Common or malaria mosquito: how to distinguish. Mosquitoes

Aghajanyan Khoren

What role do mosquitoes play in transmitting malaria diseases? What was the situation with malaria during the creation of the resort city of Sochi? Are there any on site Black Sea coast Caucasus malarial mosquitoes now? What measures need to be taken to prevent the spread of mosquitoes along the Black Sea coast? The author sought answers to these questions while conducting his research.

Download:

Preview:

Agadzhanyan Khoren Armenovich

"Mosquitoes of the genera Culex and Anopheles

and their role in the spread of malaria"

Novoselova Irina Anatolevna,

additional education teacher

Sochi Ecological and Biological Center named after. S.Yu.Sokolova

Russia, Krasnodar region, Sochi,

Municipal educational institution secondary school No. 86, Sochi

Ecological and Biological Center named after. S.Yu. Sokolova, Sochi,

circle "Ecological Bulletin"

1. Introduction. Page 2

2. Main part. Study of mosquitoes, larvae and pupae of the genus Culex. Page 4

2.1. Comparison of mosquitoes of the genus Culex and malaria mosquitoes of the genus

Anopheles (according to own observations and literary sources). Page 6

3. Conclusion. Preventive measures to prevent

the spread of mosquitoes along the Black Sea coast. Page 10

4. List of references. Page 11

5. Applications. Page 12

1. Introduction.

IN lately News agency reports are filled with information about outbreaks of malaria infection in different regions of the world. Ukraine, Greece, Madeira Island... The appearance of malaria indicates that dangerous infectious diseases can appear after a long period of calm, spread quite quickly and cover large areas.

What role do mosquitoes play in transmitting malaria diseases? What was the situation with malaria during the creation of the resort city of Sochi? Are there malaria mosquitoes on the territory of the Black Sea coast of the Caucasus now? What measures need to be taken to prevent the spread of mosquitoes along the Black Sea coast? I sought answers to these questions while conducting my research.

Purpose of the work: compare mosquitoes of the genera Culex and Anopheles and find out their role in the spread of malaria.

Tasks:

1.Study the history of malaria.

2. Study the history of the fight against the spread of malaria on the Black Sea coast of the Caucasus.

3. Conduct observations of the life and development of mosquitoes of the genus Culex, study the biology of Anopheles mosquitoes from literary sources.

4.Draw conclusions about the role of mosquitoes in the spread of malaria and about preventive measures to prevent the spread of mosquitoes along the Black Sea coast.

In my work on studying mosquitoes, I used information from the Internet, as well as books from the series “Everything that lives from an egg”, “The Life Cycle of Insects” (R. Spilsbury), “Under the Looking Glass, or the Mysterious World of a Reservoir” (V.B. Verbitsky), “ Old Sochi" (K.A. Gordon), "Guide to laboratory classes in biology" (V. Korolev), "Quirks of nature" (I. Akimushkin), "For young nature lovers" (N. Plavilshchikov), "Arthropods. Insects" (V.N. Alekseev).

The name comes from the Italian phrase mala aria - “bad air”. It is believed that people have been suffering from malaria for 50,000 years. Malaria is believed to be native to West and Central Africa.

From the history of our city, I learned that until the middle of the twentieth century, the real disaster for settlers was malaria, which was facilitated by warm and humid climate. The mortality rate was high. The highlanders did not suffer from mosquito bites, since they settled higher in the mountains, and the city area was very swampy, which was the reason for the high incidence of malaria.

Residents settlements They didn’t even think that the disease was caused by a mosquito. Many people took seriously the idea that malaria was caused by raw fruit!

The first Sochi doctor A.L. Gordon made a lot of efforts to fight malaria. He ordered imported quinine for delivery to the city - the only means of control at that time, treated the sick, promoted ways to avoid infection: settle on highlands, take quinine prophylactically, pour a small layer of kerosene into stagnant lakes and swamps to destroy mosquito larvae and pupae, close window frames with gauze nets.

