Mosquitoes, Diptera mosquito family[4]Small insects.The wings are long and narrow, grayish brown, brown or black;The body is covered with scales and fine hairs;The worm body is divided into three parts: head, thorax and abdomen;The head has a pair of compound eyes and antennae, the compound eyes are developed, and the antennae have whorls;There is a long beak, and the mosquito beak is a piercing and sucking mouthpiece;The chest is divided into three parts: forechest, midchest and hindchest. Only the midchest is developed, with a pair of wings;Each chest has a pair of feet. The feet are slender, with black and white spots and circular lines formed by scales, which is an important basis for classification.[5]There are about 3300 mosquito species in the world, and 400 species are found in China.[4]
Mosquitoes are distributed all over the world.Adults like to live in concealed, dark and poorly ventilated places. Indoor places are mostly under beds, behind cabinets, behind doors, wall seams, livestock houses, basements, etc., and outdoor places are mostly grass, caves, cellars, bridge holes, stone crevices, etc.[6]Female mosquitoes begin to suck blood 2-3 days after eclosion, mostly at night. They are not strict in their bloodthirsty habits, and generally suck animal and human blood.Male mosquitoes do not suck blood and feed on plant juice.Mosquitoes can reproduce 7-8 generations a year.Male mosquitoes live for 1-3 weeks and female mosquitoes live for 1-2 months.[5]
In addition to biting and sucking blood, mosquitoes can also spread diseases.There are 4 kinds of mosquito borne diseases in China, namelydengue fever, epidemic encephalitis Bmalariaandfilariasis。[5]The prevention and control of mosquitoes is an important means to control and eliminate mosquito borne infectious diseases. The most fundamental way is to eliminate the breeding ground of mosquitoes. Therefore, efficient and low toxic chemical pesticides should be used when necessary.In order to prevent and repel mosquitoes, people should strengthen their personal protection. In summer and autumn, they should not be naked when enjoying the cool outdoors at night, and light wormwood rope and mosquito repellent incense indoors;If possible, screens and doors can be installed and mosquito nets can be used to prevent mosquito bites.[7]
Diptera（Diptera）MosquiticidaeThere are more than 3600 kinds of insects.Important because female mosquitoes suck bloodMedical insect。spreadyellow fever、malaria、filariasisanddengue fever。The mosquito body is slender, covered with scales, and its feet are slender and fragile,mouthpartsIn the long kiss.Male mosquitoes have filamentous antennae and ring hairs, which are generally thicker than female mosquitoes.Male mosquito feedingnectarFemale mosquitoes sometimes feed on plant juice, but most of them need to suck blood once before their eggs mature.Different mosquito species have different preferences for their hosts, but there are no strict restrictions in many cases.The eggs lay on the water surface and hatch into aquatic larvae（Larvae）。Larvae swim with rapid twisting movements, eat algae and organic debris, a few carnivorous, and even eat other mosquitoes.Mosquito pupae are different from most insects. They can move and breathe by the respiratory tube on the chest.Adult mosquitoes mate immediately after they emerge from the pupal shell.The life span varies greatly according to the type.Mosquito seems to be the host of moisture, lactic acidcarbon dioxide, body heat and sports.Mosquitoes seem to be detected by smellhost。The sound of mosquitoes is caused by the rapid flapping of wings;Female mosquitoes have low frequency of fanning, so they can be recognized by males.The breeding habits are diverse.The prevention methods include eliminating breeding grounds, spraying oil layer on water to block the breathing tube of larvae, and killing larvae with drugs.Indoor synthetic organic insecticides can be used to kill adult mosquitoes.
The countries without mosquitoes in the world areIceland。The continent without mosquitoes isAntarctica。
Biological species
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Mosquitoes belong to Diptera and Culicidae, and are the most important medical insect group.Mosquitoes are widely distributed with many species. So far, there are 3 subfamilies, 35 genera, more than 3600 species and subspecies of mosquitoes recorded in the world.There are three important genera of mosquitoes.
Anopheles（Anopheles，anopheles）It is the only vector of malaria and also spreads filariasis and encephalitis.At rest, the beak, head and body are in line, but at an angle with the landing surface, so it is easy to identify.There are scales of different colors on the wings to form spots.The egg lies on the water surface alone.The larval body axis is parallel to the water surface and breathes through the back stoma of the abdomen. There is no respiratory tube for most other larvae.They often breed in the water where plants flourish.Life history varies from 18 days to several weeks.
Culex(Culex) YesViral encephalitisIt also spreads filariasis in the tropics and subtropics.At rest, the body axis is parallel to the landing surface, and the beak is slightly bent downward.veinIt has scales with the wing margin, but the color of the wings is the same.Female mosquitoes have blunt ends of abdomen and retracted tail whiskers.The larva is slender, with a breathing tube with hair bundles, hanging under its head, and forming a 45 ° angle with the water surface.It breeds in almost all fresh water (including static sewage).The eggs are lumpy in water, and the number is about 100.The life history is 10-14 days, and it may be longer in cold weather.Culex pipiens（C. pipiens pipiens）：It is mostly found in the north, with five beltsCulex pipiens pallens(C. pipiens quinquefasciatus) is mostly found in the south.
Aedes（Aedes）：It spreads yellow fever, dengue fever and encephalitis.When landing, the body is parallel to the surface and the beak is downwardCulex pipiensbe similar.The wings are monochrome, which is different from that of Culex pipiens in that the chest is silvery, with white stripes, and bristles behind the pores.Female mosquitoes have sharp ventral ends and protruding tail whiskers.The larvae are short and thick, with a pair of hair bundles in the respiratory tube, and their heads droop at a 45 ° angle with the water surface.They usually breed in floods, puddles or salt marshes, and their eggs can withstand long-term drought.The life history can be as short as 10 days, and it can be as long as several months when the climate is cool.A. aegypti：It is an important vector of yellow fever, with leucorrhea on the feet and spots on the chest and abdomen.It can be bred in various containers such as flower pots, discarded automobile tires, etc.A. sollicitans, A. taeniorhynchus and A. dorsalis are the main species of mosquitoes in salt marshes, which breed fast, fly well and harass animals and people.In China, 374 species (subspecies) of mosquitoes belonging to 18 genera have been found.
