Mosquitoes can be divided into male mosquitoes and female mosquitoes. The antenna of male mosquitoes is filiform, and the antenna hair is generally thicker than that of female mosquitoes. Their food is nectar and plant juice. The mouthparts of male mosquitoes degenerate, and female mosquitoes need to bite animals to suck blood before breeding to promote the maturation of inner eggs.
Mosquito saliva contains a substance with vasodilating and anticoagulant effects, which makes it easier for blood to gather at the bitten place. After being bitten by mosquitoes, the skin of the bitten person often appears blistering and itching symptoms. Almost everyone has an unpleasant experience of being bitten by mosquitoes, or more accurately, being bitten by mosquitoes. Mosquitoes cannot open their mouths, so they don't bite the skin. In fact, they pierce human skin with six needle-like structures. These short needles are the center of mosquito feeding mouthparts. These short needles suck human blood like blood-drawing needles; Mosquitoes also excrete saliva containing anticoagulant to prevent blood coagulation, so that they can have a full meal safely. Mosquitoes ate, drank and drifted away, leaving behind an itchy and swollen bag. However, the itchy feeling is not caused by short needles or chemicals in saliva. We feel itchy because the body's immune system releases a kind of protein called histamine to fight against foreign substances, and this immune response will trigger an allergic reaction at the bite site. When blood flows to the bite to accelerate tissue recovery, histamine will cause swelling of the tissues around the bite. The intensity of this allergic reaction varies from person to person, and some people have more serious allergic reactions after being bitten by mosquitoes.
Every time a mosquito bites, it will suck about one thousandth of a milliliter of blood. After each full meal, mosquitoes usually move within 2 kilometers of their birthplace, but as far as 180 kilometers.
Each female mosquito lays eggs about 1000 ~ 3000 in her lifetime. They usually lay eggs on the water, and two days later they hatch Cheng Shuisheng larva-Jie Jué. Cicadas feed on algae in the water. After four times of peeling, they grow into pupae and float on the water. Finally, the pupa epidermis breaks and young mosquitoes are born.
The life cycle of mosquitoes includes four parts: eggs, larvae, pupae and adults. Generally, eggs 1 ~ 2 days, larvae 5 ~ 7 days, pupae 2 ~ 3 days, adults 3 ~ 7 days after eclosion, and the whole generation 1 ~ 2 weeks. Among mosquitoes, the most hateful is the female mosquito that sucks human blood. Male and female mosquitoes have different feeding habits. Male mosquitoes are "vegetarians" who specialize in feeding on nectar from plants and juice from fruits, stems and leaves. Female mosquitoes occasionally taste the juice of plants, but once they get married, they will feed on blood. Because it can only develop ovaries after sucking blood. So only female mosquitoes bite and suck blood.
There are many spiral sensory hairs on a pair of antennae and three pairs of feet of mosquitoes, and each sensory hair is densely arranged with round or oval pores. In the dark, mosquitoes can sense the carbon dioxide emitted by the human body in the air through this sensor, respond within 1 second, and fly to the blood-sucking object correctly and quickly. Before sucking blood, mosquitoes inject saliva containing anticoagulant into the skin and mix it with blood, so that the blood becomes thin plasma that will not coagulate, and then spit out undigested old blood and suck out fresh blood. If a person bites 654.38+100000 mosquitoes at the same time, he can absorb human blood.
Mosquitoes suck human blood and are also "picky", looking for objects that meet their "tastes". When mosquitoes "buzz" around a sleeping person's pillow, they rely on proximity sensors to sense temperature, humidity and chemicals contained in sweat. Therefore, female mosquitoes first bite people with higher body temperature in love sweating. Because of the high body temperature, the odor secreted by people in love sweating contains more amino acids, lactic acid and ammonia compounds, which are easy to attract mosquitoes.