In 1921, an antimalarial station was created in Sochi. Since 1923, Dr. S.Yu. became the head of the Sochi antimalarial station. Sokolov. He set himself a very difficult task: not only to organize treatment, but also to eliminate the very cause of the disease: wetlands were drained, pollination was carried out with “Paris greens” (a composition based on copper sulfate) and the surface of standing reservoirs was covered with a thin film of kerosene, gambusia was brought in, destroys malaria mosquito larvae in large quantities in water bodies. Eucalyptus trees were planted throughout the city, which perfectly drained the soil. In 1956 malaria was eliminated in Sochi.

2. Main part. Study of mosquitoes, pupae and larvae of the genus Culex.

I conducted my mosquito research as follows. First, I studied the literature on mosquito biology. Then he examined the caught mosquitoes using a magnifying glass, and the larvae and pupae of mosquitoes using a BIOR school microscope.

The mosquito (Culex) belongs to the order Diptera and is a representative of the large family of mosquitoes (Cullcidae). A small insect (6-7 mm) with a large chest, a long narrow abdomen and one pair of narrow wings. The male differs from the female in having more developed antennae. They attack people and animals and feed on their blood exclusively by females, whose proboscis has piercing bristles. Males feed on plant juices.

Female mosquitoes spend the winter hiding in hollows, basements and other secluded places. In the spring they fly out and look for food. Only females attack people and animals (small and large animals, naked bird chicks). Having sucked on blood, mosquitoes go to secluded places to digest the blood, this is the only way eggs can mature in their bodies.

I caught mosquito larvae and pupae from a bath of rainwater. Number of larvae – 48 pcs. Pupae – 5 pcs. Observations of the larvae allowed me to become more familiar with their lifestyle.

Female mosquitoes lay eggs in bodies of water and end their lives. Eggs can withstand drying and freezing. Therefore, mosquito eggs can overwinter in the pond. Larvae emerge from the eggs. The larvae feed at the bottom of the reservoir. Their food is microscopic animals: bacteria, ciliates, larvae of other mosquitoes, algae, sludge particles.

The larvae develop very quickly: the warmer the water, the faster the larvae develop.Observing the movement of the larvae and studying them under a microscope, I saw thatTheir movement in the water is aided by swimming hairs, which sit in tufts on the body segments. The largest tuft is on the last caudal segment. If you do not allow the larva to emerge, it will suffocate. Larvae breathe atmospheric air, the supply of which in the body requires constant replenishment. When they rise to the surface, they put their tail breathing tube out of the water and draw air into the trachea. The breathing tube is a long, obliquely extending process that is clearly visible through a microscope.

The larva of the common mosquito is easy to distinguish from the larvae of other invertebrates - it seems to hang in the water at an angle (40°-60°) upside down. It is held by the surface tension of the liquid, forming an elastic film, which the larva pierces with its respiratory process and to which it is suspended from below.The larvae move upward, curving like a worm, and fall down vertically, as they are too heavy. The larva develops and, as it develops, molts three times and then turns into a pupa, which is completely different from the larva.Having compared the caught larvae with those shown in the figure, I determined thatall the larvae I caught correspond to Figure 1, i.e. belong to mosquitoes of the genus Culex.

Among the specimens I caught there were 5 pupae. They were also interesting to watch.Pupae that look like commas swim near the surface of the water: they have a large cephalothorax (since the head and chest are covered with a common shell) and a narrow curved abdomen. They move, jumping into the depths. But the larva does not stay at depth for long: it is very light and floats up by itself. In water, the pupa takes a different position than the larva. Suspended to the surface, it exposes not the rear, but the front end of its body from the water. On the dorsal side of the front part of the body it has a pair of respiratory tubes, which are visible to the naked eye and resemble small horns, giving the animal a very peculiar appearance. The pupa raises these horns out of the water when breathing.

Pupae, like larvae, dive into the water, but move differently: hitting the water with their abdomen, which ends in fins, they somersault over their heads; After staying at the bottom for some time, the pupae float up again, holding their horns up and passively rising to the surface, since their body is lighter than water, having an extensive air chamber inside. The pupa does not accept any food. The older the pupa, the darker it is. Before hatching, it turns from light brown to almost black. A ripe pupa bursts on the surface of the water.

The mosquito leaves the shell, the edges of which it clings to until its wings straighten and dry, and it flies into the air.

Usual development time common mosquito(at a temperature of 15-20°) - about a month, and in the pupal stage the insect lives on average about 2-5 days.In samples of mosquito larvae and pupae that I collected in stagnant water, mosquitoes emerged from the pupae on the third day.

