Different songflight calls of Pipistrellus kuhlii and Pipistrellus lepidus (Vespertilionidae, Chiroptera) in Europe

Abstract. We analysed and compared the structure and parameters of the songflight calls of expansive Pipistrellus kuhlii and Pipistrellus lepidus, that recently colonized Central Europe from the south and east, respectively. Bat calls were recorded mainly in urban areas of Central Europe and the Balkans, including a narrow zone of these species' recent parapatric or sympatric occurrence (around the Carpathians and the eastern part of the Pannonian Basin). The newly described songflight calls of P. lepidus consist of more elements (median 6), are longer (mean 56.4 ms) and of a higher frequency of maximum energy (mean 25.7 kHz) than those of P. kuhlii (median 3, mean 41.0 ms and mean 14.0 kHz, respectively). This finding provides new evidence that P. lepidus represents a different species, in accordance with results from previous genetic and morphological studies. Reported differences in songflight calls permit the acoustic discrimination of P. kuhlii and P. lepidus, which is not possible based on overlapping parameters of their echolocation calls. Our findings enable distributional and ecological studies of these two species, based on acoustic methods, in the context of their rapid European expansion and the local co-occurrence.