Biology, distribution, and extinction of Colias myrmidone (Lepidoptera, Pieridae) in Bavaria and its situation in other European countries

Abstract

C. myrmidone, the Danube Clouded Yellow, one of the most endangered butterfly species in Germany and listed as threatened with extinction, is very likely to be currently extinct. For C. myrmidone and several other pontic south-east European species (i.e. of the genus Cytisus) the slopes along the river Danube served as an immigration route to Bavaria. The paper describes how a period of decline followed a period of suspected dispersal. In Germany, C. myrmidone was last reported in the year 2000 although great efforts were undertaken to find the species in 2001 and 2003. A combination of factors were likely to be responsible for the decline and extinction of C. myrmidone in Bavaria and Germany. Firstly, unfavourable grassland management led to a drastic deterioration of habitat quality over the last 10 years. Furthermore, larval habitats like sun-exposed xeric hillsides constantly decreased. Lastly, heavy summer rainfalls and mild, wet winters over more recent years were probably disadvantageous. The present study and recommendations developed were too late to prevent any apparent extinction across Germany. The aim of this paper is to summarise the conservation biology of C. myrmidone, to discuss factors influencing its extinction in Bavaria and to provide insight into its conservation status in other European countries. Conclusions are given regarding the future conservation of the butterfly.