The main differences between mosquitoes and other dipteran insects are:
one
The beak is slender and several times longer than the head, which is convenient for sucking liquid food or piercing blood.
two
The veins are special and scaly.
three
The feet are long and thin, with scales on the feet and other parts of the body.
morphological structure
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form
Mosquitoes are small insects. The adult mosquito is about 1.6~12.6mm long, grayish brown, tan or black, and divided into head, chest and abdomen.
one
Head: hemispherical, withCompound eyeAnd antennae.Antennas are divided into 15 sections, the first section is called scape, the second section is called torus, and the later sections are called flagellum.Each flagellum has whorls. The whorls of female mosquitoes are short and sparse, while those of male mosquitoes are long and dense.On the antennae of female mosquitoes, there is another kind of short hair besides the round hair, which is distributed on each whip node. These short hairs respond to changes in chemical substances in the air, and are particularly sensitive to carbon dioxide and humidity. They play an important role in female mosquitoes' search for blood sucking objects.1 pair of tentacles, both sexesanophelesThe tentacles of the male mosquito are all as long as the beak, and the end of the tentacles of the male mosquito is enlarged;The female tentacles of Culex and Aedes are very short, less than half of the beak;The male tentacles of Culex are longer than the beak, and the male tentacles of Aedes are as long as the beak.Mosquito mouthparts are often called proboscisPrick suction mouthpieceIt consists of one upper inner lip, one tongue, and one pair of upper and lower jaws, which together form a slender needle like structure and are enclosed in the sheath like lower lip.The upper inner lip is long and thin, and the ventral surface is sunken to form the inner wall of the food tube. The tongue is located below the upper inner lip, and together with the upper jaw, it closes the open bottom to form an esophagus to absorb liquid food.There is one in the middle of the tongueSalivary duct。The end of the upper jaw is as broad as a knife, with fine serrations inside. It is a tool used by mosquitoes to cut skin when they are sucking blood.The end of the lower jaw is narrow and in the shape of a thin knife, and its end is serrated. When blood is drawn, it is cut with the skin and then used to cut the skin.The end of the lower lip is split into two pieces, called labella.When the female mosquito sucks blood, the needle like structure penetrates into the skin, while the lip flap holds all the piercing and sucking organs outside the skin, and the lower lip bends backward and remains outside the skin, which has the function of protecting and supporting the piercing and sucking apparatus.The upper and lower jaws of male mosquitoes degenerate or almost disappear, and cannot penetrate into the skin, so they are not suitable for blood sucking.
two
Chest: divided into front chest, middle chest and back chest.Each chest segment has 1 pair of feet, middle chest has 1 pair of wings, and back chest has 1 pairBalance bar, is a feature of diptera insects.There is one pair of spiracles in the middle chest and the back chest respectively.The midthorax is particularly developed. Its back plate almost occupies the whole chest and back, followed by the shield, the small shield and the back (Figure 18-4).The scutellum of Culex and Aedes mosquitoes is trefoil shaped, and the trailing edge of the scutellum of Anopheles mosquitoes is arc shaped.Mosquito wings are long and narrow, membranous.The veins are simple and covered with scales.The trailing edge of the wing has a longer scale, called wing sui.Scales can form pits, spots or stripes, which is an important basis for the classification of Anopheles mosquitoes.The mosquito feet are long and thin, and they are called forefoot, midfoot and hindfoot from front to back.The feet often have black and white spots and circular lines formed by scales, which is an important classification feature.
three
Abdomen: divided into 11 sections, the first section is not easy to see.The 2nd to 8th segments are obviously visible. On the back, some mosquito species have light horizontal bands, longitudinal strips or spots composed of scales.The last 3 segments became external genitalia;The female mosquito has a pair of tail whiskers at the end of its abdomen, and the male mosquito is a pincerlike clasp with complex structure, which is an important basis for identifying mosquito species.
internal structure
Mosquitoes have digestive, excretory, respiratory, circulatory and reproductive systems.
one
Digestive system: including mouth, pharynx, esophagus, stomach, intestine and anus.The stomach is the main part of the digestive tract. Digestion and absorption of food are carried out in the stomach.There is a pair of salivary glands in the forebrain, each divided into three lobes. Each lobe has a small salivary gland tube, which finally converges into a general salivary gland tube and passes into the tongue.Salivary glands secrete and store saliva.Saliva contains a variety of enzymes, including anti hemagglutinin, hemolysin and agglutinin.
two
reproductive systemMale mosquitoes have one pair of testes. The vas deferens from each testis expand at the distal end to form a seminal vesicle, and the two will form ejaculatory ducts.The distal end of the ejaculatory tube is the penis, and there are clasps on both sides of the penis.Female mosquitoes have one pair of ovaries.The enlarged part of the two oviducts before they converge into the total oviduct is called ampulla.The common fallopian tube is connected to the vagina.At the far end of the vaginaSpermatheca(spermatheca) and the opening of one pair of accessory glands.The vagina opens on the ventral surface at the junction of the 8th and 9th abdominal segments.Each ovary consists of multiple ovarian tubules.Each ovarian tubule contains three follicles with different development degrees.The top is the proliferating follicle, the middle is the young follicle, and the one near the oviduct is the oocyte.Follicles develop and mature one by one.After the eggs in the egg follicles mature and are discharged, the young follicles develop into egg forming follicles. Every time the eggs are discharged, an expansion is left on the ovarian tubules.
growth process
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Mosquito development isComplete metamorphosisThe life cycle can be divided into four stages: egg, larva, pupa and adult.In the first three periods, they lived in water and adults lived on land.
1. Egg
Mosquito eggs may be laid at three different locations on the water, near the water or in the water according to the species, such as Anopheles and mosquitoes on the water, and Aedes mosquitoes on the water.Anopheles and house mosquitoes hatch in about two days, while Aedes mosquitoes hatch in three to five days.
Female mosquitoes lay eggs in stagnant water.The mosquito eggs are small and less than 1mm long.The eggs of Anopheles are in a boat shape, with floats on both sides, and float on the water surface after being produced.The eggs of Culex pipiens are conical and free of floats. They stick together to formEgg raft。The eggs of Aedes aegypti are generally olive shaped and free of floats. After being produced, they sink to the bottom individually.Mosquito eggs can hatch only in water, and the larvae usually hatch after 2-3 days in summer.
2. Larvae
The larvae of mosquitoes are called larvae.The larvae breathe through straws.When ingesting organics and microorganisms, the brush hairs of the mouth will produce water flow to the mouth.This period lasts about 10-14 days, and becomes pupa after 4 molting.
The newly hatched larvae are about 1.5mm long and divided into four instars.After three times of molting, the body length of the fourth instar larvae increased 8 times compared with the first instar larvae.The larva body is divided into three parts: head, thorax and abdomen, each of which has hair or hair clumps.There is a pair of tentacles, compound eyes and single eyes on the head. The mouthpiece is chewy, and there are long, thin and dense mouth brushes on both sides. With the rapid swing of the mouth brush, food in the water can be absorbed.The chest is slightly square and not segmented.The abdomen is long and thin, with 9 nodes visible.The first seven segments are similar in shape, and the back of the eighth segment has stomata and valves or slender breathing tubes, which is an important basis for larval stage classification.The respiratory tube of Culex mosquitoes is long and thin, and that of Aedes mosquitoes is short and thick;Anopheles is lack of respiratory tube, but has air valve. There are palm hair on the back of each abdominal section, which can float.Under the condition of 30 ℃ temperature and sufficient food, the larval stage develops for about 5-8 days, molts for 4 times and turns into pupa.
