Common and malarial mosquitoes. Anopheles mosquito or mosquito: how to distinguish Anopheles mosquito pupa

Species belonging to this family are distributed from the tundra zone to the desert oases.

They are small in size. On the head are large compound eyes, antennae and mouthparts. Only females with piercing-sucking mouthparts are blood-sucking. It consists of a trough-shaped lower lip, upper lip in the form of a plate closing the gutter from above, a pair of lower and a pair of upper jaws in the form of bristles (stabbing apparatus) and a tongue (hypopharynx), inside which a canal passes salivary gland. All stabbing parts lie in a case formed by the upper and lower lip. The appendages of the lower jaws are the mandibular palps. In males, the apparatus is sucking, the stabbing parts are reduced. Mosquitoes feed on the nectar of flowers. Antennae lie on the sides of the mouth apparatus, in males they are covered with long hairs, in females - short. The development of mosquitoes occurs with complete metamorphosis. Places of breeding, depending on the genus of mosquitoes, can be natural and artificial reservoirs. Mating takes place in the air ("dancing mosquitoes"). After fertilization, the female needs blood to develop the eggs. The process of digestion of food and maturation of eggs received the name gonotrophic cycle. With gonotrophic harmony, one portion of blood is enough for maturation and laying eggs.

The life span of a female summer time up to 3 months, and males up to 10-15 days. In autumn, gonotrophic harmony is disturbed, and two or three times blood feeding is required for the maturation of eggs. Blood is used not only for the development of eggs, but also for the formation of a fat body, thanks to which the fertilized females hibernate.

Each type of mosquito has certain morphophysiological and ecological features. Differences exist at all stages of development.

mosquito eggs Anofeles genera develop in reservoirs with stagnant and low-flowing water. They float alone on the surface of the water. Have air chambers. Culex mosquito eggs are elongated, laid in large groups (300-400 pieces each). Sticking together, they form a "boat" floating on the surface of the water. Mosquitoes of the genus Aedes lay their eggs one at a time at the bottom of drying up reservoirs.

mosquito larvae The genus Anopheles live in clear waters. They are worm-shaped. They are parallel to the surface of the water. They are held in this position with the help of palm-shaped bristles located on the segments. There are a pair of stigmas on the dorsal side of the penultimate abdominal segment. Larvae of mosquitoes of the genus Culex can live in polluted water bodies. On the penultimate segment of the abdomen, they have a respiratory siphon in the form of a narrow tube with a stigma at the free end. Therefore, the larvae common mosquitoes located at an angle to the surface of the water. The last segment bears leaf-shaped anal gills and tufts of setae. Aedes mosquito larvae live in temporarily drying up reservoirs, puddles, tree hollows, water vessels, and can live in polluted reservoirs. The larvae feed intensively and grow, molt four times

and transform into the pupal stage.

Mosquito pupae. The body is shaped like a comma. Consists of a broad cephalothorax and a narrow segmented abdomen. The pupae do not feed. Reorganization takes place during the pupal stage internal organs, and organs characteristic of the imaginal stage appear. Main hallmark The pupae of the malarial mosquito serve as a form of respiratory siphon: the tube has a conical (funnel-shaped) shape. The pupae of mosquitoes of the genus Culex are characterized by the presence on the upper side of the anterior part of the body of two respiratory siphons in the form of cylindrical tubes.

Mature individuals (adults) are formed from pupae. Differences in winged forms are manifested in the landing, the structure of the appendages of the head and the color of the wings. When landing, the abdomen of the malarial mosquito is raised and is at an angle to the surface of the water, while that of the common mosquito is parallel to the surface. In Anopheles females, the mandibular palps are equal in length to the proboscis, in Culex females they are shorter than the proboscis and make up approximately 1/3-1/4 of its length. Anopheles males have club-shaped thickenings at the ends of the mandibular palps; Culex males have mandibular palps longer than the proboscis and do not have club-shaped thickenings.

The pubescence of the antennae is more pronounced in males and is a manifestation of sexual dimorphism.

Due to changes in environmental and socio-economic conditions in a number of southern countries CIS (Azerbaijan and Tajikistan) there are local outbreaks and epidemics of three-day malaria. Mass importation of malaria to Russia threatens the spread of malaria. The malaria situation in the Russian Federation has changed since 1996. The largest importation of malaria in big cities Russia marked in 2000.

Currently, the epidemiological surveillance of malaria in Russia is aimed at maintaining well-being in malariogenic territories, since there are many factors that increase the risk of malaria spread.

