Taxonomy of the class Insects

Class Insects (Insecta) belongs to the superclass Six-legged ( Hexapoda) subtype Trachein-breathing ( Tracheata) type Arthropods ( Arthropoda).

There is a class of Insects submandibular and the class Insects postmaxillary. In total, about $ 1 million of species are known. However, entomologists believe that this figure could reach $ 2-3 million.

Remark 1

Insects are the most numerous group of animals in terms of the number of individuals, species, and breadth of distribution.

External structure of insects

The class of occult maxillary insects has characteristics that are distinctive from the class of postmaxillary insects:

• missing wings;
• the thoracic region is slightly separated from the abdominal;
• the walls of the oral cavity are fused with the lower lip, resulting in a cavity containing the mandibles and maxilla;
• on the head there are simple eyes, antennae;
• the abdomen has motor appendages.

In the structure of the body of the class of postmaxillary insects, which make up the main class of insects, the following structural features are distinguished:

• the body is subdivided into the head, chest, abdomen;
• on the head there are three pairs of mouth limbs and antennae (antennae), most species have faceted eyes, single simple eyes;
• open mouth apparatus, can be gnawing, gnawing-licking, sucking, piercing-sucking, licking;
• the chest is three-segment, carries three pairs of legs, winged insects have two pairs of wings;
• the abdomen with a different number of segments, the rudiments of the abdominal legs are modified into genital appendages or stylus;
• most insects have developed wings;
• limbs consist of five sections: the coxa, trochanters, thighs, shins, legs.

Depending on the role played by the limbs, there are:

• running,
• digging,
• walking,
• grasping,
• swimming,
• jumping,
• suction legs.

Features of the internal structure of insects

Musculoskeletal system. The skin is represented by the hypodermis, which secretes the cuticle outward. The cuticle is chitinous, three-layered, participates in the formation of the external skeleton and forms the endoskeleton - the tentorium, to which the internal organs and muscles are attached. The muscular system is differentiated. Almost all muscles are striated. Insects are distinguished:

1. skeletal muscles, set in motion the body and appendages.
2. internal, are part of the internal organs.

Digestive system consists of three departments:

• the anterior intestine is subdivided into the pharynx, the esophagus, sometimes goiter is present, the gizzard - the proventriculus;
• in the midgut, food is digested and absorbed, it can form pyloric appendages that play the role of digestive glands; the peritrophic membrane envelops food and protects against mechanical damage;
• the hind gut can be differentiated into small, large and rectum, contains rectal glands; excrement is excreted through the anus.

Excretory organs represented by malpighian vessels that flow into the hind gut. The main excretion product is uric acid crystals. The excretion function is provided by the accumulation kidneys: pericardial cells and cells of the fatty body. Metabolic products can be deposited in the integumentary cuticle and removed during the molting process of the animal.

Circulatory system open. Hemolymph, due to the work of the heart, moves freely through the cavities of the body, washing the organs. The heart has the shape of a tube, divided into chambers closed on one side. The heart is located on the dorsal side of the body. In some insects, hemolymph is poisonous, which plays a protective function.

Example 1

Blister beetles and ladybugs have corrosive blood. In times of danger, insects spray hemolymph from the joints of the legs and segments. This voluntary bloodletting is called autohemorrhage.

Respiratory system tracheal type. Tracheas open outward with spiracles - stigmas. The number of spiracles can be different, the maximum number is $ 10 $. The tracheal system containing spiracles is called open (May beetle, bee flies), without spiracles - closed (dragonfly larvae-rocker). Tracheas can form air sacs that lighten the insect's specific gravity.

Nervous system built like the abdominal nerve chain. The brain consists of three sections: proto-, deuto-, tritocerebrum. Within the class, oligomerization of the ganglia of the abdominal nerve chain occurs. The sympathetic nerve system has been formed.

The central nervous system contains neurosecretory cells, the secret of which regulates the activity of the endocrine glands and the production of hormones.