3. Pupa
The side view shows a comma shape, and there is a pair of respiratory tubes on both sides of the chest and back, which is an important basis for classification (Figure 18-3).Mosquito pupae do not feed, but can swim in the water. They breathe by the first pair of breathing angles, often stop at the water surface, and quickly dive into the water when disturbed.The pupae have strong resistance, and can still develop into adult mosquitoes if they are kept wet without water.Fully mature after two days.
4. Adult mosquitoes
The newly emerged adult mosquito develops after 1 to 2 days, i.e. mating, blood sucking and oviposition.The time required from egg development to adult mosquito depends on temperature, food, environment and other factors. Under suitable conditions, it takes about 9 to 15 days and can reproduce 7 to 8 generations a year.
Newly born mosquitoes cannot take off (eclosion) until their wings are hard.Male mosquito after eclosion24 hoursAfter the eighth segment of the inner abdominal segment, all of them reversed 180 ° to complete the mating position.The action of mating varies according to the species. In some dusk, mosquito pillars are formed in the open fields for group dancing.Mosquito column is not necessarily formed by a single male mosquito, but several different mosquito species.At this time, when the female mosquito saw the scene of group dancing, she flew close to the mosquito column to mate with the male mosquito of the same species and left.Mating usually takes 10 to 25 seconds.Female mosquitoes mate only once in their lives. After mating, the fluid secreted by the male accessory glands forms a mating plug in the female mating hole, but gradually dissolves, and disappears completely after about 24 hours.They mate only once in their lifetime, and the eggs laid in their lifetime (more than 100 days later) can still be fertilized.
Main identification characteristics of life history of Anopheles, Culex and Aedes:
There are floats, which are scattered and often float on the water in a pattern
No breathing tube, with valve;
Palmate hair;
Parallel to the water surface at rest
The respiratory tube is thick and short, funnel shaped, wide mouthed, with deep fissures;
The body is mostly grayish brown
The female and male tentacles are as long as the beak. The end of the male mosquito is swollen and stick shaped. The wings are mostly black and white, and the feet are uncertain whether there are white rings;
At rest, the body is in line with the beak and at an angle to the landing surface
The respiratory tube is long and thin, with many pairs of respiratory hairs;
No palmate hair;
Head droops at an angle to the water surface when stationary
The respiratory tube is long and thin, tubular, with small mouth and no crack;
The body is mostly brown
The female tentacle mosquito is very short, shorter than half of its beak, while the male mosquito is longer than its beak, with more wings without black and white spots, and more feet without white rings;
At rest, the body has an angle with the beak, and the body is parallel to the landing surface
The respiratory tube is short and thick, with 1 pair of respiratory tube hairs;
No palmate hair;
The static state is the same as that of Culex pipiens
The length of the respiratory tube is different, the mouth is oblique or triangular, and there is no crack;
Body black
The female tentacle mosquito is the same as the Culex mosquito, and the male mosquito has the same length as the beak, no black and white spots on the wings, and white rings on the feet;
Same as Culex at rest
Physiological ecology
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1. Breeding habits The place where adults lay eggs is the breeding place of larvae. The distinction of breeding places of mosquitoes is of great significance in investigation and control.Various mosquitoes have certain choices for breeding environment, which can be divided into five types:
(1) Field pond type: field pond type mainly includes paddy fields, marshes, reed ponds, various ponds, straw ponds, artificial lakes and other large or large water accumulation placesAnopheles sinensis、Culex tritaeniorhynchusThe main breeding place of.
(2) Slow flow type: slow flow type mainly includes clean stream, irrigation ditch, stream bed and pondingTerrace, seepage pit shore, etc., yesAnopheles minimusThe main breeding place of.
(3) Jungle type: The jungle type mainly includes small clean water bodies such as mountain streams under the shade of the jungle, shady mountain streams and stream beds, stone caves, springs and pools, etcAnopheles dirusThe main breeding place of.
(4) Sewage type: sewage type mainly includes depression ponding, sewersewer, sewage pit, sand well, shallow pool, clean water dung tank, compost pit, sewage pool, are Culex pipiens pallens andCulex quinquefasciatusThe main breeding place of.
(5) Container type: including artificial containers (such as vats, pots, jars, barrels, basins, bowls, bottles, boxes, waste tires, etc.) and plant containers (such as tree holes, bamboo tubes, leaf axils, coconut shells, etc. that can collect water), which are Aedes aegypti andAedes albopictusThe main breeding place of.
2. Adult mosquitoes can mate 1 to 2 days after eclosion, usually before blood sucking.Mating is carried out in group dance, which is a sexual behavior of several or even hundreds or thousands of male mosquitoes flying in groups over the grassland, under the eaves or over people and animals.When female mosquitoes fly into the dance group, they mate with male mosquitoes and then leave.Generally, female mosquitoes only need to mate once in their lifetime.
Mosquito activity mainly refers to the behavior of looking for the host to suck blood. Its activity ability is related to temperature, humidity, light and wind.Most mosquito species are active in the morning, dusk or night, and Aedes mosquitoes are active in the daytime.Anopheles anthropophagus in China, such asAnopheles minimus、Anopheles anthropophagus The activity peak of Anopheles dirus is around midnight.People who also love human and animal blood, such as Anopheles sinensis, often spend the first half of the night.The blood sucking activity of Anopheles anthropophagus starts 0.5~2 hours after sunset and lasts until 5 o'clock at dawn. The peak of blood sucking is usually in the first half of the night.
3. Male mosquitoes with blood sucking habits do not suck blood, but only suck plant juice and nectar.Female mosquitoes must feed on human or animal blood to develop and lay eggs, and acquire pathogens in the blood sucking process to becomeMedia。
The selectivity of mosquitoes to their hosts varies from species to species.Anopheles dirus, Anopheles anthropophagus, Aedes albopictus, Aedes aegypti, Culex quinquefasciatus, Culex pipiens pallens and other anthropophagus;Anopheles sinensis, Culex tritaeniorhynchus, etc. prefer livestock blood.Mosquitoes that prefer human blood can suck animal blood as well as human blood.Even if it is the same mosquito species, its blood sucking habits can change, such asHainan IslandAnopheles minimus mainly sucks human blood and lives inside, while the mainland Anopheles minimus sucks livestock blood and lives outside to varying degrees.This difference is also reflected in their vector efficacy, that is, mosquitoes that prefer human blood have more opportunities to transmit human diseases and are often the main vector of mosquito borne diseases.Mosquitoes can absorb both human and animal blood, so they can spread zoonotic diseases, such asEpidemic encephalitis BAnd yellow fever.The blood sucking habit of mosquitoes is an important content to judge the relationship between mosquitoes and diseases.