2.1. Comparison of Culex mosquitoes and malaria mosquitoes genus Anopheles(according to my own observations and literary sources).

Having observed the behavior of mosquitoes, their larvae and pupae, and having read the literature about mosquitoes of the genus Anopheles, I came to the conclusion that they have many distinctive features and it is quite difficult to confuse a common mosquito and a malaria mosquito. I present the comparative characteristics of these mosquitoes in the form of a table.

Photos (digital microscope BIOR) were taken by the author, photos of mosquitoes, larvae, pupae in nature - Novoselova Alexandra.

Signs	Mosquitoes of the genus Culex	Mosquitoes of the genus Anopheles
Legs	Short	Long
Tentacles on the head	Very short tentacles	Jointed tentacles that are almost equal in length to the proboscis
Cables (antennae)	Almost the same length
Wing spots	No spots on the wings	Available dark spots
Body position	Position parallel to surface	Perpendicular position relative to the surface
Presence of a respiratory tube in the larva	There is a breathing tube at the end of the body	Absent
Location of larvae in water	Positioned at an angle to the water surface	Lie horizontally
Water quality	Water may contain large amounts of organic residues	The water must be clean. NOT be acidic.
Presence of flora and fauna in the water	Doesn't matter	The presence of representatives of flora and fauna is mandatory, especially filamentous green algae
The presence of a large number of plants on the surface of the water	Doesn't matter	The water surface should be free of surface plants (eg duckweed)
Eggs	Eggs are glued into "packages"	Eggs float on the surface of the water one by one
Enemies	Dragonfly larvae, water beetles, water bugs, some types of fish (gambusia, carp, perch).
Daily rhythm of life	24/7	Night
Seasonal rhythm of life		Males and unfertilized females die in late autumn, fertilized females overwinter in secluded places
Male nutrition	Plant food	Plant food
Feeding of females	Blood of animals, humans	Blood of animals, humans
Nutrition of larvae	Microscopic animals: bacteria, ciliates, other mosquito larvae, algae, sludge particles, diatoms (pictured).

3. Conclusion. Preventive measures to prevent the spread of mosquitoes along the Black Sea coast.

Due to the extreme danger of malaria, close attention to this disease is required. Therefore, preventing the spread of malaria throughout Russia and in Sochi is very important.

I divided the methods that are used to prevent the spread of the disease or for protection into 2 categories: global and household (“home”).

Global ones include: 1) Prevention: destruction of mosquito breeding sites - stagnant bodies of water. Specialists from Stavropol Research The Anti-Plague Institute is launching a pilot project to create a map of water bodies, including the territory of Sochi.

2) Reservoirs should be populated with the unique fish Gambusia, which is capable of eating mosquito larvae and pupae in unlimited quantities.

3) Identification of sick people at quarantine points of border territories is the task of the border and customs service.

4) At the level of research institutes, this is active work on the creation of an anti-mosquito vaccine or the creation of a genetic modification of a mosquito resistant to malaria.

At home, you can use mosquito nets, repellents, medicines to prevent bites (Menovazin, Zvezdochka balm), essential oils of some plants (mint, rosemary, fir and juniper oil, etc.), scented candles and sticks.

I would like to continue working on this topic. My future plans for studying mosquitoes are to study the action essential oils on mosquito larvae and pupae.

4. List of references.

Akimushkin I. Freaks of nature. M.Mysl.1981
Alekseev V.N. Arthropods. Insects. M. Bustard.2004
Verbitsky V.B. Under the Looking Glass, or the Mysterious World of the Pond. M. Bustard. 2002.
Gordon K.A. Old Sochi late XIX- beginning of the 20th century (memoirs of an eyewitness). Sochi. 2004.
Korolev V.A. Guide to laboratory classes in biology. Kyiv. Vishcha school. 1986
Plavilshchikov N.N. For young nature lovers. M. Children's literature. 1975
Raikov B.E., Rimsky-Korsakov M.N. Zoological excursions. M.1956.
Spilsbury R. All living things come from eggs. Life cycle of insects. Mnemosyne.2009.
gambusia.org

Mosquitoes of this genus are found everywhere except Antarctica. However, only in endemic areas is transmission of malaria by mosquitoes of different species possible. The persistent population of mosquitoes and the continuing likelihood of mosquito infection with Plasmodium malaria pose a risk of repeated outbreaks of malaria in humans.

