Berger's Clouded Yellow

(Colias alfacariensis)

Female 30/06/07 Rhône (69)

Male 16/05/06 Rhône (69)

Egg laid on Coronilla varia 16/05/08 Rhône (69)

Egg developing on Hippocrepis comosa 04/05/09 Rhône (69)

First instar caterpillar on Coronilla varia (captive bred), 06/05/09 Rhône (69)

Caterpillar in final livery on Coronilla varia (captive bred), 18/05/09 Rhône (69)

Young chrysalis on Coronilla varia (captive bred), 22/05/09 Rhône (69)

Mature male chrysalis on Coronilla varia (captive bred), 29/05/09 Rhône (69)

Male 30/04/09 Rhône (69)

Female 09/09/07 Rhône (69)

The Berger's Clouded Yellow is a species which flies over calcareous ground where an abundance of its larval food plants Hippocrepis comosa or Coronilla varia are found. Whilst it is reported as having a migratory tendency, I believe that its tight habitat requirements render it largely sedentary and locally common. Certainly this is the case in the Rhône département where the butterfly flies commonly over local, calcareous terrain and is absent outside of this area. The species is almost identical to the Pale Clouded Yellow (Colias hyale) and correct identification poses a great deal of difficulty. This is why studying habitat requirements is a distinct advantage as the caterpillar of C.hyale is reported as being rather polyphagous and feeding on a number of widespread Fabaceae such as Trifolium repens and Medicago sativa. It is also a confirmed migrant. From external features alone separating the two species is tough. The male of C.alfacariensis is apparently a stronger yellow colour and the female more of a 'clean' white in relation to C.hyale though uppersides are never seen at rest other than in some courtship ritual situations.