Why do flies rub their legs together, what does this mean?

When remembering the cleanest creatures in the world, people name, for example, cats that constantly lick their fur, removing dirt and any foreign odors. And for some reason, everyone unfairly forgets about flies, considering them to be by no means pure creatures, not worthy of mention among those who take great care of themselves. However, flies do have amazing skills in keeping their bodies clean. If you watch them, you will notice that they constantly clean their wings, head, and body. Even more often, these insects tidy up their paws.

Why do they do this, why is the cleanliness of their paws so important for flies? By studying the habits, life activities, and anatomy of these insects, you can find answers to similar questions.

What happens if you degrease the legs of a fly?

By carefully studying insects walking on uncontaminated surfaces, entomologists discovered that their tracks are similar in shape to the pads on the ends of their legs. And when conducting a chemical analysis of the traces, it was revealed that they consist of triglycerides (lipids).

Although triglycerides themselves are slippery, they cause hairs and smooth surfaces (glass, mirrors, walls, ceilings) to stick together.

Reproduction

It’s impossible to even count how many enemies the common fly has. But due to its fertility, this type of insect is protected from extermination. Their reproduction occurs at an astonishing speed. During the summer period, the female and male produce up to 40 tons of offspring (provided that the environment is comfortable and there is no threat in the form of enemies). In 12 months, up to 20 generations of the common fly can change, and in one summer - about 8.

One clutch on average contains about 150 eggs. Common flies lay from 600 to 2000 eggs over their entire life. When creating masonry, insects use manure, rotting organic waste, food, and various sewage. After only 24 hours, larvae are born, which look like thin threads. They make their way deep into organic waste, thereby receiving warmth, moisture, nutrition, as well as protection from the rays of the sun and enemies.

Stages of development

We already know how long flies live. What stages of development does this insect go through during its life? The life cycle of a fly consists of several stages:

1. egg. Its development lasts from 8 to 50 hours,
2. maggot or larva. During its life it molts three times and then becomes a pupa. All development takes from 3 to 25 days. Moreover, within a week the larvae increase in size by more than 800 times,
3. pupa – this stage of development takes 3-6 days. Pupation may be slowed down when the ambient temperature decreases,
4. imago or adult insect. Within 36 hours, after emerging from the pupa, such an individual is quite capable of reproducing.

On average, it takes a common fly 20 days from egg to adult insect.

Why don't flies fall from the ceiling?

It is well known that most flying insects can easily move even on smooth vertical surfaces. As if not obeying any laws of physics, flies land on mirrors, windows and even ceilings, leaving behind unpleasant brown traces of their presence. How do they do this? Are flies really not affected by earth's gravity?

Well, the gravitational force of our planet acts on absolutely all living and inanimate objects located on the surface or in its atmosphere. Flies were no exception in this regard. The thing is that the legs of a fly are covered with tiny hairs that secrete a special sticky liquid, similar in its chemical composition to fat. It is the presence of this natural glue in the body of flying insects that allows them to freely enter even the most inaccessible places in the room.

In addition to insects, geckos have a unique ability to “climb”. In their natural arsenal, these lizards have paws similar to flies with a large number of microscopic hairs, allowing geckos to move freely along trees, walls and other vertical surfaces.

The unusual ability of animals was noticed by man when creating a suit for moving on vertical surfaces without any climbing equipment. However, the first prototype of such a suit, with Velcro on the arms and legs, weighed too much to enter mass production.

Purchased funds

The electric fly swatter kills flies at the slightest touch, just touch the insect and it dies - no trace of dirt on your favorite wallpaper. What else can you buy to combat dipteran arthropods?

Traps

The simplest fly trap you can buy at the store is duct tape. This is a strip coated with a sticky compound that attracts flies with its smell. The device is produced under the brands Fumitox, Raptor, Aeroxon, Clean House and other manufacturers. There are also more advanced commercial fly traps:

• window - envelopes that are placed in the corners of the windows and covered with flies;
• electric - they look like amateurs who “suck” flying flies;
• ultraviolet light attracts flies, they stick to the glue and die from electric shock.

