Social vocalizations show stronger phylogenetic conservatism than echolocation calls in closely related pipistrelle bats

Natural and sexual selection pressures and evolutionary history shape the traits exhibited by organisms. Traits subject to strong phylogenetic constraints are conserved, whereas others are susceptible to environmental or social factors. Given their diverse acoustic orientation and communication systems, bats offer a compelling model for examining the strength of phylogenetic signals. We hypothesized that social vocalizations exhibit stronger phylogenetic signals than echolocation calls in pipistrelle bats because their echolocation is highly flexible and influenced by environmental factors. In this study, we investigated six closely related European bat species, including Pipistrellus hanaki , P. kuhlii , P. maderensis , P. nathusii , P. pipistrellus and P. pygmaeus , which produced echolocation calls for orientation, navigation and social vocalizations (known as trills) for rival deterrence and mate attraction. Results indicate that echolocation calls and trills allow for species-level discrimination, but trills show a stronger phylogenetic signal. Therefore, trills are more conserved across closely related pipistrelle species, while echolocation calls are more plastic and adaptable to environmental pressures. Nevertheless, a phylogenetic signal remains detectable in echolocation calls, indicating a balance among evolutionary history, morphological constraints and environmental adaptation. These results provide a comprehensive understanding of the evolutionary processes shaping bat echolocation and communication and insights into the influence of phylogenetic history and selection pressures on the acoustic behaviour of pipistrelles. • Pipistrelle social trills are more phylogenetically conserved than echolocation. • Pipistrelle echolocation is flexible, but it is still shaped by evolutionary history. • Both vocalization types enable species recognition among European species. • Social trills have deep evolutionary roots in pipistrelle communication. • Pipistrelle vocal behaviour shows a mix of ancestry and environmental adaptation.