Flies and mosquitoes. Housefly (Musca domestica)

The disease occurs as a result of the ingestion of fly eggs into the human intestine along with food. There, the larva hatches and begins to develop, causing enteritis.

pusher flies

Pusher flies are small predatory insects, whose distribution is observed in almost all parts of the planet. These flies got their name because of their bizarre behavior. Before mating during courtship, pusher males gather in flocks and begin to perform peculiar dances. So interesting way they attract the attention of females. In countries with a particularly warm climate, such performances can be observed throughout the summer.

In addition to a pleasant spectacle in the form of a dance, males achieve the location of females with gifts they bring. Usually these are dead small flies of other species, which the female eats after mating. But quite often, pusher males turn out to be very greedy gentlemen. In the most unceremonious way, they take away their gifts from the female in order to attract another female for mating.

The body of the pusher fly is gray-brown in color, up to 15 mm long. The belly has 5–7 annular divisions. Wings in a state of calm fit snugly to the back. The head is small, round with a long proboscis lowered down. The eyes of males are usually as close as possible to each other. In the oral apparatus of the fly, the lower and upper jaws are located in the form of four bristles. Insect larvae live in the ground.

Rather large size slender predatory flies. The body and limbs are covered with a dense layer of short hairs. For humans, ktyr flies do not pose any danger, but insects such as mosquitoes, midges, beetles and even bees, quite reasonably

I had no idea there were so many flies. There is no doubt about the harm that market flies bring, as well as meat flies (the people also call them dung flies). I did not know that they (or rather their larvae) are so tenacious! And now I see that indoors are also very dangerous! In general, it is necessary to fight flies and in no case do not let everything go on the brakes!

Flies, of course, disgusting insects. They multiply insanely fast, it is worth noticing a couple of flies in the house, in the morning there are already several small ones flying. We have country house in the village, there is no rest from them. Once they left the yeast on the table, returned home in the evening, and there were already a bunch of larvae. And the most unpleasant thing is that they carry diseases, so you have to hang the house with fly ribbons.

In terms of the number of currently known species (more than 80,000), this order ranks fourth in the class of insects, second only to beetles, butterflies and hymenoptera. Diptera include various mosquitoes and flies, which play a significant role in nature and human economy (mainly negative). Diptera are very widely distributed, both horizontally and vertically: they live in tropical, temperate and subpolar countries, in lowlands, plains and mountains. Diptera of these insects is apparent. In fact, they also have a second pair of wings, but it is underdeveloped and has become a special organ - the haltere, which performs an important function in flight. The halteres are especially well seen in the centipedes. Diptera are also characterized by the absence of true legs in larvae, and in some groups the larvae also lack a head. A relatively rare phenomenon of winglessness is observed in chione mosquitoes, in bloodsucking flies (sheep fleece), in flies living in anthills (wingless only females), in termite flies (rudimentary wings). The ability to fly is better developed in flies than in mosquitoes. Some flies (for example, blue carrion flies and hoverflies) are migratory. In 1953, Hilary and Tenzing discovered hover flies in the Himalayan mountains at an altitude of about 4 thousand meters, flying over the ridge along with butterflies. The mouthparts of Diptera are adapted to take liquid food and in various ways modified, forming either sucking lobes (in flies) or a stabbing proboscis (in mosquitoes).

Diptera have well-developed organs of vision in the form of a pair of large compound eyes and, in addition, 2-3 simple ocelli (not in all). The eyes are better developed in carnivorous dipterans (for example, in ktyrs), which is associated with the need not only to see the prey, but also to fix its location before it is captured. A high degree of perfection has been achieved in the eyes of male mosquitoes from the family of papilids and aximiids: in them, each eye is, as it were, divided into two parts, of which the upper one consists of large facets, and the lower one consists of small ones. Such a structure contributes to the differentiation of the perception of the environment. The location of the eyes of the diopsid flies, which live in our Caucasus and Siberia, is remarkable. Their eyes sit on the ends of long stalks diverging to the side, providing the insect with a wide spatial view, which makes it easier for him to navigate in the air. The function of such eyes is reminiscent of the operation of an artillery rangefinder, which once again indicates the possibility of coincidence of the principles of construction technical devices with the structure of animal organs of similar use. Great importance for the technical improvement of photographic equipment, the bionics studied the structure and functions of the fly's eyes, which made it possible to reproduce the cellular structure of the fly's eye and create a special device from 1329 small lenses combined into one flat disk. This device gives multiple images and is designed to reproduce the most accurate microscopic circuits in electronic computers.

The olfactory organs of Diptera are antennas covered with special tubercles capable of capturing various odors, reacting to a huge number of a wide variety of substances. Many Diptera catch slightest smells from great distances, finding suitable food or a place to lay eggs. So, for example, flies smell carrion from afar and flock to it. However, they can be deceived and attracted to the similar smell of the so-called stinky gum or the smell of flowers that have a putrid smell. Female mosquitoes flock to the smell of stagnant polluted water, where they lay their eggs. A substance isolated from such water, in negligible concentrations, is capable of attracting mosquitoes, which indicates their subtle sense of smell. As you know, female mosquitoes for the normal development of eggs must suck on the blood of animals or humans. They search for their prey by the smell brought by the wind, and in search of food they fly from 3 to 20 km. Having found a suitable object for bloodsucking, they signal this to other females with the help of a squeak of a certain tone.

In Diptera, sounds are produced during flight by the vibration of the wings and can serve as a means of communication. So, for example, males catch the sound of a flying female by the vibrations of her wings at a speed of 350 strokes per second in some species, and 500-550 in others. The receivers of sounds are the Johnston organs located on the antennas and the hairs on the antennas, vibrating like a tuning fork in unison with the perceived vibrations. One way to fight mosquitoes is to lure them to a certain place by playing a tape-recorded mosquito squeak. In the future, small ultrasonic installations will be able to free large areas from mosquitoes and other harmful insects, and a person - from the installation of expensive drainage channels in the places of the brood of these bloodsuckers. AT last years It was found that mosquitoes communicate with each other using electromagnetic waves millimeter range within a radius of up to 15 m. Moreover, each type of mosquito is characterized by a certain wavelength, at which clear signals are given.

The hairs covering certain parts of the body of Diptera (as in other insects) perform the functions of various sensory organs. Some of them are hygroreceptors that capture the degree of atmospheric moisture, others are thermoreceptors that respond to thermal effects, others are tangoreceptors that perceive touch, etc. The Canadian scientist Wright found that mosquitoes find a person by three factors that attract them: by exhaled carbon dioxide gas, released moisture and heat radiation. From this came the idea of ​​creating a mosquito trap that produces all three factors. Such a trap was made from a tin shaped like a mushroom. A candle is placed in the leg of the mushroom, and a small bath of water is placed in the hat. Heat and carbon dioxide are produced by a burning candle, and water vapor is produced by heated water. The lid of the trap is covered with a poisonous substance or Velcro. Mosquitoes sit on the lid and die on it. Schoolchildren themselves can make such a trap and check its effect in practice.

Diptera expediently react to weather changes, being living barometers. So, for example, flies fly into the premises before a bad weather, and on the roads - into the cabs of cars. Pusher flies form dancing flocks on warm summer evenings, usually on the eve of good weather. These flocks usually keep to narrow confined space(over a puddle, over a path with wet ground, or around a tree branch). Such accumulations in moist air are regarded as mating dances performed by Diptera in favorable atmospheric conditions. Horseflies raincoats are activated in cloudy weather before rain. Midge mosquitoes in calm weather at sunset or sunrise usually form swarms, flying in the crowns of trees or over grass and shrubs.

In addition to the organs signaling changes in meteorological conditions, in Diptera, dense receptors on the paws of flies deserve attention, with the help of which they determine the quality of food and its edibility. Experiments have shown that flies easily distinguish sweet greed from unsweetened water, and their threshold for distinguishing between sweets is 20 times lower than that of humans. Diptera, like other invertebrates, are able to perceive minor changes. magnetic field and navigate in accordance with the direction of its lines of force. There is an opinion according to which periodically changing electromagnetic fields of different frequencies give biological processes an unusual rhythm, distorting normal information processes. From this it is clear that animals are forced to behave in such a way as to avoid negative consequences every time when the magnetic field changes.

Diptera belong to insects with complete metamorphosis, but with one feature that others do not have, namely: in higher flies, pupae are placed in special false cocoons - puparia, formed from the larval skin with a compaction of its shell. Puparia protect pupae from damage, which increases their survival. Their role, therefore, is similar to real cocoons of butterflies and other insects, created by interweaving arachnoid filaments (silk-releasing fibers), but by origin, puparia are organs that are not homologous, but convergent. This is an example of how the same task of protecting the chrysalis from enemies and adverse influences different groups insects allowed was action natural selection by various means.

In the reproduction of some Diptera (mosquitoes of the genus Miastor), a phenomenon of pedogenesis, rare among insects, is observed (reproduction at the larval stage). In most Diptera, the larvae hatch from eggs and develop in the environment where the eggs were laid. Moreover, in each species, the females lay their eggs where the future larvae will be, surrounded by their food. In some Diptera, the survival rate of species is increased due to live births (for example, in bloodsucking flies and tachin flies). Their larvae emerge from the eggs and remain inside the mother's body, feeding on the secretions of special glands. Having completed development under the protection of the mother's body, they go outside and immediately pupate in the soil or on the animal's body (depending on the species). In manure flies, the larvae are born almost as adults, thereby, as it were, they are eliminated from dangerous competition with other inhabitants of the manure.

Success in the struggle for existence also brings care for the offspring, which is manifested not only at the egg stage, but also at the larval stage. For example, in gray blowflies, the larvae are ejected from the body of the female directly onto the substrate that serves them as food, namely: into ulcers, wounds, on the mucous membrane of the eye, nostrils and other parts of the body of animals. Something similar is also observed in nasopharyngeal gadflies, the larvae of which are splashed by the female into the nasal cavity of deer, sheep and other mammals. It should be noted the highest manifestation of care for offspring in the green carrion frog-eating fly, in which the female with mature eggs sacrifices herself in favor of the future young generation. She crawls around the frog until it is eaten by it. In the stomach of a frog, larvae emerge from the eggs of the fly, which penetrate the intestines, and from there into the nasal cavity of the host, where they complete their development.

Adult forms, using obtained from larvae nutrients, often switch to independent nutrition, usually causing one or another harm to the human economy. But some Diptera are beneficial (see more on this below). Among Diptera, there are few forms with bright coloration and attractive appearance. More than others, only buzzer flies, which feed on the nectar of flowering plants, have an elegant appearance. Green and blue carrion flies are distinguished by a metallic sheen.

Some types of hoverflies are characterized by mimicry. For their resemblance to stinging hymenoptera, these flies received the appropriate names: wasp hoverfly, bumblebee-shaped bumblebee, bee-bee elm, etc. Interestingly, one species of flies was found to imitate wasps in buzzing. They stay among the wasps and reproduce the same sounds as the wasps. Flies that are mimics tend to stick to the same habitats as the insects they mimic. So, for example, bumblebees visit the nests of bumblebees, and bees are found on inflorescences along with bees. Humpback flies, resembling ants, live in anthills.

Sexual dimorphism in Diptera is weakly expressed. In flies, for example, sexual dimorphism manifests itself more often in the size of the eyes. In rare cases, the difference between a male and a female is the unequal color of the body or its external structure. So, for example, in a garden midge, the male is black, and the female is red-brown, in a fly of the genus Platifor, the male is winged, and the female is wingless, flat, like a cockroach.

Chemical methods of dealing with harmful Diptera do not always give positive results. Unnecessarily intensive and indiscriminate use of insecticides leads to the fact that a person artificially eliminates individuals sensitive to the drug used and at the same time promotes the reproduction of individuals resistant to it. This is due to the presence in the population of Diptera, which are immune to the poison of certain substances. The well-known entomologist J. Georgiou (USA) cites data on resistance to DDT that exists among anopheles mosquitoes and house flies, and their immunity acquires a wide spectrum, including various types of insecticides and even growth hormone analogues, which usually have a disastrous effect on insects, causing them to the body is seriously impaired. The problem of combating harmful insects, in particular Diptera, is one of the most complex. It requires for its implementation a strict account of the interrelations that exist in nature.

