Distortion product otoacoustic emissions evoked by tone complexes

Distortion product otoacoustic emissions are a manifestation of nonlinear interaction between two or more stimulus components within the cochlea. Most studies employ a two-tone stimulus to evoke them. In this study we used a more complex stimulus, in which one of the primaries of the customary two-tone stimulus was replaced by an irregularly spaced tone complex. We obtained data from Mongolian gerbils, and investigated whether the novel stimulus has added value in terms of measurement efficiency, and whether it allows the derivation of information on cochlear mechanics that cannot be derived from two-tone stimuli

Anthropogenic substrate-borne vibrations impact anuran calling

Anthropogenic disturbance is a major cause of the biodiversity crisis. Nevertheless, the role of anthropogenic substrate vibrations in disrupting animal behavior is poorly understood. Amphibians comprise the terrestrial vertebrates most sensitive to vibrations, and since communication is crucial to their survival and reproduction, they are a suitable model for investigating this timely subject. Playback tests were used to assess the effects of substrate vibrations produced by two sources of anthropogenic activity– road traffic and wind turbines– on the calling activity of a naïve population of terrestrial toads. In their natural habitat, a buried tactile sound transducer was used to emit simulated traffic and wind turbine vibrations, and changes in the toads’ acoustic responses were analyzed by measuring parameters important for reproductive success: call rate, call duration and dominant frequency. Our results showed a significant call rate reduction by males of Alytes obstetricans in response to both seismic sources, whereas other parameters remained stable. Since females of several species prefer males with higher call rates, our results suggest that anthropogenically derived substrate-borne vibrations could reduce individual reproductive success. Our study demonstrates a clear negative effect of anthropogenic vibrations on anuran communication, and the urgent need for further investigation in this are