Insects have an exceptionally sensitive sense of smell, thanks to which they can not only recognize from a few scent molecules where a treat awaits them, but also communicate with each other using sophisticated chemical signals. And, given the role of smells in their lives, one could assume that insects acquired an olfactory system as soon as they left the water on land. However, according to researchers from the Max Planck Institute for Chemical Ecology (Germany), insects developed a full sense of smell unexpectedly late - somewhere simultaneously with the ability to fly. Special receptor proteins are responsible for the sense of smell in insects (as, indeed, in all animals with this sense): when added together, they form complex complexes capable of capturing even single molecules of volatile substances.
However, for example, crustaceans, which descended from a common ancestor with insects, do not have such receptors. This led to the assumption that the insects “smelled what it smelled” only when they came onto land. In addition, outside the water, it was really more important for them to create an olfactory system to replace the chemical sense with which they navigated in the water and which now became useless: from now on, chemicals had to be caught in the air. The sense of smell in insects has always been studied either on winged species or on those who subsequently lost their wings (both of them, however, constitute the majority among modern insects). However, Ewald Grosse-Wilde and his colleagues decided to study proto-wingless insects, the oldest of modern insects. For research, they chose the bristletail Thermobia domestica and the representative of the ancient jawed Lepismachilis y-signata.
As the authors of the work write in eLIFE, the bristletail, which is closer to insects on the evolutionary ladder, had some components of the olfactory system: genes for olfactory coreceptors worked in its antennae, although the receptors themselves were absent. But in the more evolutionarily older L. y-signata, no traces of the olfactory system could be found. Two conclusions can be drawn from this: firstly, different parts of the olfactory system developed independently of each other, and secondly, the very development of this system began much later than the appearance of insects on land. Most likely, insects needed the sense of smell when they began to learn to fly, and it was needed, for example, in order to navigate in flight. However, let’s not forget that one of the oldest insects (T. domestica) still has some components of the olfactory apparatus, so that individual parts of the olfactory system obviously developed for some urgent tasks before the ability to fly.
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The organs of smell and taste are both essentially chemoreceptors. The difference is that taste buds detect the presence of certain chemicals in liquids (or wet substrates), while olfactory receptors detect the presence of certain chemicals in the air, where the substances are in a gaseous state.
The organs of smell are predominantly located on the antennae, and the organs of taste are located on the oral organs. The former include distant chemoreceptors, and the latter - contact chemoreceptors. Due to the peculiarities of the perception of taste and olfactory sensations, the organs of taste and smell have some differences in structure and function.
Olfactory organs
They are special olfactory sensilla, usually of a conical or placoid (immersed) type. For the most part they are located on the antennae. (photo) Sometimes trichoid sensilla are also found among them. Bees, an insect that is very sensitive to odors, have very abundant olfactory hairs. Each worker bee antenna contains about 6,000 sensilla. And some insects have even more: for example, male butterflies Antheraea polirhemus have up to 60,000 of them.
Olfactory sensilla can be collected in pits, as, for example, in flies on the third segment of the antennae. At the base of these hairs lie groups of nerve cells (neurons) numbering up to 40-60 pieces. The surface of the sensilla has many pores (10-20), through which the terminal parts of the neuron processes come into contact with volatile substances, perceiving odors.
How do insects smell?
Food olfactory signals are recognized very well by insects. Contrary to popular belief, for them there are not only the concepts of “edible - not edible,” but also more subtle sensations. Those species that feed on flower nectar distinguish the aromas of different flowers. Other herbivores do not identify specific species by smell. flowering plants that are suitable for them as food. Thus, insects do not just accidentally find food, but purposefully go to it, smelling its smell in the air.
As a rule, what is attractive to them is not the smell “as a whole,” but its individual components. Thus, carrion beetles react to the content in the air of skatole, indole, ammonia and other volatile substances released during the decay of proteins. The dead beetle senses “tempting” odors at a distance of up to 90 cm. And mosquitoes, fleas and other blood-sucking insects sense an increased concentration of carbon dioxide and volatile components of human and animal sweat. It is not without reason that they say that a clean person attracts mosquitoes less than one who has not taken care of his hygiene. For the same reason, decoy traps that produce heat and carbon dioxide work well against midges.
Male insects usually have more olfactory receptors than females. But this is observed not at all in connection with their more active production of food, but because of gender characteristics. The fact is that with the help of sensilla, males smell the pheromones emitted by females, and thanks to this they look for a mate for copulation. Therefore, in order to participate in the “celebration of life” and leave their genetic mark on generations, they must have a developed sense of smell.
Male butterflies sense the sexual attractants of females 3-6 km away; Interestingly, if the female is already fertilized, she stops secreting these substances and becomes “invisible” to the males. senses the presence of a sexual attractant in the air when its content there is only 100 molecules per 1 m 3, and the male Saturnia pear has the ability to smell the female as much as 10 km away. This is a record among insects for sensitivity to odors. (photo)
In a colony of ants or termites, insects distinguish the smell of their relatives from different castes, identifying the so-called foragers (these are those family members who are responsible for feeding everyone else) and coming to them for food. Some insects also emit alarm odors, by which others understand that they need to beware of something. In addition, all insects sense the “smell of death” emitted by dead relatives. And in bee hives, the queen bee emits an odor that suppresses the development of eggs in worker bees.
Insects' sense of smell not only helps them obtain food and communicate with each other; with its help they recognize representatives of other species, determine best places for masonry, etc.
Organs of taste
As already mentioned, mainly chemoreceptors, which give insects the ability to sense taste, are located on their mouthparts. But there are clusters of them on other parts of the body. For example, they are found on the front, and sometimes on the antennae or even on the! The latter allows females to determine the suitability of a particular substrate for oviposition by “feeling” it with the back of their body.
The taste organs are thick-walled taste sensilla, at the base of which lie from 3 to 5 (in rare cases up to 50) nerve cells that transmit corresponding signals to the central nervous system. Their short processes (dendrites) extend upward to the top of the sensilla, where through a special opening (pore) the nerve endings of the dendrites come into contact with food substrates. (photo)
In some insects, the structure of the sensilla is somewhat more complex than it seems at first. For example, in the Phormiaregina fly there are only three neurons at the base of the taste hairs, but they all perform different functions. One is a mechanoreceptor, that is, it responds to touch, the second detects sweet taste, and the third detects salty taste. When the “sugar” neuron is stimulated, the insect develops a reflex to expand its proboscis, since the sweet substrate is attractive to it. If a salty taste is felt, this causes the fly to lose interest in the intended food.