Development can be direct or proceed with metamorphosis. Distinguish:

1. Ametabolism is the direct development of primordial wingless insects.
2. Hemimetabolism is a development with gradual metamorphosis. Found in winged insects (locusts, cockroaches, bugs, cicadas, etc.).
3. Holometabolism is a complete transformation that occurs with the alternation of phases: egg - larva - pupa - imago. Typical for Diptera, butterflies, beetles, Hymenoptera, Retinoptera and Caddis flies.

general characteristics class. It is the most numerous class with over 1 million species. By its origin, this is a group of real land animals. Insects settled in a wide variety of terrestrial habitats, soil, fresh water bodies, and coastal seas. A wide variety of habitats in the terrestrial environment contributed to the speciation and widespread dispersal of this large group of arthropods.

The abdominal region in different groups of insects consists of an unequal number of segments (most of them 9-10) and lacks real limbs.

Skin insects are similar to those of arachnids. In the skin, there are various dyes that determine the color of insects. The coloration can be protective, warning. The numerous hairs on the surface of the chitinous cuticle perform the function of touch. The integument is abundantly supplied with various glands - waxy, odorous, spinning, poisonous, etc., the secretions of which play an important role in the life of insects.

The striated musculature reaches a special development in the thoracic region, providing rapid movements of the wings (from five to a thousand strokes per second) and limbs.

Like other arthropods, digestive system insects are divided into three sections. The structure of the anterior intestine is modified depending on the food specialization of the insects. Insects that eat solid food have a gizzard (Figure 11.14). In those who eat liquid food, the oral cavity is turned into a system of canals, and the stomach is a sucking type. Salivary glands can be converted to spinning glands (butterfly caterpillars) or contain blood anticoagulants (in blood-sucking forms). In the back of the intestines of most insects, there are special glands designed to absorb water from undigested food debris.

In addition to the malpighian vessels (from 2 to 200), the fatty body also serves as the excretory organ, the main function of which is to store nutrients necessary for the development of eggs during wintering. The end product of nitrogen metabolism in insects is uric acid, which is released in the form of crystals, which is associated with the need to preserve water in their gel.

Breath insects are carried out exclusively with the help of a highly branched tracheal system. The spiracular openings are located on the lateral surfaces of the chest and abdomen. The spiracles are equipped with special valves that regulate the flow of air into them, the movement of which occurs with the help of abdominal contractions. Insects living in the water - water flies and bugs - are forced to periodically rise to the surface of the water to store air.

Fig. 11.14. Diagram of the structure of cockroach organs: 1 — esophagus; 2 — goiter; 3 — muscular stomach; 4 - midgut; five —excretory tubes; b — lateral trachea; 7 — abdominal nerve cord.

Circulatory system insects due to the structural features of the respiratory system is poorly developed and does not have any fundamental differences from that of other arthropods (Fig. 11.15). The blood is colorless or yellowish, rarely red, depending on the hemoglobin dissolved in it (for example, in the larvae of the mosquito-bloodworm).

Nervous system, like other arthropods, it is built on the type of the peri-pharyngeal nerve ring and the abdominal nerve chain. The supraesophageal ganglion reaches a high level of development, especially in social insects (bees, ants, termites), transforming into a "brain" with three sections: anterior, middle and posterior. It innervates the eyes and antennae. The behavior of social insects is complex.

The sense organs of insects are well developed. The organs of vision of an adult are represented by faceted eyes, to which simple eyes are sometimes added, located on the forehead and crown.

Some insects have color vision (butterflies, bees). The organs of balance and hearing are arranged in a peculiar way. Insects have a keen sense of smell that allows them to find food and sexual partners. The organs of touch are most often located on the antennae, and the organs of taste are located on the mouth limbs. A highly developed nervous system and perfect sense organs determine the complex behavior of insects, especially social ones. It is determined by instincts, which are innate complexes of reactions.

Fig 11 .15 ... Insect circulatory system: 1 — aorta; 2 — pterygoid muscles; 3 — dorsal vessel — "a heart".

Types of insect development. Insects are dioecious, most of them with pronounced sexual dimorphism. The sex glands are paired; males often have a copulatory organ. The eggs are rich in yolk and are deposited outside. After leaving the egg, the development of the insect's organism occurs with incomplete or complete transformation (metamorphosis).

In insects with incomplete transformation, larvae hatch from eggs, similar in appearance to an adult insect, but differing from it in smaller size and underdeveloped wings and reproductive system. With each molt, they become more and more like an adult form. On the contrary, in insects with complete transformation, development proceeds with a successive change of forms, completely unlike one another. A worm-like larva hatches from the egg (in a butterfly it is called a caterpillar), which crawls, eats a lot, sheds several times and becomes larger with each molt. As a result of the last larval molt, a pupa is formed, which does not move or feed. Pupae of different orders of insects with complete transformation have different structures, but they have in common the destruction of the anatomical structures of the larva and the use of this material to build the organs of an adult insect. The regulation of all stages of metamorphosis occurs with the participation of special hormones.