Technological advances have made it possible to use ultrasound to control insects. The device emits ultrasonic waves, invisible to humans, but unbearable to flies: dipterans try to stay away from the source of the annoying “noise.”

Fumigators

Fumigators are devices that kill insects by poisoning arthropods with vapors or gases. Two types of devices are used in the apartment to control flies.

1. Electric. A small device that connects to a grid and heats a plate that has been treated with an insecticide or liquid that is toxic to insects.
2. Aquafumigator. The container with substances toxic to insects is placed in a small bath filled with water. The poisons released are harmful to flies: penetrating through the shell, they paralyze the insect. The registration period is two hours; during this period, all family members must leave the apartment.

There is also a pyrotechnic fumigator. This is a spiral made of a porous flammable mass impregnated with an insecticide (a compound dangerous to insects, including flies). After arson, the composition begins to burn, releasing smoke that is poisonous to dipterans. Such devices cannot be used in an apartment due to the high risk of fire.

Sprays and aerosols

Such preparations are easy to use: you need to close all doors and windows, spray the product for 10-15 seconds, leave the room and after 30 minutes ventilate the room for half an hour. Under no circumstances should you come into contact with food, household items, furniture and especially children’s things. The table below will give you an idea of ​​the product range.

Table - Overview of fly sprays and aerosols

Name Active ingredients Characteristics

When treating the premises, you should not smoke, eat or drink, and it is also important to take other precautions to avoid poisoning.

• Check action. Before spraying the product onto any surface, test the reaction on a small area.
• Remember fire safety. Do not spray near hot objects or open flames.
• Do the cleaning. After treatment, wash all surfaces with a solution of laundry soap, then with clean water.
• Protects skin and mucous membranes. When working with products, wear a respirator, safety glasses, rubber gloves and clothing that covers your body. After the procedure, wash your hands with soap and water and take a shower.
• Prepare the room. Remove food, animal cages, remove or close aquariums; there should be no people or pets in the room.

If the product gets into your eyes or skin, rinse thoroughly with running water and then consult a doctor.

Experiments on flies

To understand how sensitive flies are to their limbs, you can conduct several experiments. If you catch a fly, stain it with some contaminant and release it, first of all it will take care of its wings, if they are also damaged, and then its legs. And if the legs of a fly are immersed in hexane, the sticky substance will be washed off, and it will not be able to walk on the glass for some time. Having released the fly after such a “procedure”, you will notice that it will immediately find a quiet place where it will begin to vigorously clean its legs, stimulating the production of a new portion of the sticky substance. In a few minutes, she will regain the ability to sit on glass.

Thus, flies rub their legs to maintain the entire set of organs that are located there in working order and protect them from dirt. These are not only Velcro for walking on glass or ceilings, but also organs of touch and smell. The insect cannot allow them to be contaminated, since it will remain disoriented and defenseless.

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Reproductive system

The genital organs are located in the abdomen. In males they are represented by testes, in females - by eggs, accessory glands and ducts. The structure of males is distinguished by the presence of special “grabs”. To raise offspring, each female lays from 70 to 150 eggs. Some species are viviparous (meat and cadaverous).

Interesting!

The penises of male flies were studied by Charles Darwin, who was amazed at their complex structure and the presence of growths and hooks. Modern scientists have found that their genitals have the ability to twist up to 180°, and some types of flies can rotate it up to 360°. This is necessary for ease of mating, so as not to turn upside down.

How do houseflies feed?

House flies are practically omnivorous insects. They have no teeth. A long proboscis takes part in the feeding process and performs a certain job. It is a tongue that is divided into two tubes through which the fly sucks in food.