4. Reproductive nutrition cycle and each cycle of mosquitoes of physiological age from blood sucking to oviposition is called reproductive nutrition cycle.The reproductive nutrition cycle is divided into three stages: ① looking for the host to suck blood; ②Gastric blood digestion and ovarian development; ③Look for spawning eggs.The time required for the three stages is mainly determined by the speed of gastric blood digestion and ovarian development, and is affected by the temperature and humidity in the habitat.Under normal circumstances, the interval between two blood sucking is consistent with the development of ovarian cycle, which is called reproductive nutrition coordination, usually about 2 days.However, some mosquito species need to suck blood more than twice to make their ovaries mature.Generally, mosquitoes have 3 to 7 reproductive nutrition cycles in their lifetime, and the total number of eggs laid varies from dozens to hundreds.The number of reproductive and nutritional cycles of female mosquitoes is a measure of the survival time of mosquitoes, which is called physiological age.Every time a mosquito oviposits, there is a bulge on the ovarian tubule, so the physiological age of the female mosquito can be determined according to the number of bulges on the ovarian tubule.The more times of physiological age, the more chances of spreading disease, so the judgment of physiological age is of great significance in epidemiology.
5. After sucking blood, the female mosquito will find a dark, humid and windproof place to live.Indoor polyhabitationMosquito netInside, under the bed, in the corner, behind the door, on the wall and on sundries.It mostly lives outdoors in grass, caves, trees and crops near human and livestock houses.Habits can be roughly divided into three categories: ① domestic type: mosquitoes stay indoors after full absorption of blood, and fly out of the house to look for spawning sites after digestion of stomach blood and maturation of ovaries.Such as Culex pipiens pallens and Anopheles anthropophagus. ②Semi domestic type: stay indoors after sucking blood, and then fly out to roost.Such as Anopheles sinensis and Anopheles in Sun Moon Lake. ③Wildlife type: from blood sucking to oviposition completely in the wild.Such as Anopheles dirus.This classification is not absolute. Even the same mosquito species may change their habits due to different regions, seasons or environments.The activity and habitat habits of mosquitoes are related to the application effect of pesticides, especially indoorResidual sprayingAnd the effect of mosquito net treatment.
6. Seasonal fluctuation and seasonal fluctuation of overwintering mosquitoes are closely related to temperature, humidity and rainfall.The climate in China is quite different from north to south, and the seasonal fluctuation of mosquito species is also different.Even different mosquito species in the same area, or the same mosquito species in different areas, have different seasonal fluctuations due to their own habits and environmental factors.For example, Anopheles sinensis, in the middle and lower reaches of the Yangtze River, the first generation larvae appear in early March every year, and adult mosquito density starts to rise in May, reaches a peak in July, and drops after September;However, in Taiwan Province, there are two peaks from April to September each year.In most areas of China, the adult mosquito density peak season is from June to September.The seasonal fluctuation of vector mosquitoes is related to the epidemic season of the disease.
Overwintering is a physiological adaptation of mosquitoes to seasonal climate changes.The regular physiological state of the mosquito itself is inhibited and enters the dormancy or diapause state.Female mosquitoes overwintering with adult mosquitoes do not suck blood, and their ovaries stop developing,Adipose bodyEnlarge and hide in dark, warm, humid and unventilated places such as caves, cellars, wall cracks, greenhouses and basements, without eating or moving, and the metabolism drops to the lowest point;When the spring warms the next year, mosquitoes begin to recover and fly out to suck blood and lay eggs.Culex pipiens quinquefasciatus, Culex pipiens pallens, Anopheles sinensis, etc. overwinter with adult mosquitoes;Egg overwintering is more common in Aedes, and Anopheles anthropophagus can also overwinter with eggs;Mosquitoes that overwinter with larvae are mostly found in clean water bodies, such as Anopheles minimus, and those that disturb the larvae of Aedes can also overwinter.In the tropics andSubtropical regionThe annual average temperature is above 10 ℃, and mosquitoes do not overwinter.The mechanism of overwintering is complex, which is affected by external factors such as temperature, light, endocrine regulation, species heredity and so on.
Disease type
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Mosquitoes not only suck blood, but also spread many diseases. In China, the important mosquito species transmitting diseases are as follows:
one
Anopheles anthropophagus (An. anthropophagus) Adult is grayish brown, female mosquito has thin tentacles, two white rings at the end are wide, and they are often connected with each other;The base of the leading edge of the wing is uniformly dark;The tarsal segment of the hind foot has only a narrow white ring;There is no T-shaped dark spot on the ventral membrane.This mosquito is a unique mosquito species in China, which is distributed in the south of 34 ° N, and mainly breeds in quiet water or slow flow small accumulated water with good plant shade and cool water quality, such as rice fields, water bamboo fields, puddles, irrigation ditches, etc.It's malaria andMalay filariasisThe role of malaria transmission is higher than that of Anopheles sinensis.
two
Anopheles sinensis(Anopheles sinensis) female mosquito has four white rings on its tentacles, two wide at the top and two narrow at the other;There are two white spots on the front edge of the wing, and the white spots on the tip are large;There are T-shaped dark spots on the ventral membrane;The 1-4 tarsal segments of the hind foot have narrow white rings.It is distributed in all provinces and regions except Xinjiang and Qinghai, and is an important vector of malaria and malayan filariasis in the vast plains, especially in rice growing areas.Although not an efficient communicator, it may cause an outbreak due to the large population.Larvae mainly breed in slow flowing clear water, such as streams, ditches, seepage water, etc.
three
Anopheles minimus(An. minimus) small to medium-sized brown mosquito species.Female mosquito tentacles have three white rings, two white rings at the end of which are equal in length and one black ring is about equal in length;There is a narrow white ring in the back half of the tentacles, and the black and white rings can also be changed;There are 4 white spots on the front edge of wing;The tarsomes of each foot are uniformly dark.It is distributed in mountains and hills south of 32 ° N and is the main vector of malaria in this area.
four
Anopheles dirus is a medium grey brown mosquito species.Female mosquito tentacles have 4 white rings, and the top white ring is the widest.There are 6 white spots in the veins of the front edge of the wing, and 6 black spots in the sixth longitudinal vein.There are white spots on the thigh and tibia of each foot, and there is an obvious wide white ring at the tibia and the first tarsal joint of the hind foot.Anopheles dirus is an anopheles of tropical jungle type, which mainly breeds in the shady stream bed ponding, shallow pools, pools and other places at the edge of the jungle.Anopheles dirus is mainly distributed in Hainan Island and a few areas in western Yunnan and southern Guangxi in China. It usually has a high natural infection rate and is the main target of malaria vector control in Hainan Island.
