Breathing of insects. Respiratory organs of insects Respiration of aquatic insects occurs due to
People who do not know biology well usually do not imagine the structure of invertebrates. Do they have blood and do they have a brain? Do insects breathe? The vast majority of living organisms require oxygen to live. It oxidizes incoming substances and divides them into structures that are simpler in structure. Plants also use oxygen in the process of respiration. Only anaerobic microorganisms and some multicellular animals do not require this element. However, they also breathe, they only use other organic or inorganic substances for oxidation.
World of small creatures
Insects are small organisms whose size does not exceed a few centimeters. Their structure does not allow increasing volume and weight in modern conditions. This cannot be said about the ancient arthropods that lived during the time of dinosaurs and even earlier. In those days, the atmosphere was completely different: the air density and gas composition were different. And planet Earth itself weighed less. In the distant past, dragonflies reached sizes of more than half a meter.
What do insects breathe? And what prevented them from evolving to the size of, for example, a cat in modern conditions? Scientists believe that this is a kind of respiratory system.
A bit of taxonomy
Insects belong to the tracheata subphylum. The phylum of arthropods also includes subtypes of gill-breathing (crustaceans) and chelicerates (spiders, scorpions, mites, etc.).
What do insects breathe?
The name of the subtype itself speaks about the method of breathing. However, chelicerates respire in a similar way. Insects have acquired a complex tracheal system during evolution. Tracheas are internal tubes that conduct air to the cells of the body. The tracheal system is not simple because the trachea branches into great amount thin tubes. Each of them fits a small group of cells. The tracheal network in insects is similar to the system of blood vessels and capillaries in vertebrates.
Insect spiracles
Air enters the trachea through spiracles - special openings on the body of insects. The spiracles - stigmata - are located in pairs, usually on the sides of the body. Regulation of air flow is ensured by special locking devices.
Three symmetrical large branches of the trachea usually arise from each spiracle:
- Dorsal. Provides oxygen to the spinal vessel with hemolymph and dorsal muscles.
- Visceral. Serves digestive system and genitals.
- Ventral. Serves the abdominal muscles and nerve cord.
Insect tracheoles
The endings of the trachea branch into very thin capillary tubes - tracheoles. Their diameter is less than 1 micrometer. Tracheoles branch in the intercellular space and entwine cells. They are a functional part of the tracheal system, allowing the diffusion of oxygen into the cells of the body.
Additional education
What do most insects breathe? The respiratory organs are the trachea. However, some arthropods also have air sacs. This structure is reminiscent of the lungs or, rather, the air sacs of birds to increase the volume of air in the body. Swollen areas are found in fast-flying insects (bees, flies). They lie along the tracheal trunks. As a result of contraction of the body muscles during flight, the air sacs compress and expand, increasing the flow of air in and out.
What organ do insects that live in water breathe?
For example, the silver spider, which lives in central Russia, most spends his life under water. He carries a supply of air bubbles with him. So he didn't have to change anything in his respiratory system. Spiders have a similar tracheal system to insects.
The swimming beetle is a common inhabitant of ponds middle zone Russia. It also breathes through tracheas. It periodically rises to the surface of the water and exposes the tip of its abdomen. The air enters under the elytra and is stored there. The water beetle carries a supply of oxygen with itself.
Other aquatic beetles do the same. The whirligig hunts on the surface of the pond, however, when diving in danger, it also takes air with it. It looks like a shiny membrane at the end of the abdomen.
Many water bugs also capture air in the form of a bubble from the surface. Like, for example, smoothie. It carries an air bubble attached to the end of its abdomen. This device also helps him swim better.
Some water bugs (water scorpion, ranatra) have a special tube at the end of the abdomen. It consists of two groove-shaped halves. The bug moves its abdomen - makes breathing movements. The tube carries air to the spiracles.