Factors in the spread of malaria:

a. Natural and climatic conditions: floods and floods; climate warming; the presence of numerous breeding sites for malarial mosquitoes;

b. Features of certain types of vectors and pathogens of malaria: susceptibility of mosquitoes to imported malaria pathogens; epidemiological effectiveness of local vectors; resistance of mosquitoes to certain insecticides;

c. Development economic activity population: rice cultivation; fish farming; cottage construction;

d. Migration of the population: flights of ships and aircraft to the tropics; tourism to endemic countries; the arrival of seasonal workers from endemic countries; nomadism of Tajik gypsies; business trips of businessmen to endemic countries;

e. Economic difficulties: reduced funding for antimalarial enterprises; deficit medicines for treatment and chemical prophylaxis; shortage of medical personnel exercising epidemiological surveillance;

f. Social and cultural level of the population: low level public knowledge about malaria; lack of means of protection against mosquito bites among the population; non-compliance with the regimen of taking drugs; lack of insecticidal treatments of residential premises.

Mosquito control measures and malaria prevention. For personal protection, repellents and mechanical means are used: gauze curtains, nets, etc. The main measures of public prevention is the destruction of larval forms and breeding sites of mosquitoes. The fight against larvae consists of the following measures: 1) destruction of small abandoned water tanks; 2) spraying pesticides in reservoirs serving as breeding grounds; 3) oiling of reservoirs, preventing the supply of oxygen; 4) a change in the type of vegetation in a reservoir or a change in the degree of its overgrowth; 5) drainage of the area, reclamation works; 6) biological control measures (breeding of mosquito fish); 7) use of zooprophylaxis - location livestock farms between mosquito breeding grounds and residential buildings. Insecticides are used to control winged forms.

Anopheles is commonly known as a species of malarial mosquito because it is considered the primary vector of the disease. It is also the transmitter of heartworm in dogs.

Description

The Anopheles mosquito prefers to feed on mammals, including humans.
The body of an adult Anopheles mosquito is dark brown to black in color and has 3 sections, which are the head, chest and belly.

When resting, the stomach area of ​​the insect points upward, rather than parallel to the surface, as in most mosquitoes. Anopheles females reproduce several times during their short lives, producing eggs after finding blood. Although they live only from a few weeks to a month, they produce thousands of eggs during this time.

The female mosquito lays up to 200 eggs on the surface of the water. Each of the single eggs stays on the water with the help of floats. They need from two days to three weeks to hatch, depending on the ambient temperature.

Mosquito larvae are called wigglers, as they move in a peculiar way. They lie parallel to the surface of the water to feed on fungi, bacteria, and other tiny organisms. The larvae go through four stages, after which they become pupae.
The pupae are known as tumblers. The pupae come to the surface of the water to breathe through tiny "tubes" and do not eat for 1-2 days until they become adults.

breeding habit.

Anopheles mosquitoes lay their eggs in a variety of places. Malaria mosquito breeding grounds are fresh or salt water. Ground pools, small streams, irrigated lands, freshwater swamps, forest pools, any other place with clear, slow moving water are considered prime breeding grounds for malaria mosquitoes.

Females, especially fertilized ones, survive the winter dormant in caves, which means the breeding cycle can continue. all year round. Eggs are able to withstand cold temperatures; however, freezing usually kills them.

To learn more Why do mosquitoes dream

Geography

Where do malaria mosquitoes live? Anopheles live almost anywhere in the world, with the exception of Antarctica. They are found in areas where malaria has been eradicated, so there is always the possibility that they can re-infect that area.

All that is needed is blood from a human or mammal infected with malaria in order for them to be able to pass it on to another human or mammal. The person who initially became infected may have just traveled to an area where malaria is present, or it may be an unsuspecting visitor to an endemic region who brought the disease.

As world tourism is prevalent today, the possibility of recontamination of a previously clean area always exists. In addition, regions that have never experienced outbreaks may become endemic for the first time. Where do malaria mosquitoes live? Anywhere. Effective mosquito control systems can provide protection against these pests and the diseases they transmit.

• There are about 430 species of Anopheles mosquitoes, but only 30 to 40 species of mosquitoes carry malaria.
• Many species of Anopheles mosquitoes have become resistant to insecticides through years of pesticide use.
• The Anopheles malaria mosquito is most active twice: just before dawn and just after dark. At this time of day, outdoor mosquito control is essential to provide protection from the bite.
• The Anopheles mosquito causes an outbreak of "airport malaria" when it is accidentally imported via luggage or aircraft.
• Sir Ronald Ross, who proved the transmission of malaria by the Anopheles mosquito, was not only a scientist; also mathematician, writer, poet, editor, composer, artist.

