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.