In insects with complete transformation, the larva (caterpillar) and the adult differ not only appearance, but also by the way and objects of food. So, the caterpillar of a cabbage butterfly feeds on leaves, an adult butterfly sucks flower nectar. In addition, larvae and adult insects inhabit different habitats. For example, a mosquito larva lives in fresh waters and feeds on algae and protozoa, while an adult mosquito (female) lives in terrestrial conditions and sucks the blood of humans and other mammals. Due to these differences in food sources and habitats, intraspecific competition is weakened, which contributes to the prosperity of insects.

Insect orders. The Insects class includes a large number of units. The basis for their selection is the structure of the wings, the mouth apparatus and the type of development. The characteristics of the main groups are presented in table. 11.1.

Tab. 11.1. The main orders of insects.

The detachment and its representatives	Characteristic signs	Value
1	2	3
Insects with incomplete transformation
Dragonflies (large rocker, beauties, arrows, etc.)	Two pairs of wings (the same in the suborder isoptera and somewhat different in the representatives of the suborder of the heteroptera) with a fine network of veins. Large compound eyes converging on the crown of the head. Gnawing mouth apparatus.	Being voracious predators, they destroy a large number of insect pests.
Orthoptera (grasshoppers, crickets, locusts, bears)	The forewings are rigid with almost parallel longitudinal veins. The hind wings are wider with radially diverging longitudinal veins. Gnawing mouth apparatus.	Most of the representatives of the order are plant pests. Locusts, by eating leaves and stems, harm crops. Grasshoppers damage orchards and vineyards. Bears, digging in the soil, damage the roots of plants.
Hemiptera, or Bedbugs (bugs-turtles, bedbugs, water striders, etc.)	Half of each elytra from its base is rigid and consists of a thick layer of chitin, and the other half is thinner, membranous. Some bugs (bed bugs, etc.) have reduced wings. The oral apparatus is a piercing-sucking type. Many species have an odor gland, so they have an unpleasant odor.
Insects with complete transformation
Coleoptera, or Beetles (May beetles, click beetles, weevils, bread beetle [kuzka], leaf beetles [Colorado beetle], bark beetles, swimming beetles, ground beetles, ladybugs, dung beetles, etc.)	The first pair of wings - rigid elytra - covers the second pair of membranous wings. The mouth apparatus is gnawing.	Many of the beetles harm plants, May beetles eat leaves, and their larvae eat tree roots. The larvae of click beetles are called wireworms. They feed on underground parts of potatoes and cereals. The Colorado potato beetle and its larvae eat the leaves of the potato. The larvae of the weevil, the apple flower beetle, destroy the flower ovaries, and the larvae of the beet weevil destroy the roots of the beet. Among the beetles there are also useful ones. These are predatory beetles (ground beetles and beetles) that hunt for silkworm caterpillars. Ladybugs and their larvae feed on aphids. Dung beetles and their larvae, eating manure, are a kind of orderlies.
Lepidoptera, or Butterflies (cabbage white, hawthorn, apple moth, moth, house moth, silkworms)	Two pairs of very large wings in comparison with the body of the insect, painted in different colors. The color of the wings depends on the color and location of the scales. The veins on the wings are located longitudinally. With the exception of some moths, butterflies have a sucking mouth apparatus.	The larvae of butterflies, eating the aerial parts of plants, are harmful. The larvae of the cabbage whitefish eat the leaves of cabbage and other cruciferous plants. The larvae of the boyar, apple moth and moth damage the fruit trees. The larvae of the house moth feed on the wool of fabrics or furs and damage clothing, carpets, and furniture upholstery. Pine silkworm larvae eat pine needles and harm pine forests; ringed silkworm larvae damage fruit orchards. By bringing harm at the larval stage, adult butterflies, by pollination of plants, are beneficial. The benefit of butterflies is that they are food for birds. Among butterflies, there are also domesticated forms. These are oak and mulberry silkworms. Their caterpillars have highly developed silk-secreting glands that secrete silk thread. The caterpillar envelops itself with this thread before pupation. The silky cocoon protects the pupa from adverse conditions, and for humans it serves as a raw material for producing silk.
Hymenoptera (wasps, sawflies, bees, wasps, bumblebees, ants, etc.)	The hind wings are always smaller than the front ones. Both pairs are transparent with relatively sparse longitudinal and transverse veins. The mouth apparatus in most species is gnawing, and in stinging (bees) - gnawing-sucking type. Bees, wasps, and some ants have a sting representing an altered ovipositor. The way of life is different. Some (riders, sawflies, some wasps) live alone, others (bees, ants, some wasps) live in large families and are social insects. Between individuals Within the family, there is a division of labor.	Hymenoptera are of great importance as pollinators of plants. The honey bee forms wax, bee venom, royal jelly used in medicine and perfumery. Bee honey is also useful. Riders are of great benefit. Laying eggs in the body of the larvae and eggs of many harmful insects, they help humans in the fight against them. Wasps are also useful in this regard: storing food for their larvae, they paralyze and drag them before laying eggs in the burrows of the caterpillars of many harmful insects. There are also pests among the Hymenoptera. Sawfly females have a sawtooth ovipositor, with which they saw through the plant's eggs to lay eggs. The larvae that emerge from the eggs eat the leaves of the plants.
Diptera (flies, gadflies, horseflies, mosquitoes, midges, mosquitoes, etc.)	The rear pair of wings is reduced. Their remains turned into halteres. The front pair of wings is strongly narrowed at the base. Mouth organs of the licking (in a fly) and piercing-sucking (in a mosquito) type.