How do insects taste?
From the taste sensilla, nervous stimulation is transmitted to special centers of the brain, where the insect “realizes” the taste and reacts to it.
The taste reactions of representatives of the class are very diverse. They, like humans, distinguish four basic tastes - sour, sweet, bitter and salty. Moreover, the sensitivity of insects to these tastes is in fact the same as ours, and sometimes even higher. Thus, a person perceives a sweet taste if the sugar concentration in the solution is 0.02 mol/l. Bees sense it at a content of 0.06 mol/l, and the admiral butterfly Pyrameis atalanta at 0.01 mol/l.
Insects that are “accustomed” to sweet food should, at first glance, be able to distinguish it better than anyone else, but this is often not the case. For example, lactose (milk sugar) is perceived by bees as tasteless compared to the sweet nectar they consume, and some caterpillars perceive it as a sweet substance after their usual "bland" green vegetation.
Another feature of the taste of insects is that they are not fans of salty foods. They react positively to the food substrate only when the salt concentration in it is sufficiently low. By the way, insects find the saltiest ions not sodium, as they do to humans, but potassium ions.
A remarkable feature is that representatives of Insecta, it turns out, taste distilled water, which for us has no taste. And some also develop an addiction to toxic compounds. Thus, the leaf beetle Chrysolina feeding on St. John's wort plants (photo) , has a special group of taste buds that are stimulated by the poisonous alkaloid hyperisin contained in its leaves.
Any activity of insects is associated with the continuous processing of sound, olfactory, visual, tactile and other information. Including spatial, geometric, quantitative.
An important feature of these miniature, but very complex creatures is their ability to accurately assess the situation using their own instruments. Among them are determinants of various physical fields that make it possible to predict earthquakes, volcanic eruptions, floods, and weather changes. There are internal biological clocks that keep time, and some kind of speedometers that allow you to control speed, and navigation devices.
The sense organs of insects are often associated with the head. But it turns out that only their eyes are the only organ that is similar to other animals. And the structures responsible for collecting information about environment, are found in insects in the most different parts bodies. They can determine the temperature of objects and taste food with their feet, detect the presence of light with their backs, hear with their knees, mustaches, tail appendages, body hairs, etc.
Their delicate sense of smell and taste allows them to find food. Various glands of insects secrete substances to attract brothers, sexual partners, scare away rivals and enemies, and a highly sensitive sense of smell can detect the smell of these substances even from several kilometers away.
Insects are endowed with excellent color vision and useful night vision devices. It is curious that during rest they cannot close their eyes and therefore sleep with their eyes open.
Let's get acquainted with the various analyzing systems of insects in more detail.
Visual system
The entire complex visual system of insects helps them, like most animals, to receive basic information about the world around them. Vision is necessary for insects when searching for food in order to avoid predators, explore objects of interest or the environment, and interact with other individuals during reproductive and social behavior.
Diversity in the structure of the eyes. Their eyes are compound, simple or with additional eyes, as well as larval. The most complex are compound eyes, which consist of many ommatidia that form hexagonal facets on the surface of the eye.
At its core, an ommatidium is a tiny visual apparatus that has a miniature lens, a light-conducting system and light-sensitive elements. Each facet perceives only a small part, a fragment of an object, but together they provide a mosaic image of the entire object. Compounded eyes, characteristic of most adult insects, are located on the sides of the head.
In some insects, for example, in the hunting dragonfly, which quickly reacts to the movement of prey, the eyes occupy half of the head. Each of her eyes consists of 28 thousand facets.
It is the eyes that contribute to the quick reaction of a hunting insect, such as a praying mantis. By the way, this is the only insect that can turn around and look behind itself. Large eyes provide the mantis with binocular vision and allow it to accurately calculate the distance to the object of its attention. This ability, combined with the rapid thrusting of its front legs towards prey, makes mantises excellent hunters.
And the eyes of beetles of the family of whirligigs, running on water, allow them to simultaneously see prey both on the surface of the water and under water. Thanks to their visual analysis system, these little creatures are able to constantly make corrections to the refractive index of water.
Night-vision devices. To sense heat rays, humans have skin thermoreceptors that respond to radiation only from powerful sources, such as the Sun, a fire, or a hot stove. But he is deprived of the ability to perceive infrared radiation from living beings. Therefore, in order to determine the location of objects in the dark by their own or reflected thermal radiation, scientists created night vision devices. However, these devices are inferior in sensitivity to the natural “thermal locators” of some nocturnal insects, including cockroaches. They have special infrared vision - their own night vision devices.
Some moths also have unique infrared locators to search for “their” flowers that open in the dark. And in order to translate invisible heat rays into a visible image, a fluorescence effect is created in their eyes. To do this, infrared rays pass through the complex optical system of the eye and are focused on a specially prepared pigment. It fluoresces, and thus the infrared image turns into visible light. And then in the butterfly’s eyes visible images of flowers appear, which at night emit radiation in the infrared region of the spectrum.
Thus, these flowers have radiation transmitters, and moths have radiation receivers, and they are expediently “tuned” to each other.
Infrared radiation also plays an important role in bringing together moths of the opposite sex. It turns out that as a result of ongoing physiological processes, the body temperature of some butterfly species is significantly higher than the ambient temperature. And what’s most interesting is that it depends little on the ambient temperature. That is, with a decrease in external temperature, their intraorganismal processes intensify, just like in warm-blooded animals.
The warm body of the butterfly becomes a source of infrared rays. The flapping of the wings interrupts the flow of these rays at a certain frequency. It is assumed that by perceiving these certain rhythmic vibrations of infrared radiation, the male distinguishes the female of his species from the females of other species.
Hearing organs
How do most animals and humans hear? The ears, where sounds cause the eardrum to vibrate - strong or weak, slow or fast. Any changes in vibrations provide the body with information about the nature of the sound being heard.
How do insects hear?