The main harm of mosquitoes is to spread diseases. According to research, mosquitoes spread more than 80 diseases. On the earth, no insect is more harmful to human beings than mosquitoes.
Malaria is transmitted by Anopheles mosquitoes. Malaria is also called miasma. According to the investigation of 1935 Ministry of Health, 50% of residents have plasmodium in their blood, and 72% have falciparum malaria. 1936, about 20,000 people died of malaria in Gao County, Jiangsu Province. 1876 When the Panama Canal was dug, countless workers died of yellow fever and malaria, which made 1889 have to stop working. Only after entomologists have solved the problem of mosquitoes can they continue to complete the canal project. 1930 the report of the far east tropical diseases medical association points out that about 50 people die of tiger's mouth and 50,000 people die of malaria every year in Thailand. There are 400 kinds of malaria in the world, 85 of which can spread malaria. Malaria caused by plasmodium is one of the main causes of human death in the world, especially children under five years old, who are more likely to be infected with malaria and die. Malaria kills about 3 million people every year. Anopheles mosquitoes that can transmit malaria are distributed in Central and South America, Africa, Oceania and Central Asia, especially in Africa. In Africa, a child dies of malaria every 30 seconds on average. Anopheles Gambiae is another disease of Anopheles gambiae, and most kinds of mosquitoes can spread filariasis (caused by nematodes). This disease can lead to gumma, which makes the external genitalia and thighs swell abnormally. About 65,438+200,000 people worldwide are infected with filariasis. Most species of mosquitoes can be infected with toxic diseases, including yellow fever, dengue fever, Japanese encephalitis, St. Louis encephalitis, polyarthritis, Rift Valley fever, Chikungunya fever and West Nile fever. Fortunately, AIDS is not spread by mosquito bites.
How do mosquitoes transmit pathogens into human body? When Anopheles mosquitoes suck the blood of malaria patients, they also inhale plasmodium (the source of malaria). When they bite again, plasmodium is injected into the bitten person from the mouth of the mosquito. After 10 days, plasmodium began to appear in the blood vessels near the skin. They multiply in patients' red blood cells and divide into a large number of small protozoa, which destroy red blood cells and release a toxin. Each plasmodium invades other red blood cells, constantly multiplying, making more and more plasmodium and toxins in patients, leading to chills and fever in patients. At first, malaria patients feel cold and trembling all over, but the temperature measured by thermometer is very high. About an hour later, the patient felt a fever, and then his temperature continued to rise. After three or four hours, he began to sweat and his temperature dropped. A few hours later, the patient felt relaxed and his illness seemed to have passed. In fact, at this time, the small protozoa have invaded new red blood cells and started to reproduce. When Plasmodium destroys red blood cells again, the patient becomes ill again, forming a second round. Unless proper treatment is given, this attack will continue periodically and painfully. The losses caused by malaria to human beings are considerable. The patient is weak, inefficient, and even loses his life in severe cases. Drugs can be used to treat and prevent this disease, but the best way is to eliminate Anopheles mosquitoes infected with this disease.
Japanese encephalitis (an acute infectious disease caused by viral infection) is also spread by mosquitoes. This disease is also called Japanese encephalitis, commonly known as encephalitis. The patient developed fever, headache, vomiting, convulsions, lethargy and coma. There is no specific treatment, so the mortality rate is quite high.
Mosquitoes become infectious after biting the blood of people or animals with viruses for a long time, and when biting people without immunity, they will make the bitten person sick. The mosquitoes infected with this disease are Culex pipiens and Aedes. In order to prevent the occurrence and prevalence of this disease, in addition to vaccination and infection prevention, we must also vigorously kill mosquitoes and eliminate communicators. In addition, Culex pipiens and Anopheles can also spread filariasis (elephantiasis).