The Anopheles mosquito is still found in many areas where malaria has been eradicated. Although the parasite has been eradicated, it is still present, and it is possible for malaria to recur after a single bite from a malaria mosquito.

The body of the pupa is shaped like a comma and consists of two sections. The expanded anterior section is egg-shaped and corresponds to the head and chest of the future mosquito. On the lower side of the anterior part of the body, there is an eye in the form of a dark spot, enclosed in a transparent case. Forming organs of an adult mosquito shine through the transparent cover: the rudiments of the mouth apparatus, limbs, wings.

On the dorsal surface of the anterior part of the body there are two respiratory siphons, which look like funnel-shaped tubes. A narrow segmented abdomen is tucked under the anterior part of the body.

Head of a female non-malaria mosquito Culex pipiens

The head of a female non-malarial mosquito is visible on the preparation, with its dorsal side up. From leading edge a long thin proboscis leaves the head. The proboscis is a modified lower lip that has a gutter-like appearance. The stabbing parts of the oral apparatus are located in it as in a case and are not visible under a microscope. The proboscis at the free end has two small blades used in inserting the piercing mouthparts into the skin of the host. On both sides of the proboscis, three-segmented mandibular palps are visible, four times shorter in length than the proboscis. Along the entire length they are covered with small hairs. The mandibular palps are appendages of the lower jaws and perform a tactile function. Outside of the mandibular palpi are multi-segmented, slightly pubescent antennae - the organs of smell. Short hairs are whorled at the junctions of the segments. The entire front of the head is occupied by a pair of large compound (mosaic) eyes. Outwardly, they resemble honeycombs. Each facet (eye) of compound eyes is clearly visible.

Head of a male non-malaria mosquito Culex pipiens

The head of a male non-malarial mosquito is visible on the preparation, with its dorsal side up. A long thin proboscis extends from the front edge of the head. The proboscis is a modified lower lip that has a gutter-like appearance. The stabbing parts of the oral apparatus are located in it as in a case and are not visible under a microscope. In the male, the upper and lower jaws - the piercing parts of the mouth apparatus - are underdeveloped. Therefore, the sucking oral apparatus of the male cannot pierce the skin; it provides the males with nectar and plant sap. On both sides of the proboscis, mandibular palps are visible, longer than the proboscis; all segments are of the same thickness. Along the entire length they are covered with small hairs. The mandibular palps are appendages of the lower jaws and perform a tactile function. Outside of the mandibular palps are multi-segmented strongly pubescent antennae - the organs of smell. Long hairs are whorled at the junctions of the segments. The entire front of the head is occupied by a pair of large compound (mosaic) eyes. Outwardly, they resemble honeycombs. Each facet (eye) of compound eyes is clearly visible.

Egg of the non-malarial mosquito Culex pipiens

The egg has an elongated shape, the lower end of the egg is wide and blunt, and the upper end is narrower. At the lower end of the egg, a lid protruding outward is visible. On some preparations it is visible side"boat" formed by several dozen eggs of a non-malarial mosquito.

Larva of the nonmalarial mosquito Culex pipiens

The preparation clearly shows the elongated body of the larva, 2–3 mm in size, consisting of three sections: a massive head, a large thorax, and an articulated abdomen. The head is clearly demarcated from the chest. On the sides of the head are compound eyes, in front - two fan-shaped fans and rod-shaped antennae. Fans - oral appendages, consisting of thin and long hairs, which, moving rhythmically, drive water with food particles contained in it into the mouth of the larva.

Thoracic strongly swollen. The segmented abdomen consists of 9 segments. In the middle of the abdomen in the form of a dark spot through the integument of the body, the intestines shine through. On both sides of the intestine are tubular tracheae. A long respiratory tube, the respiratory siphon, departs from the penultimate abdominal segment. Stigmas (breathing holes) are located at the end of the siphon.

The last segment contains two well-marked tufts of tail setae, which are used by the larva to enlarge the rowing surface when the larvae move. 4 elongated transparent appendages extend from the last segment - anal gills, which play an important role in the processes of osmoregulation.

The entire body of the larva is covered with numerous hairs: the thorax and the first three segments of the abdomen are covered with simple setae and stellate setae are absent, in contrast to the larva of the malarial mosquito.