The presence of taste buds on the paws allows you to taste the food first. And only after that the proboscis comes into play. House flies prefer liquid food, since solid food must be moistened with saliva before consumption. After softening with the help of the proboscis, the food ends up in the digestive system of the insect.

Favorite treats of house flies

Flies prefer to feed on various sweet foods in the form of liquids, as well as canned food. These include:

1. Fruit and vegetable juices.
2. Lemonades and compotes.
3. Sweet tea.
4. Jams and preserves.
5. Honey.

But these pests not only eat up leftover food from people. Their paws contain pathogenic bacteria that, if they enter the human body, can cause various diseases. Therefore, if you find flies in your home, you need to immediately take measures to combat them.

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Generation or life cycle

Now let's talk about the development of the fly from a scientific point of view. The life cycle of a fly follows the path of complete transformation of insects.

Attention! The complete development cycle of insects includes four stages: egg, larva, pupa and adult!

Flies are capable of laying up to one hundred and fifty eggs at a time. During her short life, the female is capable of laying more than six eggs. It is also interesting how flies lay eggs. They are able to place them in any food that has begun to spoil, which is why it is so important to monitor the accumulation of garbage and remove it from the apartment in a timely manner.

Fly eggs are very difficult to see, as they are less than one millimeter in size.

Larvae

The eggs are incubated very quickly, and literally the next day small larvae - maggots - appear. They emerge from the egg very tiny, but during development they are capable of growing more than eight hundred times.

The entire development process of maggots lasts a little more than a week under favorable conditions: an optimal temperature of 20-25 degrees Celsius and high humidity of the air and substrate in which they develop.

Maggots are in great demand among fishing enthusiasts, but for a housefly they are small and are not suitable for baiting a hook. Usually the bait is supplied by other types of flies, the so-called meat flies.

Pupae

The next stage of fly development is the pupa. The larva stops feeding and increasing body weight and size and gradually pupates. Anglers call pupating maggots caster and are also used for bait.

The caster is similar to the larva, only it has a harder shell and a brownish body color. The fly also spends about one week in this stage of development.

Our help! At low temperatures, the fly larva is not able to pupate. Therefore, fishing maggots can be stored in the refrigerator for six months or more.

Imago

A week after pupation, the last stage of flies appears. As stated earlier, adult individuals live on average for about twenty-four days, and they are able to lay eggs almost every two or three days. So these same 75 tons per year come out!

Tritocerebrum

The department is usually called the tertiary brain. His position is clear. The tritocerebrum is located between the other sections. However, the brain does not have a specific shape. The only thing we can say with certainty is that it is divided into;

• right;
• left.

There is a small jumper between the two halves. It passes under the intestines.

The main function of the tritocerebrum is to control the mouth and upper lip. The second may be absent in some types of flies.

Important: Tritocerebrum is associated with the sympathetic nervous system.

How does a fly come unstuck?

Everyone knows how difficult it is to catch a fly by surprise. If you swing it a little, it instantly takes off. With a jerk, strictly vertically, it will be very difficult for her to peel off the paw, so nature arranged it in such a way that the pad with the glands lags behind the surface gradually, in small sections. You can compare this to tearing off adhesive tape: if you pull the tape straight up along its entire length, it is almost impossible to tear it off, but gradually peeling the tape off from the surface is much easier. This happens in flies too.

In addition, two claws at the ends of the legs help the insect to peel off the pad after gluing it to the surface.

Flight mechanics

The wings of flies begin to vibrate according to electrical signals carried out by the nerves.
For example, in a grasshopper, each of these nerve signals manifests itself in one contraction of a muscle, which in turn moves the wing. Two sets of opposing muscles, known as the levator and depressor, help the wings rise and fall by pulling in opposite directions. Grasshoppers flap their wings 12-15 times per second, but smaller insects need faster speeds to fly. For example, while wasps and flies flap their wings 200-400 times per second, the speed reaches 1000 times per second in midges and in some parasites 1 mm long. Another clear evidence of creation is a millimeter-long flying creature that can flap its wings at an incredible rate of 1000 times per second without catching fire, tearing, or fraying.

