Blood-sucking mosquitoes. How mosquitoes reproduce - life cycle features

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Squeaker mosquito, or common mosquito(lat. Culex pipiens) - a polytypic species (otherwise a complex) of blood-sucking mosquitoes ( Culicidae). Distributed throughout the world and has great epidemic significance. Most mosquitoes found range in size from 3 to 7 mm. Females feed on plant juices (to maintain life) and blood (to develop eggs), mainly from humans, while the male feeds exclusively on plant juices. Female common mosquitoes transmit various human diseases, such as Japanese encephalitis, meningitis, and animal diseases, such as avian malaria. Forms of the nominative subspecies of the squeak mosquito Culex pipiens pipiens format pipiens And Culex pipiens pipiens format molestus are the main objects for research in the form.

Distribution and habitat

It is found everywhere in Europe and America, especially near water bodies.

Introduced to other continents and distant islands during the period of the Great Geographical Discoveries. His larvae arrived in barrels of leftovers fresh water, which was poured into reservoirs when drawing fresh water.

Video on the topic

History of discovery

People have always known about mosquitoes, but this species was first scientifically described by Carl Linnaeus in 1758. Later in 1775 Forskal described the same species in Egypt under the name Culex molestus. They both have close external resemblance among themselves, scientists later agreed to distinguish these mosquitoes by their willingness to bite people. Culex molestus was more abundant in Alexandria, Rashid and Cairo. Ficalbi (eng. Ficalbi) in 1890 proposed to call the squeaking mosquitoes that bite people “haematophagus”, and those that do not bite people, but feed only on nectar, to be called “phytophages”. Thus, in relation to Culex molestus Partial attention was paid to the degree of biting of people; later their behavior was designated by the term “anthropophiles”.

The second pair of reduced wings of the common mosquito

The siphon is located on the eighth segment of the abdomen and serves for breathing air. At the end of the siphon there are valves that close when the larva is immersed deep in the water. The larva moves thanks to caudal fin on the last, ninth segment of the abdomen, consisting of setae.

doll

Imago

Common mosquito adult

Front wing of a mosquito

This is a medium-sized mosquito with a dark, bristly proboscis and dark, short palps.

Reproduction

Larvae and one pupa of a mosquito

The female lays her eggs in warm, still water containing organic materials or aquatic vegetation. The eggs are laid in the form of rafts that float freely in the pond. In one raft there can be 20 to 30 testicles stuck together. The duration of development is from 40 hours to 8 days, it depends on the temperature of the water in which development occurs.

Deep terrain or waves are detrimental to mosquito larvae.

Mosquitoes and humans

Very common appearance harmful insects common in urban and suburban areas.

Humans use mosquito larvae as fish food. The name of the larvae, like aquarium food, is different - black bloodworm. Basically, in the wild, black bloodworms provide food for many tropical species.

Ecology

Nutrition

Nutrition of plant sugars

They feed on nectar on plants such as burdock ( Arctium), yarrow ( Achillea) and tansy ( Tanacetum); The observation was carried out in the vicinity of Moscow. The mosquito feeds most readily on tansy (7-10 females per flower). Among the mosquitoes that fed, the majority were virgin females, but pregnant females are rarely seen. A similar study was carried out in central and southwestern Sweden. Of the 18 species of mosquitoes collected on tansy flowers, species Colex pipiens(ssp. pipiens) And Culex torrentium were 86%, where 52% were pregnant females. Fructose had a good effect on the body of the collected mosquitoes in 81%.

Blood feeding

According to some old works (Mattingly et all, 195; Shute, 1951, etc.) the non-autogenous form is pipiens, was considered as omitophilic and, conversely, an autogenous form - molestus, belonged to the anthropophiles. Indeed, the anthropophilia of animal hosts is confirmed by a huge number of bites in urban and rural areas. However, the anthropophilia of this mosquito form should not be overestimated; caught molestus In a laboratory study, not only humans, but also birds, mice and guinea pigs were immediately bitten.

Pathogenicity

The squeak mosquito is a common mosquito in North Africa and is the main vector of filariasis in Egypt. Experimental infections by the squeak mosquito have shown that it is a carrier Brugia pahangi(in 6.3% of mosquitoes).

The body of a mosquito can harbor various worms that are pathogenic for other animals, such as a type of trematode Pneumonoeces variegatus, which is a helminth of the common spadefoot ( Pelobates fuscus ) and which enters the spadefoot's body by ingesting a squeaky mosquito and two other species of mosquitoes Anopheles maculipennis And Culex territans .

Vectors of West Nile virus

Classification

Subspecies

C. p. pallens

One of the subspecies of the common mosquito. The mosquito is on average 5.5 mm long. It has a brown body color with white patterns on the legs and mouthparts. Distributed in North America, Japan.

C. p. pipiens

The subspecies includes the following forms:

Culex pipiens pipiens format pipiens

The place of development of larvae is ground water bodies. Mosquitoes of this form are easily adaptable, and inhabit almost all types of reservoirs: puddles, flowing reservoirs, small temporary reservoirs, forest swamps, swamps, edges of lakes, and can also serve as a place of development. artificial reservoirs such as cans, car tires, barrels, etc. The larva can also develop in very polluted water.

