By Ed Yong
Edit: Month Month
In the summer, if you go for a walk along the river in Europe, you may hear an unusual song. The song sounded like a series of chirps, even at a distance of one meter, it was very loud. Incredibly, the sound was made by an insect that was only two millimeters long, belonging to the family Puloscope called Micronecta scholtzi.
Micronecta scholtzi。 Image source: wikipedia
Micronecta means "little swimmer" in Latin, and the name is apt. It is one of the smallest of the hundreds of species in the family Lycaenidae, living at the bottom of a pond all its life, moving its paddle-like legs. It is the males who can sing, and they often come to a big chorus to attract the females. Their song is so high that even if these insects live underwater, they can still be heard on the shore a few meters away.
At present, Jérôme Sueur from the Natural History Museum in Paris measured the singing voice of the little hooter with an underwater microphone, and he found that the little thing's call actually broke the record. Its call averages 79 decibels, which is equivalent to the sound of a telephone ringing or a glass of wine at a cocktail party, and some can even reach a maximum of 105 decibels, which is equivalent to the sound of a car honking or a subway whistling past.
Many animals make much louder noises than that, with the highest record being the sperm whale, which can click underwater at about 236 decibels (equivalent to 170 decibels on the ground). Other animals, such as elephants, hippos and dolphins, also make louder sounds than those of the little paddlers.
A sperm whale that can make a sound of about 236 decibels (equivalent to 170 decibels on the ground) underwater. Image source: wikipedia
But given their respective body sizes, there is no comparison. The animals mentioned above are relatively large, and the sounds emitted by large objects are also large, just think of the megaphones and headphones at the concert. In the case of the sperm whale, it can grow to 16 meters long and weigh 14 tons, while the small stalker is only two or three millimeters long. Sueher selected 227 species of animals, as large as sperm whales and insects, calculated the ratio of their call intensity to body size and compared them, and finally the small swastika dominated.
How could this little insect make such a loud noise?
It remains unclear. It looked as if it was rubbing the ridged protrusions of its abdomen with its penis, as if playing a violin, but the "bow" was only 50 microns long, and there didn't seem to be any part of the body that could amplify the sound.
But maybe the speaker isn't somewhere on its body. Like other insects in the family Tsubaki, it can use the tiny hairs around its body to fix a layer of air to help them breathe, but Sueer speculates that this layer of air may also function as an echo chamber, reflecting the sound of penis rubbing over and over again. However, exactly how it is, it is still a mystery. As Sauer writes in the article, "Observing the microscopic mechanics of such a small system is a major challenge. ”
As for why the song of the little stroke is so loud, Sue er also has his own opinion.
He believes that this sound, like the complex melody of birds or the long horns of deer, is a sexual signal, indicating that it is a strong and powerful male. If females prefer males with louder calls, over time the males will become louder and louder.
If Suehl is right, the female prefers the louder male, then this can be easily verified with speakers and some recordings. Suele also speculated that the little crow might not have followed the sound to prey on predators, otherwise these predators would eat the loudest males, thus limiting the evolution of high-pitched songs. We don't know which animals feed on small trees, and Sauer intends to find out.
Title image source: wikipedia