Respiratory organs of larvae
Adult insects breathe using tracheas. Larvae have more diverse respiratory organs. Which insect larvae breathe through tracheas? Land representatives have a tracheal system. For example, butterfly caterpillars have 9 pairs of stigmata on the sides of their bodies. The first pair is on the chest, the rest are on the abdominal segments. Sometimes the second pair of spiracles is closed.
Most aquatic insects and their larvae also have a tracheal system. However, a huge number of representatives have formations similar to gills. These are outgrowths located at the sites of the spiracles. Oxygen enters the body through the thin covers of the tracheal outgrowths. This is how the larvae of mayflies, stoneflies, and caddisflies breathe. The larvae of heteroptera dragonflies also have tracheal gills, but they are located in the intestines, that is, inside the body.
Bloodworms have filamentous gills, but large quantities absorbs oxygen throughout the entire surface of the body. The bloodworm's body always has a supply of oxygen. For this reason, it can live in polluted water bodies.
The larvae of the pinnate mosquito (the family of thick-mouthed mosquitoes) breathe oxygen dissolved in water, absorbing it over the entire surface of the body.
Respiratory organs of pupae
What do insects in the pupal stage breathe? It is believed that the third stage of insect development is motionless. However, even butterfly pupae can move their abdomen. And the doll ladybug nods its head, probably scaring off enemies. Insects at this stage breathe through tracheas.
Among the pupae of aquatic insects there are very mobile individuals. This is, for example, blood-sucking mosquitoes. Their pupae regularly rise to the surface of the water to suck in air through special tubes at the end of the abdomen.
The pupa of the pinnate mosquito is similar to the pupa of the common mosquito. But it does not rise to the surface of the water until the adult emerges. The respiratory organ is the integument of the body.
What do insects that do not have tracheae breathe? The respiratory organs of some primary wingless insects and larvae that live in tissues are the skin. They are thin enough to allow gases to pass through. Carbon dioxide is also released through the cuticle, which is partially observed in insects with tracheae.
Insects often move their abdomen - making breathing movements. The respiratory rate increases during flight. The respiratory muscles contract and relax, for example, in a bee at rest about 40 times per minute. During the flight several times more often.
In more primitive insects, the spiracles do not close. However, they are protected by hairs from debris. In more complex arthropods, stigmata are capable of opening and closing to regulate the flow of air. In addition, part of the spiracles can be used for inhalation, and the other part for exhalation of air.
Interestingly, stigmas in insects have different shapes and color. They can be round, oval, triangular. Their color sometimes differs from the color of the surrounding cuticle.
Thus, nature created the tracheal system even before the appearance of the lungs. This system is well organized. The spiracle system provides D.C. air. Oxygen is carried to all cells of the body.
Insects do not have lungs. Main respiratory system they have tracheas. The tracheae of insects are communicating air tubes that open outward on the sides of the body with openings called spiracles. The finest branches of the trachea - tracheoles - penetrate the entire body, entwining organs and even penetrating inside some cells. Thus, oxygen is delivered with air directly to the place of its consumption in the cells of the body, and gas exchange is ensured without the participation of the circulatory system.
Many insects living in water (aquatic beetles and bedbugs, mosquito larvae and pupae, etc.) must rise to the surface from time to time to capture air, i.e. they also have air breathing. The larvae of mosquitoes, centipedes and some other insects are “suspended” from below to the surface film of water using non-wettable fatty hairs while the air supply in the tracheal system is being renewed.
And aquatic beetles - water lovers (Hydrophilidae), swimming beetles (Dytiscidae) and bugs, for example, smooth beetles (Notonectidae) - having breathed at the surface, take an additional supply of air with them under the water under the elytra.
In insect larvae living in water, in moist soil and in plant tissues, cutaneous respiration also plays an important role.
The larvae of mayflies, stoneflies, caddis flies and other insects, well adapted to life in water, do not have open spiracles. Oxygen penetrates inside them through the surface of all parts of the body where the integument is quite thin, especially through the surface of leaf-shaped outgrowths, penetrated by a network of blindly ending tracheas. The larvae of bloodworm mosquitoes (Chironomus) also breathe through the skin, over the entire surface of the body.