The number of larvae varies depending on the place of development, for example, in wetlands 327-1408 ind./m², and in post-rain puddles their number decreases 110-895 ind./m², but in dung puddles this number increases sharply 152-26600 ind./m² m² and in the gutters a little more - 5400-27563 specimens/m².

Culex pipiens pipiens format molestus

City or basement mosquito. Latin name " molestus"- annoying, which is his characteristic feature.

For a long time, scientists have been arguing among themselves whether to isolate this form as a separate subspecies or leave it as an ecotype (form). This controversy stems from the difficulty of identifying individual individuals.

S. r. quinquefasciatus

Subspecies synonym: C. p. fatiganas- this subspecies lives in tropical and subtropical zones. It is a carrier of wuchereriosis and some arboviral diseases. Morphologically, it is quite reliably distinguishable from other subspecies.

Notes

1. Lopatin O. E. Mosquitoes Culex pipiens: electrophonetic variability of enzymes (Russian) // Alma-Ata: Institute of Zoology and Animal Gene Fund of the National Academy of Sciences of Kazakhstan. Siberian ecological journal. - 2000. - No. 4. - pp. 461-475. (unavailable link)
2. Econet Archived copy from April 13, 2009 on the Wayback Machine (Russian)
3. Stackelberg A. A. 4 // Fauna of the USSR. Diptera. Sem. Culicidae. Blood-sucking mosquitoes (Subfamily Culicinae) / Zernov S. A. - Moscow-Leningrad, 1937. - T. III. - pp. 212-246. - 255 s. - 1000 copies.(Russian)
4. Elena B. Vinogradova. 2 // Culex pipiens pipiens mosquitoes: taxonomy, distribution, ecology, physiology, genetics, applied importance and control / Dr. Golovatch S.I.. - Bulgaria: “Pensoft”, 2000. - T. II. - 239 p. - ISBN 954-642-103-0.(English)
5. (Legendre, 1932)
6. Pavlovsky E.N., Lepneva S.G. Mosquitoes (Family Culicidae)// Essays on the life of freshwater animals. - Soviet science, 1948.
7. Mamaev B. M. Identifier of insects by larvae. - Moscow: “Enlightenment”, 1972. - T. VI. - P. 63. - 400 p. - 40,000 copies.(Russian)

Mosquitoes, or real mosquitoes, or blood-sucking mosquitoes(lat. Culicidae) - a family of dipterous insects belonging to the long-whiskered group ( Nematocera), the female adults of which in most cases are a component of the gnus complex. The oral organs are characteristic of this family: the upper and lower lips are elongated and form a case in which long thin needles are placed (2 pairs of jaws); Males have underdeveloped jaws - they do not bite. Mobile larvae and pupae of mosquitoes live in stagnant bodies of water. Fossil mosquitoes have been known since the Cretaceous period. IN modern world there are more than 3,000 species of mosquitoes belonging to 38 genera. Representatives of 100 species belonging to the genera of true mosquitoes live in Russia ( Culex), biter ( Aedes), Culiseta, malaria mosquitoes ( Anopheles), Toxorhinchites, Uranotaenia, Orthopodomyia, Coquillettidia.

The life cycle of mosquitoes includes four stages of development: egg → larva → pupa → adult, or adult.

Etymology

Russian word mosquito goes back to praslav. *komarъ/komarь probably of onomatopoeic origin, or with the motivation “swarming, huddled in com insect."

Area

Mosquitoes are widespread throughout to the globe and inhabit all continents except Antarctica. The widest range of the common mosquito ( Culex pipiens), which is distributed everywhere where a person is found - its main victim. In warm and humid tropical regions they are active throughout the year, but in temperate regions they overwinter as adults during the cold season. Arctic mosquitoes remain active for only a few weeks of the year, when heat causes thermokarst pools of water to form on top of the permafrost. However, during this time they manage to breed in huge quantities- swarms of mosquitoes can take up to 300 ml of blood per day from each animal in a caribou herd. Eggs of mosquitoes living in temperate latitudes, are more resistant to the negative effects of cold than mosquito eggs common in warmer climates climatic zones. They can even withstand exposure to snow and freezing temperatures. In addition, adult individuals can survive throughout the winter in habitats suitable for their wintering (for example, warm and humid basements of residential buildings).

Distribution media

Spreading various types mosquitoes around the world and their movement over long distances into regions where they are not native has been driven by humans. First of all, these are journeys along sea routes, in which eggs, larvae and pupae of mosquitoes are transported in worn-out tires filled with water or containers with cut flowers. However, in addition to sea transport, mosquitoes have actively mastered moving on personal vehicles, trucks, trains and even planes. Thus, the spread of mosquitoes is difficult to control, and even quarantine measures have proven to be ineffective and difficult to implement in practice.

Morphological description

Mosquitoes are insects with thin body(4-14 mm long), long legs and narrow transparent wings (wingspan from 5 to 30 mm). The body color of most species is yellow, brown or gray, but there are black or green colored species. The abdomen is elongated, consisting of 10 segments. The chest is wider than the abdomen. The paws end in a pair of claws. The wings are covered with scales, the accumulations of which sometimes form spots. The antennae are long and consist of 15 segments. Oral apparatus piercing-sucking type. In females, the proboscis is long and consists of piercing setae; in males, it is without them.

