title: Multimodal signaling in the Small Torrent Frog (Micrixalus saxicola) in a complex acoustic environment.
abstract: Many animals use multimodal (both visual and acoustic) components in courtship signals. The acoustic communication of anuran amphibians can be masked by the presence of environmental background noise, and multimodal displays may enhance receiver detection in complex acoustic environments. In the present study, we measured sound pressure levels of concurrently calling males of the Small Torrent Frog (Micrixalus saxicola) and used acoustic playbacks and an inflatable balloon mimicking a vocal sac to investigate male responses to controlled unimodal (acoustic) and multimodal (acoustic and visual) dynamic stimuli in the frogs' natural habitat. Our results suggest that abiotic noise of the stream does not constrain signal detection, but males are faced with acoustic interference and masking from conspecific chorus noise. Multimodal stimuli elicited greater response from males and triggered significantly more visual signal responses than unimodal stimuli. We suggest that the vocal sac acts as a visual cue and improves detection and discrimination of acoustic signals by making them more salient to receivers amidst complex biotic background noise.
authors: Department of Integrative Zoology, University of Vienna, Althanstraße 14, 1090 Vienna, Austria.
authors: Doris
authors: D
authors: Preininger
authors: Markus
authors: M
authors: Boeckle
authors: Anita
authors: A
authors: Freudmann
authors: Iris
authors: I
authors: Starnberger
authors: Marc
authors: M
authors: Sztatecsny
authors: Walter
authors: W
authors: Hödl
keywords: Acoustic signal; Anura; Background noise; Multimodal communication; Visual cue; Vocal sac
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