colours were right!
So, from a limited sample, it does seem that the males are more yellow than the females I have seen, here and abroad.
I wondered if anyone has any observations or thoughts on this?
N

That's a thought, Nick. I can't tell much from my own photos because it has taken me years to learn how to photograph yellow things anyway. It used to be a matter of luck whether a swallowtail turned out yellow or white. But all my recent hilltopping males certainly look very bright yellow. I'll keep my eyes peeled this summer.


(Hilltopping male last summer)

Guy

Could this be because females are generally larger than males? An individual, say, 10% smaller with the same markings might possibly seem more intensely coloured due to the black coloration being 'squeezed' into a smaller space, thus making the lighter colour appear darker.

Probably talking nonsense, but just a thought all the same.

A couple of examples from Strumpshaw....on the same day.