). On the sides of the body there are up to 10 pairs, sometimes fewer, of spiracles, or stigmas: they lie on the meso- and metathorax and on 8 abdominal segments.
Stigmas are often equipped with special closing devices and each lead into a short transverse canal, and all transverse canals are connected to each other by a pair (or more) of the main longitudinal tracheal trunks. Thinner tracheas originate from the trunks, branching repeatedly, and entangling all the organs with their branches. Each trachea ends with a terminal cell with radially diverging processes, penetrated by the terminal tubules of the trachea (Fig. 341). The terminal branches of this cell (tracheoles) even penetrate into individual cells of the body.
Sometimes the trachea forms local expansions, or air sacs, which serve in terrestrial insects to improve air ventilation in the tracheal system, and in aquatic insects, probably as reservoirs that increase the supply of air in the animal’s body.
Tracheas appear in insect embryos in the form of deep invaginations of the ectoderm; like other ectodermal formations, they are lined with a cuticle (Fig. 341). In the surface layer of the latter, a spiral thickening is formed, which gives the trachea elasticity and prevents the walls from collapsing.
In the simplest cases, the entry of oxygen into the tracheal system and the removal of carbon dioxide from it occurs by diffusion through constantly open stigmas. This is observed, however, only in inactive insects living in conditions of high humidity.
Activation of behavior and the transition to living in arid biotopes significantly complicate the breathing mechanism. The body's increasing need for oxygen is ensured by the appearance of special respiratory movements, consisting of relaxation and contraction of the abdomen. In this case, the tracheal sacs and main tracheal trunks are ventilated. The formation of closure devices on the stigmas reduces water loss during respiration. Since the rate of diffusion of water vapor is lower than that of oxygen, when the stigmas are opened for a short time, oxygen has time to penetrate into the tracheal system, and water losses are minimal.
In many insect larvae living in water (for example, dragonflies, mayflies, etc.), the tracheal system is closed, that is, there are no stigmas, while the tracheal network itself is present. In such forms, oxygen diffuses from the water through the tracheal gills, lamellar or bushy, thin-walled outgrowths of the body, penetrated by a rich network of tracheae (Fig. 342). Most often, the tracheal gills sit on the sides of part of the abdominal segments (mayfly larvae). Oxygen enters through the thin covers of the gills, enters the trachea and is then distributed throughout the body.
During the transformation of gill-breathing larvae into an adult insect living on land, the gills disappear, the stigmata open and the tracheal system changes from closed to open.
An important physiological feature of the respiratory system of insects is as follows. Typically, oxygen is perceived by an animal in certain parts of its body and from there it is distributed by blood throughout the body. In insects, air tubes penetrate the entire body and deliver oxygen directly to the places of its consumption, i.e. to tissues and cells, as if replacing blood vessels.
How do insects breathe? and got the best answer
Answer from Elizabeth[guru]
link
How do insects breathe?
Insects do not have lungs. Their main respiratory system is the trachea. The tracheae of insects are communicating air tubes that open outward on the sides of the body with openings called spiracles. The finest branches of the trachea - tracheoles - penetrate the entire body, entwining organs and even penetrating inside some cells. Thus, oxygen is delivered with air directly to the place of its consumption in the cells of the body, and gas exchange is ensured without the participation of the circulatory system.
Many insects living in water (aquatic beetles and bedbugs, mosquito larvae and pupae, etc.) must rise to the surface from time to time to capture air, i.e. they also have air breathing. The larvae of mosquitoes, centipedes and some other insects are “suspended” from below to the surface film of water using non-wettable fatty hairs while the air supply in the tracheal system is being renewed.
And aquatic beetles - water lovers (Hydrophilidae), swimming beetles (Dytiscidae) and bugs, for example, smooth beetles (Notonectidae) - having breathed at the surface, take an additional supply of air with them under the water under the elytra.
