
Pipistrellus is a genus of bats in the family Vespertilionidae, derived from the Italian word for bat, “pipistrello.” The genus has been reduced significantly due to reclassifications in the 1990s and 2000s, with several genera like Arielulus and Neoromicia split off. However, molecular evidence suggests that Pipistrellus is not monophyletic. Species often referred to as “pipistrelles” may also belong to other genera, such as the western pipistrelle and eastern pipistrelle in North America. Southern Hemisphere species under the genus Falsistrellus are known as false pipistrelle. These bats are characterized by their weak, fluttery flight, resembling that of a butterfly, unlike their larger relatives, the noctule bats (Nyctalus).