Pupa of the non-malarial mosquito Culex pipiens

The body of the mosquito pupa is shaped like a comma and consists of two sections. The expanded anterior section is egg-shaped and corresponds to the head and chest of the future mosquito. On the lower side of the anterior part of the body there is an eye in the form of a dark spot, enclosed in a transparent case. Forming organs of an adult mosquito shine through the transparent cover of the pupa: the rudiments of the mouth apparatus, limbs, wings.

On the dorsal surface of the anterior part of the body there are two respiratory siphons, which look like cylindrical tubes. A narrow segmented abdomen is tucked under the anterior part of the body.

Mosquitoes, or real mosquitoes, or blood-sucking mosquitoes (lat. Culicidae) are a family of two-winged insects belonging to the group of long-whiskers (Nematocera). There are more than 3,000 species of mosquitoes in the world, belonging to 38 genera. Representatives of 100 species belonging to the genera of true mosquitoes (Culex), biters (Aedes), Culiseta, malarial mosquitoes (Anopheles), Toxorhinchites, Uranotaenia, Orthopodomyia, Coquillettidia live in Russia.
Mosquitoes are insects thin body(length 4-14 mm), long legs and narrow transparent wings. The body color is yellow, brown or gray. The abdomen is elongated, consisting of 10 segments. The chest is wider than the abdomen. The legs end in a pair of claws. The wings are covered with scales, clusters of which sometimes form spots. Antennae long, composed of 15 segments. oral apparatus piercing-sucking type. In females, the proboscis is long and consists of piercing bristles, in males - without them.
Mosquito insects have 4 phases of development: egg, larva, pupa, adult. At the same time, all phases, except adults, live in water bodies. Mosquito larvae and pupae living in water breathe atmospheric air through breathing tubes, exposing them to the surface. Mosquito larvae - filter feeders or scrapers - feed on aquatic microorganisms. The nutrition of adults is often dual: females of most mosquito species drink the blood of vertebrates: mammals, birds, reptiles and amphibians; at the same time, males of all mosquito species without exception feed on the nectar of flowering plants.
BREEDING. Female mosquitoes during the mating season attract the attention of males with a characteristic thin sound, reminiscent of a squeak, which is created with the help of wings. Mosquitoes pick up sound vibrations with their sensitive antennae. Females squeak a little thinner than males, young ones - not like old ones. And male mosquitoes hear this and make a choice in favor of adult females. Mosquitoes form a swarm, where males and females mate. The female mosquito lays 30-150, and even 280 eggs (for malarial mosquitoes) every 2-3 days. The egg develops into an adult mosquito within a week. To reproduce eggs, mosquitoes require blood, so the egg-laying cycle is directly dependent on blood consumption. Eggs are laid in stagnant or low-flowing reservoirs on the surface of the water (the genera Anopheles and Culex), on moist soil at the edge of the water that dry up in summer and are flooded in spring, or stick to floating and water-washed objects (Aedes).
MEDICAL SIGNIFICANCE. Mosquitoes are an integral component natural communities. The number of groups of animals for which they are food is in the tens. In addition, mosquitoes, like other insects, whose larvae actively feed in aquatic environment, are one of the main reasons for the inexhaustibility of soils
Mosquitoes are carriers of dangerous diseases: malaria, yellow fever, dengue and some encephalitis. Of these diseases, malaria alone causes about two million deaths each year. In addition, their bites can cause itching and an allergic reaction.

They are widely distributed on all continents except Antarctica. Absent in desert areas and on far north(the extreme northern point of the range is the south of Karelia). There are about 430 species in the world fauna, in Russia and neighboring countries- 10 types. In Russia, they live in the European part and Western Siberia. do not live in Eastern Siberia where the winters are too harsh for them. A mosquito becomes infected with malarial plasmodium from a person - a patient or a carrier. The malarial Plasmodium goes through a cycle of sexual reproduction in the body of the mosquito. An infected mosquito becomes a source of infection for humans 4-10 days after infection and remains so for 16-45 days. Mosquitoes serve as carriers of other types of Plasmodium that cause malaria in animals.

Malaria: pathogenic significance, diagnosis, prevention.

In malaria caused by P. malariae, the intervals between attacks are 72 hours. Asymptomatic carriage is common.

In tropical malaria, at the onset of the disease, the intervals between attacks may be different, but then they are repeated every 24 hours. With this type of malaria, the danger is great lethal outcome due to complications from the central nervous system or kidneys. Tropical malaria is especially dangerous for Caucasians.