Features of the “ears” of insects. In many cases, they also have peculiar “ears,” but in insects they are located in places unusual for us: on the mustache - like in male mosquitoes, ants, butterflies, on the tail appendages - like in the American cockroach, on the stomach - like in locusts.
Some insects do not have special hearing organs. But they are capable of perceiving various vibrations in the air, including sound vibrations and ultrasonic waves that are inaccessible to our ears. The sensitive organs of such insects are thin hairs or tiny sensitive rods.
They are located in large numbers on different parts of the body and are associated with nerve cells. So, in hairy caterpillars, the “ears” are hairs, and in naked caterpillars, the whole skin covering bodies.
The auditory system of insects allows them to selectively respond to relatively high-frequency vibrations - they perceive the slightest vibrations of the surface, air or water.
For example, buzzing insects produce sound waves by rapidly flapping their wings. Males perceive such vibrations in the air, for example the squeak of mosquitoes, with their sensitive organs located on the antennae. And thus they detect air waves that accompany the flight of other mosquitoes and respond adequately to the received sound information.
The hearing organ in grasshoppers is located on the shins of the front legs, the movement of which occurs along arched trajectories. The peculiar “ears” seem to take bearings, or scan, the space on both sides of his body. The analyzing system, having received signals, processes the incoming information and controls the actions of the insect, sending the necessary impulses to certain muscles. In some cases, the grasshopper is directed to the source of the sound with precise commands, while in others, under unfavorable circumstances for it, it flees.
Using precise acoustic equipment, entomologists have determined that the sensitivity of the hearing organs of grasshoppers and some of their relatives is unusually high. Thus, locusts and some species of grasshoppers can perceive sound waves with an amplitude less than the diameter of a hydrogen atom.
Cricket communication. The cricket is a wonderful tool for communicating with a friend. When creating a gentle trill, he rubs the sharp side of one elytra against the surface of the other. And for the perception of sound, the male and female have a particularly sensitive thin cuticular membrane, which plays the role of an eardrum.
The following experiment is indicative: a chirping male was placed in front of a microphone, and a female was placed in another room near a telephone. When the microphone was turned on, the female, hearing the species-typical chirping of the male, rushed to the source of the sound - the telephone.
Ultrasonic protection of butterflies. Insects are able to make sounds and perceive them in the ultrasonic range. Due to this, some grasshoppers, praying mantises, and butterflies save their lives.
Thus, moths are provided with a device that warns them of the appearance of bats that use ultrasonic waves for orientation and hunting. In the chest, for example, moth moths have special organs for acoustic analysis of such signals. They make it possible to detect ultrasonic pulses from hunting leatherfish at a distance of up to 30 meters.
As soon as the butterfly perceives a signal from the predator's locator, its protective behavioral actions are activated. Having sensed the ultrasonic impulses of a bat at a relatively large distance, the butterfly abruptly changes its flight direction, using a deceptive maneuver - as if diving down. At the same time, she begins to perform aerobatic maneuvers - spirals and “ dead loops"to escape pursuit. And if the predator is less than 6 meters away, the butterfly folds its wings and falls to the ground. And the bat does not detect the motionless insect.
In addition, some species of butterflies have even more complex defensive reactions. Having detected the bat's signals, they themselves begin to emit ultrasonic pulses in the form of clicks. Moreover, these impulses have such an effect on the predator that it, as if frightened, flies away. What makes such animals, which are quite large compared to a butterfly, stop pursuing and flee from the battlefield?
There are only assumptions on this matter. Probably, ultrasonic clicks are special insect signals, similar to those sent by the bat itself. But only they are much stronger. Expecting to hear a faint reflected sound from his own signal, the pursuer suddenly hears a deafening roar - as if a supersonic plane is breaking the sound barrier. But why is the bat not deafened by its own powerful signals sent into space, but only by the clicks of the butterfly?
It turns out that the bat is well protected from its own cry-impulse of its locator. Otherwise, such a powerful impulse, which is 2 thousand times stronger than the received reflected sounds, could deafen the mouse. To prevent this from happening, her body produces and purposefully uses a special stirrup. And before sending an ultrasonic impulse, a special muscle pulls this stapes away from the window of the cochlea inner ear- and the oscillations are mechanically interrupted. Essentially, the stirrup also makes a click, but not a sound, but an anti-sound one. After the scream-signal, it immediately returns to its place so that the ear is again ready to receive the reflected signal.
It is difficult to imagine how fast the muscle responsible for turning off the mouse’s hearing can act at the moment of sending a cry-impulse. When chasing prey, this is 200-250 pulses per second!
At the same time, the butterfly’s “scare” system is designed in such a way that its clicking signals, dangerous for the bat, are heard exactly at the moment when the hunter turns on his ear to perceive his echo. This means that the moth sends signals that are initially perfectly matched to the predator’s locator, causing it to fly away in fear. To do this, the insect’s body is tuned to receive the pulse frequency of an approaching hunter and sends a response signal exactly in unison with it.
Such relationships between moths and bats raise many questions among scientists.
Could insects themselves develop the ability to perceive ultrasonic signals from bats and instantly understand the danger they pose? Could butterflies gradually, through a process of selection and improvement, develop an ultrasonic device with ideally selected protective characteristics?
The perception of ultrasonic signals from bats is also not easy to understand. The fact is that they recognize their echo among millions of voices and other sounds. And no screaming signals from fellow tribesmen, no ultrasonic signals emitted using equipment interfere with the bats’ hunting. Only butterfly signals, even artificially reproduced ones, cause the mouse to fly away.
"Chemical" sense of insects
Highly sensitive proboscis of flies. Flies exhibit an amazing ability to sense the world, purposefully act according to the situation, move quickly, deftly manipulate their limbs, for which these miniature creatures are endowed with all senses and living devices. Let's look at some examples of how they use them.
It is known that flies, like butterflies, evaluate the taste of food with their feet. But their proboscis also contains sensitive chemical analyzers. At its end there is a special spongy pad - a labellum. During a very delicate experiment, one of the sensitive hairs on it was included in electrical circuit and touched the sugar with it. The device recorded electrical activity, showing that the fly's nervous system had received a signal about its taste.