The role of insects in nature, their practical significance. Insects, with their diversity and huge numbers, play an important role in nature and human life. They are plant pollinators, exterminate harmful representatives of this class and play the role of orderlies. Some beneficial insects - bees, silkworms - were domesticated by humans. At the same time, the harm caused by insects is also great. Depending on the object of attack, harmful insects are divided into several groups: pests of the field, garden, vegetable garden, granary pests, disease vectors.

In order to protect plants from insects, different methods of controlling them are used. Widely applied collection insects with the help of trapping ditches, rings, ravings, insect traps (mechanical method), etc. In addition, the fight is carried out and chemical method, in which insects are exposed to poisons. But using chemical substances leads to poisoning of soil, water, destruction along with harmful and beneficial insects. Therefore, recently, a biological method of struggle has received recognition, in which man uses the natural enemies of insects: insectivorous birds, predatory insects (ground beetles, ladybirds, etc.). The trichogramma rider is artificially bred to combat the codling moth.

MUNICIPAL EDUCATIONAL INSTITUTION

"SECONDARY SCHOOL №108

NAMED AFTER THE FIRST GUARDS ARMY OF THE CITY MAKEEVKA "

"General characteristics of the class Insects"

Lesson game

Prudnikova Anastasia Andreevna,

biology teacher

MOU "Secondary School No. 108 of the city of Makeevka"

Subject: General characteristics of the class Insects.

Laboratory work No. 5

purpose: to study the features of the structure and life of insects; trace the connection between the features of the structure and life, the environment; to reveal the traits of adaptability to the environment, to reveal the features of the complication of the organization.

Equipment and materials: presentation slides on the topic of the lesson, photographs of insects, video clips, handouts.

Basic concepts and terms: segments, oral apparatus, compound eyes, body integuments, chitin, wings, body parts, malpighian vessels, trachea, hemolymph, supraopharyngeal node.

Methods and methodological techniques: verbal (story, story with elements of conversation, search (brainstorming), visual (demonstration of insect images, videos), practical (work in groups with applications, information sheets; laboratory work).

Lesson type: combined

Lesson structure

Organizational stage (2 minutes)

Checking students' homework (8 minutes)

Communication of the topic, goals and objectives of the lesson. Motivation for learning activities (4 minutes)

Learning new material (7 minutes)

Physical education minute (2 minutes)

Learning new material (8 minutes)

Generalization and systematization of what was learned (10 minutes)

Homework (2 minutes)

Lesson summary (2 minutes)

During the classes

Organizational stage

Hello guys. As you have already noticed, today we work on the basis of team activities. You sat down the way you feel comfortable and comfortable. Let's immediately determine who will be the captain in each of the teams. Excellent! You have applications on your desks that we will use today in the lesson. Pay attention to Appendix 1, today you and I have to go through a difficult maze, on the way out of which we will know the Type Arthropods even better. I invite the teams to find a way out of our maze (students complete the task in groups). Excellent! Let's now check our routes.