The oral apparatus is hidden in the tube-shaped lower lip. Inside it there are several saw-like stiletto-like jaws (lower - lower jaws and high - upper jaws). With its jaws, the mosquito cuts a hole in the skin, immerses the proboscis deeper to the level of the blood capillaries, and through the same oral appendages, like through a collecting tube, it sucks blood without having a sucking mechanism.

Not to be confused: behind huge mosquitoes sometimes they take insects from the family Centipedes, which have similar legs and the shape of their wings.

Classification

Within the family there are three subfamilies:

Mosquito feeding

Mosquitoes feed on nectar

For most species of mosquitoes, the source of blood (“feeders”) are warm-blooded vertebrates: mammals and birds. But some species are able to feed on the blood of reptiles, amphibians and even fish.

Most of the olfactory organs or olfactory system The mosquito specializes in searching for (“sniffing out”) sources of blood: of the 72 types of olfactory receptors located on the mosquito’s antennae, at least 27 are configured to detect chemicals released in the sweat of animals and humans. In mosquitoes Aedes the search for a victim (owner) occurs in two stages: perception of the specific behavior of the object (movement), perception of its chemical and physical characteristics.

Lifestyle

Usually in temperate zone mosquitoes are active from May to October. If there was a lot of snow in the winter, and the spring is early, consistently warm and moderately humid, mosquitoes may appear as early as April.

Like all other dipteran insects, mosquitoes have 4 developmental phases: egg, larva, pupa, imago. Moreover, all phases, except adults, live in reservoirs. Mosquito larvae and pupae living in water breathe atmospheric air through the breathing tubes, exposing them to the surface. Mosquito larvae - filter feeders or scrapers - feed on aquatic microorganisms. Adult feeding is often dualistic: females of most mosquito species drink the blood of vertebrates: mammals, birds, reptiles and amphibians; at the same time, the males of all species of mosquitoes, without exception, feed on the nectar of flowering plants. However, representatives of the subfamily Toxorhynchitinae have predatory larvae, while their adults (both males and females) feed exclusively on nectar.

In summer, adult females of blood-sucking mosquitoes are found both in nature in swampy and damp places, and in animal premises, in human homes on walls, windows, and shaded places. In winter, they can be found in livestock buildings, warm basements, and other buildings, where they are in an inactive state, or in torpor (if the temperature is below 0 ° C).

When choosing a victim, the female blood-sucking mosquito is guided by the smell of lactic acid contained in sweat (several kilometers), carbon dioxide exhaled by a person (hundreds of meters) and thermal radiation(several meters), to movement, and also the female mosquito reacts to light, preferring dimly lit rooms, which is why in city apartments females are mainly nocturnal.

Average lifespan of a female S. p. pipiens f. molestus depends largely on temperature. IN laboratory conditions(such observations were not carried out in basements), on carbohydrate nutrition at 25 °C females live on average 43 days, at +20 °C - 57 days, and at +10...+15 °C - 114-119 days; In the absence of food, life expectancy is greatly reduced. The lifespan of males in all cases is much shorter, so at +25 °C it is only 19 days.

A completely different picture is observed in ecotype mosquitoes pipiens, which under certain circumstances can become long-lived. If the females hatched from pupae in July - early August, then they all diapause and go to wintering, which lasts until March-May; After wintering ends, they reproduce and live for another 1-2 months. In total, the life expectancy of such females is about a year. For comparison, the lifespan of mosquitoes Aedes diapausing at the egg stage is much shorter: they are born in the spring, reproduce and die by the fall.

The pupae are mobile. The respiratory openings of the pupa are not located on the abdomen, as in larvae and adults, but on the upper side of the chest, which the insect holds near the surface during breathing, and through which the mature adult emerges. On the empty shell of the pupa, the insect waits until its wings dry out before flying.

Reproduction

During the mating period, female mosquitoes attract the attention of males with a characteristic subtle sound, reminiscent of a squeak, which is created with the help of their wings. Mosquitoes detect sound vibrations with their sensitive antennae. Females squeak a little thinner than males, young ones - not as much as 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.

A female mosquito lays 30-150 and sometimes even 280 eggs (in malaria mosquitoes) every two to three days. The egg develops into an adult mosquito within a week. Mosquitoes require blood to reproduce eggs, so the egg laying cycle is directly related to blood consumption. Only some urban subspecies can lay eggs without drinking blood, but they lay very few eggs.

Eggs are laid in stagnant or low-flowing reservoirs on the surface of the water (birth Anopheles And Culex), on moist soil at the edge of the water of reservoirs that dry up in summer and are flooded in spring, or stick to floating objects washed by water (at Culex) . The eggs on the water surface are connected in the form of a raft. The larva leaves the egg from the lower end.

Mosquito bite

Mosquito bite sites

Before the female mosquito begins to drink blood, she injects saliva into the skin of her victim, which contains anticoagulants that prevent blood from clotting. It is the mosquito's saliva that causes itching, swelling, redness at the site of the bite, and in some cases, a severe allergic reaction. And it is through saliva that mosquito-borne infections are transmitted.

