Biomechanical and neurophysiological investigation of insect tympanal organs

Investigating how insects receive sound via the structure of their auditory organs could inspire new, more sensitive, acoustic sensor systems to be developed, where the insect hearing organs that have previously been documented are believed to be more sensitive than any man-made devices that can currently be made. Firstly though, the structure and functioning of the biological inspiration, insect tympanal hearing organs, have to be more fully understood. This Thesis research firstly investigated the biomechanical properties of the tympanal membrane of various species and orders of insect using laser Doppler vibrometry. The results were then compared between species, including the different structures and also the membrane mechanics. This chapter results highlights the different structures and also the range of frequencies that each species is tuned to. By comparing the tympanal organs shape and the mechanics on the membrane surface caused by the received sound waves hopefully this can be applied to future membrane design. Some species of insect have been found to have active hearing characteristics, in order to understand the functioning of these hearing organs these were investigated using different methods to previous studies to try and identify the origin of the active hearing. In previous studies these characteristics were recorded acoustically from the tympanal organs of a number of species. The current study aimed to record the vibration created by the emissions through the membrane this was investigated in both locust and moth tympanal organs. No active hearing characteristics were recordable on the surface of the membrane. Finally both laser vibrometry and electrophysiology recordings were used to investigate very high frequency sensitivity of a moth hearing organ. The findings have greatly extended the known range of hearing in insects. The moth hearing organ is capable of receiving and processing frequencies up to 300 kHz with a very simple tympanal organ. This discovery could inspire smaller and simpler designs of transducers at ultrasonic frequencies. Overall this thesis work demonstrates the amazing sensitivity of the insect tympanal organs and takes steps toward further understanding of the auditory processing in insect tympanal organs.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral-pg

Grantor dc:publisher.institution

University of Strathclyde

Year dc:date.issued

2012

Author dc:creator

• Moir, Hannah M.

DOI

10.48730/mwsc-b489

Identifier

T13416

OAI identifier oai:identifier

oai:strathclyde:2j62s4855