Sensory Constraints on Signal Evolution in an Acoustic Communication System

了解动物感觉处理的机制、表现和局限性，对于理解形成交流系统的进化机制至关重要。相反，要提出关于感觉系统和大脑功能的深刻问题，就需要了解进化背景。昆虫的交配叫声提供了一个很好的例子，说明在复杂的声学环境中，发送者和响应者如何进化，以优化从发送者到接收者的信号的声学特征。本项目研究了四种亲缘关系较近的蝈蝈在声学通信中呼叫频率（音高）的变化，这些物种之间的载波频率差异很大，并且它们所占据的栖息地具有明显不同的声学特性。利用行走补偿器这一强大的工具来测量昆虫对叫声的定向行为，该补偿器监测行走昆虫的转身，以评估时间和光谱声音模式识别线索的作用。细胞内记录识别的听觉神经元被用来评估神经元编码策略的声音信号模式。结果将整合信号处理的机制和进化方面，以进一步了解感觉系统和信号进化的相互依存关系。该项目的更广泛影响还包括启动年轻研究者的职业生涯，以及多学科的研究生和本科生培训。

It is important to know the mechanisms, performance and limits of sensory processing by animals to understand the evolutionary mechanisms forming a communication system. Conversely, knowledge of the evolutionary context is required to pose insightful questions about sensory systems and brain function. The mating calls of insects provide an excellent example of how the senders and responders have to evolve to optimize uses of acoustic features of the signal from sender to the receiver in complex acoustic environments. This project exploits the variety in the call frequency (pitch) in acoustic communication in four closely related species of katydid, in which the carrier frequencies vary significantly between species, and which occupy habitats with significantly different acoustic properties. Orientation behavior toward a call is measured with a powerful tool of a walking compensator, which monitors the turning of a walking insect to evaluate the role of temporal and spectral sound pattern recognition cues. Intracellular recording of identified auditory neurons is used to evaluate neuronal encoding strategies for acoustic signal patterns. Results will integrate mechanistic and evolutionary aspects of signal processing to further understand the interdependence of sensory systems and signal evolution. Broader impacts of this project also include launching a young investigator's career, and multidisciplinary graduate and undergraduate training.