And so, we have coped with this task and moved to the first point in our route. Let's check how well we know Type Arthropods.

Checking student homework

Game "Allias". You have cards on your desks with arthropod concepts. According to the rules of this game, to describe words (terms), one cannot use the same root words and foreign analogues.

Pay attention to the seating diagrams of team members, Participant number 1 from team 1, asks a question to participant No. 1 of the second team, the next question is asked by participant No. 2 of the first team, participant No. 2 of the second team, and so on. First, team # 1 plays with team # 2, then team # 2 plays with team # 3, and team # 3 plays with team # 1. At the end of the first round, 2 teams are playing. They ask 4 questions.

Excellent! Well done!

Communication of the topic, goals and objectives of the lesson. Motivation for learning activities. The second point of our route.

In the meadow, a fun ball was opened in the spring:

Komar played the trumpet, the furry bumblebee danced with Mushka naked.

And the breeze whirled, playing with leaves.

And the flower swayed to the beat, tilting its green stalk slenderly.

The dragonfly flew easily with the well-dressed Moth.

And the Snail dragged along and lay down comfortably under the cool leaf.

The May Beetle also flew in with a fat Zhychikha,

And pushing everyone around, he entered the merry circle, dashing akimbo.

The ants came in a crowd, moving their mustaches, and they went to dance! ..

Only the Spider sat in the distance, hiding behind the branches.

And he got angry and grumbled: "What kind of housewarming, what else is this ball?"

The Evil Spider did not understand happiness and fun ...

Guys, what kind of animals in question in this poem? (students make their assumptions).

That's right, about insects. Today in the lesson we will continue to study the Arthropod type using the example of the Insects class. Help me formulate the topic of our lesson (students express their thoughts, from which the topic of the lesson is formed). Well done!

The topic of our lesson "General characteristics of the class insects"

Write it down in workbook

What questions should we answer at the end of the lesson? (Features of the external structure, features of the internal structure, features of nutrition, movement of insects).

Learning new material

And so, we came to the third point of our route.

Storytelling with conversation elements

Insects appeared about 400 million years ago, and descended from the ancients annelids, which refutes the saying "Born to crawl - cannot fly." Moreover, insects were the first animals on Earth to master the air environment. Currently, about 1.5 million species of insects are known with various sizes from 0.25mm to 30cm. Write down the number of insect species in your workbook.

What are the common characteristics for all classes of arthropods? (Chitinous cover, articulated legs, segmented body).

The body of insects consists of three sections - this is the head, chest and abdomen. On the sides of the head are two large compound eyes, between which there may be several simple small eyes. A pair of antennae, or antennae, extend from the top of the head. The altered limbs on the head turned into a mouth apparatus.

The insect's chest always consists of three segments - antero-, middle-, metathorax. Pairs of walking legs are located on these segments.

The abdomen is the last section of the insect's body. It is attached to the thoracic region of the body either motionlessly, like in beetles, or, conversely, with the help of a thin stalk, like in Hymenoptera

4 point of the labyrinth, cards are laid out on the table (Appendix 2), with characteristic features insects, your task is to divide them into 3 groups, according to the number of teams. Let's get started (students work collectively with handouts).

Excellent! Commanders, get information cards, using them, complete tasks Appendix 3.

Checking Completed Assignments Using a Presentation Slide

Physical education minute

The fifth point of our labyrinth. Attention to the screen, we repeat the movements (demonstration of the video on the screen, the students repeat the movements).

Learning new material

We have come to the sixth point of the maze, let's consider internal structure insects.

Storytelling with conversation elements

Digestive system consists of the digestive tract and digestive glands. In insects in the digestive tract, the mouth, pharynx, esophagus with goiter, stomach, and intestinal sections are secreted. The ducts of the salivary glands enter the pharynx. The anterior, middle and hind gut are separated from each other by valves. Food moves in the intestine due to the contraction of its longitudinal and annular muscles. The stomach is located in front of the beginning of the midgut and serves to grind food and filter it through the valve. Digestion and absorption of nutrients mainly occurs in the midgut. In the hindgut, water is absorbed, cellulose is broken down by bacteria.