Mosquitoes that can transmit diseases in China can be roughly divided into three categories: one is Anopheles, commonly known as Anopheles mosquitoes, which mainly transmit malaria. According to incomplete statistics, during the period of 1929 1 year, about 2 million people worldwide died of malaria. The other is Culex pipiens, which mainly spreads filariasis and Japanese encephalitis. The third category is called Aedes mosquitoes, which have black and white stripes on their bodies, and are also called black-spotted mosquitoes, which mainly spread Japanese encephalitis and dengue fever.
In a suitable environment in summer, female mosquitoes lay eggs in water and hatch into larvae in a day or two, which is called dragonflies. After molting for four times, it becomes a pupa, which can continue to live in water for two or three days and then emerge into mosquitoes. It only takes about 10 ~ 12 days to complete the development of one generation, and it can reproduce seven or eight generations a year.
Scientists have found that carbon dioxide is very attractive to mosquitoes for a long time, but carbon dioxide alone cannot tell the whole story, because facts show that mosquitoes prefer to bite people's arms, legs and feet after all. Therefore, the role of carbon dioxide can not be ignored, but the skin must also release other substances that are more attractive to mosquitoes.
Scientists have found that mosquitoes react strongly to some mixtures. Among the 346 substances they tested, the mixture of three special chemicals attracted 90% mosquitoes every time. Bernier found that his own arms and hands only attracted seven mosquitoes. "Sometimes, mosquitoes mixed with 30 substances are not attracted at all," bernier said. However, in this experiment, scientists have never found that any attractant can attract mosquitoes 100%.
The researchers also found that the mixture that can release human body odor is more attractive to mosquitoes. However, this is far from being a better attractant. Because the attractant must be more attractive to mosquitoes than the human body nearby, bernier and others said, "It is very difficult to get close to the human body, and we can't do it yet."
At night, mosquitoes have phototaxis, so most mosquitoes begin to enter the house. . The corner of the room, the ceiling, the bottom of the bed, and several water sources behind the seat (especially the rooms with babies and the elderly) are places where mosquitoes like to patronize and hide. Therefore, special attention should be paid when spraying aerosol. In fact, mosquito prevention is the most important. If mosquito control is done well, the number of mosquitoes in your home will be very, very small.
Mosquitoes are a serious public health problem in most parts of the world. It is estimated that about 700 million people are infected with various diseases by mosquitoes every year, and 17 people die from various diseases infected by mosquitoes. Especially in tropical areas, many infectious diseases are often transmitted to humans through mosquitoes. However, in most temperate countries, such as the United States, Britain and New Zealand, being bitten by mosquitoes is usually only itchy, but individual phenomena are not excluded. Mosquitoes do have this "food preference". This is not because some people think that their skin is tender and their blood is sweet, which attracts mosquitoes. The main reason is that some of their breaths attract mosquitoes. Generally speaking, mosquitoes have a soft spot for the following people:
First, people with developed sweat glands and high body temperature.
People who like sweating, the acidity in the blood is enhanced, and the discharged sweat makes the lactic acid value on the body surface higher, which is attractive to mosquitoes. In addition, mosquitoes have a heated body in their antennae, which is very sensitive to temperature. As long as the temperature difference changes a little, it can be detected immediately. People who sweat lose heat quickly and attract mosquitoes.
Second, people who are tired or breathing faster.
People will breathe faster after engaging in sports or manual labor. Some people have larger lung capacity or faster breathing rhythm. In this way, the exhaled carbon dioxide is relatively large, and the carbon dioxide will form an airflow at a height of about 1 m above the head. Mosquitoes are sensitive to this and will smell it.
This shows that your body is overwhelmed, so you should go home and rest immediately, and don't overdraw your physical strength, so as not to cause more problems.
Third, people who like to wear dark clothes.
Mosquitoes don't sleep during the day and go out at night, mainly because they have the habit of dark. If they wear dark clothes, they will have a black shadow at night, and mosquitoes will chase them to darker places. The color of clothes, such as black, is the first choice for mosquitoes to attack, followed by yellow, blue purple, blue, red and green. Mosquitoes don't like to bite white. Similarly, mosquitoes like to bite people with dark skin or red skin.
