Can Mosquitoes Hear Sound From Long Distances?
WouterUntil now, mosquitoes had been thought to be unable to hear sounds that are at least a few inches away. But now researchers at Cornell University, in collaboration with Ron Miles at Binghamton University, have found that the insects can indeed detect sounds from long distances.
In a series of neurobiological experiments, Miles tested the hearing abilities of male Aedes aegypti mosquitoes. He placed the insects in a quiet room at the Binghamton campus. They were exposed to a range of flight tones. In the experiments, the tones were presented at 100-Hz intervals, in a trapezoidal envelope, with a 50-ms ramp at onset. The tones were played from 3 meters away.
The males responded to the female tones by flying. They also responded to the sounds emanating from the speaker located ten meters away. These findings demonstrate that the antennae do not need ear drums to detect sound.
Earlier research had revealed that the insect antennae are tuned to various frequencies. In addition, they were thought to be used only for close range hearing. However, a recent study conducted by Gil Menda showed that the nerves of the mosquitoes are highly sensitive to sounds from 1 to 10 meters.
Menda fitted the males with electrodes to monitor the electrical potential of their auditory nerves. They were then placed in a 40x40x40 cm cage. The insect was tethered to a stainless steel wire. The electrical stimulation from the electrode was detected.