A person can become infected with malaria not only through the bite of an infected mosquito. Infection is also possible through hemotransfusion (transfusion) of infected donor blood. Most often, this method of infection occurs with four-day malaria, since there are few schizonts in erythrocytes, they may not be detected when examining the blood of donors.

Diagnostics

It is possible only during the period of erythrocyte schizogony, when the pathogen can be detected in the blood. Plasmodium, recently penetrated into the erythrocyte, has the form of a ring. The cytoplasm in it in the form of a rim surrounds a large vacuole. The nucleus is displaced to the edge.

It occupies almost the entire erythrocyte. Further, fragmentation of the schizont occurs: a deformed erythrocyte contains many merozoites, each of which contains a nucleus. In addition to asexual forms, gametocytes can also be found in erythrocytes. They are larger, do not have pseudopods and vacuoles.

Prevention

Identification and treatment of all patients with malaria (elimination of the source of mosquito invasion) and the destruction of mosquitoes (elimination of vectors) with the help of special insecticides and reclamation works (draining swamps).

When traveling to areas unfavorable for malaria, you should take prophylactic antimalarial drugs, protect yourself from mosquito bites (use mosquito nets, apply repellents to the skin).

Common and malarial mosquitoes

The mosquito (Culex) belongs to the Diptera order and is a member of the large mosquito family (Cullcidae).
This is a well-known small insect (6-7 mm) with an outstanding chest, a long narrow abdomen and one pair of narrow wings. The male is easily distinguished from the female by the more developed, strongly feathery antennae. Only females attack people and animals and feed on their blood, in which the proboscis has piercing bristles. Males feed on plant sap.

As an excursion object of great interest are larvae mosquitoes, which in spring are found in masses in shallow fresh waters, most often stagnant, moreover, where the bottom depth is not more than 1-1.5 m: in ponds, ditches, forest puddles, pits with water, often even in uncovered gutter tubs, vats etc.

The mosquito larva looks like a legless worm with an expanded chest, a jointed abdomen and a large head, on which two black eyes are easily distinguished. On the penultimate segment of the abdomen, a long, oblique outgrowth process is seen, this is a respiratory tube, at the end of which there are respiratory openings.

Mosquito larvae. Increased 1 - larva of common mosquito (Culex pipiens); 2 - malarial mosquito larva ( Anopheles maculipennis); 3 - larva of an amphibian mosquito (Dixa amphibia); gg - respiratory openings from which two tracheal trunks begin.

It is not difficult to detect the presence of larvae in this pool, since the larvae in a calm state hang at the very surface of the water. To catch them, you need to quickly draw a net through the water before the nimble society has time to sink to the bottom. Where there are many larvae, it is easy to do without a net, simply scooping up water with some kind of vessel. To examine the caught larvae, they should be placed in a small glass jar or a wide test tube filled with clean water.
The attention of tourists first of all stops at the characteristic movements larvae. It is enough to throw some object into the water, wave something over the water, or even quickly approach the reservoir where the larvae are located, as they immediately break away from their place, sink down with characteristic snake-like movements and hide at the bottom of the reservoirs. Their movement in the water is helped by swimming hairs, which sit in bunches on the segments of the body. In particular, a large tuft is present on the last caudal segment. After some time, the larvae again float to the surface of the reservoir, where they are driven by the need for air.
The point is that the larvae breathe atmospheric air, the supply of which in the body requires constant refreshment. Larvae, rising to the surface, expose their caudal windpipes from the water and take in air into the tracheal trunks. In this case, the larva hangs at the surface of the water upside down, in a very characteristic position, at a certain angle to the surface of the water (40°-60°). It is retained by the surface tension of the liquid, which forms an elastic film, which the larva pierces with its respiratory process and to which it hangs from below.
The mass of larvae hanging in this way, dotting the surface of the reservoir, is sometimes a remarkable sight.
As soon as the larva breaks away from the surface tension film, it begins to sink into the water, since its body is heavier than water. To float to the surface, she needs to resort to active swimming movements.
feed on larvae by various microscopic organisms, for example, unicellular algae, and also, in all likelihood, parts of rotting plants.
Development The larva consists in a series of successive molts (3 molts are observed in total), and then the larva turns into a pupa, which is completely different in its structure from the larva. It somewhat resembles in appearance a small tadpole, and the front part of its body is dressed in a common shell, and only the jointed abdomen remains free. The whole body is curved like a comma. In water, the pupa assumes a different position than the larva. Suspended to the surface, it puts out of the water not the rear, but the front end of its body. On the dorsal side of the front of the body, it has a pair of funnel-shaped respiratory tubes that are visible to the naked eye and resemble small horns, giving the animal a very peculiar appearance. These horns are chrysalis and protrude from the water when breathing. When frightened, the pupae, like the larvae, dive into the water, but move differently: hitting the water with their abdomen, which ends in fins, they amusingly somersault over their heads; after holding out for some time at the bottom, the pupae again emerge, 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 take any food. At the end of a short life, the color of the pupa changes: the older the pupa, the darker it is. Before hatching, it turns from light brown to almost black.
The mature pupa bursts on the surface of the water, and a young mosquito gradually crawls out through the gap between its horns. An abandoned pupal shell floating on the surface of the water serves as a temporary boat for him, by the edges of which he clings until his wings spread and dry, and he takes off into the air. The slightest disturbance on the surface of the water at this time is detrimental to the mosquito, as it falls into the water, from where it is no longer able to get out.
Some time after fledging, having fed on blood, the females begin to lay eggs, which are released directly onto the surface of the water. These floating egg packs consist of several hundred eggs and have a very distinctive oval shape with a spoon-shaped indentation that allows them to float on the surface of the water like a tiny shuttle. At the same time, individual eggs, having an oblong cigar-shaped shape and glued into a common pack, stand perpendicular to the surface of the water.
Usual duration development an ordinary mosquito (at a temperature of 15-20 °) - about a month, and in the pupal stage the insect lives on average about 2-5 days. The duration of development is directly related to the temperature of the water and at a higher temperature it is almost halved. On the other hand, at temperatures below 12° the development of the larvae stops altogether. On an excursion, this dependence can be shown by fishing in parallel in two adjacent reservoirs, one of which is in the sun and the other in the shade (for example, under the shade of trees). While in the second reservoir we will find only young larvae, in the first reservoir most of the larvae have not only reached their maximum growth, but have already managed to turn into pupae.

