Colias alfacariensis ¦ Berger's Clouded Yellow ¦ euroButterflies

TOP

Colias alfacariensis

Berger's Clouded Yellow

euroButterflies

by Matt Rowlings

Valais, Switzerland, April/ May 2010

Valais, Switzerland, October 2010

Field notes and information

This and sister species the pale clouded yellow, C. hyale, are extremely difficult to separate by wing characteristics alone. They are both very variable and many of the supposed characteristics using colour do fade with age. The larvae are however very easily separated and this is probably the only 100% reliable method of separating the species.

This species occasionally reaches the UK on migration

Identification & Similar species: Several anaylses conclude that taken alone none of the usually reported characteristics can give reliable separation as all features are very variable and, in the case of colour, vary with the age of the specimen.

Here are some of the more usually recognised identification features for separating the males: alfacariensis vs hyale.

* Range: hyale is absent from Mediterranean regions.

* Yellow ground colour: brighter vs paler - subjective and varies with age of the specimen.

* Orange colour of central hindwing spot: brighter vs paler - subjective and varies with age of the specimen.

* Extent of black basal area of upper forewings: more rounded vs less extensive and in a triangular wedge shape.

* Shape of forewing apex: rounded vs pointed & margin concave vs straight - very variable, subtle differences

* Presence of larval foodplant, Hippocreips comosa: absent vs present.

* Habitat: hot and dry vs damp and flowery.

If an individual displays three or more of any of these features there is a good possibility you can identify it.

Distribution & Flight: A resident in much of southern and central Europe, it migrates northwards every year. The extent of the migration is limited however such that only rarely do individuals reach the shores of the UK for example.

Habitat & Behaviour: Flies fast and direct over meadows.

Variation: Vary variable in all features, which makes identification extremely difficult.