The Great Wax Moth has an incredibly simple yet powerful hearing ability that can detect ultrasound up to 300 kHz. This is in stark contrast to the human hearing range, which can only detect sounds up to 16 kHz. Scientists from the University of Strathclyde have discovered that despite their basic hearing structure, moths can hear ultrasound. This may serve as a secret communication method that even their predator, bats, cannot detect. The study, published in the Biology Letters journal, found that the moth’s hearing consists of only four cells and a membrane, yet it can detect ultrasound in the range of up to 300 kHz, surpassing the previous record holder, the Gypsy Moth.
The term ultrasound refers to all frequencies above 16 kilohertz (kHz) that cannot be detected by the human ear. Until now, it was known that bats use ultrasound as a natural radar to navigate in the dark. However, the Great Wax Moth and other insects in this family can also hear ultrasound despite their simple hearing structure. This highly sensitive hearing ability serves as protection against bats, their natural predator. By detecting the ultrasound signals that bats use for locating prey, moths can often escape from their hunters. The scientists believe that the moth’s extremely powerful hearing ability may have developed accidentally, as a byproduct of their stiff hearing membrane, which they need to recognize the correct timing of rapidly successive sounds.
The researchers also suggest that moths may use the extremely high-frequency range for communication, as it cannot be detected by bats, allowing them to exchange signals silently. The study’s lead author, Hannah Moir, believes that the moth’s hearing ability may have evolved for a different purpose, but it has become a useful adaptation for survival. This discovery sheds new light on the hearing abilities of insects and their unique adaptations to their environment.