Among other representatives of the mosquito family, the larvae of which are often found in our fresh water bodies, we note the following forms:

Amphibious mosquito(Dixa amphibia). The larvae of this mosquito are very similar to the larvae of the malarial mosquito, but they hold themselves in a completely different way. Curving its body in a steep arc, the larva of the amphibian mosquito catches on any objects protruding from the water so that the front and rear ends of its body remain immersed in water, and the middle part of the body is kept out of the water. Such a semi-terrestrial way of life of this larva was the reason for its name. Its pupa, living in water, exists for a very short time, only a few hours, and quickly passes to fledging. An adult insect lays eggs, enclosing them in a gelatinous lump, which sinks to the bottom of the reservoir.

Mosquito larvae. Increased 1 - larva of the coretra, or pinnate mosquito (Corethra plumicornis): M - air sacs; 2 - mochlonyx larva, or mosquito-shaped mosquito (Mochlonyx culiclformis).

Cirrus mosquito Choaborus (Corethra) plumicornis L. has a very interesting vitreous-transparent larva, which can be seen in the water only with a certain attention. This transparency helps the larva to elude its many enemies, in particular fish. Unlike other mosquitoes, the coretra larva never rises to the surface of the water, but constantly stays at some depth in a horizontal position; most of all, it hangs motionless in the water, from time to time making sharp jumps and bending the body at the same time. The coretra larva does not possess any respiratory adaptations, but absorbs the oxygen dissolved in water through its racing skin.
It feeds on various microscopic animals, most often small crustaceans, which it catches extremely cleverly, grabbing prey with its hook-shaped curved oral appendages.
The best way to examine a coretra caught on an excursion is to put it in a small vessel with clean water and look at the larva in the light. Due to the transparency of the cover, you can even see with the naked eye many features of its internal structure.
Two pairs of silvery bubbles immediately catch your eye - one in the front, the other in the back of the body - which are filled with air and serve as a swimming device for the larva, supporting it in the water. The intestinal canal is also visible, along its entire length, and even the tracheal trunks passing along the body. This larva presents a particularly remarkable picture when examined under a microscope or with a strong magnifying glass, which can be done when examining the material of an excursion.
When mature, the larva turns into a pupa, in general very similar to the pupa of an ordinary mosquito, but never showing itself on the surface of the water.
Adult insects lay their eggs in water, enclosing them in a gelatinous shell. Such a clutch looks like a small transparent ball, which contains oblong eggs (100 - 150 pieces), arranged in a tight spiral.
Adult insects are gray-brown in color (length about 6 mm). The males have long, fluffy, yellowish coats, from which the mosquito gets its name. Unlike the common and malarial mosquito, they do not have the ability to bite people and animals, without having piercing bristles in their proboscis.
Resembling some features of its structure, the larva of an ordinary mosquito, and others - the larva of the coretra, and is, as it were, a transitional form between them (Fig. 259). Like the larva of the common mosquito, the Mochlonix larva has a windpipe and an expanded thoracic part of the body. Like the larva of the coretra, it has two pairs of swimming air bladders and stays at a certain depth in a horizontal position, remaining motionless suspended in the water for a long time. The larva is equipped with grasping antennae and feeds mainly on small crustaceans. It is found, usually in the same reservoirs in which we find the offspring of the common mosquito.

