A newly discovered hearing organ in bush crickets’ ears could hold clue to superhuman hearing, researchers claim.
A previously unidentified hearing organ in the South American bush crickets’ ear could pave way for new advances in bio-inspired acoustic sensors, including medical imaging and hearing aid development, they said.
Researchers from the University of Bristol and University of Lincoln discovered the missing piece of the jigsaw in the understanding of the process of energy transformation in the ‘unconventional’ ears of the bush crickets or katydids.
Bush crickets have four tympana or ear drums — two on each foreleg, but until now it has been unknown how the various organs connect in order for the insect to hear.
As the tympana — a membrane which vibrates in reaction to sound — does not directly connect with the sensory receptors, it was a mystery how sound was transmitted from air to the mechano-sensory cells.
Researchers discovered a newly identified organ while carrying out research into how the bush-cricket tubing system in the ear transports sound.
The research focused on the bush cricket Copiphora gorgonensis, a neotropical species from the National Park Gorgona in Colombia, an island in the Pacific.
Results suggest that the bush cricket ear operates in a manner analogous to that of mammals.
“We discovered a novel structure that constitutes the key element in hearing in these insects, which had not been considered in previous work. The organ is a fluid-filled vesicle, which we have named the ‘Auditory Vesicle’,” Researcher Dr Fernando Montealegre-Z said.
He said this hearing organ mediates the process of conversion of acoustic energy (sound waves) to mechanical, hydraulic and electrochemical energy.
“The integration laser Doppler vibrometry and micro-CT scanning allowed us to identify the auditory vesicle and to conclude that the process relies on a tympanal lever system analogous to the mammalian ossicles.
This serves to transmit air-borne vibrations to the fluid, and also on the mechanoreceptors. Therefore the bush cricket ear performs the crucial stage of air to liquid impedance conversion and amplification just as in a mammal’s ear,” Montealegre-Z said in a statement.
In mammals, hearing relies on three canonical processing stages: an eardrum collecting sound, a middle ear impedance converter and a cochlear frequency analyser.
The study was published in the journal Science.
Keywords: Bush crickets, superhuman hearing, bio-inspired acoustic sensors, University of Bristol, University of Lincoln, katydids, tympana, mechano-sensory cells, Copiphora gorgonensis, neotropical species, National Park Gorgona in Colombia, fluid-filled vesicle, Auditory Vesicle, Dr Fernando Montealegre-Z, acoustic energy, hydraulic and electrochemical energy, Doppler vibrometry, analogous to the mammalian ossicles, cochlear frequency analyser, Science,