The fly's proboscis is automatically connected to the readings of the chemical receptors (chemoreceptors) of the legs. When a positive command from the leg analyzers appears, the proboscis extends and the fly begins to eat or drink.
During the research, a certain substance was applied to the insect's foot. By straightening the proboscis, they judged what substance and in what concentrations the fly caught. Thanks to the special sensitivity and lightning-fast reaction of the insect, such a chemical analysis lasts only a few seconds. Experiments have shown that the sensitivity of the receptors of the front legs is 95% of that of the proboscis. And in the second and third pairs of legs it is 34 and 3%, respectively. That is, the fly does not taste food with its hind legs.
Olfactory organs. Insects also have well-developed olfactory organs. For example, flies react to the presence of even very small concentrations of a substance. Their antennae are short, but have feathery appendages, and therefore a large surface area for contact with chemicals. Thanks to such antennas, flies are able to fly from afar and quite quickly to a fresh heap of manure or garbage in order to fulfill their purpose as nature's orderly.
The sense of smell helps females find and lay eggs on a ready-made nutrient substrate, that is, in the environment that will later serve as food for the larvae.
One of the many examples of flies using their excellent sense of smell is the tahini beetle. She lays eggs in the soil, finding by smell areas inhabited by beetles. The newly hatched young larvae, also using their sense of smell, search for the beetle themselves.
Beetles are also endowed with antennae of the olfactory type. These antennas allow you not only to catch the smell of the substance and the direction of its propagation, but also to even sense the shape of the odorous object.
And the ladybug’s sense of smell helps to find colonies of aphids in order to leave clutches there. After all, aphids feed not only on themselves, but also on their larvae.
Not only adult beetles, but also their larvae are often endowed with an excellent sense of smell. Thus, the larvae of the cockchafer are able to move to the roots of plants (pine, wheat), guided by a slightly increased concentration of carbon dioxide. In the experiments, the larvae immediately went to a patch of soil where a small amount of a substance that produces carbon dioxide was introduced.
Some Hymenoptera are endowed with such a keen sense of smell that it is not inferior to the famous sense of the dog. Thus, female riders, running along a tree trunk or stump, vigorously move their antennae. They “sniff out” with them the larvae of the horntail or woodcutter beetle, located in the wood at a depth of two to two and a half centimeters from the surface.
Or, thanks to the unique sensitivity of the antennae, the tiny rider Helis, by just touching them on the cocoons of spiders, determines what is in them - either underdeveloped testicles, or inactive spiders that have already emerged from them, or the testicles of other riders of their species.
How Helis manages such an accurate analysis is not yet known. Most likely, he senses a very subtle specific smell. Although it is possible that when tapping with the antennae, the rider catches some kind of reflected sound.
Taste sensations. A person clearly identifies the smell and taste of a substance, but in insects the taste and olfactory sensations are often not separated. They act as a single chemical feeling (perception).
Insects that have a sense of taste have a preference for certain substances depending on the nutrition characteristic of a given species. At the same time, they are able to distinguish between sweet, salty, bitter and sour. To come into contact with the food consumed, taste organs can be located on various parts of the body of insects - on the antennae, proboscis and legs. With their help, insects receive basic chemical information about the environment.
Thus, depending on the species, butterflies, due to their taste sensations, have a preference for one or another food item. The chemoreceptive organs of butterflies are located on their paws and respond to various substances through touch. For example, in the urticaria butterfly they are located on the tarsi of the second pair of legs.
It has been experimentally established that if you take a butterfly by the wings and touch a surface moistened with sugar syrup with its paws, its proboscis will react to this, although it itself is not sensitive to sugar syrup.
With the help of a taste analyzer, butterflies can clearly distinguish between solutions of quinine, sucrose, and hydrochloric acid. Moreover, with their paws they can feel the concentration of sugar in water 2 thousand times less than that which gives us the sensation of a sweetish taste.
The biological clock
As already mentioned, all phenomena associated with the life of animals are subject to certain rhythms. Cycles of building molecules regularly go through, processes of excitation and inhibition take place in the brain, gastric juice is secreted, heartbeat, breathing, etc. are observed. All this happens according to the “clock” that all living organisms have. Experiments have shown that they stop only with sudden cooling to 0°C and below.
In one of the experimental laboratories studying the mechanisms of action of the biological clock, experimental animals, including insects, were cooled for 12 hours. This is the most the best way influence on the time passing in the cells of their body. At the same time, the clock stopped for a while, and then, after warming up the animals, it turned on again.
As a result of such exposure to cockroaches, the biological clock went wrong. The insects began to fall asleep while the control cockroaches were crawling for food. And when they fell asleep, the experimental subjects ran to eat. That is, the experimental cockroaches did everything the same as the others, only with a delay of half a day. After all, after keeping them in the refrigerator, the scientists “turned the clock” to 12 hours.
Next, a complex microsurgical operation was performed - the subpharyngeal ganglion (part of the cockroach's brain), which controls the speed of the living clock, was transplanted into a control cockroach. Now this cockroach has acquired two centers that control biological time. But the periods when various processes were turned on differed by 12 hours, so the cockroach was completely confused. He could not distinguish day from night: he would start eating and immediately fall asleep, but after a while another ganglion would wake him up. As a result, the cockroach died. This shows how incredibly complex and necessary time devices are for all living beings.
An interesting experience was with small laboratory flies, Drosophila. They emerge from the pupae in the early morning hours, with the appearance of the first ray of sunlight. The Drosophila organism checks its development clock against sundial. If you place fruit flies in complete darkness, the clock that monitors their development becomes disturbed, and the flies begin to emerge from their pupae at any time of the day. But what is important is that a second flash of light is enough to synchronize this development again. You can reduce the flash of light even to half a thousandth of a second, but the synchronizing effect will still appear - the flies emerging from the pupae will occur simultaneously. Only a sharp cooling of insects to 0°C and below entails, as shown above, the stopping of the body’s living clock. However, as soon as you warm them up, the clock will start moving again and will lag behind exactly the same amount of time as it was stopped for.
Capabilities of insects for targeted actions
As an example demonstrating the excellent capabilities of insects for purposeful movements, consider the behavior of a fly.