When we take a closer look at these flying creatures, our amazement at the design increases even more.

It was mentioned that their wings are powered by electrical signals passing through nerves. However, a nerve cell can only transmit a maximum of 200 signals per second. How then is it possible for these small flying creatures to achieve 1000 beats per second?

Flies that flap their wings 200 times per second have a neuromuscular interface that is different from that found in grasshoppers. Here one signal is given for every ten wing beats. In addition, muscles known as fibrous muscles work differently from grasshopper muscles. The nerve signals only alert the muscles to prepare for flight, and when they reach a certain level of tension, they themselves relax.

Flies, bees and wasps have a system that turns wing flapping into an “automatic” movement. The muscles that enable flight in these insects are not directly attached to the bones of the body. The wings are attached to the thorax by a joint that acts as a rod. The muscles that move the wings attach to the lower and upper surfaces of the thorax. When these muscles contract, the rib cage moves in the opposite direction, which in turn creates a downward thrust.

Relaxation of a muscle group automatically manifests itself in a contraction of the opposite group, followed by relaxation again. In other words, it is an "automatic system". Thus, muscle movements continue without stopping until an opposing signal is received from the nerves that controls the system.

A flight mechanism of this kind could be compared to a watch that operates on the basis of a coiled spring. The parts are so strategically placed that even a single movement easily sets the wings in motion. It's impossible not to see the impeccable design in this example. God's ideal creation is obvious.

Some flies flap their wings up to 1000 times per second. In order to facilitate this unusual movement, a special system was created. Instead of directly moving the wings, muscles activate special tissue to which the wings are attached via a rod-like joint. This special fabric helps the wings flap a large number of times in one stroke.

Paw structure

The fly's foot ends in two claws and fine hairs, as well as glands that secrete an adhesive substance. At first, scientists believed that the fly, thanks to its tiny claws and hairs, clings to the smallest irregularities or bulges, invisible to the human eye, on any surface. But with the development of science and microscopes, it turned out that special glands on the legs, similar to pads, help insects overcome the force of gravity. At one time, these pads were even considered suction cups.

Over time, it turned out that these were not suckers, but glands. A thousandfold magnification helped to see that they secrete a special sticky liquid in which fats and various sugars are mixed. It is this substance that gives flies the ability to literally stick to any surface, including the ceiling, and not fall. Research in this area is carried out by Stanislav Gorb from the German Max Planck Institute for Evolutionary Biology (Max-Planck-Institut für Entwicklungsbiologie) within the framework of the project “Biological Attachment Devices for Biomimetics”.

Are dipterans beneficial?

Most people believe that flies only cause harm. Actually this is not true. Diptera are of great importance in the ecosystem. They speed up the decomposition process of plants and animal remains.

Important: fly larvae are nature's orderlies, cleansing the world of dead bodies and spoiled food

Diptera in medicine

During the First World War, when medicine was not very developed, maggots were used to destroy rotting tissue in the wounds of patients. Thus, doctors stopped the proliferation of pathogenic microflora. Insects are capable of secreting a secretion whose composition resembles a strong antibiotic. Of course, maggots were not collected from cesspools; they were raised in sterile conditions.

Diptera in science

Scientists study many insects and flies are no exception. The pest has faceted vision, thanks to which experts were able to develop a unique camera with a 360-degree view.

An important role was played by the study of the fly's body and its ability to fly. The results helped develop new technologies that were used in aircraft manufacturing. Research on the insect continues to this day.

The uniqueness of fly legs

The legs of flies are so unique that they successfully play another role - they are organs of touch. The limbs are covered with hairs, which play a tactile function and provide the insect with information about what is around at the closest distance. Considering these facts, one can understand why the winged insect treats its limbs with such care and constantly cleans them. After all, if you do not monitor the cleanliness of such organs, they will quickly cease to provide accurate information, and the insect will be completely disoriented.