Fourth, people with fast metabolism.
So children are easily bitten by mosquitoes, while old people are just the opposite.
Fifth, people who have made up.
In order to verify the allure of smell to mosquitoes, American scientists tested and analyzed more than 3,900 substances with olfactory instruments. It is found that hair gel, hand cream, facial cleanser and other cosmetics are very attractive to mosquitoes. Most cosmetics contain stearic acid (a fatty acid), so people who make up are more favored by mosquitoes.
Of course, there are also some smells that mosquitoes hate. The smell of bay leaves, lemongrass oil, citronella, garlic and geraniol will keep mosquitoes away.
Sixth, pregnant women.
Pregnant women are particularly prone to attract mosquitoes. A medical study in the United States shows that pregnant women are particularly attracted to mosquitoes, and the probability of being bitten by mosquitoes is twice that of other women.
Seventh, people who drink.
People are also easily bitten by mosquitoes after drinking alcohol, eating beef and mutton or taking antihypertensive drugs.
Note: At present, science cannot prove that mosquitoes have a preference for a certain blood type. Pest control: mosquito repellent
Prescription: fresh Herba Artemisiae Scopariae and fresh Folium Artemisiae Argyi.
Usage: twist into rope, dry in the sun, light at dinner, smoke. A mosquito is sucking blood. Did you slap it in the past and let it "break into pieces" to dispel your hatred, or did you wave it away? Do you dare to vent your hatred when you read the report that "killing mosquitoes that are sucking blood will lead to death" in authoritative medical journals?
The cause of the incident was a report in the New England Journal of Medicine: A 57-year-old woman in Pennsylvania, USA, died of a muscle infection caused by a fungus of Microsporum. The researchers speculated that the woman shot the mosquito to death on the skin, and the smashed mosquito debris entered the skin, causing infection. Because the New England Journal of Medicine is the longest-running medical magazine in the world, this incident has attracted more attention from netizens.
It is almost shocking that killing a mosquito that is sucking blood will lead to death. Some experts have analyzed that mosquitoes will leave wounds on their skin when they suck blood. When it is sucking blood, if it is suddenly killed by a shot and the mosquito's mouthparts are too late to be pulled out, then the wound on human skin will not heal. The deadly fungi carried by mosquitoes may invade the human body with unhealed wounds, causing bacterial infection and eventually leading to death. Of course, if people have wounds and are infected with fungi carried by mosquitoes that have been photographed, it will also be very dangerous.
Coyle of Albert Einstein College of Medicine in new york is one of the authors who wrote in the New England Journal of Medicine that killing mosquitoes can kill people. He seriously put forward a seemingly ridiculous suggestion: "If mosquitoes are biting people, it is best to bounce them off gently instead of slapping them to death."
Many netizens have had a heated discussion on the "bloody case" caused by mosquitoes. Many netizens shouted: "It's terrible. I won't dare to fight mosquitoes in the future." Some people said half humorously and half seriously, "That means you are either killed or itchy!" "You're kidding! I don't know how many mosquitoes that are sucking blood have been killed. This is not a hundred deaths, not alive! " A netizen thinks this kind of incident is incredible. More netizens questioned.
Professor Li Pingfei, deputy director of the Pest Control Department of Changsha CDC, said that such incidents rarely occur and the probability of such incidents can only be said to be "very low". Although mosquitoes spread many diseases, whether people get sick depends on two factors: one is the virulence and quantity of viruses, and the other is the strength of human resistance. When the human body has strong resistance and the virus is weak, the virus is eliminated. On the contrary, people will get sick.
