Meeting Abstract

S1.1  Sunday, Jan. 4  Influence of environmental noise on the evolution of communication systems NARINS, P.M.; Univ. of California, Los Angeles pnarins@ucla.edu

Many species of animals, including man, face the formidable task of communicating in naturally noisy environments. In this talk, I shall emphasize the effects of noise on both the calling behavior of anurans (frogs and toads) and the temporal and spectral filtering ability of the amphibian auditory pathway. Moreover, the role of spectral, temporal and spatial separation in minimizing masking by background noise will be examined. I shall review the evidence for the remarkable ability of amphibians to shift their call timing in response to both high-level interfering tones or to small intensity shifts in the background noise. Finally, I shall present behavioral evidence that broadband environmental noise may act as a strong selective force in sculpting the acoustic communication systems of two species of Old World arboreal frogs. The dramatic frequency shift into the ultrasonic range of the harmonic content of the advertisement calls likely represents an adaptation that minimizes signal masking by the intense broadband background noise from local streams. Supported by NIH Grant no. DC-00222.