Novodobá expanze soumračníka podobného (Pyrgus armoricanus [Oberthür, 1910]) v České republice (Hesperiidae, Lepidoptera).

This paper present new findings on the distribution changes of the Oberthür's Grizzled Skipper (Pyrgus armoricanus) in the Czech Republic, documenting its re-expansion, including expansion to historically unoccupied regions, most likely explained by warmer climate of the past few years. It also documents the range of host plants used for larval development (based on oviposition records from field), and current habitat and management preferences. It is based on revision of all available archival records (museums, literature), and butterfly recording data, which substantially increased in recent years. Until mid-20th century, the species was relatively widely distributed in warmer region of the country (southern and south-eastern Moravia, central, eastern and north-western Bohemia). This was followed by a steep decline, so that only a handful of mapping grid quadrates were occupied in late 20th century, typically hosting very small colonies. The current and well recorded re-expansion has already reached regions, from which there are no past records (Nový Jičín and Vsetín districts). In Moravia, the most frequent larval host plant appears to be Potentilla reptans, but oviposition of Fragaria vesca is also reported. The currently occupied habitats include steppe grasslands, rocky sites and quarries, but also non-intensive livestock pastures and even frequently mown dry lawns in villages and towns. Very short and sparse sward, and abundant host plant presence, seem to be the necessary conditions for the species presence. We call for increased recording effort in areas historically occupied by the butterfly, and give recommendations for managing its sites. [ABSTRACT FROM AUTHOR]