Research scientists in the United Kingdom have discovered details about insect hearing that may help advance hearing technology and other devices for humans. According to a paper published in the December 17, 2014 issue of the Journal of Comparative Physiology, Dr Fernando Montealegre-Z, from the School of Life Sciences, University of Lincoln, and Dr Daniel Robert from the University of Bristol, explain how the development of hearing in katydids may have wider implications for further research and technological development.

According to the researchers, animals and insects have evolved a vast diversity of mechanisms to detect sounds in order to survive in their environments. For their study, the researchers were particularly interested in the acoustic production and hearing mechanisms of cicadas, crickets, katydids, and grasshoppers. In these groups, males sing to attract females. The Tettigoniidae (or bushcrickets) ear has evolved in the context of intraspecific communication and predator detection. Dr Montealegre-Z has been studying how katydids evolved incredible ultrasonic hearing abilities.

“Some insects, like katydids, have evolved biophysical mechanisms for auditory processing that are remarkably equivalent to those of mammals,” said Montealegre-Z, PhD. “Located on their front legs, katydid ears are small, yet capable of performing several of the tasks usually associated with mammalian hearing. These tasks include air-to-liquid impedance conversion, signal amplification, and frequency analysis.”

According to Dr Montealegre-Z, katydids and tetrapods have evolved remarkably different structural solutions to common biophysical problems. His paper discusses the biophysics of hearing in katydids and the variations observed across different species.

A cochlear organ for frequency selectivity was thought to be unique to hearing in mammals until Dr Montealegre-Z and his research team discovered a similar mechanism for frequency analysis in the ears of bushcrickets in South American rainforests two years ago. The research conducted by Dr Montealegre-Z and his colleagues aims to develop an integrated understanding of the evolution of ultrasonic hearing in bushcrickets; specifically how they developed cochlear-like systems in response to changing evolutionary pressures over millions of years.

Scientists believe the discovery of this previously unidentified cochlear organ in some insects could pave the way for technological advancements in bio-inspired acoustic sensors, including medical imaging devices, and hearing aids.

Source: University of Lincoln

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