Dip listening refers to our ability to catch brief 'acoustic glimpses' of speech and other sounds when fluctuating background noise levels momentarily decrease. Exploiting dips in natural fluctuations of noise contributes to our ability to overcome the 'cocktail party problem' of understanding speech in multitalker social environments. We presently know little about how nonhuman animals solve analogous communication problems. Here, we asked whether female grey treefrogs, Hyla chrysoscelis, might benefit from dip listening in selecting a mate in the noisy social setting of a breeding chorus. Consistent with a dip-listening hypothesis, subjects recognized conspecific calls at lower thresholds when the dips in a chorus-like noise masker were long enough to allow glimpses of nine or more consecutive pulses. No benefits of dip listening were observed when dips were shorter and included five or fewer pulses. Recognition thresholds were higher when the noise fluctuated at a rate similar to the pulse rate of the call. In a second experiment, advertisement calls comprising six to nine pulses were necessary to elicit responses under quiet conditions. Together, these results suggest that in frogs, the benefits of dip listening are constrained by neural mechanisms underlying temporal pattern recognition. These constraints have important implications for the evolution of male signalling strategies in noisy social environments.
Bibliographical noteFunding Information:
We thank N. Buerkle, B. Chicoine, J. Cook, C. Espegard, S. Feingold, N. Gordon, N. Hein, K. Heino, J. Henly, S. Hinrichs, J. Kleinschmidt, B. Linehan-Skillings, J. Mertz, C. Nguyen, S. Peterson, A. Rapacz Van-Neuren, M. Rodionova and especially S. Tekmen for help collecting and testing frogs, M. Crawford, M. Linck, J. Moriarty, E. Quinn and D. Pereira for access to frog breeding sites, and B. Pettit, E. Love, K. Schrode and S. Tekmen for feedback on earlier versions of the manuscript. Different aspects of this work were supported by a University of Minnesota Graduate School Thesis Research Grant and a Dayton-Wilkie Fellowship to A. Vélez and by grants from the National Science Foundation ( NSF IOS 0842759 ) and the National Institutes of Health ( NIDCD 5R01DC009582 ) to M. Bee.
- Acoustic communication
- Cocktail party problem
- Dip listening
- Gray treefrog
- Hyla chrysoscelis
- Masking release