Nityananda Vivek, Balakrishnan Rohini
Centre for Ecological Sciences, Indian Institute of Science, Bangalore, 560012, India.
J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2007 Jan;193(1):51-65. doi: 10.1007/s00359-006-0170-1. Epub 2006 Sep 16.
In several bushcricket species, individual males synchronise their chirps during acoustic interactions. Synchrony is imperfect with the chirps of one male leading or lagging the other by a few milliseconds. Imperfect synchrony is believed to have evolved in response to female preferences for leading chirps. We investigated the mechanism underlying synchrony in the bushcricket species Mecopoda 'Chirper' from Southern India using playback experiments and simulations of pairwise interactions. We also investigated whether intrinsic chirp period is a good predictor of leading probability during interactions between males. The mechanism underlying synchrony in this species differs from previously reported mechanisms in that it involves both a change in the oscillator's intrinsic rate and resetting on a chirp-by-chirp basis. The form of the phase response curve differs from those of previously reported firefly and bushcricket species including the closely related Malaysian species Mecopoda elongata. Simulations exploring oscillator properties showed that the outcome of pairwise interactions was independent of initial phase and alternation was not possible. Solo intrinsic chirp period was a relatively good predictor of leading probability. However, changing the intrinsic period during interactions could enable males with longer periods to lead during acoustic interactions.
在几种螽斯物种中，雄性个体在声学互动过程中会使它们的鸣叫同步。同步并不完美，一只雄性的鸣叫会比另一只提前或滞后几毫秒。据信，不完美的同步是为了响应雌性对领先鸣叫的偏好而进化出来的。我们利用回放实验和成对互动模拟，研究了来自印度南部的螽斯物种Mecopoda “Chirper” 中同步现象的潜在机制。我们还研究了在雄性之间的互动中，固有鸣叫周期是否是领先概率的良好预测指标。该物种中同步现象的潜在机制与先前报道的机制不同，因为它既涉及振荡器固有频率的变化，也涉及逐个鸣叫的重置。相位响应曲线的形式与先前报道的萤火虫和螽斯物种（包括亲缘关系密切的马来西亚物种长瓣螽）的不同。探索振荡器特性的模拟表明，成对互动的结果与初始相位无关，并且不可能交替。单独的固有鸣叫周期是领先概率的一个相对较好的预测指标。然而，在互动过程中改变固有周期可以使周期较长的雄性在声学互动中处于领先地位。