Notice how the fly scurries around on the table, touching all objects with its moving legs. So she found sugar and greedily sucks it with her proboscis. Consequently, a fly can sense and select the food it needs by touching its legs.
If you want to catch a restless creature, it will not be easy at all. You carefully bring your hand closer to the fly, it immediately stops its movements and seems to become alert. And at the last moment, as soon as you wave your hand to grab it, the fly quickly flies away. She saw you, received certain signals about your intention, about the danger threatening her, and escaped. But after a short time, the memory helps the insect to return. In a beautiful, well-directed flight, the fly lands exactly where it was driven from to continue feasting on sugar.
Before and after a meal, a neat fly will gracefully clean its head and wings with its legs. As you can see, this miniature animal exhibits the ability to sense the world around it, act purposefully in accordance with the situation, move quickly, and deftly manipulate its limbs. For this purpose, the fly is endowed with excellent living devices and surprisingly useful devices.
She can take off without a run, instantly stop her fast flight, hover in the air, fly upside down and even backwards. In a matter of seconds, she can demonstrate many complex aerobatic maneuvers, including a loop. In addition, flies are able to perform actions in the air that other insects can only do on the ground, such as cleaning their legs in flight.
The excellent structure of the organs of movement provided to the fly allows it to run quickly and move easily on any surface, including smooth, steep, and even on the ceiling.
The fly's leg ends in a pair of claws and a pad between them. Thanks to this device, it exhibits an amazing ability to walk on surfaces on which other insects cannot even simply stand. Moreover, with its claws it clings to the slightest irregularities on the plane, and moves along a mirror smooth surface it is supported by pads covered with hollow hairs. Through these microscopic “hoses” an oily secretion is released from special glands. The surface tension forces it creates hold the fly on the glass.
How to roll the perfect ball? The ability of one of nature’s orderlies, the dung beetle, to make perfectly round balls from manure never ceases to amaze. At the same time, the scarab beetle, or sacred copra, prepares such balls exclusively for use as food. And he rolls balls of another strictly defined shape to lay eggs in them. Clearly coordinated actions allow the beetle to perform quite complex manipulations.
First, the beetle carefully selects the piece of dung necessary for the base of the ball, assessing its quality using its sensory system. Then he clears the lump of adhering sand and sits on it, clasping it with his hind and middle legs. Turning from side to side, the beetle selects the desired material and rolls the ball in its direction. If the weather is dry, hot, this insect works especially quickly, rolling up a ball in a matter of minutes while the dung is still wet.
When making a ball, all the beetle's movements are precise and streamlined, even if it is doing it for the first time. After all, the sequence of appropriate actions contains the hereditary program of the insect.
The ideal shape of the ball is given by the hind legs, the curvature of which is strictly observed during the construction of the beetle's body. In addition, his genetic memory retains in encoded form the ability to perform certain types of stereotypical actions, and when creating a ball, he clearly follows them. The beetle invariably finishes the job only when the surface and dimensions of the ball coincide with the curvature of the shins of its legs.
Having finished the work, the scarab deftly rolls the ball with its hind legs towards its hole, moving backwards. At the same time, with enviable patience, he overcomes thickets of plants and mounds of earth, pulls the ball out of hollows and grooves.
An experiment was set up to test the perseverance and intelligence of the dung beetle. The ball was pinned to the ground with a long needle. The beetle, after much torment and attempts to move it, began to dig. Having discovered the needle, the scarab tried in vain to lift the ball, acting as a lever with its back. The beetle did not think of using the pebble lying nearby for support. However, when the pebble was moved closer, the scarab immediately climbed onto it and removed its ball from the needle.
Sometimes dung beetles try to steal a food ball from a neighbor. In this case, the robber, together with the owner, can roll him to the desired place and, while he begins to dig a hole, drag away the loot. And then, if he is not hungry, leave him, having first ridden him a little for your pleasure. However, scarabs often fight even when there is an abundance of dung, as if they were in danger of starvation.
Manipulations of talented pipe divers. To create a cozy “cigar” nest from young tree leaves, female tubeworm beetles perform very complex and varied actions. Their “tools of production” are the legs, jaws and scapula - the female’s elongated and widened head at the end. It is estimated that the process of rolling a “cigar” consists of thirty clearly and consistently carried out operations.
First, the female carefully selects a leaf. It should not be damaged, since it is not only building material, but also a supply of food for future offspring. To roll a poplar, walnut or birch leaf into a tube, the female first pierces its petiole in a certain place. She knows this technique from birth; it reduces the flow of juices into the leaf - and then the leaf quickly withers and becomes pliable for further manipulation.
On the withered leaf, the female makes markings with precise movements, determining the line of the upcoming cut. After all, a tube cutter cuts out a piece of a certain rather intricate shape from a sheet. The “drawing” of the pattern is also encoded in the genetic memory of the insect.
The once German mathematician Gaines, struck by hereditary “talents” little bug, derived a mathematical formula for such cutting. The accuracy of the calculations that the insect is endowed with is still surprising.
After preliminary work, the bug, even a very young one, slowly but surely folds the leaf, smoothing its edges with a spatula. Thanks to this technological technique, sticky juice is released from the rollers on the leaf cloves. The bug, of course, doesn’t think about it. Squeezing glue to fasten the edges of a leaf in order to provide a reliable home for future offspring is predetermined by the program of its expedient behavior.
The work of creating a comfortable and safe nest for babies is quite painstaking. The female, working day and night, manages to roll only two leaves per day. She lays 3-4 eggs in each, thereby making her modest contribution to the continuation of the life of the entire species.
Purposeful actions of the larva. A classic example of innate sequence of actions is demonstrated by the antlion larva. Its feeding behavior is based on an ambush strategy and has a number of complex preparatory operations.
The larva, hatched from the egg, immediately crawls onto the ant path, attracted by the smell of formic acid. The larva inherited knowledge about this signal smell of its future prey. On the path, she carefully selects a dry sandy area to build a funnel-shaped hole-trap.
To begin with, the larva, with amazing geometric precision, draws a circle in the sand, indicating the size of the hole. Then she starts digging with one of her front paws.
To throw sand outside the circle, the larva loads it onto its own flat head. Having done this, she moves back, gradually returning to her original position. Then he makes a new circle and digs the next groove. And so on until it reaches the bottom of the funnel.