Mosquito development.

Evolution occurs in four stages: egg, larva, pupa, and adult. The first three stages take place in water and the adult insect lives 5-14 days, depending on the species and ambient temperature.

Adult females lay 50-200 eggs. The eggs are laid in water, are not resistant to drying out and open within 2-3 days, when unfavorable conditions can exist until the next stage for up to 2-3 weeks.

The larvae of mosquitoes of the genus Anopheles are not adapted to breathing in water and therefore are located near the surface, breathing through spiracles located in the 8th abdominal segment.

The larvae feed on algae, bacteria and other microorganisms and swim in jerky movements. The larvae also develop in 4 stages, the change of stages is accompanied by a change in the outer chitinous shell - molting. For the development of a mosquito, it is necessary to have reservoirs with fresh, clean water- swamps, mangrove swamps, rice fields, grassy ditches, banks of streams and rivers, temporary rain ponds, possibly in pools and even in the axils of leaves filled with water.

The mosquito pupa is shaped like a comma and is also located at the surface of the water for breathing. The duration of evolution from egg to adult mosquito depends on the species and habitat conditions, on average 10-14 days in tropical conditions.

Adult mosquitoes

Like all mosquitoes, adult anophelines are distinguished by a head, thorax and abdomen. The head contains eyes, sensory antennae, and a proboscis for feeding. On the chest there are 3 pairs of legs and a pair of wings. The stomach contains the digestive and reproductive organs. The abdomen can increase significantly in size as it fills with blood and the eggs mature. Blood is digested over a long period of time. Mosquitoes of the genus Anopheles can be distinguished by the palps located next to the proboscis, by the presence of a distinct pattern on the wings, as well as by their typical situation before the bite. After turning from a pupa, adults are inactive for several days; males gather in flocks to attract females for mating. Males live for about a week and feed on plant nectar. Females can also feed on nectar, but for the normal development of their offspring they need to receive blood. After the bite, the females rest for several days, during which time the blood is digested and the eggs mature. Duration depends on external conditions, usually takes 2-3 days in tropical conditions. As soon as the eggs are fully mature, the female lays them in a pond and again looks for an opportunity to feed on blood until she dies. The lifespan of a female reaches 1 month.

Factors associated with malaria transmission and malaria control

For the transmission and development of plasmodia in the body of a mosquito, a certain lifespan of the intermediate host, the mosquito, is required. On average, it takes 10 to 21 days for Plasmodium to develop into a form that is infectious to humans. Consequently, shortening the life of a mosquito will lead to a decrease in human morbidity. This is facilitated by the use of insecticides

The feeding factor of mosquitoes during the crepuscular (active at dusk or dawn) or nocturnal (active at night) period, place of feeding and rest after feeding - outdoors (exophilic and exophagic) or indoors (endophilic and endophagic). Limiting the ability of a mosquito to bite at a time and place convenient for it through the use of mosquito nets and the construction of premises with limited access will also lead to limiting the transmission of malaria from mosquito to person.

A factor in reducing the number of places where the mosquito’s aquatic phase develops is draining swamps and moving away from dwellings.

Insecticide resistance

Resistant to chemicals may occur quite quickly in connection with birth large quantity generations throughout the year. There are more than 125 species of mosquitoes that are resistant to one or more insecticides.

Modern developments.

Some Anopheles species are able to independently eliminate plasmodia that have entered the body. These species are being carefully studied with the goal of introducing a similar mechanism to the entire mosquito population.

The malaria mosquito has spread almost throughout the world. It exists even in countries where the malaria it spreads is an officially eradicated disease. In Russia, a representative of this species of mosquito can also be found - it lives in the European part and in Western Siberia. But climatic conditions Eastern Siberia They are not suitable for it, since the winter there is especially cold and protracted. This insect in itself does not pose a danger, and it can only give a person a dangerous disease after it becomes infected.

Malaria mosquito - a threat to human health

Description of the species

An Anopheles mosquito is only a threat to humans if it has previously bitten a victim infected with malaria. On its proboscis it carries plasmodia and infects its next source of saturation with them. And since, it is they who pose the danger.