At the same time, Diptera, being objects of attack from numerous enemies, are an essential link in the food chains of various animals. The enemies of Diptera primarily include insectivorous birds, especially swallows, swifts, nightjars, and mammals - the bats, from insects - dragonflies. In the water, mosquito larvae and pupae are eaten by fish, dragonfly larvae, water bugs and beetles, as well as an insectivorous plant - pemphigus. In peat bogs, small flies, midges and mosquitoes are caught by other insectivorous plants - sundew and diryanka. It has been established that, for example, sundew catches up to 17 mosquitoes in 1 hour.

Order Diptera, or flies and mosquitoes (Diptera) (B. M. Mamaev)

Among the 33 modern orders of insects, the Diptera order occupies one of the first places in terms of abundance and diversity of representatives, yielding in this respect only to beetles, butterflies and hymenoptera. To date, 80,000 species are known in this order. Undoubtedly, in the near future this figure will increase significantly, since the study of Diptera is still very far from being completed.

The main features that separated Diptera from other orders of insects are, firstly, the preservation in the adult stage of only the first pair of wings - organs of fast and perfect flight, and, secondly, the radical transformation of the larval stage, expressed in the loss of legs, and in higher Diptera also in the reduction of the head capsule and, ultimately, in the development of extraintestinal digestion.

The body shape of adult dipterans is very diverse. Everyone knows slender long-legged mosquitoes and stocky short-bodied flies, but only experts will attribute to this order a microscopic wingless "bee louse" or a female of one of the humpback species found in anthills, which looks more like a very small cockroach.

The organs of vision - large compound eyes - in Diptera often occupy most of the surface of their rounded head. Additionally, on the crown there are, although not all, 2-3 dotted eyes.

Antennae, or antennae, are located on the frontal surface of the head, between the eyes. In mosquitoes, they are long, multi-segmented, which is one of the most distinct characters that distinguish the suborder of long-whiskered Diptera (Nematocera). In flies belonging to the other two suborders, the antennae are greatly shortened and usually consist of only three short segments, the last of which bears a simple or pinnate bristle. Antennae are mainly organs of perception of smells. On the surface of each of the segments there are olfactory tubercles specially adapted for this purpose. Often, the antennae of male Diptera are much more complex than those of females. These secondary sex differences are usually seen in mosquitoes; in flies, they appear more often in the size of the eyes.

The mouthparts of Diptera (Fig. 407) are strongly modified and are suitable for taking mainly liquid food. The most perfect adaptation for this is the proboscis of higher flies, formed by the lower lip and ending in sucking lobes.

In blood-sucking mosquitoes, the mouth parts are strongly elongated, the lower lip forms a groove in which piercing stylets are located: needle-shaped upper jaws (mandibles) and lower jaws (maxillas). Between them is the subglottis, through which the duct of the salivary glands passes. From above, the groove of the lower lip is covered by the upper lip.

In some blood-sucking flies, mandibles do not develop and the proboscis is arranged differently than in mosquitoes. Their lower lip forms a stiletto-like solid groove, the opening of which is covered by an upper lip of the same shape, linked to the lower one by special outgrowths. The teeth, which in the proboscis of higher flies are located on the sucking lobes and serve most species for scraping off solid food particles, are greatly enlarged in bloodsuckers and are used to open the integument of animals. In this case, the fly puts its proboscis vertically against the skin of the animal and sets in motion the rollers on which the pre-oral teeth are located. Notching the top protective layer skin, these teeth rather quickly drill out the wound. Stingers, the tse-tse fly, and other closely related species of Diptera have such proboscises. When piercing the integument of insects with predatory flies - ktyrs and greenfinches - the main role is played by the lower lip together with the subglottis. In such bloodsuckers as horseflies, the wound is applied mainly by mandibles.

Three thoracic segments of Diptera are tightly soldered together, forming a strong thoracic region - a receptacle for powerful muscles. It serves as a reliable support for the wings during fast flight. Halteres are also located here - short club-shaped appendages, which are a modified second pair of wings. They are considered organs of balance. The mesothorax - the most powerful thoracic segment - is equipped with a semicircular outgrowth - a shield on the posterior edge.

At rest, the wings are folded over the abdomen in a roof-like manner, horizontally one above the other, or simply retracted back and to the sides. Many families of Diptera are best distinguished by wing venation, the pattern that is formed on transparent wings by their skeleton, the veins. In good flyers, the leading edge of the wing is especially strongly reinforced with veins. The surface of the wings is often covered with large and small hairs or scales, and sometimes has additional sensory pores. At the base of the wing, in many flies, the pectoral and wing scales, as well as the winglet, are isolated.

The structure of the legs of Diptera is closely related to their way of life. Movable, fast-running flies have short strong legs. Mosquitoes, on the other hand, usually hiding among the vegetation during the day, have long limbs adapted for climbing among the interweaving of grass stalks or in the foliage of trees and shrubs. The paws of the legs end in claws, at the base of which 2-3 special suction pads are attached. With their help, Diptera can move freely on a completely smooth surface.

Ingenious experiments have shown that in flies these pads serve not only for movement, but are additional taste organs, signaling the edibility of the substrate on which the fly has settled. If a hungry fly is brought to a sugar solution so that it touches it with its paws, then the fly puts forward its proboscis for sucking. When the sugar solution is replaced with water, the fly does not react at all.

Both the thorax and the abdomen, which in Diptera consist of 5-9 visible segments, often have a characteristic coloration and are covered with hairs and setae. The location of these setae is often used as a feature for distinguishing individual families, genera, and species of the order.

The idea of ​​Diptera larvae as whitish, legless, and headless "worms" swarming in manure and rubbish heaps does not at all reflect the true diversity of their forms and is based on the most superficial acquaintance with the order.

First of all, it should be emphasized that in the larvae of all long-horned Diptera, the head is well developed and often equipped with strong jaws, with the help of which the larvae feed on plant roots or decaying organic matter. The only exception is a rare family of long-whiskered dipterans - hyperoscelididae (Hyperoscelididae). Hyperoscelidid larvae completely lack a head capsule, their head segment bears only a pair of antennae and a mouth opening. These larvae live in decaying wood and feed exclusively on liquid food.

The head capsule never develops in the larvae of higher flies, the entire oral apparatus of which is usually represented by only two sclerotized hooks.

The loss of the head capsule, which is so characteristic of the larvae of higher dipterans, is associated with the development in them of a peculiar method of digestion, which is called extraintestinal. With this type of digestion, food is pre-digested outside the body of the larva under the influence of the digestive juices secreted by it, and only then is it swallowed and absorbed.

The body shape of the larvae is varied. Usually it is worm-like, but sometimes it is so unusual that it can baffle an inexperienced taxonomist. Very bizarre, for example, flat larvae living in fast mountain streams deuterophlebiid(Deuterophlebiidae) - a small family distributed in the mountains of Altai, Tien Shan, the Himalayas and the Rocky Mountains of North America. Each segment of the larvae bears from the sides along a long outgrowth with a sucker at the end. Alternately moving these outgrowths, the larvae are able to move slowly over the stones at the bottom of the fastest streams. Their tracheal system is completely absent - a rare case not only in Diptera, but also in insects in general, and they breathe with the help of anal gills.

Very remarkable larvae ptychopterid(family Ptychopteridae), developing in fresh water. They have a well-developed head, dense integument with dense rows of spines, and a long windpipe formed from the last two segments of the abdomen. There are spiracles at the end of the tube, and two respiratory filaments are attached to its middle part. The significance of the tube in the life of the larvae is clear: with its help, the larva can, without losing contact with the atmospheric air, search the bottom of shallow water or the underwater parts of plants in search of food.

Very interesting slug-like larvae of mosquitoes of the genus ceroplatus(Ceroplatus of the Ceroplatidae family), found openly on the surface of fungi and molds. They have a rare ability among Diptera to emit in the dark a weak phosphoric light, the source of which is their fat body. The glow continues in the pupa, but disappears in the adult mosquito.

Perhaps the only constant feature of Diptera larvae is the absence of pectoral (true) legs. The absence of legs in fly larvae is in some cases compensated by the development of various outgrowths of the body, resembling the "false legs" of butterfly caterpillars. With the help of these outgrowths, the larvae can move relatively quickly over the surface of the substrate. Such larvae are known, for example, in the family bekasnits(Leptidae), numbering more than 400 species. In most of them, the larvae are worm-like and outwardly do not differ from the larvae of a house fly. But in the larvae of the ibis fly (Atherix ibis), which live among the stones at the bottom of fast-flowing rivers, each body segment has a pair of hooked " false legs which serve as perfect organs of motion.

Diptera larvae are found in large aggregations in an abundant food substrate. Ordinary places mass development of larvae of higher flies are decomposing animal corpses, garbage dumps, latrines, etc.

Mushroom mosquito larvae (Mycetophilidae) bring a lot of frustration to mushroom pickers. In most cases, it is their long white larvae with a black head that teem on the breaks of "wormy" mushrooms, making them completely unusable. True, fungal mosquitoes cannot be considered exclusively inhabitants of fungi, some of their groups are associated with decaying wood, plant debris, etc., where they also form large colonies.

Also, larvae of leaf mosquitoes are found in large clusters ( family Sciaridae). In some cases, when food is scarce, these masses of larvae may undertake massive migrations. Larvae military mosquito(Sciara militaris) are grouped into a long ribbon up to 10 wide cm, which, slowly wriggling, moves in search of a favorable place. The appearance of such "snakes" aroused superstitious fear in people, they were considered a harbinger of crop failure, war and other disasters. Hence the name of the mosquito - "military".

The process of transformation of an adult larva into a pupa in Diptera has its own characteristics. Usually in insects with complete transformation, after the pupa is formed under the covers of the larval skin, these covers are shed and the pupa is completely released.

Long-whiskered Diptera are no exception to this rule. But a whole group of higher flies has a special additional protective device that protects the pupa from damage and is called puparia. In this case, the skin of the adult larva not only is not discarded as an unnecessary shell, but, on the contrary, hardens, acquires a barrel-shaped form and is strengthened by various deposits. The pupa is formed inside this skin, and the adult fly, in order to be free, breaks out a round exit hole in it (Table 55).

This biological feature formed the basis for the allocation of Diptera in the order, except suborderlong-whiskered, or mosquitoes(Nematocera), two more suborders: short-horned diptera(Brachycera-Orthorrhapha) without puparia, and short-whiskered diptera(Brachycera-Cyclorrhapha), developing with a puparium. It is interesting that the larvae of some groups of Diptera, although they do not form a typical puparia, still pupate inside the larval skin. Among the long-whiskered Diptera, this method of pupation is characteristic of a small family scattopsid(Scatopsidae), numbering about 130 species, and for a few species of the family gall midges(Cecidomyiidae), such as the Hessian fly and some others. Lion larvae pupate inside the slightly altered larval skin from the short-horned straight-sutured Diptera.

The adaptability of Diptera to various living conditions is unusually wide. Their larvae have mastered a wide variety of habitats: fast streams and stagnant waters, clean, transparent reservoirs, including seas with salt water, and fetid sewers, the thickness of the soil, various rotting plant substances that enter the soil, tissues of living plants, and, finally, , the body cavity of insects and other invertebrates, as well as the intestinal tract, subcutaneous tissue and respiratory tract of vertebrates, and in some cases, humans.

Diptera larvae lead a hidden lifestyle and are incapable of long-term movements. To attach their offspring to suitable conditions is the task of adult flies, which are therefore good flyers. Many of them have interesting adaptations that increase the survival of larvae. It suffices to recall the birth of live larvae, which is common among higher Diptera, and in some cases the feeding of larvae with the secretions of special glands, when the larva leaves the mother's body, being already quite an adult.

However, it is usually not the adult flies that feed their larvae, but, on the contrary, the larvae store the nutrients necessary for the life of the adult phase.

It is not uncommon for adult Diptera to live solely on the nutrients that the larva has accumulated and do not feed at all. For other species it is enough to drink water, flower nectar or sweet juice flowing from injured trees. But not all adult Diptera are so harmless. Mosquitoes, horseflies, midges, midges, mosquitoes are annoying bloodsuckers. However, only females suck blood from them, while males are completely harmless. If the females of these Diptera do not drink blood, they will remain barren. Their bloodthirstiness is also explained by the fact that they need to drink a lot of blood, otherwise only part of the eggs will develop in the ovaries or the supply of nutrients will not be enough at all.