In insect larvae living in water, in moist soil and in plant tissues, cutaneous respiration also plays an important role.
The larvae of mayflies, stoneflies, caddis flies and other insects, well adapted to life in water, do not have open spiracles. Oxygen penetrates inside them through the surface of all parts of the body where the integument is quite thin, especially through the surface of leaf-shaped outgrowths, penetrated by a network of blindly ending tracheas. The larvae of bloodworm mosquitoes (Chironomus) also breathe through the skin, over the entire surface of the body. Source: link
Answer from DOLPHINE[guru]
Insects do not have lungs, and their body is supplied with oxygen through microscopic pores in the chitinous shell. The chitinous shell is a kind of distributed lung. The breathing of insects resembles the breathing of mammals; their tracheal tubes quickly compress and unclench, providing a 50% renewal of oxygen within one second (this is, for example, the indicator of a person performing physical exercise medium intensity
In insects, the respiratory organs are represented by tracheae, which begin with openings - spiracles, through which air enters the trachea and through their branches into individual cells. The openings of the spiracles are located on the lateral surfaces of the chest and abdomen. The opening and closing of the spiracles is regulated by a special closure apparatus. Ventilation of the trachea is facilitated by contraction of the abdomen. Insects living in water - water beetles and bedbugs - periodically rise to the surface of the water to store air. Air is captured by the hairs of the limbs. The larvae of many aquatic insects breathe oxygen dissolved in water. In dragonfly larvae that live in bodies of water, respiration occurs due to the circulation of water in the hindgut.
Answer from Z.O.Ya[guru]
Many insects breathe in a very unusual and interesting way. If you look closely at their abdominal cavity, you can see many small holes, or pores. Each of these pores is the entrance to a tube called the trachea. It functions just like a human breathing tube, or windpipe! Thus, insects breathe the same way as we do, with the only difference being that they can have hundreds of breathing tubes. In small creatures such as insects, these tubes do not take up much space. But can you imagine what would happen if humans had the same respiratory system? There would hardly be enough space for the rest of the organs!
Answer from Evsyukov Alexander[guru]
What a horror! Holes in the chitin, examine the abdominal cavity... Do you have any idea what you're talking about? In insects, invaginations of the ectodorm (i.e., the outer integument) form into the body in the form of branching tubes called trachea. The openings of the trachea are usually located on the sides of the body. In many beetles they are mainly in the back. In wasps and bees, some pairs of trichaea are located in the head, others are dispersed throughout the body. The feeding ends with the smallest tubes - tracheoles, which are filled with liquid. The blood of insects is practically incapable of carrying oxygen, so the tracheoles approach the internal organs. Large tracheas have rings that give them rigidity, so they are not capable of contraction and the movement of gases in them is not forced. Some larvae that offend in water have the so-called. gills, but the question of their participation in respiration is quite controversial. Many consider them organs that maintain salt balance.
Answer from User deleted[active]
All living creatures must breathe in order not to die. The process of breathing is simply the inhalation of air to obtain oxygen and the exhalation of waste. The air we exhale no longer contains oxygen; there is more carbon dioxide and water vapor. The oxygen we inhale is needed to “burn” certain foods so that the body can digest them. Waste containing water vapor and carbon dioxide, are partially destroyed by the body, and partially exhaled. The simplest form respiration is probably possessed by jellyfish and most worms. They have no respiratory organs at all. Oxygen dissolved in water is absorbed through their skin, and dissolved carbon dioxide is expelled through the same route. That's all that can be said about their breathing. Earthworms - creatures with a more complex structure - have a special fluid - blood, which carries oxygen from the skin to internal organs and carries back carbon dioxide. By the way, frogs sometimes also breathe in this way, using the skin as a respiratory organ. But she also has lungs, which she uses in case of lack of oxygen. Many insects breathe in a very unusual and interesting way. If you look closely at their abdominal cavity, you can see many small holes, or pores. Each of these pores is the entrance to a tube called the trachea. It functions just like a human breathing tube, or windpipe! Thus, insects breathe the same way as we do, with the only difference being that they may have hundreds of respiratory tubes located on their abdominal cavity. In small creatures such as insects, these tubes do not take up much space. But can you imagine what would happen if humans had the same respiratory system? There would hardly be enough space for the rest of the organs! By the way, the breathing rate (that is, how often we inhale air) largely depends on the size of the creature itself. The larger the animal, the slower it breathes. For example, an elephant inhales about 10 times per minute, and a mouse about 200!