This innate program even provides for changing the tired “working” leg before the start of each cycle. Therefore, the larva makes the next groove in the opposite direction.
The larva forcefully throws small pebbles along the way outside the funnel. The larva deftly lifts a large stone, often several times heavier than the insect itself, onto its back and pulls it up with slow, careful movements. And if the stone is round and constantly rolls back, she gives up the useless work and begins to build another hole.
When the trap is ready, the next important stage for the insect begins. The larva buries itself in the sand, exposing only its long jaws. When any small insect finds itself at the edge of the hole, the sand under its feet crumbles. This serves as a signal to the hunter. Using its head as a catapult, the larva knocks down an unwary insect, most often an ant, with surprisingly accurate shots of grains of sand. The prey rolls down towards the waiting “lion”.
In this behavioral complex, all the actions of the larva are ideally consistent and perfectly coordinated - one strictly follows the other. However, the young insect not only carries out its stereotypical actions, but also adapts them to specific conditions associated with varying degrees of weediness and moisture content of the sandy soil.
The most sensitive sense of smell is recorded in these insects, because the male senses the female 11 km away
Alternative descriptionsUnit of quantity of substance
Butterfly, pest of things
Insect, pest
German botanist (1805-1872)
Rafting of timber in bulk
. "Shoe-eater"
Butterfly in the closet
Butterfly in a fur coat
Butterfly from grandma's chest
Butterfly from the closet
Butterfly, harmful insect
A butterfly hibernating in a closet
Butterfly being applauded
A butterfly that loves fur coats
Butterfly "wardrobe attendant"
Butterfly "fur-eater"
Harmful butterfly
Wardrobe rodent
F. aphid (from small) tiny moth (butterfly), panicle; its caterpillar, which wears furs and woolen clothing, Tinca. There are fur moths, clothing moths, cheese moths, bread moths, and vegetable moths. Moths disappear from hops and camphor. Vegetable moth, aphid, moth, broom, with which the caterpillar eats honeycombs. The smallest fish, recently hatched, molga, molka, molyava, lyavka, malga, see small. Fresh smelt is also called moth; novg. the smallest snowball. Moths smolder clothes, and sadness smolders the heart (or a person). Stuff your nose with tobacco, you won't get moths in your head! There are calluses on my teeth, my nails are swollen, my hair has been eaten by moths. Molie, molie cf. collect mole. Molitsa old moletocha aphids, moths, worms, moths. Yadyakhu... molits, crushed and mixed with dumplings and straw, in hunger. Moletochina, moleedina, egg. -poison is a place in things, in clothes, pierced by moths; damage from moths. Mole, molar, related to moths. Moth grass, St. John's wort, steppe seven-leaf plant, knoflic, Verbascum Blattaria. Molly, moly, full of moths
Timber floated down the river, not tied into rafts
Fur lover
M. in music: minor or sad mode, soft consonance, opposite gender. dur, major. Molny, related to moths
Little butterfly
A small butterfly whose caterpillar is a pest of fur, wool, grains, and plants
small butterfly
Fur Fighter
Butterfly
The story of the Russian writer A. G. Adamov "Black..."
Eater of fur coats and blouses
Rafting of timber in bulk, individual logs
Big fan of wool products
Unit of measurement of quantity of substance
Insect is a pest; units amount of substance
Fur loving insect
Unit of measurement of quantity of substance
. "fur-eater"
The story of the Russian writer A. G. Adamov “Black...”
Poisoned by mothballs
Victim of mothballs
She eats fur coats
Play by Russian playwright N. Pogodin
Pest in the closet
Butterfly “wardrobe attendant”
Loves to eat fur coats
Butterfly "fur-eater"
Butterfly - wool gourmet
Butterfly - wool gourmet
Chemical feeling
Animals are endowed with general chemical sensitivity, which is provided by various sensory organs. In the chemical sense of insects, the sense of smell plays the most significant role. And termites and ants, according to scientists, are given a three-dimensional sense of smell. It is difficult for us to imagine what this is. The insect's olfactory organs react to the presence of even very small concentrations of a substance, sometimes very distant from the source. Thanks to the sense of smell, the insect finds prey and food, navigates the area, learns about the approach of an enemy, and carries out biocommunication, where a specific “language” is the exchange of chemical information using pheromones.
Pheromones are complex compounds secreted for communication purposes by some individuals in order to transmit information to other individuals. Such information is encoded in specific chemicals, depending on the type of living creature and even on its membership in a particular family. Perception through the olfactory system and decoding of the “message” causes a certain form of behavior or physiological process in the recipients. A significant group of insect pheromones is known to date. Some of them are designed to attract individuals of the opposite sex, others, traces, indicate the way to a home or food source, others serve as an alarm signal, others regulate certain physiological processes, etc.
The “chemical production” in the body of insects must be truly unique in order to release in the right quantity and at a certain moment the entire range of pheromones they need. Today, more than a hundred of these substances of complex chemical composition are known, but no more than a dozen of them have been artificially reproduced. After all, to obtain them, advanced technologies and equipment are required, so for now one can only be amazed at the arrangement of the body of these miniature invertebrate creatures.
Beetles are provided mainly with antennae of the olfactory type. They allow you to capture not only the smell of the substance itself and the direction of its spread, but even “feel” the shape of the odorous object. An example of an excellent sense of smell is burying beetles, which clean the earth from carrion. They are able to smell it hundreds of meters away and gather in a large group. A ladybug Using the sense of smell, it finds colonies of aphids in order to leave clutches there. After all, aphids feed not only on themselves, but also on their larvae.
Not only adult insects, but also their larvae are often endowed with an excellent sense of smell. Thus, the larvae of the cockchafer are able to move to the roots of plants (pine, wheat), guided by a slightly increased concentration of carbon dioxide. In experiments, the larvae immediately move to an area of soil where a small amount of a substance that produces carbon dioxide has been introduced.
The sensitivity of the olfactory organ, for example, of the Saturnia butterfly, the male of which is able to detect the smell of a female of his species at a distance of 12 km, seems incomprehensible. When comparing this distance with the amount of pheromone secreted by the female, a result that surprised scientists was obtained. Thanks to his antennae, the male unmistakably finds, among many odorous substances, one single molecule of a hereditarily known substance in 1 m3 of air!