Meaning in human life

Mosquitoes are involved in transmission various types diseases in more than 700 million people per year, in Africa, South America, Central America, Mexico, Russia and much of Asia, with millions of deaths - at least two million people die annually from these diseases, and the incidence rate is many times higher than officially registered.

Methods used to prevent the spread of disease or to protect individuals from mosquitoes in areas where the disease is endemic include:

• vector population control aimed at mosquito control or eradication;
• prevention of mosquito-borne diseases using prophylactic drugs and vaccine development;
• preventing mosquito bites: using insecticides, mosquito nets and repellents.

Since most of these diseases are transmitted by older female mosquitoes, some scientists have suggested focusing on them to avoid resistance to evolution.

Mosquito control

All mosquito repellents can be divided into:

For mass struggle The use of environmentally friendly biological preparations based on bacteria turned out to be highly effective against mosquitoes Bacillus thuringiensis. Larval-eating fish are very effective, but systematic work is rarely carried out with them, with the exception of the Sochi nursery "Gambusia" - which distributes Gambusia and eucalyptus fish for free. The larval stage of mosquitoes is the most vulnerable, this is what the effect of the drug is based on Bacillus thuringiensis- kill mosquitoes in larval stage, without waiting for them to turn into an adult and scatter throughout the area. The composition of the drug includes spores and protein crystals of a special microbial culture Bacillus thuringiensis. Swimming in the water, mosquito larvae eat spores and protein crystals and die.

Mosquitoes are very sensitive to odors, which helps in the fight against them. For example, mosquitoes do not like the smell of tomato tops, fresh leaves walnut, basil flowers, bird cherry, elderberry branches, wheatgrass, anise, cloves, valerian, eucalyptus, lavender, thyme, geranium, mint, cedar oil, birch bark tar. [ ]

To combat the spread of a number of viral infections (dengue, Zika and chikungunya fevers), infection of the mosquitoes that carry them is used (in particular, Aedes aegypti And Aedes albopictus) Wolbachia, which suppresses the reproduction of viruses. The bacterium spreads among mosquitoes, infects up to 90% of the population in 10-20 weeks and persists in it for at least 5 years. The method is used in Australia, Vietnam, Indonesia, Colombia, Brazil and China.

Genetic modification

Another way to combat these infections is to genetically modify mosquitoes, as a result of which they produce non-viable offspring. The proliferation of enough of these males causes a radical decrease in population size. The method was tested in 2009 in the Cayman Islands: a batch of modified males was released on an area of ​​0.16 km2 Aedes aegypti, and the number of mosquitoes there has decreased by 96%. Later there were successful tests in Panama, Malaysia and Brazil. Unlike infection control by infecting mosquitoes with Wolbachia, this method requires the annual release of prepared mosquitoes. Methods of genetic modification of mosquitoes are also being developed, leading to the suppression of dengue virus replication and to cell apoptosis in response to the presence of the virus.

Notes

1. Life of animals. Volume 3. Arthropods: trilobites, chelicerates, trachea-breathers. Onychophora / ed. M. S. Gilyarova, F. N. Pravdina, ch. ed. V. E. Sokolov. - 2nd ed. - M.: Education, 1984. - P. 394. - 463 p.
2. Gornostaeva R. M., Danilov A. V. Mosquitoes of Moscow and the Moscow region. - M.: KMK Scientific Press, 1999
3. Etymological dictionary Slavic languages. - M.: Nauka, 1983. - T. 10. - P. 169-171.
4. Toporov V.N. From Hittite-Luwian etymology: theophoric name Kamrušepa// Etymology 1983. - M.: Nauka, 1985. - P. 150-151.
5. Mullen, Gary. Medical and Veterinary Entomology / Gary Mullen, Durden. - London: Academic Press, 2009.
6. Fang, Janet (July 21, 2010). "Ecology: A world without mosquitoes." Nature(Nature) 466 (7305): 432–4. DOI:10.1038/466432a. PMID 20651669.
7. Hawley, W. A., Pumpuni, C. B., Brady, R. H., & Craig, G. B. (1989). "Overwintering survival of Aedes albopictus(Diptera: Culicidae) eggs in Indiana." Journal of Medical Entomology 26 (2): 122–129. PMID 2709388.

The mosquito (Culicidae) belongs to the class of insects, order Diptera and family of blood-sucking mosquitoes. This insect has lived on the planet for more than 145 million years.

Types of mosquitoes.

- a type of mosquito that is found everywhere, overwhelming humans and animals with its intrusiveness. Adult squeak mosquitoes measure 3-8 mm. Only females are “bloodsuckers”, since they need blood to produce offspring. The male mosquito is an exceptional vegetarian and feeds on plant juices. The squeak can become a carrier of quite serious diseases, spreading viruses of meningitis, infectious eczema, etc.

lives where there is high humidity: shady thickets near shallow bodies of water, swamps, forest thicket with a nearby lake. Often the large centipede (some individuals reach 4-8 cm in length) is mistaken for an analgesic mosquito, which is a mistake. Long-legged mosquitoes do not bite, feed on nectar and plant juices, and are absolutely safe for humans, but they can cause significant damage to farmland and forest plantings. The larvae of the Karamora mosquito are especially voracious - they feed both in water and on land, eagerly eating algae, young seedlings and tender roots of cultivated plants.