One of the Diptera families fruit flies (Drosophilidae) - forever entered the history of science, since its representatives served as one of the main objects in the study of the role of the smallest structures of the cell nucleus - chromosomes in the phenomena of heredity. And this is no coincidence: in experimental conditions Drosophila larvae develop very quickly on artificial media, and after 7-10 days it is possible to evaluate the results of the experiment. When adult flies or their larvae are exposed to X-ray or radioactive radiation, numerous changes occur in their offspring - pigmentation of the eyes disappears, wings are underdeveloped, sometimes an ugly limb grows instead of one of the antennae, etc. In the experiment, it was possible to obtain flies that were several times larger than normal, ugly specimens were also obtained in which one half of the body had signs of a male, and the other female or many signs of an individual were of an intermediate nature. The results of all these experiments formed the basis of many important scientific conclusions about the laws of heredity, which are studied by genetics.

Diptera are one of the most numerous groups of insects and therefore represent a great force of nature. And this force, if we evaluate the importance of Diptera as a whole, causes enormous damage not only to the economy, but also to human health.

In nature, there are numerous foci of various diseases that wild animals suffer from. In many cases, these diseases are not dangerous to humans, but some of them pose an extremely serious threat to humans. There are also diseases that are not transmitted from person to person, but are nonetheless very widespread. Blood-sucking Diptera, attacking animals and humans, along with other blood-sucking arthropods, widely spread these diseases, transmitting the pathogen during blood sucking.

The main danger from the malarial mosquito is not that it inflicted a painful bite, but that at the same time it can introduce malaria pathogens into the blood, and only this disease alone killed human lives far more than all the wars in the history of mankind put together.

Equally dangerous carriers of infections are synanthropic Diptera, i.e., species that live in human dwellings. Visiting garbage and feces, they carry pathogenic microorganisms and helminth eggs on their bodies and in their intestines, leaving them on dishes, food, furniture, etc. It is not without reason that many teams of scientists are working to study the biology of one of these insects - the housefly - with the aim of her extermination.

Diptera larvae can also be serious pests of food stocks. Great harm, for example, brings nondescript cheese fly(Piophila casei), belonging to the family pyophilide(Piophilidae). Its white, shiny larvae develop in old cheese, ham, lard, salted fish, destroying these products. Adult larvae emerge from the food and look for places to pupate in the debris of dark corners, crevices and cracks. They are sometimes called "jumpers" for their ability to curl up into a ring and straighten up sharply to make jumps.

For human health, cheese fly larvae pose a danger when foods contaminated with them are eaten. In the human intestine, the larvae are able to remain viable for a long time, causing ulceration of the intestinal wall, with symptoms reminiscent of typhoid fever.

One should not underestimate the negative significance of those Diptera that attack a person during his work in field conditions, significantly reducing labor productivity, and in some cases making this work impossible in certain periods.

The positive role of Diptera in nature and in the human economy is small in comparison with the harm they bring. They are tireless orderlies, cleaning the surface of the land from the waste accumulating here. Some groups of Diptera are known as soil formers and as enemies of harmful insects, which inhibit their reproduction.

Diptera are very widely distributed: from the tropics to the ice borders in the north and in the mountains. But even among the tropical representatives of the order, there are almost no particularly large and brightly colored species. Insect lovers pay little attention to them, preferring beetles and butterflies, although biologically Diptera are no less interesting and peculiar.

Suborder Long-whiskered Diptera (Nematocera)

Mosquitoes have a slender elongated body and thin, usually long legs, less often they are dense, squat, with short legs. Their antennae consist of more than three segments. In larvae, the head capsule is well developed. Covered pupae.

Long-legged (family Tipulidae) are those large mosquitoes that fly out from under the feet in a wet meadow or forest glades and, lazily flying several tens of meters, again hide among the grass.

Representatives of this family are distinguished by a slender body, long wings and very long, thin and weak legs, which serve them not only for climbing among the vegetation, but also are a kind of protection from enemies. When the mosquito sits, its legs are widely spaced, and the approaching predator grabs the weevil by the legs. But it is impossible to hold these mosquitoes by the legs, their limbs immediately come off, and instead of big booty there are only one or two convulsively trembling legs. This method of protection is widespread in nature. Suffice it to recall the haymakers, who also flee from the enemy, leaving him several of their limbs, lizards, which leave only the end of their tail in the teeth of the pursuer, octopuses, sacrificing their tentacles, etc.

Long-legged larvae - inhabitants humid environment: soil, bedding, rotting wood or fresh water. They have a large dark well-developed head and strong gnawing jaws. Most species feed on decaying plant remains, but some also gnaw on living plant roots.

The process of digestion of these larvae is interesting. Plant foods, which consist mainly of very persistent substances - fiber and lignin, are difficult to digest. Single-celled animals come to the aid of the centipedes. They multiply en masse in the intestines of the larvae, releasing enzymes that promote the digestion of fiber. As a result, the food is enriched with substances that are absorbed by the larvae of the weevils. Interestingly, the intestines of the larvae are equipped with special blind outgrowths, where food is retained and where especially favorable conditions are created for the reproduction of microorganisms. This type of digestion, when plant foods are digested in the intestines with the participation of symbiotic microorganisms, is found not only in insects, but also in vertebrates, for example, in a horse, in which the stomach is also very complicated.

Among the few harmful species of weevils, it is worth mentioning garden weevil(Tipula paludosa) is an extremely widespread species, the larvae of which gnaw the roots of plants, including cultivated ones. In total, there are more than 2500 species in the family.

Family retina(Blepharoceridae), which includes only 160 species, is famous for the originality of its larvae that live in fast mountain streams. The head of the larvae merged with thoracic region into a single whole, as well as the end segments of the abdomen. On the middle abdominal segments there are six powerful suckers of a complex structure, the soles of which are covered with strong setae. With the help of suction cups, the larvae slowly move along the stones in jets of a fast stream, scraping off various growths from them.

Before pupation, the adult larva firmly attaches itself to the stone, the skin on its dorsal side bursts and its fragments are quickly carried away by stream jets, exposing the tender pupa. The integument of the pupa soon hardens, it darkens and becomes inconspicuous.

Mosquitoes emerging from pupae emerge from the bottom of the stream and fly to damp, shaded places, usually to rock crevices, where for the most part they hang quietly, clinging to ledges with long and thin legs.

In all zones the globe, starting from the tundra and ending with the tropics, with the exception of only sultry deserts, one of the most annoying insects in warm weather are real mosquitoes (family Culicidae). In swampy areas, these insects pursue animals and humans in clouds, inflicting painful injections with a long proboscis (Table 56), from which even the fabric of clothing does not protect a person if it is not thick enough. Perhaps no other group of Diptera has such a perfect bloodsucking tool as this stylet, which essentially consists of several stylets: two needle-shaped mandibles and two maxillae, an upper lip and a subglottis enclosed in a case - the lower lip. By the presence of a proboscis, it is easy to distinguish true mosquitoes from twitching mosquitoes, in which the mouth organs are not developed.

However, not all types of mosquitoes are aggressive. Many of them use their proboscis only to feed on nectar. In blood-sucking species, blood saturation is also obligatory only for females, while males are content with plant juices.

The environment for the development of mosquito larvae are small stagnant reservoirs or micro reservoirs - forest puddles, accumulations of water in hollows, rain barrels, and even cans with rain water. Overwintered females of our common bloodsuckers from the genera Culex, Aedes, Anopheles lay their eggs here.

common eggs malarial mosquito(Anopheles maculipennis) swim alone on the surface of the water. After 2-3 days, larvae appear from the eggs, all further development of which takes place near the surface of the reservoir. Most of the time the larvae spend in horizontal position, attached to the surface film by non-wetting humeral lobes, groups of special hairs on the abdominal segments and a stigmal plate; at the surface, they are held by surface tension forces. In this position, the larvae feed on organic residues or small aquatic organisms that are constantly present in stagnant water. The air necessary for breathing enters the tracheal system through the stigmal openings brought to the surface. In an additional way respiration is gas exchange through the skin and gills, two pairs of which surround the anus. Food is actively obtained by the larva. Its upper lip is equipped with brushes, the main purpose of which is to direct the flow of water with food particles to the mouth, where food is caught by a filter of hairs. oral apparatus. In addition to this method of feeding, the larvae are able to scrape food from plants and other objects submerged in water.

The disturbed larvae quickly dive, making sharp movements with the end of the abdomen. After stopping at the bottom or in the water column, the larvae begin to rise to the surface with their tail forward, making the same movements. In about a month, the larva molts three times and increases in length by more than 8 times. Adult larvae transform into characteristic humpbacked pupae, which also stay near the surface of the water and breathe through a pair of respiratory tubes located on the dorsal side of the cephalothorax. In case of danger, however, the pupae quickly dive, waving the end of the abdomen several times, and then passively rise again to the surface.

The skin of a mature pupa bursts on its back, and through the gap, first the head with antennae appears, and then the chest of the mosquito, the wings and limbs are released, and the mosquito, having grown stronger, flies into the coastal vegetation.

In the evening, mosquito swarming can be observed: many dozens of males jostle in the air, forming a kind of "singing" cloud, while females fly into the swarm one after another and immediately leave it, dragging one of the males.

In fertilized females, the instinct of bloodsucking awakens. A hungry female is capable at a distance of up to 3 km determine the location of large concentrations of warm-blooded animals and humans and quickly overcome this distance. In one act of sucking, the female absorbs an amount of blood in excess of her original body weight. In the process of digestion of this blood, due to the incoming nutrients, the first portion of 150-200 eggs is formed in the ovaries of the female. The female becomes aggressive again only after she lays these eggs in the nearest body of water. From now on, if the first time a female has drunk the blood of a person with malaria, she becomes dangerous, since her saliva is now teeming with sporozoites - initial stage development of malarial plasmodium.

Having re-sucked blood, the female again loses interest in food until maturation and laying the next batch of eggs. The female lives in the summer for about 2 months. By autumn, females appear, preferring to feed on nectar. At the same time, their ovaries do not develop, but reserve fatty substances accumulate in the body. These females climb into cool and empty shelters, caves, hollows, burrows, cellars, where they hibernate. The development cycle of other types of blood-sucking mosquitoes is very similar.

From a practical point of view, it is important to distinguish between harmless mosquitoes and vectors of malaria. Our ordinary squeaker mosquito(Culex pipiens), an annoying but harmless bloodsucker, differs well from the malarial in its landing (Fig. 410): it holds its body almost parallel to the surface on which it sits, while the abdomen of the malarial mosquito deviates at an angle of 30-40 °. The larvae of the squeaker mosquito hang vertically at the surface of the water, upside down (Table 57), while in the malarial mosquito the larvae are held horizontally.

Mosquitoes are of great importance as carriers of such serious diseases as malaria in its various forms, yellow fever caused by a virus, Japanese encephalitis, encephalomyelitis, etc. Only a well-developed scientific system for the prevention of these diseases in the USSR and some other countries made it possible to sharply reduce the incidence of people. To combat mosquitoes, not only chemical, but also biological control measures have been successfully applied. A small viviparous gambusia fish imported from America acclimatized in Central Asia, where it became one of the main enemies of mosquito larvae. Interestingly, the larvae of some harmless species of mosquitoes are predatory, destroying the larvae of bloodsucking mosquitoes. One larva toxorhynchus mosquito(Toxorhynchites splendens), common in the tropics, destroys up to 150 larvae of other mosquitoes. This species has been successfully introduced to some Pacific islands to control harmful mosquitoes. In total, there are about 2000 species in the mosquito family.

Mosquitoes are the first of the five main families of blood-sucking Diptera, the complex of which has been aptly named "gnus". Together with horseflies, biting midges, midges, and in the south also mosquitoes, mosquitoes form hordes of Diptera, which, especially in swampy taiga places, do not give a minute of rest in the summer months, attacking animals and humans.

This is how zoologists who have visited the taiga describe this phenomenon.

“In summer and autumn, on a bright sunny day and in cloudy weather, from morning to evening, myriads of mosquitoes and especially midges besiege humans and animals. eyes are covered with tears. Calves and foals sometimes die, bitten by midges. Large wild animals, for example, deer, make long migrations in the summer to the mountains and to the sea, where they escape from midges thanks to the wind. In coastal villages, field work is often stopped during the day due to midges , which are transferred at night.Pets stop eating and gather under a canopy, where smokers are bred to drive away midges.