By 2005, science had studied and described 7 subgenera of malaria mosquitoes, which include about 440 species. About 10 species of these insects are found in Russia, and they settle mainly in the territories of the European and Far Eastern parts.

Body structure

An adult insect has an elongated body, a thin proboscis located on a small head, and long legs. The body is quite fragile and its strength suffers under mechanical stress. Thin wings are covered with scales and, when folded, are located horizontally above the abdomen.

The structure of a malaria mosquito will be as follows:

the head is round in shape, the proboscis is its natural continuation; compound eyes and antennae are located on the head; on the lower part of the forehead there is a clypeus; there are scales and hairs on the crown and back of the head, on both sides of the head in front of the eyes there are cheeks shaped like plates;
has a proboscis complex structure and consists of two upper and two lower jaws, upper and lower lips and subpharyngeal; there are palps on the lower jaws; the upper jaws are represented by a thin strip of chitin, the flat end of which forms a blade; on the front half of the outer edge of this blade there are small teeth, the number of which can range from 30 to 50;
the antennae are sensory organs, they are located in front of the eyes and are attached to a wide base plate; the second segment, located at the base of the antennae, contains Johnson's organ, which is presumably the organ of hearing; each antenna has fine hairs, which are much more numerous in males than in females;
the chest consists of three parts: prothorax, mesothorax and metathorax; the prothorax bears the head, the mesothorax - the legs, wings and spiracles, the metathorax - the posterior thoracic spiracle;
the abdomen is divided into 10 segments, the last two of which are part of the reproductive apparatus; the first eight segments are connected by the pleura, which stretches and allows the abdomen to increase in size during the act of eating and when bearing eggs.

Stages of development

A female malaria mosquito can lay 50 to 200 eggs at a time. She places the clutch on the surface of the water and each egg is able to find its comfortable position. Over time, the eggs sink to the bottom of the reservoir, where pupae form.

The malaria mosquito larva is born in about 2-3 days. But if the climatic conditions are unfavorable and the air temperature drops below the permissible level, then the miracle of birth can happen only 15-20 days after the female lays eggs.

The best development of the malaria mosquito occurs in a clean reservoir, which has not yet been overgrown with duckweed. Acidic waters with poor flora and fauna are not suitable for larvae, since during the growth process they simply will have nothing to eat. Food acceptable to them is found in reservoirs with slightly alkaline and neutral waters.

Note! Filamentous algae also grow there, in which the larvae can hide from fish and other predators for whom they are a tasty morsel!

The body cover of the Anopheles mosquito larvae is a waterproof cuticle, covered with spines and hairs. Thanks to the hairs, it can move and catch the slightest vibrations in the water.

Larvae of the first, second and early third instars have one pair of eyes covered with scales. As they grow, at the end of the third instar and in the fourth instar, a second pair of eyes is formed - these are the rudiments of the compound eyes of an adult. In addition to the eyes, the larva's head has antennae and a mouth organ.

Note! If the basis of nutrition is plankton, then the antennae will be especially long, if the larva feeds from the surface of the film and scrapes food from the bottom - short!

At the end of each of the four instars, the larva sheds its skin. With the end of the fourth instar, the development of the larva stops and it turns into a pupa. This stage is the last phase of growth - the cephalothorax cracks and the pupa becomes an adult.

Common and malarial mosquito: differences

As can be seen from the body structure, malaria mosquito looks almost the same as a regular one, but differences still exist:

the legs of the malaria mosquito are much longer than those of a normal mosquito, especially the hind legs;
the tentacles of a female Anopheles are almost equal in size to the proboscis, in ordinary ones the length of the tentacle is equal to ¼ of the proboscis;
the wings of an ordinary mosquito have a uniform color, while the malarial mosquito has spots on them;
when Anopheles sits, its body is located at an angle and the back part will be noticeably raised; the body of an ordinary mosquito in a sitting position will be almost parallel to the surface;
The malaria mosquito, before landing on the body of the victim, seems to be dancing in the air, which is different from the usual one.

Nutritional Features

The main source of nutrition for the female malaria mosquito is blood. Moreover, the victim in this case can be humans, mammals and even some invertebrates. Females choose their prey according to several criteria:

size;
level of radiated heat;
odor emitted.