A small mosquito found on every continent except icy Antarctica. The main habitats of the biters are shady forests and the tundra zone. Distinctive feature biters - spectacular white stripes on the body and limbs. Females of this mosquito species lay eggs in late autumn along the banks of swamps and other bodies of water, and as soon as the snow melts, numerous biting mosquito larvae begin to develop in the melt water. Adults can be carriers of dangerous diseases.

Chionei (winter mosquitoes). Similar at the same time to centipedes or large spiders, winter mosquitoes are strikingly different from them in their lifestyle. Adults of this species of mosquitoes are 10-20 mm long and are found almost all year round– in spring, autumn and even in cold weather winter months, for which they got their name. They live in damp caves, settle inside rotten stumps and half-rotten trees, feeding on decomposed plant waste.

This type of mosquito is not a “bloodsucker”, preferring to feed on plant nectar. The female swamp mosquito lays eggs in water, damp moss or damp soil. During the growth period, the meadow grass larva happily eats the remains of algae and plants that have decomposed in the reservoir, although some are also predators in terms of food preferences. Swamp mosquitoes live in flooded meadows and forests with an abundance of moss.

A harmless mosquito that lives only 2-5 days lives in reed thickets of ponds, along the banks of shallow rivers or swamps. Adults most often have a yellowish-green color, less often dark brown, and have long limbs. Huge clouds of bell-bellied mosquitoes hover over the water surface of reservoirs on warm evenings, without causing inconvenience to humans or animals, since they prefer to feed on plant ingredients.

Or an adult.

Etymology

Russian word mosquito goes back to praslav. *komarъ/komarь probably of onomatopoeic origin, or with the motivation “swarming, huddled in com insect."

Area

Mosquitoes are widespread throughout the globe and inhabit all continents except Antarctica. The widest range of the common mosquito ( Culex pipiens), which is distributed everywhere where a person is found - its main victim. In warm and humid tropical regions they are active throughout the year, but in temperate regions they overwinter as adults during the cold season. Arctic mosquitoes remain active for only a few weeks a year, when heat causes thermokarst pools of water to form on top of the permafrost. However, during this time they manage to breed in huge quantities - swarms of mosquitoes can take up to 300 ml of blood per day from each animal in a caribou herd. The eggs of mosquitoes living in temperate latitudes are more resistant to the negative effects of cold than the eggs of mosquitoes common in warmer climate zones. They can even withstand exposure to snow and freezing temperatures. In addition, adults can survive throughout the winter in habitats suitable for their wintering (for example, warm and wet basements residential buildings).

Distribution media

The spread of various species of mosquitoes throughout the world and their movement over long distances into regions where they are not native has been driven by humans. First of all, these are journeys along sea routes, in which eggs, larvae and pupae of mosquitoes are transported in worn-out tires filled with water or containers with cut flowers. However, in addition to sea transport, mosquitoes have actively mastered traveling on personal vehicles, trucks, trains and even airplanes. Thus, the spread of mosquitoes is difficult to control, and even quarantine measures have proven to be ineffective and difficult to implement in practice.

Morphological description

Mosquitoes are insects with a thin body (4-14 mm long), long legs and narrow transparent wings (wingspan from 5 to 30 mm). The body color of most species is yellow, brown or gray, but there are black or green colored species. The abdomen is elongated, consisting of 10 segments. The chest is wider than the abdomen. The paws end in a pair of claws. The wings are covered with scales, the accumulations of which sometimes form spots. The antennae are long and consist of 15 segments. The mouthparts are piercing-sucking type. In females, the proboscis is long and consists of piercing setae; in males, it is without them.

The oral apparatus is hidden in the tube-shaped lower lip. Inside it there are several saw-like stiletto-like jaws (lower - lower jaws and high - upper jaws). With its jaws, the mosquito cuts a hole in the skin, plunges the proboscis deeper to the level of the blood capillaries, and through the same oral appendages, as if through a collection tube, it sucks blood.

Not to be confused: Insects from the family of centipedes, which have similar legs and the shape of their wings, are sometimes mistaken for huge mosquitoes.

Classification

Within the family there are three subfamilies:

Mosquito feeding

For most species of mosquitoes, the source of blood (“feeders”) are warm-blooded vertebrates: mammals and birds. But some species are able to feed on the blood of reptiles, amphibians and even fish.

Most of the olfactory organs or olfactory system The mosquito specializes in searching for (“sniffing out”) sources of blood: of the 72 types of olfactory receptors located on the mosquito’s antennae, at least 27 are configured to detect chemicals released in the sweat of animals and humans. In mosquitoes Aedes the search for a victim (owner) occurs in two stages: perception of the specific behavior of the object (movement), perception of its chemical and physical characteristics.

Lifestyle

Typically, in the temperate zone, mosquitoes are active from May to October. If there was a lot of snow in the winter, and the spring is early, consistently warm and moderately humid, mosquitoes may appear as early as April.