Mosquito larvae and pupae. Increased (According to Porchinsky.) On the left - common mosquito; on the right is a malarial mosquito.

Heads of female common mosquitoes (Culex) - on the left. Gone strongly. (According to E. N. Pavlovsky.) 1 - antennae; 2 - tentacles; 3 - proboscis and malarial mosquito (Anopheles maculipennis) - on the right. Gone strongly. (According to E. N. Pavlovsky.) 1 - antennae; 2 - tentacles; 3 - proboscis.

1. The malarial mosquito has longer legs than the common mosquito.
2. The female malarial mosquito has jointed tentacles on its head, which are almost equal in length to the proboscis, while the female common mosquito has very short tentacles, not exceeding a quarter of the length of the proboscis (do not mix the tentacles with the screeds (antennae), which are the same in both species length).
3. The malarial mosquito has dark spots on its wings, while many representatives of the genus Culex (C. pipiens) do not have them.
4. At rest, the sitting malarial mosquito holds its body more or less perpendicular to the surface on which it sits, while the common mosquito holds its body more or less parallel to the substrate.
5. The larvae of the malarial mosquito differ from the larvae of the common mosquito in that they do not have a long respiratory tube at the end of the body, and their respiratory openings are sessile. Being on the surface of the water, they do not hold at an angle to the surface, like the larva of an ordinary mosquito, but lie horizontally.
6. Malarial mosquito larvae live in clean water and do not settle in water bodies rich in organic residues, while common mosquito larvae are often found in such water bodies.

Reservoirs heavily overgrown with high marsh vegetation (reeds), as well as waters completely covered with a green cover of duckweed, are not very suitable for the breeding of larvae. In addition, the larvae are very sensitive to water reactions and do not occur in acidic waters, preferring neutral or slightly alkaline ones. For this reason, the water of peat bogs, rich in humic acids, is free from Anopheles larvae. Water bodies poor in flora and fauna are also usually not populated by malarial larvae.
Especially often you can find the larvae of the malarial mosquito where there is an accumulation of various filamentous algae in the water, among the thickets of which they successfully hide. For these reasons, the larvae of the malarial mosquito are much more difficult to detect than the larvae of the common mosquito, and their finding requires a more or less thorough survey of the reservoir /
The disturbed larva dives and sinks to the bottom, where it can stay for quite a long time, but then again rises to the surface, as it breathes atmospheric air.
The larvae feed on small aquatic organisms, which are captured by the movement of the mouth brushes and carried into the mouth opening. Sometimes the larvae also feed on plant foods, gnawing on filamentous algae, etc.

Wings of malarial mosquitoes. Gone strongly. (According to E. N. Pavlovsky.) 1 - common malarial mosquito (Anopheles maculipennis); 2 - forest (Anopheles bifurcatus); 3 - Pallas mosquito (Anopheles hyrcanus).

The body of the larva consists of a head, thorax and abdomen. On the abdomen, 9 segments covered with setae can be distinguished. The last segment bears a bundle of long setae, the so-called oar. In addition, on the last segment, 4 thin leaf-shaped appendages, called anal gills, can be distinguished (Fig. 266). The size of the larvae increases with age from 1 to 8-9 mm. There are four instars of larvae, and the color of the larvae sometimes changes with age. The larvae of the first age are black, the second and third instars are black or grayish, the larvae of the fourth age usually lighten and are greenish or reddish, but sometimes retain a dark color.
The larvae develop faster, the higher the water temperature. At 20-25°C, development ends in 3-4 weeks, at a temperature of 25-30°C, 8-10 days are enough for this. During the summer in the south of the USSR 4-5 or more generations of anopheles are hatched. In the northern parts of the Union at the latitude of Leningrad, 2-3 generations take wings.
The enemies of the larvae of the malarial mosquito are many small aquatic predators: larvae of dragonflies, water beetles, water bugs, as well as some types of fish (carps, perches). A small, very voracious and hardy viviparous fish gambusia (Gambusia affinis) imported from South America, which has been acclimatized in the USSR since 1924 (on the Black Sea coast of the Caucasus), plays a special role in the extermination of Anopheles larvae.
The pupa of the malarial mosquito is very similar to the pupa of the common mosquito, only it is more curved and has shorter respiratory horns.