Why is it dangerous?

Phases of fly development. Well, let’s even start with the fact that the bite of a burner is very painful. It is not without reason that this type of fly received such a name. At the moment of the bite, the person feels a fairly strong burning pain.

This is not at all a harmless mosquito bite that appears only some time later, no. The zhigalka acts, let's say, much rougher. A mosquito next to a fly is simply a jeweler in his field.

In addition to, in fact, a painful puncture with the proboscis, the burner fly also introduces saliva that irritates the affected area, which has an inflammatory effect at the site of the bite.

Flies.

What kind of memory does a fly have? Anatomy of a fly - external structure

The general plan of the structure of dipterans, the skeleton of a fly is the same as that of other insects - head, chest, abdomen. The head contains the mouthparts, antennae, and eyes. The chest consists of three segments, with a pair of transparent wings, and three pairs of legs. The space in the chest is filled with powerful muscles. The abdomen includes most of the digestive organs and the reproductive system.

On a note!

Flies have pronounced sexual dimorphism, when the appearance and structure of the female differs from the male.

Fly head

Includes the organs of vision, nutrition, and hearing.

• Oral apparatus. Regardless of the differences in nutrition of many species of flies, their oral apparatus is represented by a proboscis of a sucking, licking type. A pair of extended blades of the upper and lower lips come into contact with food. The fly's jaws are powerful. Numerous tubules converge in the fly's proboscis, at its central point. The mouthparts of a fly that feeds on blood are additionally equipped with hard, sharp scales that serve as teeth and help pierce the skin of animals and humans. The liquid is drawn into the head using a pharyngeal pump.
• The eyes occupy most of the head. They form a complex system, which was taken as the basis for the development of a modern photo camera. They consist of many simple eyes that look like a faceted mesh from the outside. The insect receives a comprehensive but mosaic image of objects. Each eye includes several hundred or thousands of facets. The housefly has about 4 thousand of them. Many species have 3 simple eyes located on the crown of the head. This structure allows you to instantly capture movement, but does not provide a complete picture of the image.
• Mustache. A kind of antenna serves as a landmark. They help to catch odors and determine the direction of movement. In the process of evolution they changed, there are differences in males and females.

Species and habitat

Some species of dipterans that live near humans are among the most ancient insects. This is exactly what the common housefly is, which, according to scientists, has been living on the planet for 145 million years.

Diptera are widespread on the planet, numbering more than 5 thousand species, of which a fifth lives in Russia. The most famous: domestic (indoor), meat, etc. They all have a similar body structure, differing only in size, color and habitat.

On a note!

The smallest flies in the world are Megaphragma caribea (length 0.17 mm) and representatives of the family Myrmaridae (2.1 mm), the largest are the South American Mydas hero (grow up to 6 cm in length with a wingspan of up to 12 cm) and the New Zealand species Egsul up to 5 cm long.

Features of fly anatomy

Housefly foot under a microscope

Every person knows perfectly well how deftly flies can run along ceilings, walls, and any other surfaces. They do not have to maintain balance or make efforts to move “upside down” - the legs hold the insect in any position. After all, they end in special pads, onto which an adhesive substance is released through hollow hairs. It holds the fly on the objects it needs without difficulty, and if necessary, does not interfere with walking - the anatomy of the limbs of flies is unique in this regard.

Constant walking wastes a lot of sticky substance. In addition, dust particles and pollutants stick to the adhesive surface, which do not contribute to its normal functioning. To continue to crawl freely even on window glass, the fly must regularly clean itself up, removing dirt and stimulating the release of a sticky substance. Only then will she continue to move effectively and do her usual things.

