Neuronal correlates of a preference for leading signals in the synchronizing bushcricket mecopoda elongata (orthoptera, tettigoniidae)

Hashim, Rosli and Hartbauer, M. and Siegert, M.E. and Romer, H. (2011) Neuronal correlates of a preference for leading signals in the synchronizing bushcricket mecopoda elongata (orthoptera, tettigoniidae). Journal of Experimental Biology, 214 (23). pp. 3924-3934. ISSN 0022-0949

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Official URL: http://jeb.biologists.org/content/214/23/3924.full...

Abstract

Acoustically interacting males of the tropical katydid Mecopoda elongata synchronize their chirps imperfectly, so that one male calls consistently earlier in time than the other. In choice situations, females prefer the leader signal, and it has been suggested that a neuronal mechanism based on directional hearing may be responsible for the asymmetric, stronger representation of the leader signal in receivers. Here, we investigated the potential mechanism in a pair of interneurons (TN1 neuron) of the afferent auditory pathway, known for its contralateral inhibitory input in directional hearing. In this interneuron, conspecific signals are reliably encoded under natural conditions, despite high background noise levels. Unilateral presentations of a conspecific chirp elicited a TN1 response where each suprathreshold syllable in the chirp was reliably copied in a phase-locked fashion. Two identical chirps broadcast with a 180 deg spatial separation resulted in a strong suppression of the response to the follower signal, when the time delay was 20 ms or more. Muting the ear on the leader side fully restored the response to the follower signal compared with unilateral controls. Time-intensity trading experiments, in which the disadvantage of the follower signal was traded against higher sound pressure levels, demonstrated the dominating influence of signal timing on the TN1 response, and this was especially pronounced at higher sound levels of the leader. These results support the hypothesis that the female preference for leader signals in M. elongata is the outcome of a sensory mechanism that originally evolved for directional hearing.

Item Type: Article
Additional Information: Institute of Biological Sciences, Faculty of Science Building, University of Malaya, 50603 Kuala Lumpur, MALAYSIA
Uncontrolled Keywords: Acoustic Stimulation, Animals, Audiometry, Pure-Toney Female, Gryllidae/*physiology Male, Neurons/*physiology, Tape Recording, Time Factors, Trees, Vocalization, Animal/*physiology
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculty of Science > Institute of Biological Sciences
Depositing User: Miss Malisa Diana
Date Deposited: 09 Sep 2013 01:53
Last Modified: 31 May 2019 05:04
URI: http://eprints.um.edu.my/id/eprint/8346

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