They need blood before laying eggs.

Malaria mosquito males and, as observations show, even females, but only under forced circumstances, feed on nothing more than pollen and nectar of plants.

Note! For male representatives, the extracted carbohydrates are quite enough for normal life activities, but for the female half, such a diet is not the most acceptable, since they lose the ability to lay eggs.

Symptoms and consequences of bites

tingling at the site of the bite;
joint pain;
intense headaches;
vomit;
convulsions;
chills;
fever;
enlarged spleen;
anemia;
blood impurities in the urine;
cerebral ischemia.

The bite of a malaria mosquito is especially dangerous for women during pregnancy and children under 5 years of age. Having bitten the victim, the insect introduces plasmodium into its body, which after half an hour reaches the liver, where they develop. Over time, the liver increases in size and its cells gradually die.

The malaria mosquito is dangerous because every year it infects about 400 million people, and about 1.5 million die. Residents of Africa suffer the most from this disease - their number is 86%. And the forecasts are disappointing, since it is believed that within 20 years the mortality rate of Africans from malaria will double.

When a malaria mosquito bites a pregnant woman, it can lead to premature birth, eclampsia and death.

Babies may experience:

diarrhea;
vomit;
convulsions;
abdominal pain;
chills at the beginning of the illness;
at the end of the development of the disease, sweating;
spots and hemorrhage on the skin;
rapid development of anemia.

Symptoms in older children are similar to those in adults. Malaria in children is a particularly dangerous case. Death in such situations is common, especially between the ages of 6 months and 5 years. In this case, the most striking symptom is paroxysm, which is absent in children with malaria.

Malaria is one of the most widespread diseases in the world. About 1 million people die from it every year around the world. The main areas where malaria spreads are hot tropical countries: Africa, Central and South America, countries Southeast Asia, Papua New Guinea and others.

TO general information, distribution area of these dangerous insects very extensive. They are found almost everywhere, including on the territory of our vast Russia. Only people living in the most isolated areas are protected from meeting them. northern regions and on the territory of Eastern Siberia. Well, they don’t like mosquitoes very much low temperatures, real Siberian winters are very harsh for them.

This may sound a little ridiculous, but malaria mosquitoes are mostly found where there are outbreaks of malaria. In other areas, encountering them is very rare. These mosquitoes themselves are not dangerous until they have tasted the blood of a person with malaria.

How do they differ from our usual “blood brothers and sisters” and how to protect ourselves from this disease we will now find out.

I propose not to beat around the bush and immediately begin to consider the main signs that distinguish an ordinary mosquito from a malarial one.

First, the malaria mosquito is easily identified by its long hind legs. BUT! It should not be confused with large long-legged mosquitoes, which are kind-hearted creatures and feed exclusively on plant juices. They are completely harmless to humans.

Secondly, when landing on the surface, its body is located at a large angle to it, almost perpendicular, and all “thanks to” the long hind legs. Our ordinary mosquito behaves more modestly and tries not to stand out, placing its body almost parallel to the surface.

The wings of the malaria mosquito are decorated with small black spots - this is the third difference.

Fourthly, female malaria mosquitoes have jointed tentacles on their heads, equal in length to the proboscis. In female common mosquitoes they are much shorter. But you are unlikely to look closely at the head of a mosquito that lands on your hand, so be guided by the more obvious and simple signs listed above.

The first is the habitat. The mosquitoes dear to our hearts cannot live without water, because almost all of them life cycle connected with her. Their childhood, adolescence and youth pass in a variety of bodies of water, from ordinary puddles to large ponds :).

Reservoirs are habitats for mosquito larvae

Most often, clean or sparsely overgrown bodies of water, which are not overgrown with duckweed and are suitable for the larvae, serve as a home for the larvae of the malaria mosquito. Acidic waters and reservoirs poor in flora and fauna are not suitable for them (since there will be nothing to eat).

But there are plenty of them in neutral or slightly alkaline waters and where filamentous algae grow, which are an excellent refuge for larvae from fish and other aquatic predators who want to enjoy them.

Malaria mosquito larva

The larvae of ordinary mosquitoes are not so picky and can live in bodies of water rich in organic matter and even in sewer water (this applies to urban mosquitoes).