A person takes shelter indoors, and in the open air he uses smoke, nets, and ointments for his protection. But neither the room, nor the tent, nor the clothes protect against bloodsuckers: annoyingly attacking, the insects pierce the tissues, climb under the clothes and into the room. In a person besieged by midges, after a few minutes drops of blood appear on the face and on the hands. You grind dozens of insects swollen with blood, hundreds of new ones land on you.

At night, midges subside, but mosquitoes and midges are still active; midges, due to their insignificant size, penetrate through the smallest cracks in tents, in doors and windows and attack the sleeping ones; their injections are especially painful."

The blood-sucking Diptera are most numerous in the virgin, untouched taiga. With its development, the number of bloodsuckers decreases, but even large-scale systematic measures to combat midges do not yet give such an effect that one can talk about the final victory over this army of enemies of animals and humans.

Extensive, numbering over 3000 species family twitching mosquitoes, or bells(Chironomidae), closely associated with large and small water bodies. In the quiet warm evenings over the banks of ponds and small rivers overgrown with reeds, you can hear a thin melodic ringing. This ringing is emitted by swarming mosquitoes, which then sharply soar up, then passively fall down. The bells are usually pale yellow or light green, less often dark in color, their forelimbs are strongly elongated, raised and serve as organs of touch, the mouth organs are not developed, the antennae of males are densely pinnate.

After washing a portion of silt from the bottom of the pond on a sieve, it is almost always possible to detect larvae of ringing mosquitoes. These larvae do not need atmospheric air: absorption of oxygen dissolved in water and release carbon dioxide occurs in them through the tracheal gills and partly through the integument of the body. Red larvae live in the silt of various water bodies, including heavily polluted ones with a low oxygen content in the water. bloodworm(Chironomus plumosus) and a number of related species. These larvae intensively feed on microorganisms that colonize the silt, hiding in spider webs from their numerous enemies. They are very readily eaten by fish, for which they serve as one of the main food sources, and are well known to lovers of aquarium fish farming. The respiratory pigment hemoglobin is dissolved in their hemolymph - a useful adaptation to life in conditions of lack of oxygen.

In some lakes, bell larvae descend to a depth of more than 300 m, at such a depth they are the only representatives of insects. In some Arctic lakes, which freeze to the bottom in winter, the larvae of these mosquitoes successfully hibernate in the thickness of the frozen silt, i.e., under conditions that would be fatal for many other insects.

Larvae have adapted to living in sea water pontomies(Pontomyia natans). The females of this species have lost their wings and legs, turning into worm-like animals that do not leave the water. Males, on the other hand, look for females by running along the surface of the water.

biting midges (family Ceratopogonidae) - small mosquitoes, their body length rarely exceeds 3-4 mm. They are close to ringing mosquitoes, from which they differ good development oral apparatus in adult mosquitoes. Recall that adult bell mosquitoes do not feed and their mouth organs are underdeveloped. There are more than 1000 representatives in the family of biting midges, but only a few hundred species of bloodsuckers are well studied. Most of these species have variegated wings and, on this basis, are well distinguished from such blood-sucking Diptera as mosquitoes and midges.

The environment for the development of biting midge larvae can be very diverse, but always wet. Most often, larvae can be found in a layer of silt along the banks of fresh water bodies, in marshy soil, in temporary micro-reservoirs, such as puddles on roads, rainwater in hollows of trees, midge larvae are not uncommon in flowing tree sap, wet, rotten wood, etc.

Thin and long larvae of biting midges of white or pinkish color with a dark brown head and a naked, smooth body are able to move quickly in mud or swim in water, wriggling serpentine. The terms of development of various species range from two weeks to two months. Pupation occurs amicably, and already after 5-7 days adult mosquitoes begin to appear from pupae, and in terms of emergence, males are slightly ahead of females.

Hatching biting midges usually stay near the breeding grounds among grass, shrubs and in the crowns of trees. Many species swarm in the evenings or early in the morning in calm weather, and the swarm consists mainly of males. Blood-sucking biting midges often enter livestock buildings en masse.

Adult biting midges feed on plant sap and are often found on flowers. Only representatives of some genera, primarily the genus Culicoides, are malignant mass bloodsuckers. Like many other blood-sucking insects, blood feeding in these biting biting species is characteristic only of females. Biting biting bloodsuckers attack people, domestic and wild animals, not only warm-blooded mammals and birds, but also amphibians and reptiles. There are cases of attacks even on other insects, most often on mosquitoes and butterflies.

Biting mid-latitudes appear in May - June and, developing in several generations, reach the highest number in July - August. Most blood-sucking species are active in the morning and evening; on cool cloudy days, biting midges also attack during the day.

A single saturation with blood is sufficient for the full development of eggs in the ovaries of the female. After laying the first batch of eggs, the females attack the animals again and, if bloodsucking is successful, lay eggs again.

The harm from midges is not limited to the toxic effect of their saliva, which is especially severe during a mass attack. Although the role of biting midges as carriers of pathogens has not yet been fully elucidated, it has been proven that some species of this family are intermediate hosts of filariid nematodes; midges are considered one of the possible carriers of hemosporidium of the tularemia microbe, as well as some viral diseases- Japanese encephalitis, equine encephalomyelitis, etc.

The most common and massive of the blood-sucking midges, not found only in the tundra, is burning midge(Culicoides pulicaris), which gives several generations over the summer. Its larvae are found in polluted fresh water bodies.

To family midges(Simuliidae) include small humpback mosquitoes, whose body length does not exceed 6 mm. They are easily distinguished from real mosquitoes by shorter, strong legs and a short proboscis. Their wings at rest fold horizontally one above the other; short antennae usually consist of 9-11 segments.

Midges are known as annoying bloodsuckers. Together with mosquitoes and midges, they make up hordes of midges and equally willingly attack wild animals, livestock and humans. There are especially many midges where there are fast rivers that serve as places for the development of their larvae.

The female midges are experienced divers. To lay eggs, they descend under water, clinging to stones and plant stems. Some species of midges, however, prefer to lay their eggs on a calmer coastal strip or drop their eggs into the water while flying over a stream.

The larvae emerging from the eggs are immediately fixed on the substrate by the posterior end of the body, where there are hooks and powerful muscles. Females lay eggs in groups, often several females in one place. Therefore, midge larvae often form large colonies in the stream channel. Under especially favorable conditions for 1 cm 2 surfaces account for up to 200 midge larvae.

The appearance of these colonies is peculiar. The fast, changeable course of the stream rhythmically vibrates the larvae, which passively obey the jets and more resemble small aquatic plants than living beings. Only periodically contracting "fans" located near the mouth opening of the larvae indicate that an intense life flows inside these organisms.

Fans are complex formations consisting of numerous hairs and bristles and serving to trap food. They were formed from the lateral sections of the upper lip. The food of the larvae - organic residues suspended in water or small aquatic organisms - is filtered out like a sieve from running water and accumulates in fans of larvae. Then the fans are reduced, and the food bolus is adjusted to the mouth opening and enters the intestines. With this method of feeding, the faster the current, the more water is filtered through the fans and the more food is captured. Therefore, midge larvae inhabit the sections of the channel with the fastest flow. This is all the more necessary because midge larvae are very sensitive to a lack of oxygen and quickly die in stagnant or low-flowing water with a high content of decaying organic residues.

It is hard to imagine that these legless larvae can move in fast current jets. However, an experienced observer will immediately notice a cone-shaped outgrowth at the anterior end of the body of the larva, the sole of which bears rows of hooks.

The meaning of this outgrowth, called the "foot" of the larva, becomes clear only when the larvae begin to crawl. At the same time, the larva lubricates the nearest part of the surface with sticky cobweb secretion, attaches itself to it with its thoracic "leg" and pulls up the posterior end of the body. Having fixed the posterior end of the body on the arachnoid platform, the larva releases the thoracic "leg" and, straightening up, looks for a new platform for attachment. Along the entire path of movement, the larva weaves a cobweb thread, on which it is held if it is torn off by the current.

With sharp violations of the conditions of the reservoir, the larvae of some midges release a cobweb up to 2 m and for some time they keep on it in the jets of the stream. When the regime of the reservoir is restored, they return along the cobweb to their original place.

The entire colony of larvae pupates very amicably. Before pupation, the adult larva weaves a cocoon that looks like a cap, from which the pupa sticks out. On her cephalothorax there are branched respiratory tubes that provide gas exchange. Adult midges emerge from pupae in 1.5-2 weeks. Leaving the pupal skin, the midge is enveloped in an air bubble, in which it rises to the surface, and comes out of the water completely dry.

Adult midges feed only in hot weather. sunny days, in cloudy weather, at dusk and at night they are inactive. Only females are bloodsuckers, males feed on flowers.

The short proboscis of midges with sawing mandibles and tearing maxillae is well suited for piercing the skin of animals. It would seem that bloodsucking for all midges is the most natural way nutrition. However, this is not the case. In some areas, despite the significant abundance of midges, they do not attack animals and humans. Specially designed experiments have shown that female midges can successfully feed on flowers, while the eggs in their ovaries mature normally.

The activity of adult bloodsuckers is also not the same in different zones their distribution: it decreases from north to south. So, broad-legged midge(Eusimulium latipes), decorated midge(Odagmia ornata), creeping midge(Simulium repens) in the tundra are the scourge of humans and animals, and to the south - in the forest-steppe and steppe zones not registered as bloodsuckers at all. It is quite likely that the need for blood feeding arises in adult midges if their larvae developed under unfavorable conditions and did not accumulate sufficient reserves of nutrients. Among midges, however, there are species for which bloodsucking is necessary step in the life cycle. It is these species that pose the greatest danger.

A midge injection is a whole surgical operation. At the time of the injection, saliva containing anesthetics is injected into the wound. Therefore, the pain quickly disappears and reappears only after the midge sucked blood and flew away. At the same time, substances that prevent blood clotting are introduced into the wound.

The saliva of midges is poisonous. At the injection site, swelling develops within a few minutes, burning and itching appear. With numerous bites, the body temperature rises, signs of general poisoning appear, hemorrhages and swelling of the internal organs begin, which can lead to a rapid death.

The scourge of animal husbandry in the Danubian countries is columbian midge(Simulium columbaczense). The larvae of this species develop into major rivers and especially numerous in the Danube. The larvae of the Columba midge pupate in the first half of May, and by the end of this month, coastal bushes are covered with swarms of flying mosquitoes. After fertilization, the males die, and the females fly off in swarms from the coast for 5-20 km and attack livestock. In some years, tens of thousands of cattle died from this midge.

In the USSR, bloodsucking midges are most diverse in the taiga zone. The most malicious bloodsuckers here are tundra midge(Schoenbaueria pusilla), Midge Kholodkovsky(Gnus cholodkovskii), decorated midge(Odagmia ornata) and a number of other species. These midges attack at temperatures from 6 to 23 ° C, and in autumn Kholodkovsky's midge is active even after snow falls.

The harm from midges is aggravated by the fact that they are carriers of such serious diseases as anthrax, glanders, tularemia, plague, leprosy. The causative agents of these diseases are transmitted by the female, who has interrupted feeding on a sick animal, during a quick attack on a healthy one. In Africa, midges carry human filaridiasis.

Butterflies (family Psychodidae) are very peculiar small mosquitoes, distinguished by a densely hairy body and wide shaggy wings with a dense network of longitudinal veins.

In damp and dark rooms, it is often found on the windows of a harmless common butterfly(Psychoda phalaenoides), reaching far to the north.

The southern relatives of butterflies are not so harmless - mosquitoes(Phlebotomus), common in the tropics and subtropics, and in the USSR found in Central Asia. Starting from April, female mosquitoes, like female mosquitoes, leave their daytime shelters at dusk and attack various mammals, birds, reptiles, delivering many difficult minutes to people. Feeding blood for females is absolutely necessary, otherwise they will not leave offspring. The nectar of flowers, although consumed by mosquitoes for food, fully provides only males, while female mosquitoes are particularly bloodthirsty. Having sucked the blood, the females begin to digest it. At the same time, the maturation of eggs in the ovaries begins.

