Just bite me, why are you buzzing at me?

Review expert: Mo Jianchu, Professor of Institute of Insect Science, Zhejiang University

If humans need to vote for the most annoying creature on earth, I believe mosquitoes will firmly take the throne with a crushing advantage. After all, they love to suck blood, spread diseases, and can bite a lot of lumps on the body. They are one of the most notorious creatures on earth.

The worst thing is that when you are sleeping, mosquitoes will fly around your ears, making a buzzing sound that can be called the devil's whisper. When you find the right opportunity to slap yourself hard, thinking that you can slap the mosquito on your face into the second dimension, the buzzing sound starts again, causing your blood pressure to soar as you are about to fall asleep again, and the only thing left in your mind is the obsession of getting rid of it as soon as possible.

Source: Dingxiang Doctor

So why do mosquitoes make such sounds? For mosquitoes that need to suck blood from the human body, wouldn't a quieter method of action increase their success rate?

1Mosquito Sounder

A tiny mosquito has no lungs, no syrinx, and no vocal cords. How do they make sounds? Many people believe that mosquitoes make buzzing sounds because they flap their wings quickly when flying, and the wings vibrate the air to make this sound. But the truth is not that simple.

It took scientists a long time to figure out the mosquito's sound-making mechanism. They found that there is an organ at the base of the mosquito's wings. When the mosquito flaps its wings, the wings rub against this organ and make a buzzing sound that annoys us.

Because of their small size, the buzzing sound does not travel over a wide range. Under normal circumstances, it is difficult for us to hear this annoying buzzing sound unless the annoying mosquito gets close to our ears.

So how do mosquitoes locate their victims?

In our common understanding, it is easy to associate it with the carbon dioxide produced by human breathing that attracts mosquitoes to fly to the head. But in fact, carbon dioxide is an agonist for mosquitoes , that is, when mosquitoes sense carbon dioxide in the air, it means that there is a target nearby that can exhale carbon dioxide and suck blood. The more accurate positioning of mosquitoes depends on other compounds produced by human metabolism, such as 3-octen-1-ol.

Of course, the towel blanket we cover ourselves with when we sleep will also interfere with the mosquitoes' location to a certain extent, and the head "exposed" outside is relatively easier to attract mosquitoes. Sometimes, the smell of ears that have not been cleaned in time will also attract them to visit frequently, and the annoying buzzing of mosquitoes will become more obvious.

2

The buzzing sound is actually a mate search

Mosquitoes make this annoying buzzing sound not to deliberately annoy you, but to attract their mates for mating.

Female mosquitoes are larger than male mosquitoes and flap their wings at a lower frequency, about 450hz, making a lower sound; male mosquitoes flap their wings at a faster frequency, about 600hz, making a sharper sound.

Male mosquitoes rely on the difference between two buzzing sounds to identify the opposite sex. When they find a female mosquito, the two will begin to flap their wings in coordination, while increasing the vibration frequency of their wings to around 1200hz. If the coordination is perfect and reaches a state of "harmony", they will begin to mate.

But there is still a question: mosquitoes don't have ears, so how do they hear and recognize each other's buzzing?

It turns out that there is a very sensitive airflow receptor hidden in the antennae of mosquitoes, which looks like a small black dot. It can receive the airflow emitted by other mosquitoes when they vibrate their wings, and can also help them quickly avoid obstacles and fly smoothly in the dark. Because this organ was discovered by scientist Christopher Johnston, it is called the Johnston organ .

Source: Zhihu @苏澄宇

When the mosquitoes finish mating, the pregnant female mosquitoes will start to try to suck our blood. The reproductive capacity of female mosquitoes is extremely strong. They only need to mate once to lay eggs for the rest of their lives, and can lay hundreds of eggs in their lifetime. So if you fail to kill the female mosquitoes that sucked your blood in time, then the toilets, trash cans, flower pots and other humid places in your home will become the "treasure pots" of mosquitoes, and even your home will become a mosquito nest after a while.

3. Mosquitoes are everywhere

In order to get rid of mosquitoes, many people think that they should live on higher floors. After all, a mosquito that looks small cannot fly high.

But if you really think so, you are totally wrong. Mosquitoes can't fly high, but you can take the elevator to go up to a high building, so can't mosquitoes lie on you and take a "downwind ladder"? Before entering the elevator, I believe that most people will not pat their whole body first, right?

In addition to hitchhiking, mosquitoes' small size also allows them to soar up to higher floors with the help of suitable strong winds .

The National Institute of Allergy and Infectious Diseases (NIAID) of the United States once sampled local mosquitoes in the Sahara region. They installed sticky nets on helium balloons and released them to different heights to catch mosquitoes. The highest balloon reached 290 meters.

Source丨Huestis DL, Dao A, Diallo M, et al. Windborne long-distance migration of malaria mosquitoes in the Sahel[J].Nature, 2019, 574(7778): 404-408.

The data summarized after collection overturned people's cognition. Even at an altitude of 290 meters, there are still many mosquitoes, even more than the number below 290 meters!

Not only that, people have also found mosquitoes in the Himalayas, where the average altitude is about 8,000 meters. Mosquitoes are simply everywhere.

Sources of mosquito species and numbers at different heights | Huestis DL, Dao A, Diallo M, et al. Windborne long-distance migration of malaria mosquitoes in the Sahel[J]. Nature, 2019, 574(7778): 404-408.

Many netizens have lamented, Sister Mosquito, it’s okay if you suck a few mouthfuls of blood, it’s okay if you bite me and leave bruises all over my body, and I can even tolerate your unwiped mouth full of viruses, but you can’t fly around my ears and buzz when I’m sleeping. For workers who work 996 hours a day, not letting them sleep is tantamount to chronic murder.