According to a new study, the immortal ghost-faced moth in the movie "The Silence of the Lambs" has a fast-moving, accordion-like mouthpiece and is therefore able to make sounds.
In the Middle Ages, the appearance of the ghost-faced moth in a candle-lit room was thought to be a harbinger of death.
Photo by Blickwinkel, Alamy
Written by: James Owen
In the horror movie The Silence of the Lambs, it's a symbol of immortality; in many folklore, it's a sign of doom — it's the ghost-faced moth, a creepy moth.
But to be honest, the most frightening thing about the ghost-faced moth is that it can make a strange squeaking sound.
Many insects can make sounds by rubbing against external body parts, such as wings and legs. However, insects that make noise through the inside of the body are rare, and only some moths we know can make squeaking sounds.
The ghost-faced moths are named after the skull motif on their heads, and how they make sounds has always been an unsolved mystery.
Now, using advanced equipment, scientists have for the first time recorded the operation process of the internal sound system of the ghost-faced moth and found the principle of its sound: the sounding system of the ghost-faced moth is composed of two parts, similar to an accordion, which can produce sound through rapid movement.
Muscles that move quickly
The new study was published in the July issue of the journal Natural Science. As early as 1920 and 1959, two neglected studies described the two-stage vocal mechanism of the ghost-faced moth, and the latest research further confirmed both studies.
One of the aims of the new study is to test previous hypotheses using modern methods, including microcomputer tomography and X-ray footage, says Gunnar Brehm, a zoologist and research leader at the University of Jena in Germany.
The team studied one of the three species of ghost-faced moths, the only one native to Europe, and found that it can squeak at both stages.
First, the ochre-banded ghost-faced moth inhales air, which causes rapid vibrations in the inner lip between its mouth and throat. Then, the inner lip opens to release air, which creates a sound.
"The vocal system of the ochre-banded ghost-faced moth is basically an accordion with inhale and exhalation parts," Brehm says.
Scientists have found that the vocal system of the ochre-banded ghost-faced moth moves very fast, requiring only 0.2 seconds for each inhalation and exhalation.
Ghost-faced moths and bees
The new study also explains another anomalous behavior of the ghost-faced moth: sneaking into the hive and stealing honey.
"Honey is much thicker than nectar, which may have facilitated the evolution of the valve-like inner lip of the ghost-faced moth, enabling it to suck on viscous honey," Brehm explains.
Similarly, the head muscles of the ghost-faced moth are strong, and sucking honey may be as easy as inhaling and exhausting.
"With strong head muscles, it's not hard to make sounds," Brehm says.
Ian Kitching, an entomologist and moth expert at the Natural History Museum in London, also supports the theory, arguing that the honey-sucking behavior of the ghost-faced moth can explain its squeaking sound.
"My guess is the same or similar, that muscle movements lead to eating and vocal behavior of the ghost-faced moth." Kitching said he was not involved in the new study.
Why does it squeak?
However, no one knows the exact reason why the ghost-faced moth squeaks.
One theory is that the ghost-faced moth confuses predators by squeaking and buying time for itself. The ghost-faced moth is huge, with a wingspan of up to 13 centimeters, and needs to be warmed up before taking off, so that the body temperature reaches 40 ° C.
As for their ability to cause fear, Brehm says you just have to hand over a ghost-faced moth to an unsuspecting person and see how he reacts. "It's so unexpected, people are usually scared." he said.
Other scientists believe that the reason for the sound of the ghost-faced moth is related to its habit of stealing honey.
One view is that the squeaking sound of the ghost-faced moth mimics the sound of a colony queen: when the moth strikes, the queen makes a sound to notify the worker bee to stop moving or stand still.
Despite the lack of convincing evidence for the theory, Kitking of the Natural History Museum said researchers have observed that "the ghost-faced moth squeaks when approaching the swarm, and continues to make a sound after entering the swarm." ”
In addition, he said the sounds made by the three species of ghost-faced moths are different, just as the sounds of their respective target bees are different, so "the squeaking sound they make may be the result of adaptations to cope with different bees." ”
Therefore, the exact reason why these ghost-faced moths squeak is still unanswered.
(Translator: Stray Dog)