The second is the structure of mosquito larvae. Malaria mosquito larvae do not have a long breathing tube at the end of the body; its role is played by sessile breathing holes.

In addition, the larvae of the common mosquito are located at a large angle to the surface of the water, while the larvae of the malaria mosquito take on an almost horizontal position. So they float quietly and peacefully on the surface from 8 days to 4 weeks. It all depends on the water temperature; the higher it is, the faster the development of the larvae occurs.

Of the approximately 150-350 eggs of a malaria mosquito (their number most often depends on how hearty the mother managed to eat), not all survive. Many of them act as excellent food for dragonfly larvae, water bugs and beetles, as well as carp, perch and some other fish. The female common mosquito lays from 30 to 150 eggs.

After laying eggs, the female turns into a vegetarian for 2 days and switches to plant juices. And then a new mating, a new “victim” and a new portion of eggs on the surface of the water.

The entire body of mosquito larvae (both malarial and common) is covered with many bristles. As they grow older, they grow from 1 mm to 8-9 mm and at each stage of development they change their color. So at first they will be black, then they gradually turn gray and in the end, before “hatching”, they become green or reddish, but sometimes they retain a dark color.

Malaria mosquito pupa

Malaria mosquitoes are nocturnal and during the daytime they hide somewhere in dark, secluded places. Therefore, most of their attacks occur in the dark, when a person is sleeping.

Blood drunk female

The menu of adult females, males and their larvae is completely different. The former prefer to drink blood, in addition to 2 days of vegetarianism after laying eggs; the second - feed exclusively on plant juices, and the third - small aquatic organisms, which are caught with the help of oral brushes and sent into the mouth. If there are filamentous algae nearby, they will feast on them too.

Male drinking plant juice

Females live longer than males. Their lifespan can reach up to 2 months if they are not slaughtered first. Males live for a few days at most.

How to protect yourself from malaria:

1. Mosquito nets, curtains or mats treated with a special insecticide (this is if you are vacationing in a country where there is a risk of contracting malaria).

Anti-mask nets

2. Use of mosquito coils and other fumigants (toxic vapors or gases).

3. When it gets dark, wear clothes that cover exposed areas of the body - long-sleeve shirts, pants, long skirts.

4. Reducing the number of mosquito larvae:

- using kerosene or fuel oil. If you pour a little of them into a stagnant pond with mosquito larvae, a thin film forms on the surface of the water, which prevents the larvae from breathing. After 2 days they die;

— colonization of reservoirs with fish fry that feed on mosquito larvae. Most often these are representatives of the carp family.

Mosquitoes (family Culicidae)

Distributed everywhere. The three most common mosquito genera are Anopheles, Culex and Aedes.

Morphological features: adult mosquitoes have a slender, elongated body of small size. The head contains large compound eyes, long antennae and mouthparts. Females have piercing-sucking mouthparts. In males, the oral apparatus is sucking, its piercing parts are reduced. They feed on the nectar of flowers. On the sides oral apparatus segmented antennae lie. A pair of transparent wings is attached to the mesothorax. The abdomen is formed by 10 segments, the last two are modified into genital appendages (Fig. 65).

Biology of mosquitoes. A new generation of mosquitoes hatching from pupae undergoes a period of physiological maturation that lasts about four days. At this time, they live near water bodies and feed on nectar. Then, at dusk, the males form a swarm, the females fly into it, mating occurs, after which the females must drink blood for the development of eggs. They actively search for prey at a distance of up to 3 km from a body of water, flying indoors. Having drunk blood, females hide for several days in darkened rooms or thickets of bushes. During the digestion of blood, eggs mature (gonotrophic cycle) . Mosquitoes can only go through one gonotrophic cycle per summer. (monocyclic) or several (polycyclic). Female mosquitoes in summer time live about 1 month, males - 10-15 days.

After the eggs mature, the female flies to the pond and lays eggs (350450) on its surface. Larvae emerge from the eggs. The duration of larval development depends on the water temperature. The minimum development period is 15 days at the optimal temperature (250 C). Development begins at a water temperature of at least 100 C. The larvae feed on bacteria and plant debris, molt several times and turn into pupae, from which a new generation of adults emerges. In polycyclic species, during the warm season there are from 2 to 5-7 generations (depending on natural conditions).

