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Today I have snapped a pale clouded yellow in our garden. Help me with ID, please: Is it C. hyale or C. alfacariensis?

I live in a region where alfacariensis is a common resident and hyale is, I think, a relatively scarce visitor. In fact, I'm not sure I've ever confirmed a female hyale here for certain - the one currently on my website is undoubtedly alfacariensis and I should remove it! I have identified some males with certainty as hyale (only a few each year).

That's my caveat. Here's the diagnosis: I think the female in those pictures is alfacariensis. It is certainly well within the shape boundaries of my local ones and clearly different from the recent female hyale you posted laying on clover.

Distributionally, both species occur in your region. C. alfacariensis is a sedentary species of calcareous areas, whereas hyale is more mobile and not so restricted in terms of habitat. In my region, hyale is commoner in the second, summer brood, whereas alfacariensis, not being an immigrant, is more constant. The ecological clues are useful, and with females the laying preferences are obviously very useful.

I'd be interested to know if others who have experience of the two species agree your present insect is alfacariensis.

Here is a recent female alfacariensis:



Here is a male hyale, showing the very different wing shape:



As I say, I don't have a confirmed female hyale, so the comparison isn't really very fair, but here's a male alfacariensis to set against the male hyale:



Guy

traplican wrote:Today I have snapped a pale clouded yellow in our garden. Help me with ID, please: Is it C. hyale or C. alfacariensis?

Are all images of the same individual?

Cheers,

- Pete

Pete Eeles wrote:

traplican wrote:Today I have snapped a pale clouded yellow in our garden. Help me with ID, please: Is it C. hyale or C. alfacariensis?

Are all images of the same individual?

Cheers,

- Pete

Yes, they are. Dye differences are caused by different illumination.

Hi Guy,

That wing shape trick could be very useful. Is it the same in the two females as well?

In my opinion, the wingshape on Traplican's shots matches your female alfacariensis rather than the male hyale.

Cheers

Lee

Hi Lee,

The wing shape is probably a strong indicator but I should say that Roger Gibbons, Tim Cowles and I have been looking at it for some time and not found a 100% reliable way of assessing it. We still disagree on some individuals (usually, on potential hyale, as we all see far more alfacariensis and most of these are quite unambiguous).

There are clearer indications on the upperside, especially of males, and I have found a strong correlation between upperside markings and wingshape. I don't like using colour as a guide (except the colour of the orange spots) because all males vary from bright lemon to a rather more watery hue during their lives.

Guy

PS - I've recently invested in a super new net where you can see every detail of a butterfly and its colours through the netting (my old one had much more opaque black netting). This should mean I can check more butterflies, more easily, and perfect my ID of these two difficult species.

Good stuff Guy.

I imagine I will still be asking you guys for ID help if I am ever lucky enough to be somewhere both species fly!

Cheers

Lee