Some Hymenoptera have such a keen sense of smell that it is not inferior to the well-known sense of a dog. Thus, female riders, when running along a tree trunk or stump, vigorously move their antennae. With them they “sniff out” the larvae of the horntail or woodcutter beetle, located in the wood at a distance of 2–2.5 cm from the surface.
Thanks to the unique sensitivity of the antennae, the tiny rider Helis, by just touching them on the cocoons of spiders, determines what is in them - whether they are underdeveloped testicles, inactive spiders that have already emerged from them, or the testicles of other riders of their species. How Helis makes such an accurate analysis is not yet known. Most likely, he senses a very subtle specific odor, but perhaps when tapping his antennae, the rider catches some kind of reflected sound.
The perception and analysis of chemical stimuli acting on the olfactory organs of insects is carried out by a multifunctional system - the olfactory analyzer. It, like all other analyzers, consists of a perceptive, conductive and central department. Olfactory receptors (chemoreceptors) perceive odorant molecules, and impulses signaling a specific odor are sent along nerve fibers to the brain for analysis. There the body’s immediate response occurs.
When talking about insects' sense of smell, we can't help but talk about smell. Science does not yet have a clear understanding of what smell is, and there are many theories regarding this natural phenomenon. According to one of them, the analyzed molecules of a substance represent a “key”. And the “lock” is the olfactory receptors included in odor analyzers. If the configuration of the molecule matches the “lock” of a certain receptor, the analyzer will receive a signal from it, decipher it and transmit information about the smell to the animal’s brain. According to another theory, the smell is determined chemical properties molecules and distribution electric charges. The newest theory, which has won many supporters, main reason smells in the vibrational properties of molecules and their components. Any aroma is associated with certain frequencies (wave numbers) of the infrared range. For example, onion soup thioalcohol and decaborane are chemically completely different. But they have the same frequency and the same smell. At the same time, there are chemically similar substances that are characterized by different frequencies and smell differently. If this theory is correct, then both fragrant substances and thousands of types of odor-sensing cells can be assessed using infrared frequencies.
"Radar installation" of insects
Insects are endowed with excellent organs of smell and touch - antennae (antennae or antennae). They are very mobile and easy to control: an insect can spread them apart, bring them closer together, rotate each individually on its own axis or together on a common one. In this case, they both externally resemble and are essentially a “radar installation”. The nerve-sensitive element of the antennae is the sensilla. From them, an impulse is transmitted at a speed of 5 m per second to the “brain” center of the analyzer to recognize the object of stimulation. And then the response signal to the received information instantly reaches the muscle or other organ.
In most insects, on the second antennal segment there is a Johnston's organ - a universal device, the purpose of which has not yet been fully elucidated. It is believed that it perceives movements and vibrations of air and water, contacts with solid objects. Locusts and grasshoppers are endowed with surprisingly high sensitivity to mechanical vibrations, which are capable of registering any shaking with an amplitude equal to half the diameter of a hydrogen atom!
Beetles also have a Johnston's organ on the second antennal segment. And if the beetle running on the surface of the water is damaged or removed, it will start to bump into any obstacles. With the help of this organ, the beetle is able to catch reflected waves coming from the shore or an obstacle. It senses water waves with a height of 0.000,000,004 mm, that is, the Johnston's organ performs the task of an echo sounder or radar.
Ants are distinguished not only by a well-organized brain, but also by an equally perfect bodily organization. The antennae are of utmost importance for these insects; some serve as an excellent organ of smell, touch, knowledge of the environment, and mutual explanations. Ants deprived of antennae lose the ability to find the road, nearby food, and distinguish enemies from friends. With the help of antennas, insects are able to “talk” to each other. Ants transmit important information, touching each other's antennae with their antennae. In one of the behavioral episodes, two ants found prey in the form of larvae different sizes. After “negotiating” with their brothers using antennas, they headed to the place of discovery together with mobilized assistants. At the same time, the more successful ant, who managed to convey information about the larger prey he found with the help of his antennae, mobilized much more large group worker ants.
Interestingly, ants are one of the cleanest creatures. After every meal and sleep, their entire body and especially their antennae are thoroughly cleaned.
Taste sensations
A person clearly identifies the smell and taste of a substance, but in insects the taste and olfactory sensations are often not separated. They act as a single chemical feeling (perception).
Insects that have a sense of taste have a preference for certain substances depending on the nutrition characteristic of a given species. At the same time, they are able to distinguish between sweet, salty, bitter and sour. For contact with the food consumed, taste organs can be located on various parts of the body of insects - on the antennae, proboscis and legs. With their help, insects receive basic chemical information about the environment. For example, a fly, just touching an object that interests it with its paws, almost immediately recognizes what is under its feet - drink, food or something inedible. That is, she is able to carry out instant contact analysis of a chemical substance with her feet.
Taste is a sensation that occurs when a solution of chemicals acts on the receptors (chemoreceptors) of the insect’s taste organ. Taste receptor cells are the peripheral part complex system taste analyzer. They perceive chemical stimuli, and this is where the primary coding of taste signals occurs. Analyzers immediately transmit volleys of chemoelectric impulses along thin nerve fibers to their “brain” center. Each such pulse lasts less than a thousandth of a second. And then the central structures of the analyzer instantly determine the taste sensations.
Attempts continue to understand not only the question of what smell is, but also to create a unified theory of “sweetness”. So far this has not been possible - maybe you, biologists of the 21st century, will succeed. The problem is that completely different chemical substances, both organic and inorganic, can create relatively identical taste sensations of sweetness.
Organs of touch
Studying the sense of touch in insects is perhaps the most difficult. How do these chitinous shell-clad creatures perceive the world? Thus, thanks to skin receptors, we are able to perceive various tactile sensations - some receptors register pressure, others temperature, etc. By touching an object, we can conclude that it is cold or warm, hard or soft, smooth or rough. Insects also have analyzers that determine temperature, pressure, etc., but much about the mechanisms of their action remains unknown.
Touch is one of the most important senses for the flight safety of many flying insects to sense air currents. For example, in dipterans the entire body is covered with sensilla that perform tactile functions. There are especially many of them on the halteres to sense air pressure and stabilize flight.