In most species of mosquitoes (Anopheles and Culex species), fertilized females overwinter, and in species of the genus Aedes, eggs. When autumn comes

During cold weather, males fertilize females and die. Females feed on blood to form a fat body, on which they survive during the winter. Egg development is inhibited. With the onset of warm weather spring days females fly out of their shelters and again feed on blood to mature their eggs. From the laid eggs, a new generation of males and females consistently develops.

Eggs. Anopheles mosquitoes lay their eggs in stagnant or weakly flowing, unshaded bodies of water with clean water. The eggs have a belt with air chambers and float one at a time (Fig. 66).

Rice. 66. Morphology of mosquitoes. A – eggs of mosquitoes of the genus Culex, B – larva of Culex, C – pupa of Culex, D – head of a male Culex, E – head of a female of Culex, E – eggs of mosquitoes of the genus Anopheles, G – larva of Anopheles, H – pupa of Anopheles,

head of a male Anopheles, head of a female Anopheles.

Aedes mosquitoes lay eggs one at a time in temporary reservoirs: puddles, cans, hollows, etc. The eggs have an elongated oval shape without air chambers.

Culex eggs are wedge-shaped without air chambers and are laid on the surface of the water glued together in a boat shape.

Larvae. The larvae of Culex and Aedes mosquitoes have a respiratory siphon on the penultimate abdominal segment in the form of a narrow tube, at the end of which stigmata (tracheal openings) are located. The larvae are located at an angle to the surface of the water and breathe atmospheric air.

The larvae of Anopheles mosquitoes do not have a siphon and are located parallel to the surface of the water. A pair of stigmata, through which they breathe atmospheric air, is located on the penultimate abdominal segment.

Aedes mosquitoes are characterized by non-simultaneous hatching of larvae from eggs of the same clutch; it lasts for weeks and even months (adaptation to living in periodically drying up water bodies).

Pupae. The pupae are comma shaped. On the dorsal side of the cephalothorax there is a pair of respiratory siphons. With their help, the pupae are “suspended” to the surface film of water. In Culex and Aedes mosquitoes, the siphons are cylindrical, while in Anopheles they are funnel-shaped (conical).

Adult forms (imago). Adults differ in their position, the pattern of their wings, and the structure of their head appendages.

U mosquitoes For Culex and Aedes, the abdomen is located parallel to the surface on which they sit; in Anopheles mosquitoes, the rear end of the abdomen is raised.

Some species of malaria mosquitoes have dark spots on the wings; non-malaria mosquitoes do not have them.

The heads of males of all mosquitoes have heavily pubescent mandibular antennae, while in females they are weakly pubescent.

U In Anopheles females, the mandibular palps are equal in length to the proboscis,

A in females Culex and Aedes they are 1/3-1/4 length of proboscis.

U In Anopheles males, the mandibular palps are equal in length to the proboscis and have club-shaped thickenings at the end; in non-malarial mosquitoes they are usually longer than the proboscis and have no thickenings.

Anopheles mosquitoes are specific carriers and definitive hosts of malaria pathogens, specific vectors and intermediate hosts wucherer and brugi

Aedes mosquitoes are specific carriers of pathogens of Japanese encephalitis, yellow fever, Dengue fever, lymphocytic choriomeningitis, anthrax, wuchereriosis, brugiosis, tularemia.

Culex mosquitoes are specific carriers of the pathogens of Japanese encephalitis, tularemia and wuchereriosis.

Mosquito control measures come down to the following areas:

1. Direct protection against mosquito attacks (wearing closed clothing, using repellents, covering the windows of residential premises, animal prevention - creating biological barriers ( livestock farms) between mosquito breeding sites and residential buildings, etc.).

2. Fight against winged mosquitoes – spraying insecticides in wintering and overnighting areas of mosquitoes (basements, attics, barnyards).

3. Fight against larvae:

a) drainage of small reservoirs of no economic importance; b) use of pesticides; c) shading of reservoirs by trees;

d) reclamation work to drain swamps, deepen reservoirs, straighten river beds;

e) spraying mineral oils over the surface of reservoirs, clogging stigmas; f) breeding gambusia fish (biological control method).