LAUSR

The paper represents results of surveys carried out in the Western Stara Planina Mts within the last four years in order to improve the knowledge of the butterfly fauna, especially in the Bulgarian part of the mountain. A total of 150 species of Lepidoptera (Papilionoidea) was recorded with comments on their distribution in the Bulgarian part of the studied region. Nineteen species were recorded for the first time in the Bulgarian part of the mountain and one species (Apatura metis) – for the Serbian part. It has been found that the highest butterfly diversity is linked to the largest limestone area in the mountain near Komshtitsa Village where 101 species were observed. Interesting records for some rare or endangered species (Muschampia cribrellum, M. tessellum, Lycaena helle, Kirinia climene, Apatura metis, Nymphalis vaualbum, Melitaea didyma, M. arduinna, M. diamina and Brenthis ino) are discussed in detail. The high conservation value of the studied region proves by the species considered as threatened at the European level, of which seven species are included in the Annexes II and IV of the Habitats Directive, 12 species are listed in the Red Data Book of European butterflies and 26 in the European Red List of Butterflies.