Unlike mosquitoes, mosquitoes are not associated with water. Their larvae develop in various organic remains, however, at a sufficiently high humidity. In settlements, mosquito development sites are spaces under the floor, garbage pits, latrines, barnyards, in nature - caves, hollows, damp pits and, especially in desert areas, burrows of turtles and rodents. The duration of development of one generation of mosquitoes is about 2 months.

A person should carefully guard against the bites of these small insects. With their saliva, causative agents of serious diseases can be introduced into the blood - the papatachi fever virus, as well as leishmania, which cause visceral and cutaneous leishmaniasis-pendinus ulcer. Especially dangerous is visceral leishmaniasis, which affects the internal organs of a person - the liver, spleen, bone marrow.

gall midges(Cecidomyiidae) - family Diptera, numbering over 3000 species. This includes small mosquitoes, mostly orange color, with long antennae and legs and with very weak wings, reinforced only by 3-4 longitudinal veins. Adult gall midges do not feed and live only 2-3 days, so the prosperity of this family is explained by many useful gadgets that have developed in their larvae.

The smaller the insect, the more enemies it has. But the larvae of gall midges, which can be examined in detail only with a magnifying glass, are not afraid of enemies - they are securely hidden inside the gall both from predators and from the adverse effects of the external environment.

Galls - abnormally altered parts of organs, and sometimes entire organs of a plant (flowers, fruits, shoots, leaves), transformed by larvae into a more or less closed chamber (Table 58). In such a chamber, the larvae are provided with nutritious food - vegetable juice, they are not afraid of the vicissitudes of the weather - the walls of the gall reliably isolate them from adverse effects.

The gall formation process is very complex. Gall midge larvae do not gnaw on plant tissue; their tiny head and piercing mouthparts are unsuitable for this. The larva acts differently: it secretes specific growth substances onto the surrounding tissues, under the influence of which the plant cells begin to grow rapidly and divide. As a result of close and precise interaction between the larva and the plant, a gall of a strictly defined characteristic shape is formed, so that the type of gall midge can also be easily determined from the shape of the gall. Adult larvae sometimes pupate in the gall, sometimes fall into the soil, where they weave a silky cocoon.

Inside the cocoon, the larva quickly turns into a chrysalis. Adult gall midges emerging from pupae must find a plant suitable for the development of larvae. There are a lot of phytophagous gall midges, but each species is strictly confined to a particular plant species. If the female makes a mistake, the larvae that hatch from the eggs will not be able to form a gall on an alien plant and will die. But such errors are very rare, since gall midges distinguish plants very accurately, guided by subtle features their scents.

Many species of gall midges are common and very widespread. In the forests on the petioles of aspen leaves in summer there are reddish rounded galls. aspen petiolate gall midge(Syndiplosis petioli, pl. 58, 2). The tips of willow shoots are transformed into a characteristic gall, resembling a rose flower in structure, larvae willow roseforming gall midge(Rhabdophaga rosaria, tab. 58.5). Galls caused by saxaul gall midges in deserts are especially diverse.

Gall midges periodically breed in incredible numbers. Particularly dangerous during periods of mass reproduction are species that damage cultivated plants. Common in Europe, Asia and North America hessian fly(Mayetiola destructor) - the scourge of grain breads. The females of this gall midge lay their eggs on the leaves of seedlings of wheat, rye or barley. The larvae develop in the leaf sheaths, damaging the stem so much that it breaks off from the wind. Fields affected by Hessian look as if trampled by cattle.

However, not all groups of gall midges develop in plant tissues. Primitive gall midges still retained a strong connection with their primary habitat - soil, litter, rotting wood. Particularly noteworthy are the gall midges of the genus miastor with a single species - Miastor metraloas. Colonies of larvae of this species number thousands of specimens (Tables 58, 12), and each colony originated from one egg. Miastor is distinguished by the ability, rare among insects, to reproduce at the larval stage. As soon as the larva of this species reaches maturity, numerous daughter larvae quickly form inside it, which, eating the insides of their parent, break the wall of her body and go outside. They eventually suffer the same fate, and the colony of larvae grows rapidly. Only after multiplying strongly, all the larvae of the colony finally pupate together, and adult gall midges scatter in search of new habitats.

This rare method of reproduction, first studied by N. Wagner in these gall midges, was called pedogenesis. Further pedogenesis in the class of insects was also discovered in one of the North American beetles.

Family pachyderms(Bibionidae) includes about 400 species, the significance of which in nature lies in the active processing of organic matter entering the soil and improving soil properties. This processing is carried out by large, up to 1.5 cm, gray larvae with a large head, strong jaws and numerous fleshy outgrowths on the body. The larvae live in separate colonies, each of which is the offspring of one female, who has laid her entire supply of eggs in a given place. Only some dilofus (Dilophus) feed on living plants, the larvae of which gnaw the roots.

Adults appear very amicably during the warm spring months. They often accumulate en masse on flowers, grass, leaves of shrubs or lazily fly in the sun. Peculiar eyes of thick-legged. In males, each eye is divided into two parts, and the facets in the upper half are much larger than in the lower. Usually the eyes are densely covered with hairs. Antennae short, composed of 9-12 segments. The tibiae of the forelegs are thickened and provided with spines. Often, males and females differ in color. At garden skein(Bibio hortulanus) the male is black, the female is red-brown, but her head, shield and legs are black.

The expressive appearance of slow, clumsy, brilliantly black or brown mosquitoes from families aximiid(Axymyiidae) reminds of those distant times when dipterans were still in their infancy.

Indeed, many of the structural features of these mosquitoes are inherited from their distant ancestors. First of all, attention is drawn to their wings, adapted to a slow and heavy flight, sluggish, clumsy legs, and the whole appearance of an insect, unable to either fly away quickly, or run away, or in any other way protect itself from enemies. Only the eyes of these mosquitoes have reached a high degree of perfection: they occupy almost the entire surface of the head, and in males they each consist of two sections - the upper, of large facets, and the lower, of smaller facets. The mouthparts of mosquitoes are reduced, and the antennae are greatly shortened, but have a large number of short segments, which range from 13 to 17.

How did such helpless insects survive to this day? This became possible because the almost complete defenselessness of adult mosquitoes was compensated by the development of very advanced adaptations in their larvae, which passed on to life in wet, rotten wood. They have a large head and strong jaws, with which they cut short passages. Their thick whitish body ends with a long respiratory tube, at the base of which 2-4 bead-like outgrowths are attached with a dense plexus of tracheae inside. All this is a complex breathing apparatus in wood saturated with water. Other insects could not adapt to life in such an environment, and therefore the aximiids have very few enemies and competitors. But even under these conditions, only 4 species of this family have survived to this day, distributed only in the northern hemisphere.

Relatively recently, in 1935, when it seemed that all families of Diptera were already known, a description of a strange mosquito found in the mountains of Japan was published. This find immediately attracted the attention of scientists, since the described insect could not be included in any of the known families of the order. Thus, the first information about the new family nymphomiids(Nymphomyiidae), whose representatives were also recently found in North America.

white nymphomia(Nymphomyia alba) differs from other Diptera primarily in its large elongated triangular wings with very weak venation. The anterior and especially the posterior margin of the wings are covered with dense rows of very long hairs, which increase total area wing. The head of mosquitoes is directed straight forward, the underdeveloped eyes merge not with the upper, but with the lower side, the mouthparts are underdeveloped, and the antennae consist of only 3 segments with a small appendage at the end.

Even more amazing is the white nymphoma chrysalis, which has a free movable head. The only thing known about the larvae of this amazing mosquito is that they live along the banks of mountain streams. This is established because insect pupae were found there, but no one has ever seen the larvae themselves.

Among modern Diptera, there were no forms with which nymphomiids could be brought closer. They cannot rightfully be considered long-whiskered Diptera, since their antennae consist of only 3 segments. They also differ sharply from short-haired ones. Only from the Upper Triassic deposits studied in Central Asia are known fossil Diptera with a similar structure. When the nymphomiid larvae are studied, it may be possible to answer the question of which modern Diptera are their closest relatives. So far, this family in the Diptera order occupies a separate position.

Suborder Short-legged Diptera (Brachycera-Orth0rhapha)

These are typical flies with a compact, short body and broad, strong wings. Their antennae consist of 3 segments, but the last of them may retain traces of additional dissection. The head capsule of the larvae is strongly reduced. The larval skin is usually shed during pupation. The pupa is covered; when the fly emerges, its thorax is ready to crack along a T-shaped line.

horseflies (family Tabanidae) are large blood-sucking Diptera. A female horsefly is capable of taking up to 200 mg of blood in one bloodsucking, that is, as much as 70 mosquitoes or 4,000 midges drink. If we add to this that in the swampy areas during the hot summer months, herds of domestic animals are attacked by tens of thousands of horseflies, the enormous negative significance of horseflies in nature and human economy becomes clear. Their harmfulness is aggravated by the fact that at the time of bloodsucking, horseflies carry pathogens. anthrax, tularemia, poliomyelitis and other serious diseases, and also transmit some diseases caused by nematodes.

Livestock losses from horseflies are great. Often the most productive pastures along lakes and in river valleys are empty during the summer months, as they cannot be used due to the abundance of bloodsuckers. Even with a moderate attack of horseflies, cows reduce their milk yield by 10-15% and quickly lose weight. Scientists have calculated that in a day the loss of strength in animals that are bothered by horseflies and flies is equivalent to malnutrition 400 G oats per head of cattle. And this is understandable, since the largest of horseflies reach a length of 2-3 cm, their bites are extremely painful and are accompanied by swelling, which is caused by saliva that enters the wound during bloodsucking.

Horseflies are sometimes incorrectly called gadflies. However, it is enough to make sure that a fly caught on an animal has a short, piercing proboscis in order to confidently attribute it to horseflies. The large eyes of horseflies are beautiful - golden, shimmering with all the colors of the rainbow. Their wings are sometimes transparent, sometimes with smoky spots, the abdomen is always flattened.

The life cycle of horseflies has much in common with the main features life cycle other bloodsuckers. Males feed exclusively on the nectar of flowers and sugary secretions of aphids, mealybugs, scale insects, as well as sweet juice flowing from injured trees.

Unfertilized females also follow the same diet, however, once fertilized, their aggressiveness has no limits. They attack animals and humans on hot days from morning until sunset, rainflies are active in cloudy weather, especially before rain. Among their victims in the first place are large animals: deer, elk, roe deer and especially livestock. Horseflies are also capable of attacking small animals - rodents, birds, especially fledgling chicks, and even lizards - monitor lizards, takyr roundheads, etc. They do not even neglect animal corpses in the first 2-3 days after death, which makes horseflies especially dangerous vectors infections.

At close distances, horseflies are guided by vision and perceive the contours and movement of objects. Often they make mistakes and pursue moving cars, boats, steamers for a long time, even flying into train cars.

Horseflies usually do not differ in food selectivity. However, in complex plant communities, for example, in multi-layered tropical forests, individual species complexes are found mainly in one plant layer. In the humid forests of Cameroon, for example, Ethiopian motleys(Chrysops silvacea, Ch. centuriones) stay in the crowns of trees and pursue herds of monkeys.

Females sucking blood quickly digest it. Already after 24 hours, the blood clot in the stomach is significantly reduced, and the absorbed nutrients are fed to the gradually growing ovaries. After 48 hours, only not a large number of semi-digested blood, and maturing egg cells grow strongly. After 76 hours, digestion ends, the eggs finally ripen. Thus, oviposition is produced on average 3-4 days after bloodsucking. As a result of repeated bloodsucking, female horseflies can go through up to five such cycles, laying over 3500 eggs as a result. The fecundity of different horsefly species can, however, vary greatly.

Eggs are laid on plants, usually above the water of lakes and swamps. The larvae emerging from the eggs fall into the water and live in the moss cover, plexuses of roots or in upper layers wet soil, in some species feeding on decaying plant debris, in others - actively predatory. Their victims include larvae of other insects, amphipods, earthworms.

bull horsefly(Tabanus bovinus) is one of the largest species. It is dark brown, the chest with dark stripes and yellowish hairs, the abdomen is bordered by a yellow-brown border with a strip of light triangular spots in the middle part.

