Sexually selected vocalizations of neotropical bats

Abstract

Acoustic signals are by far the best studied component of bats’ social communication. Various different vocalization types cover diverse social interactions, which are either under natural selection pressures, such as mother-pup recognition and group cohesion, or under sexual selection pressures, such as male-male aggression, territoriality, and courtship. Here, we summarize the current knowledge about sexually selected vocalizations in Neotropical bats. Specifically, we highlight research findings on sexually selected vocalizations in two species whose social organization and natural history are well understood, namely Seba’s Short-tailed Bat Carollia perspicillata (Phyllostomidae) and the Greater Sac-winged Bat Saccopteryx bilineata (Emballonuridae). Males of both species exhibit resource-defense polygyny and use distinct vocalizations during aggressive male-male interactions and to announce territory ownership. While territorial vocalizations are structurally more complex in S. bilineata than in C. perspicillata, the latter species uses a more sophisticated, ritualized suite of behavioral displays to mediate male-male aggression than S. bilineata. Moreover, males of both species exhibit acoustic courtship which displays with differing degrees of complexity. In S. bilineata, courtship vocalizations are long and elaborate, while courtship vocalizations of C. perspicillata are comparatively simpler, with one variable syllable repeated in succession. As a synopsis, we discuss whether differences in social organization and behavioral interactions may have implications for the structural complexity and information content of sexually selected vocalizations.