Synchronising bushcricket males achieve synchrony by delaying their chirps in response to calling neighbours. In multi-male choruses, males that delay chirps in response to all their neighbours would remain silent most of the time and be unable to attract mates. This problem could be overcome if the afferent auditory system exhibited selective attention, and thus a male interacted only with a subset of neighbours. We investigated whether individuals of the bushcricket genus Mecopoda restricted their attention to louder chirps neurophysiologically, behaviourally and through spacing. We found that louder leading chirps were preferentially represented in the omega neuron but the representation of softer following chirps was not completely abolished. Following chirps that were 20 dB louder than leading chirps were better represented than leading chirps. During acoustic interactions, males synchronised with leading chirps even when the following chirps were 20 dB louder. Males did not restrict their attention to louder chirps during interactions but were affected by all chirps above a particular threshold. In the field, we found that males on average had only one or two neighbours whose calls were above this threshold. Selective attention is thus achieved in this bushcricket through spacing rather than neurophysiological filtering of softer signals.
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We thank the Ministry of Environment and Forests, Government of India, for funding part of this project. We are grateful to Prof. Sumantra Chattarji for use of the software for spike analysis. The experiments comply with the legal principles of animal care and animal welfare of the Government of India. The project was supported by the Austrian Science foundation (FWF), project P17540-B06 to H.R.
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Nityananda, V., Stradner, J., Balakrishnan, R. et al. Selective attention in a synchronising bushcricket: physiology, behaviour and ecology. J Comp Physiol A 193, 983–991 (2007). https://doi.org/10.1007/s00359-007-0251-9
- Selective attention
- Omega neuron