Diversity and functional significance of echolocation call design in neotropical bats
Globally, bats (Chiroptera) represent with more than 1100 species the second largest order of mammals. Local species assemblages in the tropics may contain more than 100 co-existing species. The development of echolocation is seen as one of the key innovations that permit bats access to a wide range of habitats and resources at night. Bats use echolocation for orientation in space and in part also for finding food. Echolocation behaviour and call design are rather flexible. This flexibility is interpreted mainly as an adaptation to environmental conditions such as the distance of bats towards cluttered background or food. Furthermore, flexibility in call design permits fine-grained niche partitioning among ecologically similar species. New data from extensive field research combined with behavioural experiments suggest, however, that call design and echolocation performance of bats is even more varied than expected. This is particularly true in the species-rich assemblages in the neotropics Evidence accumulates that the functional significance of echolocation goes beyond orientation at night and finding food, but also includes important information regarding the identity of the sender. This, in turn, permits unambiguous species identification and leads to a distinct separation of acoustic channels between co-existing species. Furthermore, signal design clearly contains phylogenetic information. The new findings challenge the previous assumption that signal structure is mainly constrained by physics and that convergence in call design prevails in species that live under similar ecological conditions. It opens up new venues to put echolocation call design of bats into a broader context including the use of call signatures for species inventories as well as addressing questions regarding partitioning of acoustic space and traits that may code phylogenetic associations.
Prof. Dr. Elisabeth K. V. Kalko
Universität Ulm
Ort: Hörsaal des Museum Alexander Koenig
Zeit: 30.11.2006, 17.15 Uhr
Zeit: 30.11.2006, 17.15 Uhr