Brightly colored smaller common lacewing(Chrysops caecutiens), which actually has bright emerald gold eyes. The abdomen of this species at the base with yellow spots. More modestly painted ordinary raincoat(Chrysozona pluvialis), whose wings are distinguished by a complex smoky pattern. In total, there are over 3,500 species in the horsefly family.

long-proboscis(Nemestrinidae) - small family Diptera, distributed mainly in tropical and subtropical regions. Adult flies resemble gadflies, but are well distinguished from them by a strongly elongated proboscis, which is usually much longer than the body. With its help, flies suck the nectar of flowers. However, it is not so easy for long-proboscis women to get to the nectar - their proboscis does not bend, and the fly, especially in windy weather, has to work hard to satisfy its hunger.

North American females trichopsides(Trichopsidea clausa) lay their eggs in cracks in tree trunks or telegraph poles. The fertility of females is very high - several thousand eggs, and this is understandable, since the original larvae that emerged from the eggs, equipped with numerous outgrowths, are simply carried in different directions by the wind. Meeting with the host, which is the locust, largely depends on chance, so most of the larvae die without reaching the goal. But if this encounter occurs, the larva penetrates the body of the locust through one of the spiracles and, feeding on the tissues of the host, completes its development by autumn and hibernates. Adult flies appear in spring.

In total, about 250 species are known in the family of long-proboscis.

large family lion cub(Stratiomyiidae), which includes about 2000 species, is distributed mainly in the humid tropics. Only about a hundred species are found in the northern forests of Eurasia.

It is easy to distinguish a lion cub by their wide, flattened body, usually painted in bright colours often with a metallic sheen, along short transparent wings and peculiar antennae with an annular last segment.

It is this form that common lion(Stratiomyia chamaeleon), which is often found on flowers. Its black belly with yellow spots, brown chest with a yellow shield and red-yellow legs harmonize well with the bright color of the corollas of flowers, hiding the insect from enemies.

The larva of this fly, which lives in small polluted reservoirs, is peculiar. Its fusiform body, which in an adult larva reaches a length of 20 mm, ends with a long "tail", which is formed from several elongated last segments of the abdomen. At the end of the "tail" is a stigmal plate with two holes for breathing. There is also a corolla of long, non-wettable hairs. The larva breathes, hanging by the rear end of the body to the surface of the water. In this case, non-wettable hairs straighten out, stigmas open, and the larva itself is passively held by surface tension forces. Having inhaled, the larva sharply bends, breaking away from the surface film. At the same time, the hairs fold and close the stigmal area. Then the larva slowly sinks to the bottom, where it burrows among the silt and algae, swallowing decaying organic matter. The pupa is formed inside the skin of an adult larva.

Many species of lion cubs develop in soil, manure, and rotting wood. Among them, metallic green or blue ones are especially peculiar. geosargus(Geosargus), whose larvae are common in manure. The integuments of the larvae are impregnated with calcium carbonate and serve as good protection for both the larva and the pupa, which is formed inside the larval skin.

About 5000 species families ktyrey(Asilidae) - mainly inhabitants of open spaces - steppes and deserts. These slender flies, whose body is covered with dense short hairs, usually bask in the sun, ready to take off instantly when danger or in pursuit of prey. Everything in their appearance speaks of adaptation to predation. The sharpness of the bulging eyes, deeply separated by the crown, is so great that it is difficult to approach the sitting spikes unnoticed. Although there are no mandibles in their proboscis, other parts of the oral apparatus - maxillae, subglottis and lower lip - form a very perfect stabbing organ. The saliva of ktyri contains a strong poison, from which insects die instantly. A ktyr caught by hand sometimes bites a person. Such a sting is as painful as a bee sting.

The speed and accuracy of the reaction of the ktyrs is surprising: a moment, a short take-off, and the lifeless insect is already sucked out by the ktyr, which has returned to its original place. The aggressiveness of ktyrs is so great that they come out victorious in a fight with such well-armed insects as bees, wasps, horse beetles; the extraordinary voracity of these flies makes them hunt incessantly.

The larvae of ktyrs are also predators. In the soil, they pursue the larvae of other insects, and can withstand prolonged starvation. But in the case of a successful hunt, they grow very quickly.

Peculiar larvae lafriy(Laphria), chasing larvae of longhorn beetles or lamellar beetles in wood. Their body bears numerous outgrowths that help the larva to move in the passages. Adult lafriya sit on the bark of trees. Sometimes they are painted in bright colors, such as golden red lafriya(L. flava).

Large ktyri reach a length of 4-5 cm. Such giant ktyr(Satanas gigas), found in the steppes.

Among Diptera, there are few other groups whose representatives could be compared in speed and dexterity of flight with flies from families buzzed(Bombyliidae). The appearance of most of the buzzers is very peculiar: a short stocky body covered with long dense hairs, wings at rest directed to the sides and back, resembling the position of the wings of high-speed aircraft, and, finally, a needle-shaped proboscis, which in some species is not inferior to the length of the body.

The proboscis is an excellent adaptation for sucking nectar from flowers with a deep corolla, which are inaccessible to many insects. But the buzzers would not have been able to use this advantage if they were not excellent flyers. With amazing dexterity, feeding flies literally hang in the air above the flowers, plunging their proboscis into the nectaries at this time, and, without sitting on the flower, suck out the nectar.

In the modern fauna, the buzzing family is among the flourishing ones and includes about 3000 species.

Predators are like adult flies families pushers(Empididae) and their larvae living in the soil. The nectar of flowers, on which adult flies are often found, serves as an additional source of food for them. The long, needle-shaped proboscis of pushers is equally well adapted for sucking out insects and for absorbing plant juices. The prey - small Diptera - is captured by the front legs, the hips of which are planted with spikes, and the shins are tightly applied to them, forming strong forceps.

A disproportionately small round head and slightly pubescent body complement the characteristic appearance of the representatives of this family. But the "dances" of pushers during the nuptial flight are especially peculiar. They are not only quite complex in their execution, but are also notable for the fact that at this time males drag along silky "parachutes" or elliptical "balloons" with foamy walls, inside of which lies dead prey - small fly or a mosquito. Before mating, the male offers this prey to the female and thereby saves his own life, since aggressive females often eat males after copulation. Such "dances" are observed in representatives of the most common genera - empis(Empis) Gilara(Hilara) c others

greenfinch flies (family Dolichopodidae) - metallic shiny or grayish small diptera with long legs and a laterally compressed body. There are more than 3500 species in the family. Greenfinches are not uncommon in wet meadows, along the banks of ponds and rivers, but they are difficult to notice against the background of green parts of plants. They attack small mosquitoes and midges, killing them with a proboscis, consisting of pointed appendages of the lower lip and spines of the subglottis; the mandibles of these Diptera are not developed.

Most closely related to water greenfinches-water striders(Hydrophorus) gliding over its surface like water bugs. They hunt for small insects which often stick to the surface of the water. Their larvae, like those of most other greenfinch species, prey on moist soil.

Useful greenfinches-medeters(Medetera), whose larvae destroy bark beetles in their passages under the bark of trees. Adult flies of a grayish color are often caught on trunks in the forest.

Suborder Short-eared dipteran (Brachycera-Cyclorhapha)

Typical fly with a short, compact body and broad, strong wings. Their antennae are shortened, 3-segmented, with a seta on the third segment. The head capsule of the larvae is completely reduced, only the mouth hooks are preserved. The larval skin does not shed during pupation, acquires a barrel-shaped shape and hardens, being saturated with special secretions, forming a false cocoon - puparia. The doll is free. When an adult fly emerges, the puparium opens in a rounded line under pressure from the head or frontal vesicle, which in most cases is well developed.

hunchbacks(family Phoridae) are very small nondescript flies with a swollen hump-shaped chest, strong legs, whose hips are thickened. The transparent wings are reinforced along the anterior margin by two thick closely spaced veins; the rest of the veins of the wing are much thinner; there are no transverse veins in the wing.

In anthills there are representatives of the genus platyphora(Platyphora). The winged male of these flies retains all the features of the family, while the female is wingless, her body is flattened like that of a cockroach, outwardly she does not resemble a fly in any way.

Peculiar species live in termite mounds termitaries(Termitoxenia, Termitomyia), which are sometimes distinguished into a separate family Termitoxeniidae. They have a soft, elongated body, an elongated head with a piercing proboscis, short antennae, and tenacious legs (Fig. 420, 3). The wings are represented by small stumps, for which termites usually drag them; the abdomen is soft, unusually strongly swollen.

On the flowers of Umbelliferae and Compositae, often next to wasps and bumblebees, flies very similar to them from families hoverflies(Syrphidae, pl. 59). Although these flies are completely harmless, the birds do not dare to touch them, mistaking Hymenoptera armed with a sting. There are about 4500 species in the hoverfly family.

The flight of these flies is original. Along with normal flights, hoverflies can hang in the air for a long time, continuously working their wings, but not moving. The study of such a "standing" flight showed that only when the wing is lowered is its plane directed horizontally - the lift force arising in this case balances the weight of the insect. In the lower position, the wing turns 45 ° and returns upward, cutting the air with its sharp leading edge. Naturally, no translational force arises in this case.

The way of life of hoverfly larvae is unusually diverse, in contrast to adult flies, which part with nectar-bearing flowers only in order to lay their eggs in a suitable place. Females of some species fly for this to dirty, fetid streams, others rush under the forest canopy, looking for trees with fermenting juice flowing from wounds, still others look for aphid colonies or nests of bumblebees, fourth ones fuss around anthills, etc.

Of the syrphid larvae that develop in water, the larva common bee(Eristalis tenax), which is figuratively called the "rat". The body of this larva is barrel-shaped, indistinctly segmented, with outgrowths - "false legs" - on the abdominal surface. The last three segments of the abdomen form a characteristic "tail" - a breathing tube. These segments are thin, and each subsequent one can be drawn into the previous one or, conversely, quickly move out of it. At the end of this device are two spiracles, and two thick tracheae pass inside the tube. The fully extended respiratory tube of adult larvae reaches a length of 12-15 cm(Fig. 421, 5).

Rice. 421. Hoverfly flies: 1 - conosirphus (Conosyrphus volucellum); 2 - decorated spherophoria (Sphaerophoria scripta); 3 - bakha (Baccha elongata); 4 - chrysotoxum (Chrysotoxum festivum); 5 - "rat" - larva of the common bee (Eristalis tenax); 6 - larva of the wasp hoverfly (Temnostoma vespiforme)

Its significance in the life of the larvae becomes clear if you move the bottom of the reservoir in which they live with a stick. From there, silt will rise, undecomposed organic matter and bubbles of fetid gases will appear. Meanwhile, the bee larva boldly descends into this rotting mess, where it finds abundant food - after all, it leaves the end of the breathing tube on the surface of the water, through which gas exchange occurs. When the larva dives into the deeper layers, it is forced after a while to rise to the surface for breathing. The larva pupates in the soil next to the pond. The pupa is formed inside the larval skin. An adult fly with a brownish chest and a yellow-black spotted abdomen is very reminiscent of a bee (Table 59, 2). It was on this similarity that the assertion, which arose in the early stages of the development of science, was based, that bees can be born from mud. Now such a statement can only cause a smile.

Very similar to wasps adult hoverflies from the genus darkstomy(Temnostoma). Their larvae are active wood destroyers of wet stumps and dead trunks. How can these larvae of higher Diptera, which are known to be devoid of a head capsule and gnawing jaws, gouge through wood? To do this, the larvae turned out to have completely unexpected adaptations: the bases of their prothoracic spiracles greatly increased, partially separated and turned into two powerful scrapers, the edges of which were lined with teeth. They scrape wood in the same way that a mollusk - a shipworm - uses the remains of its underdeveloped shell for the same purpose.

However, the most common of the hoverflies are species that live in aphid colonies. It is hard to imagine that the greenish or gray larvae resembling small leeches crawling in colonies of aphids belong to the same family as the "rat", but this is so. It is enough to look at adult hoverflies from the genus sirphs(Syrphus). Their appearance is quite typical: a dark chest with a metallic sheen and the same abdomen, on each segment of which there are two crescent spots.

The larvae of our common sirphs (Syrphus balteatus, S. ribesii) are serious enemies of cabbage aphids (Tables 59, 16). One adult larva sucks over 200 aphids per day. Given that the feeding period lasts about 20 days, it can be calculated that each larva will destroy up to 2000 pests during this time, and there are several hundred such larvae in the offspring of only one female. Attracting syrphid to the fields by sowing nectar-bearing flowers, you can successfully fight many harmful aphids.