Like all other dipteran insects, mosquitoes have 4 developmental phases: egg, larva, pupa, imago. Moreover, all phases, except adults, live in reservoirs. 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. Adult feeding is often dualistic: females of most mosquito species drink the blood of vertebrates: mammals, birds, reptiles and amphibians; at the same time, the males of all species of mosquitoes, without exception, feed on the nectar of flowering plants. However, representatives of the subfamily Toxorhynchitinae have predatory larvae, while their adults (both males and females) feed exclusively on nectar.

In summer, adult females of blood-sucking mosquitoes are found both in nature in swampy and damp places, and in animal premises, in human homes on walls, windows, and shaded places. In winter, they can be found in livestock buildings, warm basements, and other buildings, where they are in an inactive state, or in torpor (if the temperature is below 0 ° C).

When choosing a victim, the female blood-sucking mosquito is guided by the smell of lactic acid contained in sweat (several kilometers), by carbon dioxide exhaled by a person (hundreds of meters) and by thermal radiation (several meters), by movement, and the female mosquito also reacts to light. preferring dimly lit rooms, which is why in city apartments females are mainly nocturnal.

Average lifespan of a female S. p. pipiens f. molestus depends largely on temperature. In laboratory conditions (such observations were not carried out in basements), on carbohydrate nutrition at 25 °C females live on average 43 days, at +20 °C - 57 days, and at +10...+15 °C - 114-119 days; In the absence of food, life expectancy is greatly reduced. The lifespan of males in all cases is much shorter, so at +25 °C it is only 19 days.

A completely different picture is observed in ecotype mosquitoes pipiens, which under certain circumstances can become long-lived. If the females hatched from pupae in July - early August, then they all diapause and go to wintering, which lasts until March-May; After wintering ends, they reproduce and live for another 1-2 months. In total, the life expectancy of such females is about a year. For comparison, the lifespan of mosquitoes Aedes diapausing at the egg stage is much shorter: they are born in the spring, reproduce and die by the fall.

The pupae are mobile. The respiratory openings of the pupa are not located on the abdomen, as in larvae and adults, but on the upper side of the chest, which the insect holds near the surface during breathing, and through which the mature adult emerges. On the empty shell of the pupa, the insect waits until its wings dry out before flying.

Reproduction

During the mating period, female mosquitoes attract the attention of males with a characteristic subtle sound, reminiscent of a squeak, which is created with the help of their wings. Mosquitoes detect sound vibrations with their sensitive antennae. Females squeak a little thinner than males, young ones - not as much as 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.

A female mosquito lays 30-150 and sometimes even 280 eggs (in malaria mosquitoes) every two to three days. The egg develops into an adult mosquito within a week. Mosquitoes require blood to reproduce eggs, so the egg laying cycle is directly related to blood consumption. Only some urban subspecies can lay eggs without drinking blood, but they lay very few eggs.

Eggs are laid in stagnant or low-flowing reservoirs on the surface of the water (birth Anopheles And Culex), on moist soil at the edge of the water of reservoirs that dry up in summer and are flooded in spring, or stick to floating objects washed by water (at Culex) . The eggs on the water surface are connected in the form of a raft. The larva leaves the egg from the lower end.

Mosquito bite

Before the female mosquito begins to drink blood, she injects saliva into the skin of her victim, which contains anticoagulants that prevent blood from clotting. It is the mosquito's saliva that causes itching, swelling, redness at the site of the bite, and in some cases, a severe allergic reaction. And it is through saliva that mosquito-borne infections are transmitted.

Meaning in human life

mosquitoes are involved in transmitting various types of disease to more than 700 million people per year, in Africa, South America, Central America, Mexico, Russia and much of Asia, with millions of deaths - at least two million people die from these diseases every year, and the incidence rate is many times higher than officially registered.

Methods used to prevent the spread of disease or to protect individuals from mosquitoes in areas where the disease is endemic include:

• vector population control aimed at mosquito control or eradication;
• prevention of mosquito-borne diseases using prophylactic drugs and vaccine development;
• preventing mosquito bites: using insecticides, mosquito nets and repellents.

Since most of these diseases are transmitted by older female mosquitoes, some scientists have suggested focusing on them to avoid resistance to evolution.

Mosquito control

All mosquito repellents can be divided into:

For mass mosquito control, the use of environmentally friendly biological preparations based on bacteria has proven to be highly effective. Bacillus thuringiensis. Larval-eating fish are very effective, but systematic work is rarely carried out with them, with the exception of the Sochi nursery "Gambusia" - which distributes Gambusia and eucalyptus fish for free. The larval stage of mosquitoes is the most vulnerable, this is what the effect of the drug is based on Bacillus thuringiensis- destroy mosquitoes in the larval stage, without waiting for them to turn into adults and scatter throughout the area. The composition of the drug includes spores and protein crystals of a special microbial culture Bacillus thuringiensis. Swimming in the water, mosquito larvae eat spores and protein crystals and die.