five
Culex pipiens pallens(Culex pipiens palens) and Cx. P. quinquefasciatus are medium-sized brown, reddish brown or light brown mosquitoes.The common characteristics of adult mosquitoes are: no white ring on the beak;There is no pale ring in each tarsal segment of foot;There is a basic leucorrhea on the back of the abdomen.The morphology and ecological habits of Culex pipiens quinquefasciatus and Culex pipiens pallens are similar, but their geographical distribution is different in China. At the boundary of 32~34 ° north latitude, Culex quinquefasciatus is distributed in the vast areas of the south, and Culex pipiens pallens is distributed in the Yangtze River basin and the areas to the north. Their intermediate types can be found in the boundary area.Both of them are called "house mosquitoes", common blood sucking stinging mosquitoes indoors, and one of the main targets of mosquito control in cities.Larvae mainly breed in small, especially polluted pits, ditches and container ponding.Culex pipiens pallens and Culex quinquefasciatus areBancroftian filariasisThe main media of.
six
Culex tritaeniorhynchus(Cx. tritaeniorhynchus) small brown mosquito species.There is a wide white ring in the middle of the beak, and the tip of the tentacles is white;There is a thin white ring at the base of each tarsal node;The dorsal surface of the 2nd to 7th ventral segments has a pale band at the base.Widely distributed in all provinces and regions except Xinjiang Uygur Autonomous Region, it is the dominant species of rice field mosquitoes in most regions, but it also widely breeds in swamps, ponds, irrigation canals, low-lying water and other places.The female mosquito absorbs both human and animal blood, while the female mosquito absorbs cattle, horses, pigs, dogs and other blood, which is the main vector of Japanese encephalitis in China.
seven
Aedes albopictus(Aedes albopictus) small and medium-sized black mosquito species with silvery white stripes.On the midthorax shield, there is a white longitudinal line in the middle, which extends from the front end to the back of the small shield at the wing base level and bifurcates.The posterior tarsal 1-4 segments have a basic white ring, and the distal segment is completely white.There are 2~6 basal leucorrhea on the back of abdomen.It is widely distributed, reaching Shenyang in the north (about 41.8 ° north latitude) and northwestBaojiFrom the southwest to the Tibet Autonomous Region, but it is common to the south of 34 ° north latitude, and most of them are found in residential areas and their surrounding containers (such as tanks, pots, basins, waste tires, etc.), plant containers (such as bamboo tubes, tree holes, etc.), and small ponding such as stone caves.
eight
Aedes aegypti(Ae. aegypti) A medium-sized mosquito species with dark brown or black and silvery white or white stripes.There is a pair of long handle sickle shaped spots formed by white broad curved scales on both shoulders of the back of the midthorax, and a pair of golden yellow longitudinal lines between the two white spots, forming a string of zither shaped stripes.Its distribution is limited to Hainan to the south of 22 ° N, parts of Guangdong and Guangxi, and the south of Taiwan Province.It mainly breeds in the accumulated water in indoor and surrounding containers.Female mosquitoes tend to suck human blood, and have the habit of multiple blood sucking in a reproductive nutrition cycle, thus increasing the chances of spreading diseases.Aedes aegypti and Aedes albopictus are Chinesedengue feverMedia.
Prevention and control principle
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Due to the increasingly serious insecticide resistance of mosquitoes, together with the environmental pollution of pesticides and the impact on ecological balance, it is not advisable to rely solely on chemical mosquito control. At present, comprehensive management methods are adopted, including environmental management, chemical control, biological control and legal control.
1. Environmental governance changes the breeding environment through environmental treatment and environmental transformation.Intermittent irrigation, weeding on the bank and fish culture in paddy fields should be adopted for the treatment of paddy fields;For the treatment of sewage grassland, the purpose of reducing mosquito breeding areas can be achieved by dredging sewers, sewage ditches, changing the public ditches into underground ditches and sealing them, covering sewage wells, filling sewage pools, etc.For container breeding grounds, measures such as environmental sanitation, filling pits, blocking tree holes, handling bamboo tubes, turning over tanks and cans, removing waste containers, and strengthening the management of tire stacking should be taken.
2. Chemical control of dithionFenthion, toxaphene, fenitrothion and phoxim are the main drugs to kill mosquito larvae.The following methods can be used to kill adult mosquitoes:
(1) Indoor quick killing: chemical compound is usually used to spray indoor or mosquito habitats with sprayers, aerosol cans and other equipment.The compound formulation of aerosol cans is usually composed of knockdown agent, lethal agent, synergist andessence, deodorized kerosene, propellant, etc.
(2) Indoor residual spraying to kill mosquitoes: it is mainly used for the control of vector anopheles, which is one of the main measures for malaria control, and has obvious effect on domestic mosquitoes.Common residual spraying pesticides include DDTmalathionMethion, pyrethroids, etc.Wettable powderThe prepared water suspension agent is suitable for spraying the clay wall and brick wall with strong water absorption, and the emulsion is suitable for the wall surface with smooth wood, cement, etc.
Since the 1980s, it has been used in ChinaDeltamethrinOr other pyrethroid insecticides to soak or spray mosquito nets. Through field tests, it has obvious effects on reducing the density of Anopheles anthropophagus, Anopheles sinensis and Anopheles dirus and controlling the incidence of malaria. It is an important progress in vector control in anti malaria work in recent years.
(3) Outdoor mosquito control: It is generally used for treatment of some mosquito borne diseases, such as dengue fever or Japanese encephalitis, regionally or indoors, outdoors and around the patient's home.Ultra low volume spraying method is used to quickly kill mosquitoes in large areas of epidemic areas, and phoxim and malathion mixture is generally used in residential areas;Malathion emulsifiable concentrates can be used around villages.
3. Biological controlBiological controlIncluding stocking mosquito eating fish and releasingBiological insecticide。For example, stocking in ditches, pools, rivers and streamsWicker fishIn the lotus vats, Taiping vats and small pools in the hotel park, ornamental fish are stocked; in the drinking water vats, pond characters, Nile tilapia, Chinese betta are stocked; in the rice fields, carpAfrican crucian carpAnd stocking grass carp in irrigation ditches.For sewage pools, reservoirs, fire pools that can not be transformed at the moment, as well as general water pools in the city, investment can be usedChemical insecticideOr biological pesticides such asBacillus thuringiensis(Bacillus thuringiensis) Bti-14 strain or B. sphaericus (Bs) preparation method.
