A fly in your ear!

By JW Dowey - 23 Jul 2014 13:32:0 GMT
A fly in your ear!

This Ectophasia fly and other Tachinids are parasitic on many types of insect Just as the Ormia fly here attacks only crickets ; Fly image; Credit: © Shutterstock

Parasitic flies are rarely in the news, despite some usefulness in biological control. The dispatch of crickets by em>Ormia ochraea is similar to the death of caterpillars. Eaten from the inside by parasitic wasp larvae. Yukky, but even more fascinating is the acute hearing employed by the fly to locate its prey. As the adult fly is so small, there is a tiny distance of 1.5mm within its sensory apparatus. With the cricket's song wavelength 50X that distance, this species alone has evolved a different method of sound localisation and detection.

We have reported on several sound and ultrasound topics such as cricket catching in the Secrety Squeaking Tarsier. Here we have a genuine new hearing aid that could change the lives of 10% of a population. Sorry it won't be in the shops yet, folks!

This fly has unique sound processing system of multiple vibration modes. These amplify and localise the crickets' chirrups. To mimic this, engineers have created multiple piezoelectric sensing ports in a silicon structure that measure both sound pressure and pressure gradients in sound. Those who are hard of hearing might like to pay full attention now, as the piezoelectric system avoids the usual hearing aid power consumption problems

The invention of such a precise locating device also has applications in dark environments and for the usual military and spying listening devices, and possibly smartphones. Sound is being amplified in a see-saw like effect and was used to inspire a microphone invention in 2013. In the 20 years since the original paper on the fly's hearing, this is the first time that such a small device has been created for helping human hearing.

The application of the device would be in adaptively focussing on a single sound or conversation, removing much of the annoyance caused by overamplification in current hearing aids. Michael L. Kuntzman and Neal Hall of the University of Texas in Austin produced the Open Source paper in Applied Physics Letters as - Sound source localization inspired by the ears of the Ormia ochracea.