The project is a follow-up on the previous project funded by a grant of Czech Science Foundation, which focused on interspecific differences in the distribution of two cryptic species of bats – Pipistrellus pipistrellus and P. pygmaeus – within the Czech Republic. Achieved results suggest intraspecific variability of genetic characters as well as echolocation parameters and ecological requirements. Hitherto, this variability has not been studied in the cryptic species of the genus Pipistrellus. The aim of the proposed project is to get an understanding of the life history of both cryptic pipistrelle species including the mechanisms of development of ecological and behavioural adaptations. Based on intraspecific variability the probability of character displacement will be studied within sympatric populations in the area of the Czech and Slovak Republics. Methods of molecular ecology (microsatellites, mtDNA) as well as analyses of echolocation signals and ecological requirements will be used.