4. Laws and regulations are used to prevent the introduction of vector mosquitoes, supervise the prevention and control of mosquitoes, and enforce mosquito control.In particular, quarantine at airports and ports should be strengthened to prevent media from entering the country and spreading through means of transport.
Life habits
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Mosquitoes also have the following life habits.
Breeding habits
Mosquitoes all breed in water, and different types of mosquitoes breed in different water quality and ponding types.Controlling or reforming breeding grounds is a measure to control mosquitoes.
Water body type
Mosquito species
Seriously pollute water, such as cesspita septic tanketc.
Disturb Aedes
Slightly polluted water body, sewage pit (ditch), cesspit, ponding in depression, etc
Culex quinquefasciatus, Culex pipiens pallens
Large clean water bodies, such as paddy fields, lotus ponds, marshes, etc
Anopheles sinensis, Culex tritaeniorhynchus
Clean and flowing water, such as mountain stream or stream bed
Anopheles minimus
Small natural water bodies, such as ponding in tree holes, bamboo tubes, jars, cans, etc
Aedes albopictus, Aedes inchuan
Utensils inside and outside the house, such as water tanks, coconut shells, etc
Aedes aegypti
Vampire habit
Mosquitoes also transmit diseases through blood sucking. Understanding the blood sucking habits of mosquitoes can detect their relationship with diseases.
Only female mosquitoes can suck blood, and female mosquitoes must suck blood to develop their ovaries and reproduce.Most female mosquitoes begin to suck blood 2-3 days after eclosion. Temperature, humidity, light and other factors can affect the blood sucking activities of mosquitoes.Blood sucking starts when the temperature is above 10 ℃;Generally, Aedes mosquitoes mostly suck blood in the daytime, while Anopheles and Culex mosquitoes mostly suck blood at night;Some prefer human blood, while others prefer to suck the blood of livestock, but there is no strict selectivity, so mosquitoes can spreadZoonosis。
Habits
Mastering the habitat habits of mosquitoes is the basis for formulating mosquito control measures.
Mosquitoes must find a place to live after eclosion and blood sucking. Mosquitoes generally prefer to live in concealed, dark and poorly ventilated places, such as under beds, behind cabinets, behind doors, wall cracks, livestock houses, basements, etc. indoors, and in grass, caves, cellars, bridge holes, stone cracks, etc. outdoors.
Mosquitoes can be divided into the following three types according to their different habitats after blood sucking: domestic type: such as Anopheles minimus and Anopheles anthropophagus.Semi domestic type: such as Anopheles sinensis and Anopheles heliocentricus after blood sucking, some live indoors and some live outdoors.Wild type: such as Anopheles dirus, Aedes albopictus and other blood sucking mosquitoes fly outdoors to digest the blood in the stomach.
Mosquito longevity
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The life span of mosquitoes is about 7 to 10 days after male mosquitoes mate under natural conditions, but it can live for 1 to 2 months in the laboratory;[1]
Female mosquitoes can live for at least 1 to 2 months, and have lived for 4 months in the laboratory.
Mosquito damage
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Among mosquitoes, the most abominable one is the mosquito that sucks human blood.The feeding habits of male and female mosquitoes are different. Male mosquitoes are "vegetarian" and feed on plant nectar and juice in fruits, stems and leaves.Female mosquitoes occasionally taste the juice of plants, but once they get married, they must suck blood.Because it can only make the ovary develop after blood sucking.Therefore, only female mosquitoes bite people and suck blood.
A pair of tentacles and three pairs of feet of mosquitoes are distributed with many whorled sensory hairs, and each sensory hair is densely arranged with round or oval pores.In the dark, mosquitoes can use this sensor to sense the carbon dioxide emitted by the human body in the air, respond within 1 ‰ second, and fly to the bloodsucker correctly and quickly.Before sucking blood, mosquitoes first inject saliva containing anticoagulant into the skin to mix with blood, so that the blood becomes thin plasma that will not coagulate, and then spit out the old undigested blood overnight to suck fresh blood.If a person bites 10000 mosquitoes at the same time, he can suck up the human blood.
Mosquitoes suck human blood, but also "pick and choose", specifically looking for objects that meet the "taste".Mosquitoes rely onProximity sensorTo sense temperature, humidity and chemical composition contained in sweat.Therefore, female mosquitoes first bite people with high temperature and sweating.Because the odor secreted by people with high body temperature and sweatiness contains moreamino acid, lactic acid and ammonia compounds are very easy to attract mosquitoes.
The main harm of mosquitoes is to spread diseases.According to research, more than 80 diseases are transmitted by mosquitoes.On the earth, no animal is more harmful to human beings than mosquitoes.
Malaria is a disease transmitted by Anopheles mosquitoes.MalariaMiasma。According to the investigation of the Health Department in 1935, there wereplasmodium50%, patientspernicious malaria72%.About 20000 people died of malaria in Gaoxian County, Jiangsu Province in 1936, and the excavation was started in 1876panama canalAt that time, countless workers were killed by yellow fever and malaria, so that in 1889, they had to stop working.After entomologists solved the problem of mosquitoes, they were able to continue to complete the canal project.In 1930, the Far East Tropical Diseases Medical Association reported that about 50 people died of tiger's mouth every year in Thailand, and 50000 died of malaria.
How do mosquitoes transmit pathogens to humans?When malaria mosquitoes ingest the blood of malaria patients, they also ingest the malaria parasites (the source of malaria).When they bite again, the malaria parasite is injected into the victim's body from the mosquito's mouth.Ten days later, malaria parasites began to appear in blood vessels close to the skin.They reproduce in the red blood cells of patients and divide into a large number of small protozoa, which destroy red blood cells and release a toxin.Each small malaria parasite invades other red blood cells and continues to reproduce, increasing the number of malaria parasites and toxins in the infected body, causing the patient to feel cold and feverish.The patient suffering from malaria first gets cold and shakes all over, but the thermometer tests that the temperature is high.After about an hour, the patient felt feverish. At this time, the temperature continued to rise. Three or four hours later, the patient began to sweat and the temperature dropped. After a few hours, the patient felt relaxed. The disease seemed to pass. In fact, the small protozoa had invaded new red blood cells and began to breed again.When the malaria parasite destroys red blood cells again, the patient gets sick again and forms the second round.Unless proper treatment is obtained, this attack will continue regularly and make people miserable.Malaria has caused considerable losses to human beings. Patients are weak, inefficient, and even lose their lives in serious cases.At present, drugs can treat and prevent this disease, but the best way is to eliminate the mosquito that infects this disease - malaria.
Epidemic encephalitis B (which is caused byFiltration virusIt is also carried by mosquitoes. This disease is also calledJapanese encephalitisIt is commonly calledEncephalitis。The patient has fever, headache, vomiting, convulsion, lethargy, coma, etc.There is no specific drug for treatment, so the case fatality rate is quite high.
