The Secret of a Miniature Ear Discovered

“In the past decade, biologists discovered a new mechanism by which animals locate sounds,” says Science News. “The finding emerged from the observation that a parasitic fly stalks crickets by sound, even though the fly’s head is too small for any of the previously known sound-localization mechanisms to work.” Such mechanisms usually depend on a sizable distance separating two eardrums.

According to a recent study carried out at Cornell University, U.S.A., “female flies of the species Ormia ochracea pinpoint sounds to within 2 compass degrees​—as precisely as an owl does,” even though their two joined eardrums span only about a millimeter! The fly’s owllike acoustic precision can be credited to an ingenious hearing apparatus.

The insect’s eardrums are joined by a bridge of material that allows the two membranes to swing back and forth as a single unit​—you might think of a teeter-totter at a playground. When the sound emitted by a cricket reaches the fly, vibrations in the nearer eardrum are transferred almost instantaneously to the other, dampening the latter’s response to the same incoming sound waves. Hence, the membrane nearer to the cricket vibrates more strongly. This enables the fly to locate and home in on a potential target.

Of what practical use is this discovery? Researchers believe that it could help them improve the design of things like microphones and hearing aids. The latter, for instance, could be designed so that they “gather sound primarily from the direction the listener is facing,” says the report. Yes, what wisdom is manifest in Jehovah’s amazing creations!​—Job 42:2.

[Picture Credit Lines on page 31]

R. Hoy/Cornell University

Top two photos: R. Wyttenbach/ Cornell University