Cruel Fly Inspires the Next Generation of Hearing Aids

The remarkably sensitive hearing of parasitic flies helps them find their prey even in poorly lit environments. Now researchers think this same super-hearing could one day help deaf humans hear, as its unique mechanisms have inspired the next generation of hearing aids.

As described in the journal Applied Physics Letters, researchers at the University of Texas Austin have developed a prototype device that mimics the unique hearing mechanisms of the Ormia ochracea fly.

This tiny fly is infamous for its remarkably cruel and parasitic breeding process. Experts have observed the flies home in on male crickets and inject their larvae directly into the exoskeleton. The larvae then eventually eat their way out in a metamorphosis event reminiscent of the sci-fi classic Alien.

To find its prey, researchers have long suspected that the fly simply follows the chirps, tracing cricket songs back to a signing male. Interestingly, a standard understanding of hearing says that such accuracy should be impossible in insects that small.

According to the American Institute of Physics, acute hearing is traditionally made possible when the brain discerns the location of a sound's source based on how quickly a sound wave hits each ear. For instance, if a sound were to hit the left eardrum first, and then the right, it is clear that the sound's source is closer to the left.

O. ochracea is too small for this to work, with most sound waves hitting its ears nearly simultaneously. However, a study conducted in 2006 revealed that the flies certainly aren't finding their prey by chance alone, indicating a the presence of a hyper-evolved mechanism that allows the fly to tell differences in sound mere milliseconds apart.

Now in a study funded by the Defense Advanced Research Projects Agency (DARPA), researchers believe they have reproduced that mechanism on a slightly larger scale, creating a device that can amplify a four-millionths of a second time delay and allow for acute source detection.

Study author Neil Hall explained in a recent statement that the device may one day be a boon for dissatisfied hearing aid consumers, who often have a hard time discerning between primary and background noises.

Still, it will require much more fine tuning before it can be ready to face consumer demands.