Super hearing in flies may improve hearing aid ...( The secret to better hearing aid t...)

The secret to better hearing aid technology may lie in the "super" hearing abilities of parasitic flies, according to researchers at the University of Toronto and Cornell University.

In a study to be published in the April 5th issue of Nature, the researchers report that Ormia ochracea, a parasitic fly measuring less than one centimetre in length, can determine the direction of a sound within a range of two degrees - a feat previously ascribed to only keen-eared owls, cats and humans. "Their sense of hearing is remarkable because their ears are so close together that directional hearing would be impossible in any other animal," says Andrew Mason, a zoology professor in the Division of Life Sciences at the University of Toronto at Scarborough and lead author of the study. The study's other authors are Michael Oshinsky, postdoctoral fellow at Thomas Jefferson University and Ron Hoy, professor in the department of Neurobiology and Behaviour at Cornell University.

Most flies have no sense of hearing at all, explains Mason. But Ormia is a specialist at locating singing crickets, on which they deposit tiny larvae that grow into large maggots by eating the crickets from the inside out. Ormia can detect singing crickets using a unique set of eardrums that are located behind the head as reported in Science by Hoy and his post doctoral fellow, Daniel Robert in 1992.

The flies' unique mechanism of directional hearing has inspired a new generation of hearing aid technology and nanoscale microphones. Miniature listening devices based on the Ormia ear are under development at several industrial and engineering labs in the U.S. This new technology will enable the manufacture of directional hearing aids that are smaller, simpler and cheaper than currently available devices.

But the researchers didn't suspect how well this system could work until they directly measured the flies' ability to track changes in the location of
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Contact: Sue Toye
sue.toye@utoronto.ca
416-978-0260
University of Toronto
4-Apr-2001