Hoverfly larvae from the genus microdon(Microdon), living in anthills, was first taken for molluscs and described as a special genus of these invertebrates. This mistake is not accidental: the larva has a rounded body with a flat bottom surface without any traces of articulation and even some semblance of a shell, which is formed by its hemispherical hardened outer covers, bearing layers of dust and dirt. However, bronze-green flies eventually emerge from these larvae, whose belonging to hoverflies is beyond doubt.

Various species have achieved the greatest success in imitating the stinging hymenoptera. bumblebee, or hairy(Volucella), which are similar to bumblebees both in body shape and in the arrangement of thick fluffy hairs, painted, like in bumblebees, in various colors (Table 59, 8). This similarity arose, in all likelihood, because the bushes are biologically closely related to bumblebees. Their larvae develop in the nests of bumblebees, feeding on the corpses of dead larvae or always available excrement and garbage.

It is hard to imagine that the sticky resin flowing from injured firs can hide living larvae. But hoverflies have adapted to this habitat. Larvae black chylosia(Chilosia morio) grow only in resin. The whitish body of these larvae is immersed in its thickness, and a short breathing tube is brought to the surface, providing an unimpeded air supply. In the spring, also without leaving the resin, these larvae pupate in a kind of puparia. Completely black hoverflies that have flown out lay their eggs in wounds with fresh resin.

Another interesting example of imitation of stinging hymenoptera is found by representatives families big-headed(Conopidae), numbering over 600 species. The abdomen of adult flies is slender, weakly stalked, slightly curved downwards - signs that make the painheads look like wasps. The head of the flies is very large, the antennae are often elongated; the proboscis is long, thin, with one or two articulated bends; the body is painted in black, brown and yellow tones.

One of the largest species in the family yellow-footed bighead(Conops flavipes), up to 15 long mm. Her body is black, her head is with yellow spots, and there are also 2-3 yellow bands on her abdomen.

cereal flies (family Chloropidae) have become infamous as pests of grain bread, no less dangerous than the Hessian fly. Almost all representatives of this vast family, numbering over 1300 species, develop on wild and cultivated cereals. Adult flies are common in meadows, forest clearings, on the margins of agricultural fields, where they can be collected in large numbers with an ordinary net. The size of cereal flies does not exceed 3-5 mm, body naked, brilliant black, yellow or greenish; in many species, the chest is on top with longitudinal dark stripes on a yellow background.

The larvae damage the apical part of the stem of cereals, often resulting in a characteristic spindle-shaped accumulation of leaves. As a result, the plant either dies or begins to bush, developing weak adventitious stems.

Most species of grass flies are food selective; each of them successfully develops on a few, strictly defined plant species. Most economic important species of this family, although they are also found on wild cereals, they show a clear preference for cultivated ones.

One of the most dangerous pests cereal bread is swedish fly(Oscinella frit). New studies of these flies, however, give reason to believe that this is not one species, but a whole complex of species, each of which prefers one of the grain crops - wheat (O. vastator), barley (O. pusilla) or oats (O. frit ).

Damage to cultivated cereals by swedish fly varies well depending on the time of oviposition. If the attack of the pest coincides with the tillering phase of spring crops, then the larva lives under the leaf sheaths at the rudiment of the ear, which is destroyed. When the next generation of the Swede flies, the bread is already earing. In this case, the eggs are laid directly in the ear and the larvae eat the grains.

Another harmful species from this family is green-eyed(Chlorops pumilionis) is a yellow fly with black stripes on the chest. In spring, it most often infects spring wheat and barley, and in autumn - seedlings of winter wheat and winter rye. The green-eye larva lives under the leaf sheaths, causing shortening and thickening of the internodes.

speckwings (family Trypetidae) - small or medium size flies with a peculiar, characteristic for each species pattern on the wings. The drawing is made either with dark stripes and spots on transparent wings, or one or another number of light spots appears on a general dark background. Spotted is often the abdomen. In total, about 2500 species are known in the family.

Adult flies feed on the nectar of flowers or the secretions of aphids. Their larvae are typical phytophages, that is, they feed on living plant tissues. Many species of variegated insects have adapted to the development inside the baskets of composite plants, where they eat away the ovaries of flowers and the receptacle. Having broken large baskets of burdock (Arctium), very often you can find dirty white larvae. orellias(Orellia tussilaginis). There are also larvae of variegated flies in the succulent fruits of cherries, barberries and other plants.

cherry fly(Rhagoletis cerasi) brown-black with a yellow head and shield, legs, with the exception of the thighs, are also yellow. Females lay their eggs under the skin of ripening cherries, the larvae feed on the pulp of the fruit, causing them to rot and fall off.

Some species of variegated insects enter into more complex relationships with plants, causing the formation of pathological growths - galls.

In all cases, the representatives of this family have a pronounced food selectivity - certain types families are able to develop not on any, but only on strictly defined plant species.

Extremely interesting from a biological point of view mining flies (family Agromyzidae). Representatives of this relatively large family, which includes 1000 species, like variegated flies develop in living plant tissues. As with the variegated flies, the nature of the damage caused by the larvae of mining flies is diverse. The family includes species that form galls, there are species that inhabit the inflorescences of Compositae or their seeds, pests of grass stems, and even species that have moved to living in trunks and branches of trees. But miner species reach the greatest prosperity, the larvae of which eat away vast slit-like cavities in the leaf parenchyma, called "mines".

Most mining flies are characterized not only by the damaged plant species, but also by the shape of the mine, which is sometimes so specific that it makes it possible to accurately determine the type of pest. It is interesting to note that representatives of this family have adapted to life on almost all groups of plants - from primitive ferns and horsetails to the historically youngest Compositae.

Some species of mining flies that have switched to feeding cultivated plants, have proven to be serious pests. Cabbage and other cruciferous plants are harmful phytomysis(Phytomyza atricornis), which, unlike most species of the family, is distinguished by a significant indifference to food. About 300 species of plants from 30 different families are known, on which the larvae of this fly were found. The appearance of adult specimens is typical for the family: body length - 2-3 mm, the back is brilliant black, the legs and sides of the chest are yellow.

In some places in the forest zone, miners from the genus dizygomysis(Dizygomyza) associated with tree species. Willows, birches and some fruit trees are especially affected by them.

Family coasters(Ephydridae), which includes more than 1000 species, reaches its peak in the forest zone. These very small, nondescript flies, painted in gray and black tones, are notable for their biology.

A completely unusual way of feeding larvae oil psilope(Psilopa petrolei) found in California oil wells. Numerous bacteria were found in the oil, as well as in the intestines of the larvae, capable of decomposing paraffin and, presumably, providing the larvae with food. So far, however, it is not clear how the larvae obtain the nitrogenous substances necessary for the synthesis of proteins.

Among the harmful species of the family are barley shore(Hydrellia griseola). The larvae of this small, transparent-winged gray fly develop in mines on the leaves of cereals, including barley, wheat and rice, and sometimes cause significant damage.

dung flies (family Scatophagidae) got their name because their most common species are common on animal excrement, i.e., they are coprobionts. Takova red dung beetle(Scatophaga stercoraria) - large fly, up to 10 mm, yellow-brown in color with dense rusty-yellow hairs and slightly lighter wings of the same shade (Table 60, 8). Its larvae prey on manure and faeces.

However, paradoxically, most species of dung flies are not associated with manure. Among them, plant pests are of particular interest, the larvae of which, like the larvae of mining flies, develop in leaf mines or live in the generative organs of plants.

Pests of ears of wild and cultivated cereals (rye, timothy grass) are larvae of ear flies (Amaurosoma).

There are more than 500 species in the family. Many of them are associated with accumulations of decaying plant remains.

There are over 3000 species in family real flies(Muscidae). Their appearance is easy to imagine, remembering the well-known housefly.

Many species of real flies are synanthropic, that is, more or less closely related to humans. Some of them, for example housefly(Musca domestica, Fig. 423), are no longer found in wild nature outside towns and cities. Manure, feces, various garbage - these are the garbage where the larvae of the house fly develop - a constant companion of human settlements. The reproduction rate of this species is amazing. At one time, the female lays on average about 100-150 eggs, but with sufficient nutrition, egg-laying is repeated at intervals of 2-4 days, so that her total fertility is 600, and in countries with a hot climate 2000 or more eggs. If the larvae, pupae and flies themselves did not die, then the offspring of only one female by the end of summer could exceed 5 trillion (5,000,000,000,000) copies.

The larvae of the housefly, like other higher flies, do not have a head. They dilute food by releasing digestive juices onto it - this method of digestion is called extraintestinal. As a result, the entire colony of fly larvae turns out to be floating in a liquefied, semi-digested medium, which they constantly swallow (Table 55). As a result, food is used with amazing savings. In one liter of horse or cow dung or in the same amount of kitchen waste, from 1000 to 1500 fly larvae can simultaneously develop, and up to 4000 in pig manure.

House flies are dangerous spreaders of infections. Each of them, having been on feces and various kinds garbage, carries about 6 million microorganisms on the surface of its body and at least 25-28 million in the intestines. And I must say that the pathogenic bacteria in the intestines of the fly are not digested and quite viable stand out. On the flies, typhoid and paratyphoid bacilli, dysenteric bacillus, vibrio cholerae, tubercle bacillus, anthrax spores, the causative agent of diphtheria, and also worm eggs were found. Therefore, the fight against houseflies is an important link in common system fight against human diseases.

Along with housefly larvae, many other species of this family develop in manure and garbage. Larvae house fly(Muscina stabulans) also begin their lives as consumers of decaying plant matter, but then, having grown stronger, they begin to feed on the larvae of other Diptera, that is, they become predators. One of the most active predators in manure are larvae. common denticle(Hydrotaea dentipes), which destroy the larvae of houseflies, zhigalok and other species of Diptera.

Competition among the inhabitants of manure is usually extremely fierce. Some species of flies have developed a special life rhythm that allows them to avoid this competition. big losses: they do not lay eggs in manure, but live larvae, often already quite large. So, the larvae of some species of the genus dasiphora(Dasyphora) develop in the body of the mother up to the third stage, that is, they enter the dung when they are already almost adults.

It is often said that by autumn the flies become angry and begin to bite. Such folk omen arose because it is by autumn that flies-zhigalki appear, first of all autumn burner(Stomoxys calcitrans). This fly, equipped with a piercing proboscis, is a bloodsucker and is harmful as a mechanical carrier of anthrax, tularemia and other diseases.

Another blood-sucking fly has become infamous, carrying a special type of trypanosoma - the causative agents of "sleeping sickness", common in Africa. Trypanosomes themselves are constantly found in the blood of antelopes, which are not harmed. Tse-tse fly(Glossina palpalis), having drunk the blood of such an antelope, often then bites a person, passing him trypanos. The disease is expressed in deep exhaustion and usually ends in death.

Another species from the same genus, Glossina morsitans, spreads a similar disease, which, however, affects only animals. Interestingly, in these flies, the larva develops completely inside the swollen abdomen of the female, feeding on special secretions of the accessory glands. After leaving the mother's body, the larva immediately pupates in the soil.

Very serious pests are real flies that develop in living plant tissues. Plants affected by flies usually rot and die. Cabbage and other cruciferous cabbage flies are very harmful, the grayish color of which makes them very similar to houseflies. Their larvae make holes in the roots of damaged plants, contributing to the spread of root rot. Especially dangerous spring cabbage fly (Chortophila brassicae), the first generation of which attacks seedlings, causing the death of plants.

Similar to cabbage, but lighter colored onion fly(Ch. antiqua). The larvae of this pest eat the insides of the bulbs in the gardens. Beets are damaged by larvae beet fly(Regomyia hyosciami), which eat bubble-shaped cavities in the leaf parenchyma. Lives in stems of cereals winter fly(Hylemia coarctata). Its larvae cause lesions resembling those of a Swede. Larvae spring fly(Phorbia genitalis), also living in the stems of wheat and barley, gnaw out spiral passages in them.

* (Sakharov's locust-eater described below is sometimes classified as a separate family Acridomyiidae or included in the family Anthomyiidae.)

carrion flies(Calliphoridae) - a predominantly tropical family with about 900 species, some of its representatives are common up to the most northern regions. Like many tropical insects, they have a bright color of green or blue tones with a metallic sheen (Table 60).

In tropical countries, closely related species also attack humans. Typically, the females of these species lay their eggs on the earthen floor in the hut where people live, and the larvae then actively infiltrate under the skin of humans and domestic animals.