Insect excretory organs- Malpighian vessels - flow into the intestine between the middle and hind gut. They carry substances into the intestines, together with water, to be removed from the body. The water is then absorbed by the intestinal walls.

In insects respiratory system represented by tracheas, which are characterized by large branching. Large insects, in order to provide themselves with a large amount of oxygen, ventilate the trachea, contracting and relaxing the abdomen.

Circulatory system insects are not closed, i.e. part of its path the blood does not pass through special vessels, but in the body cavity. The central organ is the heart, or dorsal vessel. Insect blood is called hemolymph. It is usually unstained and does not contain hemoglobin or similar oxygen scavengers delivered directly by the tracheal system. Hemolymph carries out transport of nutrients and excreta, as well as functions of immunity.

Insects have complexly developed nervous system and senses. Insects have a large epopharyngeal node, which can already be called a brain. In the abdominal nerve chain, the number of nodes does not correspond to the number of body segments, usually there are fewer of them, and they differ in size.

The organs of sight, smell, taste, touch in insects are very well developed. Insects have developed color vision, the organs of smell are antennas carrying many special sensitive receptors. Only some insects have specially developed hearing organs. Taste receptors are mainly concentrated in the mouth. In the skin of insects, in addition to numerous tactile receptors, some receptors register pressure, temperature, microvibration of the medium, and other parameters.

Insects are dioecious and often have pronounced sexual dimorphism. The insect reproduction system consists of testes in males and ovaries in females, pathways connecting these organs with the genital opening near the anus, as well as accessory glands and structures that ensure fertilization.

Pay attention to Appendix 3, using the information received about the internal structure of insects, individually complete the tasks. You have 2 minutes to complete the tasks. Great, now exchange them with your deskmates and, looking at the presentation slide, check with each other how correctly the assignments were completed.

Generalization and systematization of the studied material

The seventh point of our labyrinth

Laboratory work No. 5

Subject: Study of the adaptation of the external structure of insects to their habitat

Purpose: study the features of the external structure of insects; to reveal the features of adaptation of insects to different habitats.

Equipment and materials: insect photographs, insect videos, information sheet.

Progress

1. ____________________________ 6.______________________________ 2._____________________________ 7.______________________________

3._____________________________ 8._______________________________

5._____________________________ 9._______________________________

9._____________________________ 10.______________________________

Take a close look at video fragments illustrating insects in different habitats. Where do insects live? ______________________________________________________________________________________________________

Homework

The eighth point of our labyrinth is homework. Open the diaries, write down your homework: paragraph 46, answer the questions.

Lesson summary

Congratulations guys! We got to the finish line of our lesson.

Bibliography

WINGS

WALKING

ADHESIVE PILLOWS

SPEED

ORAL APPARATUS

FOOD

PROBOSCIS

NEKRAT FLOWER

EPITHELIUM

CUTICLE

CHITIN

PAINTING

FULL NAME_________________________Appendix 3

1. Provide the correct statements:

1. Respiratory organs of insects - lungs.

2. Excretory organs of insects - Malpighian vessels.

3. The circulatory system of insects is not closed.

4. Hemolymph is not colored and has no hemoglobin.

5. Digestion and absorption of nutrients in insects mainly occurs in the stomach.

6. Insects have poorly developed sense organs.

7. Insects are hermaphrodites.

8. Malpighian vessels drain into the stomach.

9. Insects have developed color vision.

10. Insects have a large subpharyngeal node, which can already be called the brain.

2. Draw the nervous system, circulatory system, digestive system, genitourinary system, and respiratory system.

________________________________________________

________________________________________________

________________________________________________

________________________________________________

________________________________________________

Full name _______________________________ DATE ________________

Laboratory work No. 5

Subject. Study of the adaptation of the external structure of insects to their habitat

Purpose. __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Equipment and materials. photographs of insects, video, information sheet.

Progress

Indicate the elements of the external structure of the beetle in the figure

1. _________________________________ 2.________________________________

3._________________________________ 4.________________________________

5._________________________________ 6.________________________________

7._________________________________ 8.________________________________

9._________________________________ 10.________________________________

Take a close look at video fragments illustrating insects in different habitats.