Thanks to the sense of touch, the fly is not so easy to swat. Its vision allows it to notice a threatening object only at a distance of 40 - 70 cm. But the fly is able to react to a dangerous movement of the hand, which caused even a small movement of air, and instantly take off. This ordinary housefly once again confirms that there is nothing simple in the living world - all creatures, young and old, are provided with excellent sensory systems for active life and their own protection.
Insect receptors that record pressure can be in the form of pimples and bristles. They are used by insects for various purposes, including for orientation in space - in the direction of gravity. For example, before pupation, a fly larva always clearly moves upward, that is, against gravity. After all, she needs to crawl out of the liquid food mass, and there are no guidelines there other than the gravity of the Earth. Even after emerging from the pupa, the fly still strives to crawl upward for some time until it dries out in order to fly.
Many insects have a well-developed sense of gravity. For example, ants are able to estimate the slope of a surface to be 20. And the rove beetle, which digs vertical burrows, can determine the deviation from the vertical to be 10.
Live weather forecasters
Many insects are endowed with an excellent ability to anticipate weather changes and make long-term forecasts. However, this is typical for all living things - be it a plant, a microorganism, an invertebrate or a vertebrate. Such abilities ensure normal functioning in their intended habitat. There are also rarely observed natural phenomena - droughts, floods, cold snaps. And then, in order to survive, living beings need to mobilize additional protective means in advance. In both cases, they use their internal “weather stations”.
By constantly and carefully observing the behavior of various living beings, you can learn not only about weather changes, but even about upcoming natural disasters. After all, over 600 species of animals and 400 species of plants, so far known to scientists, can serve as barometers, indicators of humidity and temperature, predictors of thunderstorms, storms, tornadoes, floods, and beautiful cloudless weather. Moreover, there are live “forecasters” everywhere, wherever you are - near a pond, in a meadow, in a forest. For example, before the rain, while the sky is still clear, green grasshoppers stop chirping, ants begin to tightly close the entrances to the anthill, and bees stop flying for nectar, sit in the hive and hum. In an effort to hide from the approaching bad weather, flies and wasps fly into the windows of houses.
Observations of poisonous ants living in the foothills of Tibet have revealed their excellent ability to make longer-range forecasts. Before the onset of heavy rainfall, the ants move to another place with dry, hard soil, and before the onset of drought, the ants fill dark, damp depressions. Winged ants are able to sense the approach of a storm within 2–3 days. Large individuals begin to scurry along the ground, and small ones swarm at low altitudes. And the more active these processes are, the stronger the bad weather is expected. It was revealed that over the course of a year, the ants correctly identified 22 weather changes, and were mistaken only in two cases. This amounted to 9%, which looks quite good compared to the average weather station error of 20%.
The appropriate actions of insects often depend on long-term forecasts, and this can be of great service to people. For an experienced beekeeper, bees provide a fairly reliable forecast. For the winter, they seal the hive entrance with wax. You can judge the upcoming winter by the hole for ventilation of the hive. If the bees leave big hole– the winter will be warm, and if it’s small, expect severe frosts. It is also known that if bees begin to fly out of their hives early, we can expect an early, warm spring. The same ants, if the winter is not expected to be harsh, remain to live near the surface of the soil, and before a cold winter they settle deeper in the ground and build a higher anthill.
In addition to the macroclimate, the microclimate of their habitat is also important for insects. For example, bees do not allow overheating in the hives and, having received a signal from their living “instruments” about the temperature being exceeded, they begin to ventilate the room. Some of the worker bees are arranged in an organized manner at different heights throughout the hive and move the air with rapid flapping of their wings. A strong air flow is created and the hive cools. Ventilation is a long process, and when one group of bees gets tired, it is the turn of another, and in strict order.
The behavior of not only adult insects, but also their larvae depends on the readings of living “instruments”. For example, cicada larvae that develop in the ground come to the surface only in good weather. But how do you know what the weather is like up there? To determine this, they create special earthen cones with large holes above their underground shelters - a kind of meteorological structures. In them, cicadas evaluate temperature and humidity through a thin layer of soil. And if weather conditions are unfavorable, the larvae return to the burrow.
The phenomenon of rainfall and flood forecasting
Observing the behavior of termites and ants in critical situations can help people predict heavy rainfalls and floods. One of the naturalists described a case when, before a flood, an Indian tribe living in the jungles of Brazil hastily left their settlement. And the ants “told” the Indians about the approaching disaster. Before a flood, these social insects become very agitated and urgently leave their habitable place along with their pupae and food supplies. They go to places where water will not reach. The local population hardly understood the origins of such amazing sensitivity of ants, but, submitting to their knowledge, people escaped from trouble following the little weather forecasters.
They are excellent at predicting floods and termites. Before it begins, the entire colony leaves their homes and rushes to the nearest trees. Anticipating the magnitude of the disaster, they rise to exactly the height that will be higher than the expected flood. There they wait until the muddy streams of water, which rush at such speed that trees sometimes fall under their pressure, begin to subside.
A huge number of weather stations monitor the weather. They are located on land, including in the mountains, on specially equipped scientific ships, satellites and space stations. Meteorologists are equipped modern devices, apparatus and computer equipment. In fact, they do not make a weather forecast, but a calculation, a calculation of weather changes. And the insects in the given examples of reality predict the weather using their innate abilities and special living “devices” built into their bodies. Moreover, weather forecaster ants determine not only the time of approach of a flood, but also estimate its scope. After all, for a new refuge they occupied only safe places. Scientists have not yet been able to explain this phenomenon. Termites presented an even greater mystery. The fact is that they were never located on those trees that, during a flood, were carried away by stormy streams. According to the observations of ethologists, starlings behaved in a similar way, which in the spring did not occupy birdhouses that were dangerous for settlement. Subsequently, they were actually blown away by hurricane winds. But here we are talking about a relatively large animal. The bird, perhaps, by the swinging of the birdhouse or other signs, assesses the unreliability of its fastening. But how and with the help of what devices can very small but very “wise” animals make such predictions? Man is not only unable to create anything like this yet, but he also cannot answer. These tasks are for future biologists!
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