Recently, many media in the United States have reported on the "cicada disaster", mainly because the two cycles of cicadas will wake up at the same time this year, when trillions of cicadas will break through the ground at the same time, and this cicada disaster will be the first time since 1803 that the United States has encountered such a large-scale phenomenon.
The simultaneous appearance of these cicadas will affect the local ecological balance to a certain extent, but what is even more terrifying is that the loud sound made by these cicadas chirping at the same time will collapse the local residents.
The cicada is considered to be the loudest insect on the planet, with a single cicada easily emitting a sound of more than 70 decibels, with some species such as the American red cicada reaching 140 decibels. It is conceivable that if hundreds of billions of cicadas chirp at the same time, the sound must be deafening.
According to the National Institute for Deaf and Other Communication Disorders, constant exposure to 85 decibels of noise can be harmful to the human body, and can even cause permanent damage to the hair cells in the cochlea, ultimately causing hearing loss.
Specifically, the following are the maximum tolerable times for the average person who may have hearing damage:
85 decibels: It is about the sound of honking the horn in a traffic jam, which can damage the cochlear hair cells, and the loudness of the sound wave impact for more than 8 hours will damage the hearing.
110 decibels: If you stay in noise above 110 decibels for 1 minute, it can also cause permanent damage to your hearing!
So with such a loud noise, why is the cicada okay on its own, will it deaf itself?
Although the cicadas' chirpings are loud, they do not deafen themselves, which is related to their special physiology.
The cicada's vocal organs are located on both sides of the abdomen, with two small round caps and a transparent membrane inside called valves. When the male cicada chirps, it uses its muscles to make the eardrum vibrate, and the vibrato it makes expands in the valve. In this way, the sound of the cicada is actually made by the valves. The female cicada's abdomen has an incomplete structure of vocal organs, so it cannot make sounds, but its auditory organs are more powerful and sensitive than those of the male cicada.
The auditory organ of the cicada consists of the auditory membrane, the ridge of the auditory membrane, and the auditory sac, which contains auditory receptors. Both male and female cicadas have a pair of huge mirror-like membranes on their abdomen called the eardrum, which function as ears. When a male chirps, the tendon contracts, causing the eardrum to relax, creating a fold. In the case of folding, the tension of the eardrum decreases, the sensitivity to the sound decreases by about 20 decibels, and the cicada can still hear the sound it makes. Although the sound is still loud, at least it does not break the eardrum.
In this way, the cicada reduces its own hearing impairment and at the same time adjusts its dynamic hearing range to adapt to its own sounds and the sounds around it, maintaining maximum sensitivity for sound propagation and responding to changes in its surroundings in a timely manner.
So, cicadas are not deaf by their own voices, they can effectively protect themselves, but Americans may become deaf if they don't wear noise-canceling headphones when they go out.