After mosquitoes bite and suck the blood of people or animals infected with the virus, they become infectious after a considerable period of time. When they bite people without immunity, they can make the victim sick.The mosquitoes that infect this disease are called Culex and Aedes.In order to prevent the occurrence and prevalence of the disease, besides vaccination and infection prevention, efforts must be made to eliminate mosquitoes and the carriers.In addition, Culex and Anopheles mosquitoes also transmit filariasis（Elephantiasis）。
Mosquitoes that can transmit diseases in China can be roughly divided into three categories: Anopheles, commonly known as Anopheles, mainly transmit malaria.According to incomplete statistics, in 1929, about 2 million people died of malaria in the world.The other is called Culex, which mainly transmits filariasis and epidemic encephalitis B.The third type is called Aedes mosquito, which has black and white stripes on its bodyaedes , mainly spreading epidemic encephalitis B and dengue fever.
In a suitable environment in summer, female mosquitoes lay their eggs in water and hatch into larvae one or two days later, calledLarvae。After four times of molting, the larvae become pupae. The pupae continue to live in the water for two or three days, and then they can become mosquitoes.It only takes about 10-12 days to complete the development of one generation, and seven or eight generations can be reproduced in one year.Most female mosquitoes begin to suck blood 2-3 days after eclosion. Temperature, humidity, light and other factors can affect the blood sucking activities of mosquitoes.Blood sucking starts when the temperature is above 10 ° C;Generally, Aedes mosquitoes mostly suck blood in the daytime, while Anopheles and Culex mosquitoes mostly suck blood at night;Some prefer human blood, while others prefer to suck the blood of livestock, but there is no strict selectivity, so mosquitoes can transmit zoonosis.[1]
Scientists have found that carbon dioxide has a strong attraction to mosquitoes for a long time, but carbon dioxide alone cannot explain all the problems, because facts show that after all, mosquitoes prefer to bite people's arms, legs and feet.Therefore, although the role of carbon dioxide cannot be ignored, the skin must also release other substances that are more attractive to mosquitoes.
The scientists found that mosquitoes reacted very strongly to some mixtures. The mixture of three special chemicals in the 346 substances they tested attracted 90% of mosquitoes each time.But Bernier found that his arms and hands attracted only seven mosquitoes."Sometimes when 30 substances are mixed with mosquitoes, they are not attracted at all," said Bernier.However, in this experiment, scientists have never found any attractant that can attract mosquitoes 100%.
The researchers also found that the mixture that can release human body odor has a higher attraction to mosquitoes.However, this is far from producing better attractants.Because the attractant must be more attractive to mosquitoes than the human body near it to achieve the effect, Bernier et al. said that "it is very difficult to get close to the human body, and we still cannot do it."
Eliminating mosquitoes is the key to ensuring human health and avoiding disease transmission.The life of mosquito goes through four stages: egg, larva (larva), pupa and adult.Mosquitoes like to lay their eggs in clear water, such as small rivers, rain pools, ponds, ponds, paddy fields and mountain streamsflowing waterEtc;In warm seasons, eggs can hatch into larvae in about three days and begin to eat tiny microorganisms and protozoa that grow in water.They draw air near the water surface by two air holes at the end of their bodies.After molting, the larvae finally stop eating and become pupae due to reduced activities.About two or three days later, the pupa comes to the water surface again, molts and peels off its skin, and emerges as an adult (i.e., a mosquito).Male and female mating is mostly in the morning or evening. First, male mosquitoes fly in groups around the top of dwarf trees, eaves, windows or open spaces. Female mosquitoes see the opportunity to join the team and mate quickly in flight.Male mosquitoes only suck grass juice, live on nectar, and do not suck blood.Female mosquitoes must suck blood (human or animal blood) to develop their eggs after mating, so only female mosquitoes can transmit diseases.Female mosquitoes can lay eggs once after taking a full dose of blood. They can lay eggs six to eight times in their lifetime, 200 to 300 eggs each time. Therefore, if one mosquito is killed early, hundreds or thousands of mosquitoes will be killed.It is important to know the life history and breeding place of mosquitoes.We can apply this knowledge to vigorously kill mosquitoes.Mosquito larvae are the easiest to kill, because the larvae must live in water. If you can fill the lowlands, dredge the stagnant water, and often clean up the water containers, the larvae will have nowhere to live, and mosquito eradication will certainly achieve good results.
Mosquitoes begin to fly into the house at dusk, so this is the best time to kill mosquitoes.Mosquitoes like to hide in the corners, ceiling, bed bottom and back of seats of the house, so pay special attention when spraying aerosol.
Coping methods
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The first move of physical mosquito repellent: eliminate the living environment of mosquitoes (there is no way to do it in the dormitory, there are too many grassgarbage）
Some people have poor living environment, and there are many stagnant water around, so they need to spray medicine frequently. This not only makes it difficult to kill mosquitoes, but also costs a lot of money.So we might as well use some physical methods to kill mosquitoes.
Solution: Clean up the garbage in time and do not leave stagnant water.
Physical mosquito repellent second move: soapy water
Close the doors and windows, place a basin in front of the window, add some water mixed with washing powder in the basin, and the next day, there will be some dead mosquitoes in the basin.
Using this method every day can almost eliminate the need to spray insecticide to kill mosquitoes.And there will be fewer and fewer mosquitoes.
There are also two magic weapons to repel mosquitoes. You must try them. These are garlic and (peanut) vitamin B.
The fourth move of physical mosquito control: saline watertoothpaste
If you are accidentally bitten by mosquitoes, don't rush to grasp them.A little salt water or toothpaste can quickly stop itching when applied to the affected part.
Let's take a look at another method - gently drop a few drops of essential balm on the used mosquito repellent incense pills that have lost their potency, and plug in the power supply to achieve a strong mosquito repellent effect and save the pills.In case of power failure, one or two used pills can be ignited one by one. In a few minutes, it will have the effect of mosquito control.
Mosquito venom can be detoxified in case of high temperature. After being bitten by mosquitoes, mosquito venom is most afraid of high temperature. Immediately apply hot towel for 5 minutes.Or use a hot water bottle stopper (there must be hot water in the bottle, of course) to slightly scald the bottle, and apply a small packet to it, subject to no scald.3-5 minutes.
You can also try the above money saving mosquito control methods.If you are used to usingAerosolTo deal with mosquitoes, we should choose the best time and key parts to kill mosquitoes.
Spread hepatitis
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Could some unexplained cases of hepatitis C infection be caused by mosquito bites?researcherThe discovery that viruses can combine and replicate in mosquito cells provides some evidence for this possibility.However, many experts disagree with the view that mosquitoes can transmit hepatitis C virus.