The pathogens of most diseases transmitted by mosquitoes must first enter mosquitoes to proliferate and develop, and then be released through saliva before they can infect people. This is an indispensable link in the natural circulation of pathogens. Mosquitoes are the most important vectors of insect-borne diseases. Therefore, the monitoring of mosquitoes in Changsha CDC is relatively comprehensive, including the methods of attracting mosquitoes by using their phototaxis, attracting mosquitoes to attract eggs and collecting water containers. Therefore, it is impossible to kill mosquitoes that are sucking blood in Changsha, and citizens need not panic. The probability of pregnant women being bitten by mosquitoes is higher than that of non-pregnant women 1 times. The gas exhaled by women during pregnancy contains many different chemicals, so it becomes the target of Anopheles mosquitoes. In addition, pregnant women have higher body temperature and sweat more, which is a good base for skin bacteria to breed. These two reasons make pregnant women more vulnerable to mosquito bites than other women.
Many people think that the stronger the pungent smell, the better the mosquito killing effect. Strong pungent smell is harmful to human body. For example, some people with allergic constitution may be allergic to cigarettes, smells and even the active ingredients themselves, which may cause some discomfort.
In addition, for the elderly, children, pregnant women or asthma patients, because they are all susceptible people, other people who also use certain mosquito repellent products may feel at ease, but they are likely to feel uncomfortable. Therefore, it is best to choose mosquito repellent products that are smokeless and tasteless and have little irritation to them. At the same time, it is suggested that you should keep the window half open when using them.
In addition, many people are used to lighting mosquito-repellent incense before going to bed at night, but in fact, outdoor mosquitoes love to fly into the house at dusk to attack people. If mosquito repellent is used at night, it can effectively prevent outdoor mosquitoes from flying into the house through the gap between doors and windows, and can also make mosquitoes originally in the house be smoked away, thus reducing the number of mosquitoes indoors.
It takes about two hours for mosquito-repellent incense to spread evenly in the room after it is lit, so the best mosquito repellent time should be at night or two hours before going to bed. It is common sense that mosquitoes are pests and can spread many diseases. However, when you are bitten by a mosquito, someone will say humorously: the mother mosquito bit you. In other words, it seems that male mosquitoes don't bite or suck blood. Is that really the case?
Look at the mouth (mouthparts) of mosquitoes before jumping to conclusions. First of all, catch the mosquitoes that bite us carefully and observe them carefully with a magnifying glass. At this time, you will see that its head has two tentacles similar to Ceratophyllum, and the hair of the tentacles is sparse. Look at its mouthparts carefully. Its mouthparts are like needles. Look carefully, this needle is composed of six slender oral needles, two of which are the upper jaw, two are the lower jaw, one is the tongue and the other is the lips. When sucking blood, first pierce the skin with the lower jaw, and other oral needles follow into the wound until the blood vessels suck human blood. If you catch more blood-sucking mosquitoes, you will find that their mouthparts and tentacles are the same structure. It turns out that they are all female mosquitoes-female mosquitoes. Among the mosquitoes that suck human blood, it seems that no male mosquitoes can be caught. At this time, you can catch some mosquitoes in the grass with a washbasin or insect net coated with soapy water, and then observe their tentacles and mouthparts with a magnifying glass. At this time, you will see that there is another mosquito besides that mosquito, which has the same structure as above. There are many thick long hairs on its tentacles, just like a feather duster. Look at its mouth again, and you will find that its chin is short and thin. Such a thin chin can't pierce human skin, so it can't suck human blood. This is a male mosquito. So generally speaking, male mosquitoes don't bite and can't suck human blood.
Why do female mosquitoes feed on blood? It turns out that the mated eggs of female mosquitoes can't mature if they don't suck blood. After mating, every time a female mosquito sucks blood, it will fly to the surface to lay eggs. After laying eggs several times, the female mosquito will die. Some female mosquitoes can overwinter indoors. Male mosquitoes generally come from nectar, plant juice and dew, and their life span is very short, usually only 6-7 days. Most male mosquitoes will die soon after mating with female mosquitoes.