The eggs of the malarial mosquito are never connected in large shuttle-shaped packages, but float on the surface of the water in small piles, several pieces together. At the same time, the eggs are not glued together in packs, but lie on the water with their long side.
Adult malarial mosquitoes usually stay close to the breeding grounds and do not fly far. It is believed that they rarely fly further than 1-2 km. In the vertical direction, mosquitoes rise no higher than 15-20 m. In their way of life, these are completely nocturnal animals. During the day, they hide in dark places, climb into barns, latrines, where they sit motionless on walls or ceilings. At night, they fly away and at dawn again climb into their shelters, where they are easy to find and catch, since during the day they are in a lethargic, passive state. Therefore, malarial mosquitoes very rarely attack a person during the day, and most often bite sleeping ones.

Mosquito larvae.
Left - malarial mosquito (Anopheles); on the right - an ordinary mosquito (Aedes cinereue); 1 - tentacles; 2 - rosettes of abdominal hairs; 3 - spiracles; 4 - antennae; 5 - 9 abdominal segment; 6 - brush; 7 - head; 8 - chest; 9 - abdomen (I-VIII segments of the abdomen); 10 - scallop of spines; 11 - respiratory siphon; 12 - spiracles; 13 - anal gills.

Adult males and females feed differently. Males take exclusively plant food, feeding on plant juices. Females also feed on plant foods for a long time, but during the breeding season they need the blood of animals as a nutrient material for the formation of eggs. Having sucked blood, the female digests it for about 2 days and again looks for food.
The life span of males and females is not the same. Males live only a few days and therefore are rare, females are up to two months (not counting the wintering time). By autumn, males and unfertilized females die. Fertilized females that have not yet laid eggs remain for the winter. They hibernate in rooms sheltered from the wind and sharp fluctuations in temperature (cellars, basements, etc.), where they climb into dark corners (often onto cobwebs) and fall into a numb state. A gradual decrease in temperature to - 30 ° C is tolerated by mosquitoes without harm to themselves. In the spring, overwintered females fly out when the average daily air temperature reaches 5-7 ° and the sun begins to warm the reservoirs sufficiently. 10-15 days after departure from wintering, females start laying eggs for the first time.

Females lay their eggs in water when it warms up to a temperature of 10-11 ° C. Egg laying in water bodies occurs several times, and one female can lay up to 200 eggs at a time.

Pupa of a common mosquito. Gone strongly. (According to E. N. Pavlovsky.) Pupa and breathing tube.

In the European part of Russia, the following types of malarial mosquitoes are found:
Anopheles vulgaris(Anopheles maculipennis Meig.) - the most common species, which is the only one and is found in the northern parts of Russia and is the main vector of malaria. The color of the mosquito is brown-brown with two blackish stripes on the sides of the middle back. There are four spots on the wings of clusters of black-brown scales arranged in the form of a Roman numeral V. Length 6-10 mm.
Anopheles forest(A. bifurcatus L.). Color black-brown. Wings without dark spots. Length 6-8 mm. Found in forests. Less likely to attack a person than the previous species. It occurs in the forest region of Russia, in the forest-steppe Ukraine, in the Crimea, in the Caucasus.
Anopheles blackfoot(A. plumbeus Steph.). The color is blackish gray with a leaden tint. Wings without spots. Legs are black. The size is less than the previous ones, 4-5 mm long. Forest view. Lays eggs in tree hollows filled with water. It is found in the forest-steppe Ukraine, in the Crimea, in the Caucasus.
Anopheles Pallas(A. hyrcanus Pallas). Dark in color with a predominance of dark coloration on the wings. Tarsi with white rings at the top of the first 3-4 segments. Length 5-6 mm. It is found in vast swamps and floodplain meadows. It is found in the south (southern Ukraine, the Lower Volga region, Crimea, the Caucasus).
In addition to these species, there are several more found only in Transcaucasia, Turkestan.
In the most common species Anopheles maculipennis, several (4-5) forms are currently distinguished, so that they can only be sorted out by the microscopic features of the eggs (color, size of the swimming chambers).