How do insects breathe, and do they breathe at all? The body structure of the same beetles differs significantly from the anatomy of any mammal. Not all people know about the vital functions of insects, because it is difficult to observe these processes due to the small size of the object itself. However, these questions sometimes come up - for example, when a child puts a caught beetle in a jar and asks how to ensure a long, happy life for it.
So do they breathe, how is the breathing process carried out? Is it possible to close the jar tightly so that the beetle does not run away or suffocate? These questions are asked by many people.
Oxygen, respiration and insect size
Modern insects actually have small sizes. But these are extremely ancient creatures that appeared much earlier than warm-blooded animals, even before dinosaurs. In those days, conditions on the planet were completely different, the composition of the atmosphere was also different. It’s amazing how they were able to survive millions of years, adapt to all the changes that took place on the planet during this time. The heyday of insects is behind us, and at the time when they were at the peak of evolution, they could not be called small.
Interesting fact: Fossilized remains of dragonflies prove that in the past they reached half a meter in size. During the heyday of insects, there were other exceptionally large species.
IN modern world insects cannot reach such sizes, and the largest are tropical individuals - a humid, hot, oxygenated climate gives them more opportunities to thrive. Literally all researchers are convinced that it is their respiratory system with its specific design features that prevents insects from thriving on the planet in today’s conditions as they did in the past.
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When classifying insects, they are classified as tracheal-breathing subtypes. This already answers many questions. Firstly, they breathe, and secondly, they do this through the trachea. Arthropods are also classified as gill-breathing and chelicerate, the former including crayfish, and the latter - mites and scorpions. However, let us return to the tracheal system, characteristic of beetles, butterflies, and dragonflies. Their tracheal system is extremely complex; evolution has been polishing it for millions of years. The tracheae are divided into numerous tubes, each tube goes to a specific part of the body - in much the same way as the blood vessels and capillaries of more advanced warm-blooded animals, and even reptiles, disperse throughout the body.
The trachea fills with air, but this is not done at the expense of the nostrils or oral cavity, as in vertebrates. The trachea is filled with spiracles, these are numerous holes that are located on the body of the insect. Special valves are responsible for air exchange, filling these holes with air, and closing them. Each spiracle is supplied by three branches of the trachea, including:
- Ventral for nervous system and abdominal muscles,
- Dorsal for the dorsal muscles and the dorsal vessel, which is filled with hemolymph,
- Visceral, which works on the reproductive and digestive organs.
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At their end, the tracheae turn into tracheoles - very thin tubes that weave around every cell of the insect’s body, providing it with an influx of oxygen. The thickness of the tracheole does not exceed 1 micrometer. This is exactly how the respiratory system of an insect works, due to which oxygen can circulate in its body, reaching every cell.
But only crawling or low-flying insects have such a primitive device. Flyers, such as bees, also have air sacs like those found in birds in addition to their lungs. They are located along the trunks of the trachea; during flight, they are able to contract and swell again to ensure maximum air flow to each of the cells. In addition, waterfowl insects have systems for storing air on the body or under the abdomen in the form of bubbles - this is important for swimming beetles, silverfish, and others.
How do insect larvae breathe?
Most larvae are born with spiracles; this is especially true for insects living on the surface of the earth. Aquatic larvae have something like gills that allow them to breathe underwater. Tracheal gills can be located both on the surface of the body and inside it - even in the intestines. In addition, many larvae are able to obtain oxygen through the entire surface of their body.