Bat songs as acoustic beacons - male territorial songs attract dispersing females

Male song in birds and mammals is important for repelling rivals, stimulating mates or attracting them to a specific location. Nevertheless, direct experimental evidence for the mate attraction function of male song is limited to a few studies. Here, we provide strong experimental evidence that male songs attract wild female bats (Saccopteryx bilineata). Playbacks of territorial songs reliably elicited phonotaxis in females but not males. Most females captured during playbacks were subadults searching for new colonies to settle in. In S. bilineata, multiple males sing simultaneously at dawn and dusk, thereby creating a conspicuous chorus which encodes information on colony identity and size. Since territorial songs have a large signalling range, male songs constitute acoustic beacons which enable females to localize new colonies. In our playbacks, females strongly preferred local territorial songs over foreign territorial songs from two different locations, indicating that song familiarity influences phonotaxis. Our study provides the first clear experimental evidence that male song elicits female phonotaxis in a non-human mammal. Bats are an especially promising taxon for studying mammalian song since male song has been described in different species with diverse social organisations and natural histories, thus providing exciting opportunities for phylogenetically controlled comparative studies.