Mosquitoes are very sensitive to odors, which helps in the fight against them. For example, mosquitoes do not like the smell of tomato tops, fresh walnut leaves, basil flowers, bird cherry, elderberry branches, wheatgrass, anise, cloves, valerian, eucalyptus, lavender, thyme, geranium, mint, cedar oil, birch bark tar. [ ]

To combat the spread of a number of viral infections (dengue, Zika and chikungunya fevers), infection of the mosquitoes that carry them is used (in particular, Aedes aegypti And Aedes albopictus) Wolbachia, which suppresses the reproduction of viruses. The bacterium spreads among mosquitoes, infects up to 90% of the population in 10-20 weeks and persists in it for at least 5 years. The method is used in Australia, Vietnam, Indonesia, Colombia, Brazil and China.

Genetic modification

Another way to combat these infections is to genetically modify mosquitoes, as a result of which they produce nonviable offspring. The proliferation of enough of these males causes a radical decrease in population size. The method was tested in 2009 in the Cayman Islands: a batch of modified males was released on an area of ​​0.16 km2 Aedes aegypti, and the number of mosquitoes there has decreased by 96%. Later there were successful tests in Panama, Malaysia and Brazil. Unlike infection control by infecting mosquitoes with Wolbachia, this method requires the annual release of prepared mosquitoes. Methods of genetic modification of mosquitoes are also being developed, leading to the suppression of dengue virus replication and cell apoptosis in response to the presence of the virus.

Notes

1. Life of animals. Volume 3. Arthropods: trilobites, chelicerates, trachea-breathers. Onychophora / ed. M. S. Gilyarova, F. N. Pravdina, ch. ed. V. E. Sokolov. - 2nd ed. - M.: Education, 1984. - P. 394. - 463 p.
2. Gornostaeva R. M., Danilov A. V. Mosquitoes of Moscow and the Moscow region. - M.: KMK Scientific Press, 1999
3. Etymological dictionary of Slavic languages. - M.: Nauka, 1983. - T. 10. - P. 169-171.
4. Toporov V. N. From Hittite-Luwian etymology: theophoric name Kamrušepa// Etymology 1983. - M.: Nauka, 1985. - P. 150-151.
5. Mullen, Gary. Medical and Veterinary Entomology / Gary Mullen, Lance Durden. - London: Academic Press, 2009.
6. Fang, Janet (July 21, 2010). “Ecology: A world without mosquitoes.” Nature. Nature. 466 (7305): 432-4. DOI:10.1038/466432a. PMID.
7. Hawley, W. A., Pumpuni, C. B., Brady, R. H., & Craig, G. B. (1989). “Overwintering survival of Aedes albopictus(Diptera: Culicidae) eggs in Indiana.” Journal of Medical Entomology. 26 (2): 122-129. PMID.
8. Hanson, S. M., & Craig, G. B. (1995). “ Aedes albopictus(Diptera: Culicidae) eggs: field survivorship during northern Indiana winters.” Journal of Medical Entomology. 32 (5): 599-604. PMID.
9. Romi, R., Severini, F. & Toma, L. (2006). “Cold acclimation and overwintering of female Aedes albopictus in Roma". Journal of the American Mosquito Control Association. 22 (1): 149-151.

The process of procreation is an important part of the life of any living creature, and insects are no exception. How do mosquitoes reproduce? Probably, few people have thought about this issue, and its subtleties are known only to biology buffs. Although this is quite an interesting process from the point of view of knowledge about the living world, which has its own characteristics and interesting facts.

A brief introduction to insects

Mosquitoes (other “official” names are true or blood-sucking mosquitoes) - from the point of view of biological classification, represent the family Culicidae, assigned to the group of Long-whiskers and the order of Diptera insects, which are characterized by sexual reproduction and complete transformation (metamorphosis from egg to adult: they will be discussed in detail below).

Adult female mosquitoes drink human blood and are part of the midges - a group of blood-sucking insects, for which they have earned strong dislike from people

Mosquitoes are small flying insects. The length of their thin and soft body ranges from 4 mm to 15 mm. All representatives of the Culicidae family are characterized by the presence of long legs, which end in 2 claws for better grip on surfaces and stability, and narrow transparent wings, consisting of many scales. Their span ranges from 5 mm at the most miniature species up to 30 mm.

In tropical regions there are real giants: for example, long-legged mosquitoes, or caramors, in favorable conditions grow up to 10 cm in length, which is a record figure.

Most species of the Mosquito family have a nondescript color: gray, brown, yellow. Much less often (and mainly in southern countries) there are black or green specimens. The thoracic region of insects is wider than the abdomen. The long antennae, necessary for orienting the insect in space, are formed by 15 segments.

The mosquito's mouthparts are a piercing-sucking type. It is hidden in the lower lip of the insect, which is shaped like a tube. Inside it are sharp jaw stilettos, similar to blades. They are needed to cut a microscopic hole in the skin, through which the sucking proboscis then penetrates to the layer of capillaries. Moreover, in females it consists of piercing bristles, which are absent in males.

By the word “mosquito,” people most often mean the squeaky mosquito. It is he who annoys people with his obsessive buzzing and painful bites.

In total, the Mosquito family has 3,000 species, divided into 38 genera. Most of them live in southern countries with tropical climate. Only 100 species are found on the territory of Russia, representing 3 genera: true mosquitoes, biting mosquitoes and malaria mosquitoes.

