Behavioral responses of anuran amphibians to biotic, synthetic and anthropogenic noise

Abstract

Many species of animals, including man, face the formidable task of communicating in noisy environments. In this paper, I shall discuss the effects of biotic, synthetic and anthropogenic noise on the calling behavior of anuran amphibians. Moreover, the role of spectral, temporal and spatial separation in minimizing masking by background noise will be examined. For example, presenting high-level, periodic (or aperiodic) tones at the male's Co-note frequency to males of the Puerto Rican treefrog, Eleutherodactylus coqui results in a clear shift in their calling pattern in an attempt to minimize acoustic overlap with the interfering playback stimulus. Amphibians also have a remarkable ability to shift their call timing in response to small intensity shifts in the background noise. Males of E. coqui are capable of reliably detecting a change in interfering tone intensity as small as 2-4 dB. Finally, I shall present behavioral evidence that biotic/anthropogenic noise may act as a strong selective force in sculpting the acoustic communication systems of several species of Old World frogs. Supported by grants from the NIDCD (no. DC-00222), UCLA Academic Senate (3501) and the P. F. Veneklasen Research Foundation.