About 170 million people around the world are infected with hepatitis C virus, which causes liver inflammation in patients, which may eventually lead to cirrhosis andliver cancer。In most cases, the virus is infectedBlood productsAnd contaminated needles, but there is no such risk factor in about 20% of infected people.Hepatitis C belongs toFlavivirusThe genus, which includes viruses that can be transmitted by insects, such asWest Nile virus，Dengue virusAnd yellow fever virus.This led a research group led by Emmanuel Drouet of University é Joseph Fourier Grenoble I in La Tronche, France, to wonder whether hepatitis C virus can replicate in mosquito cells.
The researchers isolated the virus from the body of a person infected with hepatitis C virus and added it to the cells of Aedes pseudoscutellaris mosquito and the kidney cells of African green monkeys, both of which are commonly used culture cell lines of other flavivirus.In the published Journal of Medical Virology, the research team reported that by measuring the RNA level of the virus up to 28 days after infection, the virus can combine with the cells of mosquitoes and monkeys and replicate in the cells.On the contraryB cellThe infection failed in live liver cancer cells about one week later.Drouet said this may indicate mosquito transmissionHepatitis C virusThe possibility exists, although no one has found hepatitis C virus in mosquitoes.
US ArmyMichael Turell, an entomologist at the Medical Research Center for Infectious Diseases, said that due to the relationship between hepatitis C virus and flavivirus, it is not surprising that this virus can replicate in mosquito cells.
Many scientists strongly oppose the idea that mosquitoes can transmit hepatitis C.They pointed out that hepatitis C virus infection has no regional or seasonal distribution characteristics, which are the characteristics of mosquito transmission.They believe that some unexplained cases at present may only be sexually transmitted or conceal the fact of drug abuse.David Thomas, an epidemiologist at Johns Hopkins Medical School, said: "There is still no evidence that mosquitoes transmit this disease."
Mosquito repellent method
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Relevant experts suggest that the following safe and natural mosquito repellent methods should be used in summer:
one
Use mosquito nets or screens to isolate mosquitoes. The mosquito nets can not only prevent mosquitoes and wind, but also absorb falling dust, especially suitable for children.Screen windows allow fresh air to enter the room and harmful smoke to flow outside.
two
Put several boxes of uncoveredCooling oilAnd essential balm, or place one or two pots of blooming evening primrose, jasmine, Milan, mint or roses, mosquitoes will escape because they can't stand their smell.
three
Install orange light bulbs indoors, or use transparent orange cellophane to cover the bulbs. After turning on the lights, mosquitoes will flee because of fear of orange light.
four
Put sugar water or beer in an empty bottle or cup in the shade. When mosquitoes smell sweet wine, they will drill into the bottle and be stuck to the sugar water or beer to death.
five
Eating garlic raw, taking vitamin B orally, and excreting it from sweat through human physiological metabolism will produce a smell that mosquitoes dare not approach.
It is understood that chemical synthetic mosquito repellents, such as mosquito repellents and mosquito (insect) killing aerosols, are irritating and can easily cause nervous system diseases, skin diseases and other diseases if used incorrectly, and can even cause cancer in case of inferior products.Natural mosquito repellents such asMosquito repellent toilet waterAlthough it has the functions of cooling, relieving itching and repelling mosquitoes, it is not suitable for infants, pregnant womenAllergic。However, the elderly and infants have weak respiratory resistance and are more sensitive to external stimuli, so the use of Chinese herbal medicine to repel mosquitoes shows advantages.
According to Zhu Lihong, a Chinese pharmacist who is deputy director of the pharmacy department of Suzhou Municipal Hospital, the traditional Chinese medicine mosquito repellent bag has been proved to be environmentally friendly, safe and effective by clinical use.The mosquito repellent herbal formula of the municipal hospital headquarters is 12 grams of peppermint, 10 grams of honeysuckle, clove, wormwood leaf, angelica dahurica, agastache, calamus tatarinowii, and perilla leaf. Wrap the eight herbs together in a breathable cloth bag, and emit odor through the herbs to achieve the goal of mosquito repellency.
Mosquito and ecological chain
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The ecological gap caused by the disappearance of a mosquito will soon be filled by other creatures
Many people will say that the answer to the question of mosquitoes is very clear: catch them all and wipe them off the surface of the earth.No one has ever proposed such a proposal to wipe them out of history or punish them, which also shows how insignificant mosquitoes are in the world.The good times are not long for mosquitoes.
If mosquito extinction is really good for living things, this result may be attributed to the insignificance of this species and the fast changing nature of nature;It may even be because those species that eat mosquitoes only treat them as snacks.No animal starves because of its disappearance, and can live well.
In other places, mosquitoes really do not represent a necessary link in the biological chain, they can be simply replaced;In many cases, there will be a competing insect willing to replace the mosquito niche.A frog with a diet of 50% mosquitoes and 50% moths will love to eat only moths, if the number of moths that can be eaten can be doubled.However, it must be recognized that when calculation fails, the extinction of mosquitoes may lead to the extinction of some predatory fish or birds, which may cause a wavy cycle of the local ecosystem.What remains unchanged is that mosquitoes do not really control any population, so it is impossible to see any outbreak of dangerous species trapped by this common mosquito population.
However, scientists found that in many cases, the ecological gap caused by the disappearance of a mosquito would soon be filled by other organisms.Life will be the same as before, even better.Considering that they are the main vectors of disease transmission, "it is difficult to say what harm will be caused by eliminating them, but it is not possible to have some collateral damage."illinois state university OfInsect ecologySteven Juliano said.A world without mosquitoes will be "safer for us". Carlos Brisola Marcondes, a medical entomologist from the Federal University of Santa Catalina in Brazil, said, "The disappearance of mosquitoes has a great impact on human beings."
Can people clean up this vampire?A booming movement gave a positive answer.If we take a step forward, we are most likely to use the weapon genetic weapons;If the spray and mosquito net are not enough, the task may be successfully completed.
Nature News published a research paper on June 10, openly describing the "gender distortion" method used to control the number of mosquitoes.This idea came out 60 years ago, but only now has it been successfully demonstrated for the first time.
In this research conducted by Imperial College of Technology in Britain in cooperation with its counterparts in the United States and Italy, they tried to giveAnopheles gambiaeInject an "endonuclease" to "cut" and destroy the DNA in the mosquito's X chromosome, so that these mosquitoes can only reproduce male offspring.[2-3]
Mosquito fossil
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In December 2023, the scientific research team of Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences found the oldest known mosquito fossil in Lebanese amber about 130 million years ago.This new discovery also proves that in the early stage of mosquito family evolution, male mosquitoes also suck blood, and reveals that the early blood sucking behavior of insects is more complex than we thought.This achievement was published in the international academic journal Contemporary Biology on December 4.[8]