During the First World War, an incident occurred that helped to discover a completely unexpected beneficial effect of the larvae of carrion flies, which settled in festering wounds. Two seriously wounded soldiers of the German army were picked up only seven days after the battle, and the wounds of each of them were teeming with carrion fly larvae.

After the wounds were washed, they were in such good condition that this fact attracted the attention of surgeons, especially since such wounds usually ended in death.

The study of the action of fly larvae, such as green carrion flies(Lucilla) blue carrion flies(Calliphora), and others showed that, feeding on decaying wound tissues, they not only remove these tissues and small fragments of bones, but also prevent the reproduction of pathogenic bacteria with their secretions. In addition, they secrete allantoin into the wound, a substance that promotes their healing.

However, the use of flies from the natural environment is not always successful, as they can bring tetanus sticks or gangrene bacilli into wounds. Therefore, for the clinical treatment of difficult-to-heal wounds, flies are bred in the laboratory and completely sterile, that is, free from any pathogenic microbes, larvae are obtained.

Larger family gray blowflies(Sarcophagidae), numbering over 2000 species, is poorly represented in the tropics and reaches its peak in the more temperate zones of the northern hemisphere.

The body of these flies is most often painted in ash-gray tones with black checkered pattern or rounded spots.

In the forest zone, larvae develop on carrion common blowfly(Sarcophaga carnaria). Adult flies, gray with a black pattern, can be found on flowers, their sizes reach 20 mm, but there are also dwarfs only 6-8 mm.

Common in Southern Europe and Central Asia wolffart fly(Wohlfahrtia magnifica), distinguished from other species by the presence of three rows dark spots on a gray belly. The females of this species, like most other species of the family, are viviparous. They forcefully throw larvae into ulcers and wounds, as well as into the eyes, ears and nostrils of various animals. The larvae feed on living tissues, causing severe suffering, often ending in death. This species is especially harmful in pastoral areas.

There are many cases when the victim of the larvae of the Wolfart fly turned out to be a person in whom they usually caused prolonged suppuration (miasis) on the head or penetrated into the nasal cavity. Laying passages in the tissues, the larvae not only give rise to painful sensations: damaged areas they swell and fester, the tissues partially die off, bleeding begins from the nose. After removal of the larvae, all these phenomena disappear.

Family subcutaneous gadflies(Hypodermatidae), as its name implies, includes species whose larvae develop in nodules under the skin of animals.

Interesting are the adaptations of subcutaneous gadflies to ensure that a high number of adults is created in strictly defined periods in nature, which is important for the successful reproduction of species. Although gadfly larvae fall out of fistulas into the soil at different times, the first pupae formed in spring develop more slowly than those that form somewhat later. Therefore, the vast majority of pupae complete their development almost simultaneously, and within a few days a large number of adult flies emerge from them at once. Moreover, gadflies emerge from pupae at a strictly defined time of day, in the temperate zone usually from 7 o'clock. 30 min. up to 8 o'clock. 30 min. morning. All individuals that have appeared flock from large areas to the same points, constant from year to year, usually to the tops of some hills or mountains, to certain sections of roads, paths, etc. There are significantly more males in these clusters than females. If the gadflies are scared away from these places, then after a while they return there again. On the basis of these observations, even proposals were made to combat adult gadflies precisely in the places of their accumulation.

The females of the hypodermic gadflies laying eggs are very active and for a long time pursue animals in flocks, which turn into a stampede. It is possible to milk cows during the flight of gadflies only when they are standing in the water - gadflies do not attack them at this time. The amount of milk supplied by tired animals is halved, their fatness drops sharply. Northern reindeer husbandry suffers huge losses from subcutaneous gadflies, as the value of skins pierced by larvae is greatly reduced.

Sometimes, though very rarely, a person is a victim of subcutaneous gadflies. Usually these are people who care for pets. The migration of larvae of subcutaneous gadflies in the human body often ends with their penetration into the head - after all, the larvae migrate, like in animals, upwards. The most severe diseases are caused by the introduction of larvae into the eye. In this case, an operation is necessary to extract the larva, which leads to partial loss of vision.

bull gadfly(Hypoderma bovis) is common in Europe, North Africa and Asia. Females of this species lay their eggs on the hairline of animals, mainly on the legs. Mainly cattle are affected. After 4-6 days, larvae emerge from the eggs and, having penetrated under the skin, begin complex migrations. First, they rise along the connective tissue layers to the esophagus and penetrate into its walls, then descend into the chest and here they exit to the place of their final development, which proceeds under the skin in the intercostal spaces, where nodules are formed.

An adult gadfly reaches a length of 14 mm, its body is covered with thick hairs. Hairs on thorax yellowish gray in anterior half, black in posterior half; abdomen with black hairs in middle part, its end rufous, and base even paler.

Deer are very heavily infected with northern subcutaneous. On average, 200 gadfly larvae develop on one deer, and the maximum infection is estimated at 1000-1500 larvae.

Larvae different types stomach gadflies (family Gastrophilidae) develop not only in the stomach, but also in other parts of the intestinal tract. At the same time, females lay eggs on the hairline of the animal, but in strictly defined places - more often on the hairs of the lips, cheeks or intermaxillary space. In this case, the larvae emerging from the eggs independently reach the oral cavity and descend into the intestines. Some gastric gadflies lay their eggs on the hairline of those parts of the animal's body that it scratches with its teeth. In this case, the larvae do not leave the shell of the egg, remaining viable for 90-250 days - a period of time sufficient for the animal to accidentally lick the eggs of gadflies during scratching, from which larvae immediately appear in the oral cavity. Further migration of the larvae to the stomach or any other part of the intestine occurs quickly. Here, the larvae attach to the walls with mouth hooks, feed on the secreted mucus and blood, and when they reach maturity, they are carried out along with the feces. They pupate in the soil.

Gadfly-hook(Gastrophilus intestinalis) is one of the most numerous gastric gadflies. This is a large yellowish-brown species, up to 15 mm, with spotted wings. The thorax of the fly is covered with protruding light yellow or brownish hairs; the hairs on the abdomen are straw-yellow with some admixture of dark ones.

The female lays her eggs on the hairs of the host's lips. There is evidence that the female is also able to stick eggs into the skin of the animal with a sharp attachment process. The larvae emerging from the eggs develop in the oral cavity before the first molt, and then descend into the stomach. At the end of development, the larvae are carried into the rectum, where they reattach to the walls and live for a long time.

An interesting development cycle of representatives families nasopharyngeal gadflies(Oestridae), Females of all species of this group are viviparous, however, by the time they emerge from pupae, the larvae in the eggs do not have time to develop. Females spend almost three weeks in complete immobility, waiting for the moment when young larvae appear in their abdomen from eggs. After this, a period of active search for host animals begins. The female sprays several larvae each time directly into the nasal cavity of the animal, where they develop due to mucous and bloody pathological secretions. Together with the larvae, the female also sprays out a certain amount of liquid. The larvae are very sensitive to desiccation, and even before the evaporation of this liquid, they must get on the mucous membrane of the nasopharynx. Some animals, such as deer, during the attack of gadflies inhale dust and fine sand, thereby drying the nasal cavity and to some extent protecting itself from larvae.

In conditions temperate climate young larvae of gadflies overwinter, in spring and summer their development is completed. Adult larvae exit through the host's nostrils.

There are cases of attacks of nasopharyngeal gadflies on a person. In this case, females usually spray larvae into the eye. The larvae quickly spread and scratch the mucous membrane of the eye with their hooks, causing inflammation (conjunctivitis).

Great harm to livestock kruchak, or sheep gadfly(Oestrus ovis), which develops in the nasal cavity, frontal sinuses and cavities at the base of the horns of sheep. The female of this species lives up to 25 days, and the first 12-20 days are necessary for the final formation of larvae. Then the female energetically searches for the host and quickly attaches the offspring, since even a slight delay in laying the larvae leads to the fact that the larvae spread in the body of the female and cause her death. In total, the female can lay up to 500 eggs.

The losses caused by the kruchak are very great. With the development of more than 50 larvae in the nasal cavity and frontal sinuses in sheep, a “false whirlwind” is observed - a disease in which sheep circle in one direction and die after a few days. When the larvae enter the respiratory tract, death occurs from pneumonia.

The harm from gadflies is extremely great. Huge amounts of money are annually spent on the fight against these Diptera, however, the fight against gadflies is effective only when it is carried out according to plan and on time. large territories. In the USSR in the last decade, as a result of the use of a complex of chemical and preventive measures struggle, significant progress has been made in the extermination of gadflies.

The body of adult flies, especially the abdomen, is usually covered with strong bristles; the last segment of the antennae is laterally compressed. Tahini are sun-loving insects, in summer they are most often found on flowers, where flies feed on nectar or honeydew. However high temperature they avoid and hide in shelters during the hot hours of the day. Only a few species of tahini are characterized by a twilight period of activity.

Although fertilization occurs in the first hours after the appearance of females from puparia, eggs are not laid immediately. In various types of tahini, it takes from 8 to 25 days for the eggs to ripen in the ovaries. After that, the entire behavior of females changes dramatically, since the period of feeding on plants is replaced by a period of intensive search for a host.

Among the representatives of the family, there are relatively few monophage species that develop exclusively at the expense of any one animal species. Most tahini successfully attach their offspring to large numbers different hosts, belonging, however, to any one family or order, i.e., more or less related. The larvae that hatch from eggs swallowed with food pierce the intestinal wall and reach certain organs with the hemolymph current, where they develop. In some species, the larvae are located in the supraoesophageal ganglion, in others they penetrate the salivary glands or linger in the muscle tissue.

Growing up, the larvae begin to experience difficulty in breathing and usually attach with the posterior end of the body to one of the tracheal trunks of the host so that the spiracles of the larvae emerge into the lumen of the trachea.

The larvae that have successfully entered the body of the host begin to feed on its tissues, but in the first period they spare the vital organs. Only at the final stage of development, the larva secretes a large amount of digestive juices into the tissues of the host, causing their complete digestion. Having finished feeding, adult larvae most often exit through the integument of the body and pupate in the soil.

Bloodsucker eggs mature in the body of the female, and larvae hatch from them there. The food of the larvae is the secretion of special adnexal glands. Eggs in the ovaries are formed alternately, and therefore the female feeds one larva in each subsequent period of time. The larva grows rapidly on nutritious food and leaves the mother's body only to pupate immediately after climbing into the soil. Therefore, bloodsuckers and some other Diptera, which give birth to larvae ready for pupation, are often combined into a group of "puppets".

Bird bloodsuckers can generally live successfully on many bird species. When birds come into contact with each other, flies often change hosts. The species composition of bloodsuckers on birds of prey that prey on other birds is especially diverse: at the time when the predator eats its prey, all bloodsuckers living on it move to a new host.

In bloodsuckers of bats, two ways of attaching the born larvae have been noted. The females of most species during this period leave the host and attach the larvae to some kind of substrate - on stone walls caves, on the bark of trees, on the walls of attics, where mice hide during the day, etc. The bloodsucker that came out of the puparium searches for the owner on its own. Only a few species attach the born larvae to the fur of bats.

In total, there are about 150 species in the family. All of them are relatively small - length common bloodsucker bats(Nycteribia pedicularia) 2-3 total mm. Despite some external similarities, bat bloodsuckers are not considered closely related to the Hippoboscidae family discussed above. It is assumed that they arose independently of Diptera, which initially developed on the garbage in the shelters of bats, and then adapted to feeding on their blood.

There are over 100,000 species of flies in the world. Some buzz, some bite, some spread disease. The most famous is the housefly, a frequent visitor to our house in warm weather. Flies can be found in almost every corner of the planet Earth. They look very different - for example, blue flies, weevils, houseflies, midges and mosquitoes look very little alike.
The fly is one of the most common and annoying insects on Earth. Her flight both delights us with its accuracy and gets on our nerves. And since this ubiquitous gossip has excellent eyesight and speed, it is not easy to catch it, despite the fact that it has only one pair of wings.
Flies belong to the phylum Arthropoda, class insects, order flies and mosquitoes, family flies. The body length of the fly ranges from a few millimeters (drosophila) to 1.5 cm (house fly) and even up to 2 cm. large species flies is about 7.5 cm. The fly lives from 1 to 2.5 months.