Listening carefully: increased perceptual acuity for species discrimination in multispecies signalling assemblages. (March 2015)

• Record Type: Journal Article
• Authors: Bastian, Anna; Jacobs, David S.
• Is Part Of: Animal behaviour. Volume 101(2015)
• Page Start: 141
• Page End: 154
• Publication Date: 2015-03
• Subjects: acoustic assemblages -- acoustic communication -- acoustic communication hypothesis -- bats -- echolocation -- functional extension -- habituation–dishabituation -- receivers' perception acuity -- Rhinolophus -- species discrimination; Animal behavior -- Periodicals; 591.5
• DOI: 10.1016/j.anbehav.2014.12.010
• Languages: English
• ISSNs: 0003-3472

Abstract

Abstract : Communication is a fundamental component of evolutionary change because of its role in mate choice and sexual selection. Acoustic signals are a vital element of animal communication and sympatric species may use private frequency bands to facilitate intraspecific communication and identification of conspecifics (acoustic communication hypothesis, ACH). If so, animals should show increasing rates of misclassification with increasing overlap in frequency between their own calls and those used by sympatric heterospecifics. We tested this on the echolocation of the horseshoe bat, Rhinolophus capensis, using a classical habituation–dishabituation experiment in which we exposed R. capensis from two phonetic populations to echolocation calls of sympatric and allopatric horseshoe bat species ( Rhinolophus clivosus and Rhinolophus damarensis ) and different phonetic populations of R. capensis . As predicted by the ACH, R. capensis from both test populations were able to discriminate between their own calls and calls of the respective sympatric horseshoe bat species. However, only bats from one test population were able to discriminate between calls of allopatric heterospecifics and their own population when both were using the same frequency. The local acoustic signalling assemblages (ensemble of signals from sympatric conspecifics and heterospecifics) of the two populations differed in complexity as a result of contact with other phonetic populations and sympatric heterospecifics. We therefore propose that a hierarchy of discrimination ability has evolved within the same species. Frequency alone may be sufficient to assess species membership in relatively simple acoustic assemblages but the ability to use additional acoustic cues may have evolved in more complex acoustic assemblages to circumvent misidentifications as a result of the use of overlapping signals. When the acoustic signal design is under strong constraints as a result of dual functions and the available acoustic space is limited because of co-occurring species, species discrimination is mediated through improved sensory acuity in the receiver. Highlights: Functional extension: echolocation for orientation and species discrimination. Sender and perceiver adaptations for species discrimination in species assemblages. Acoustic signal divergence and fine-tuned receiver perception within one species. Rephrasing of the acoustic communication hypothesis. Species discrimination is complemented by the evolution of multiple acoustic cues.