Ribbe, 1905
Berger's Clouded Yellow
Description:
Berger's Clouded Yellow is a butterfly of dry, open grasslands on calcareous soils. In the northern part of its distribution range, it often occurs on the south-facing slopes of hills or mountains. The Berger's Clouded Yellow is much more sensitive to cold than the Pale Clouded Yellow (C. hyale), the caterpillars growing less quickly, and even undergoing periods of inactivity in bad weather.
Eggs are mostly laid on Horseshoe Vetch (Hippocrepis comosa), also on Crown Vetch (Coronilla varia). Hibernation takes place on the food plant, or on the ground in the litter layer. For pupation the caterpillar attaches itself to a food plant, turning into a light-green chrysalis, suspended by a silken girdle.
This species has two or three broods a year.
Berger's Clouded Yellow and the Pale Clouded Yellow are so similar that it is not possible to identify them with certainty. Habitat helps a little, Berger's Clouded Yellow being almost only seen on calcareous grasslands with Horseshoe Vetch, whereas the Pale Clouded Yellow prefers lucerne fields. However, when migrating, it can turn up almost everywhere.
Habitat:
Dry calcareous grasslands
Similar species:
Colias hyale
Colias erate