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Evol Ecol (2014) 28:122
DOI 10.1007/s10682-013-9658-7
ORIGINAL PAPER
Manjari Jain Swati Diwakar Jimmy Bahuleyan
Rittik Deb Rohini Balakrishnan
Received: 26 October 2012 / Accepted: 1 June 2013 / Published online: 13 June 2013 Springer Science+Business Media Dordrecht 2013
Abstract A rain forest dusk chorus consists of a large number of individuals of acoustically communicating species signaling at the same time. How different species achieve effective intra-specic communication in this complex and noisy acoustic environment is not well understood. In this study we examined acoustic masking interference in an assemblage of rain forest crickets and katydids. We used signal structures and spacing of signalers to estimate temporal, spectral and active space overlap between species. We then examined these overlaps for evidence of strategies of masking avoidance in the assemblage: we asked whether species whose signals have high temporal or spectral overlap avoid calling together. Whereas we found evidence that species with high temporal overlap may avoid calling together, there was no relation between spectral overlap and calling activity. There was also no correlation between the spectral and temporal overlaps of the signals of different species. In addition, we found little evidence that species calling in the understorey actively use spacing to minimize acoustic overlap. Increasing call intensity and tuning receivers however emerged as powerful strategies to minimize acoustic overlap. Effective acoustic overlaps were on average close to zero for most individuals in natural, multispecies choruses, even in the absence of behavioral avoidance mechanisms such as inhibition of calling or active spacing. Thus, call temporal structure, intensity and frequency together provide sufcient parameter space for several species to call together yet
Electronic supplementary material The online version of this article (doi:http://dx.doi.org/10.1007/s10682-013-9658-7
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M. Jain R. Deb R. Balakrishnan (&)
Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India e-mail: [email protected]
S. Diwakar
Department of Environmental Studies, University of Delhi, Delhi 110007, India
J. Bahuleyan
Department of Computer Science and Automation, Indian Institute of Science, Bangalore 560012, India
A rain forest dusk chorus: cacophony or sounds of silence?
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communicate effectively with little interference in the apparent cacophony of a rain forest
dusk chorus.
Keywords Katydids Acoustic interference Western...