Green carrion

Despite its partiality to various kinds of carrion and sewage, this fly is a very beautiful insect with a glossy emerald body and translucent smoky wings with a faint openwork pattern. Its body length is about 8 mm. The fly's eyes are large, reddish, its abdomen is round, its cheeks are white. Green flies live mainly in dirty places: on decaying animal corpses, in manure, waste, but sometimes they can be

meet among flowering plants with a strong aroma. They feed on organic rotting matter, where they lay their eggs.

After mating, the female lays about 180 eggs. The egg has a grayish or light yellow tint. She tries to hide them as deep as possible in carrion, where they develop within 6–48 hours to the larval stage. The length of the larvae's body varies between 10–14 mm. After 3–9 days they leave their habitat and move to the soil to pupate. The pupal stage lasts from 10 to 17 days (depending on weather conditions), after which the insect emerges to the surface as an adult fly.

The role of the limbs

Paws are needed by insects to move on a hard surface, but their functions are not limited to this. The pulvillas have short but numerous setae, which are organs of touch and taste. Feet analyzed Probably, many people have noticed a strange feature of flies: when they sit on something, they certainly begin to do a certain thing - they rub their front legs and legs against each other. To find out why they do such manipulations, turn to chemistry and zoology.

Paws are needed by insects to move on a hard surface, but their functions are not limited to this. The pulvillas have short but numerous setae, which are organs of touch and taste. The feet analyze food better than a person can with the tongue. This is another answer to the question why flies rub their legs. To prevent the organs of smell and touch from losing their full functions, you have to constantly wipe your paws and clean them.

Reasons for this action

These insects clean all parts of the body, but most of all they do it with the help of their limbs. Entomologists have spent many hours studying the anatomy of such parasites, so they can easily explain why flies rub their legs.

This action cleanses the limbs of dirt and dust, but not for reasons of personal hygiene, but for another physiological reason.

Their foot ends in two small anatomical pads (pulvillia). They are covered with fine bristles that secrete a sticky substance consisting of a mixture of carbohydrates and lipids.

Thanks to the attractive force of the capillaries and the presence of a sticky (liquid) secretion of the bristles, dipterans masterfully adhere to smooth surfaces.

If his paws are dirty, his grip will be seriously impaired. As a result, it will simply fall or become prey to other insects.

And even a person can cope with it faster, armed with sneakers or a newspaper. That's why they rub their paws against each other so actively. They also sense food with their feet, as they have taste and other receptors that act as senses of touch.

general characteristics

According to various sources, there are currently about 80,000 different species of flies on planet Earth. But at the same time, the most common is the indoor one, which is quite rare in nature.

The size of an adult housefly reaches 0.6-0.8 cm. On the body, which has a gray color, in the chest area on top there are four longitudinal stripes of black color, while the bottom of its abdomen is yellowish in color.

The entire body of the insect is covered with long, sparsely growing hairs. The eyes are faceted, large in size, and dark red in color. Females are larger than males. During flight, only the front wings are used, similar to all dipterans. And the back pair of wings is needed solely so that the insect can maintain balance while in the air.

What is the weight of the fly?

A medium-sized insect weighs about 0.12-0.16 g. The mass of an African insect can vary from 0.012 kg. up to 0.015 kg. The length of the carrion is almost several times greater than that of its indoor relatives, and its weight is 0.025 - 0.032 kg. Regardless of how much a fly weighs, anyone can feel it on their body. This happens solely due to the movements that the insect makes.

How long can flies live?

Another interesting fact is how long the common fly lives. Its lifespan is approximately 10-20 days, and in the most comfortable temperature conditions for it - up to 1.5 months. The best conditions for her life are considered to be +22-26 degrees with air humidity not exceeding 80%.

These insects survive at ambient temperatures from +11 to +45 degrees, which undoubtedly affects their lifespan. As the temperature drops, the activity of the insect also decreases. With the onset of cold weather, already at +10 degrees and below, its activity drops, and it goes into hibernation. The duration of this state directly depends on the air temperature. Fly pupae and larvae can also hibernate, allowing them to survive in their environment.