Hello,
This is in fact a reply to a prompt by Celery in the Favourite Photo thread regarding Clouded Yellow ID tips.
Hi Celery, following your sightings in France this year, I'm by no means an expert on the matter, but I've picked up a couple of identifiers you may be interested in in order to discriminate between Clouded Yellows (C. crocea) and Berger's Clouded Yellow (C. alfacariensis). Excuse me if I state the obvious, but I have to start somewhere.
Your photos in the Favourite Photo thread are clearly of a male C. crocea.
The dark areas on the forewings are uniform. Male:
Male C. crocea seen from the underside, by transparency, exhibits the same uniform dark shadow.
Female C. crocea on the other hand has clear patches within the dark area. The area circled on the photo shows a dark band which distinctly isolates the clear patch from the ground colour.
- crocea32_13 female Vitrolles scrub 24Sept15 (2aa).JPG (59.16 KiB) Viewed 335 times
We should also consider the female C. crocea form
helice, as the light ground colour seen in flight, can sometimes cause confusion with female C. alfacariensis. On the upperside of C. crocea form
helice, we see the same distinct dark band as on the regular female C. crocea, circled in red here.
This effect is also visible by transparency on an underside view of female C. crocea, regular
and form
helice. Dark band distinctly isolating the clear patch:
If we now look at the female C. alfacariensis, we note that a view of the uppersides shows that the clear patch is not completely isolated from the ground colour. The dark band is incomplete:
This effect is also visible by transparency on an underside view of female C. alfacariensis:
Moral of the story, try to also get back-lit shots of the Colias genus.
Underside of male C. alfacariensis. In flight, the male is more of a pale lime green colour.
Any observations are welcome.
Chris
