This season I decided to breed G. rhamni and after 35 days the first butterflies started to hatch. Nothing unusual until today when I found a yellow female! From the underside it is whitish as a regular rhamni female, but upperside is yellow. Compared to males it is slightly paler, especially on the forewings. I checked the abdomen several times and it is 100% female specimen, no claspers.
I have never seen anything like this, so I would like to hear your oppinions about this form.
An extraordinary specimen! Probably an extreme rarity as well. I cannot comment on what causes such color (morphs) as I am sure someone else out there has a better understanding of the topic than I. Perhaps Bobw can elaborate as he is a Colias specialist I believe. What I can say is that here in America our Common Sulphur (Colias philodice) has males of a sulphur yellow color but, on very rare occasions singular individuals are simply "white" males with the typical black borders and no yellow whatsoever.... They are quite rare in collections and are probably picked up by someone thinking that they were capturing an albino form female (as there are 2 color forms of the female). On the other forum a member some years ago posted a photo of one of these "white buffalos" of the butterfly world (so to speak) which he had collected in Indiana.