Mosquito breeding process

These are bisexual creatures, so a male and a female participate in the reproduction of mosquitoes. Future offspring go through 4 stages of development, which are typical for insects with complete transformation:

• egg;
• chrysalis;
• imago (sexually mature individual).

Moreover, insects are “land” creatures only in the very last stage of mosquito development: all the rest live in bodies of water or in the immediate vicinity of them. After all, they need water to develop.

Reproductive system of mosquitoes

Among family members internal fertilization: the male’s seed, after mating, enters the female’s reproductive tract, after which the formation of eggs begins. The reproductive organs of mosquitoes are located inside their abdomen: ovaries in females and testes in males. The microscopic external genitalia of the male are very complex structure, the features of which are key point to distinguish species that are externally similar to each other. Females have a small ovipositor in the form of a short tube: eggs are born through it.

"Marriage Games"

The type of mosquito mating is called “eurygamy” in biological terms. Its peculiarity is the formation of a swarm - a dense cloud of male insects staying close to each other. Surely everyone has seen such flocks on summer evenings.

Female mosquitoes attract the attention of the opposite sex with a thin buzzing sound similar to a squeak. This sound is created by the movement of the wings. Its frequency depends on the age of the individual, and males, with the help of their sensitive antennae, detect the slightest differences in sound, giving preference to more mature “girlfriends”.

When approaching a cloud of males, the female flies into it and finds herself fertilized by the one who managed to do it first. To complete the job, males have special appendages next to their genitals, with the help of which he holds the female in flight together.

It is noteworthy that mosquito populations living in cities are characterized by stenogamy - reproduction without swarming, the implementation of which is difficult due to the lack of large and free space.

After a short mating, the male flies away from the female and returns to the others. The female goes in search of blood necessary for the continuation of offspring.

Reproductive activity directly depends on the degree of saturation of the female with blood: with sufficient nutrition, she lays eggs every 2-3 days, after which she returns to the swarm of males.

Eggs

Each time, females make large clutches containing 30–150 mosquito eggs. The malarial species are the most prolific, producing about 280 pieces. The exact number depends directly on the amount of blood drunk by the female, which explains the aggression of insects towards humans.

Usually the female lays eggs directly on the surface of the water. To do this, she chooses freshwater, calm and stagnant bodies of water with a minimum flow speed. Ponds and quiet backwaters of lakes overgrown with reeds are ideal. Less commonly, the mosquito lays eggs on well-moistened soil along the banks or near temporary reservoirs that dry up in the summer and refill in the spring after the snow melts. Sometimes the female chooses floating objects and plants (this is more typical for the genus of True mosquitoes, to which the famous squeaking mosquito is included).

Larva

Under favorable conditions, after just a few days, larvae enter the water from the lower end of the eggs. They look like small worms covered with hairs. The body color of a mosquito larva depends on the species. For example, in the squeaker they are dirty gray, and in the jerk they are green or red. The latter are used in fishing and aquarium farming, where they are known as bloodworms.

The larva and the pupa that subsequently emerges from it necessarily need sufficient quantity air. The larvae of some species live at the very bottom of reservoirs, buried in silt or mud, but must rise to the surface every 15 minutes to obtain oxygen. Others can swim for a long time, bending their whole body, on the very surface with the “tail of the body” upward, because this is where the worm’s respiratory organs are located - special tubes through which it breathes.

During its entire development, which lasts an average of 20 days, the larva undergoes 4 molts, after which it turns into a pupa. During them, she sheds her old exoskeleton, which allows her to increase in size each time. For example, immediately after emerging from the egg, the length of the larva does not exceed 1 mm, and after the last molt it can reach 1 cm. At the same time, the volume of the larva’s body increases even more: almost 500 times.

doll

The mosquito pupa is the penultimate stage of insect development and has a more complex system structure internal organs. It also lives in water and periodically floats to the surface, preparing to transform into a flying individual. The waiting time takes approximately 5 days. Gradually it becomes darker in color.

The answer to the question whether a mosquito has a pupa is positive, since it is an insect with full cycle transformations.

The behavior and nutrition of the larva and pupa are almost identical, but the latter has one interesting feature: thanks to their shape and well-developed tail, they can move rapidly in the water column with spasmodic movements.

Imago

An adult is an adult insect that lives on land and participates in reproduction. Males live only 3 weeks, while females live 3 months, if the air temperature stays around 10–15 °C. At unfavorable conditions life expectancy is reduced.

Reproduction is impossible without saturating the females with human blood. Therefore, mosquitoes are spread over almost all areas of land where humans live. They stay close to settlements so that they can drink the blood of people at any time.

Each species has its own preferences in temperature and lighting conditions. Some people like shady ponds, others like well-lit ones. Biologists have calculated that the larvae are able to develop when the water temperature is 10–35 °C, but between 25 °C and 30 °C is considered most comfortable.

Mosquitoes rarely lay eggs in large bodies of water where many fish live, because they readily feed on eggs.

The larva will die if the water is contaminated with oil products: they form a film on the surface through which the worms cannot breathe. But some species show enviable adaptation, having adapted to use oxygen dissolved in water for breathing.

The process of how mosquitoes appear has been sufficiently studied by science. These insects are characterized by high fertility and nutrition human blood. Both of these traits are directly dependent on each other.