Where do insects live? _____________________________________________________________________________________________________________________________________________________________________________________________

Using photographs and information sheets, identify the features of the external structure of insects, depending on the habitat.

Enter the results of your research into the table

Draw a conclusion by indicating how by the external structure you can distinguish insects from crustaceans and arachnids.

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Insect habitat

Do insects live underground?

The earth, especially in forests and fields, hides millions of insects. Each handful of forest land is home to up to a thousand Fork-tails. Many insects feed on fungi, decayed leaves and other plant and animal debris, contributing to the cycle of substances in nature. Plants serve as food for other insects, such as root aphids and beetle larvae. Predatory larvae of ground beetles, short-winged and click beetles prey on insects, earthworms and snails. Several species of beetles live in the darkness of caves. The eyes of most of them have atrophied in the process of evolution, but their sense of touch is developed to an incredible degree. For cave beetles, the dark color of the body is not as important as for their relatives of other species, they do not need protection from harmful ultraviolet rays. Sometimes there are light yellow or reddish species. Colorless and blind is the cave grasshopper, a wingless predatory inhabitant of karst caves.

Are insects found in ice ?

In summer, in the mountains, snow and glacial fleas multiply at such a rate that the snow, due to the variegated color of insects, acquires a "bloody" hue. They feed on pollen and organic particles that the wind brings.

Can insects survive in the desert?

The beetles that live in the South African Namib Desert do an excellent job of coping with the lack of moisture. Darkling beetles of the genus Lepidochim dig grooves in the sand perpendicular to the direction of the wind. When the wind brings humid air from the Atlantic, moisture settles at the edge of the groove. Other types of beetles make headstands during wet winds. Droplets of moisture roll down the body of the beetle, and he licks them off.

Water striders

The largest water bodies in the world - the seas - are practically not inhabited by insects. An exception is the Halobates water strider. Like ordinary water striders living in our area, they hunt animals that have fallen into the water. Halobates can sometimes be found in a closed ocean bay.

How insects breathe underwater

Clean streams and rivers from source to mouth are the habitat of many insects. Dragonflies, mayflies, caddis flies, stoneflies and other dipterans on early stages development live at the bottom of streams. Stagnant water bodies such as ditches, puddles and ponds are also home to many larvae and adult insects. The larvae of mayflies, dragonflies, caddis flies and stoneflies have no breathing holes through which oxygen-saturated air could enter their body. These insects absorb oxygen dissolved in water through filamentous, leaf-like or bundle-like appendages - trachea. Underwater adult insects store air on their bodies. The swimmer is bordered - under the wings, where its respiratory openings fit. Other water beetles and bugs have a silvery container on their abdomen. The fine hairs in the airway guide the water, preventing it from moving back. Some insects, such as the water scorpion and mosquito, breathe through an air-filled tube on the surface of the body of water.

Insects are the youngest of the invertebrates and the most numerous class of animals, numbering over 1 million species. They have completely mastered all habitats - water, land, air. They are characterized by complex instincts, omnivorousness, high fertility, for some - a social way of life.

During development with transformation, the habitat and food sources are divided between larvae and adults. The evolutionary path of many insects is closely related to flowering plants.

More highly developed insects are winged. In the cycle of substances in nature, grave beetles, dung beetles, consumers of plant residues play an important role, and at the same time, insects - pests of agricultural plants, gardens, food supplies, leather, wood, wool, books - cause great damage.

Many insects are carriers of pathogens of animal and human diseases.

Due to the reduction of natural biogeocenoses and the use of pesticides, the total number of insect species is decreasing, therefore, 219 species are included in the Red Book of the USSR.

General characteristics of the class

The body of adult insects is divided into three sections: head, chest and abdomen.

• Head, consisting of six merged segments, distinctly detached from the chest and movably connected to it. On the head there is a pair of articulated antennae or cords, an oral apparatus and two faceted eyes; many also have one or three simple eyes.

  Two compound, or faceted, eyes are located on the sides of the head, in some species they are very strongly developed and can occupy most of the surface of the head (for example, in some dragonflies, horseflies). Each compound eye contains from several hundred to several thousand facets. Most insects are blind to red, but they see and are attracted to ultraviolet radiation. This feature of insect vision is based on the use of light traps, which emit most of the energy in the violet and ultraviolet regions, to collect and study the ecological features of nocturnal insects (some families of butterflies, beetles, etc.).

  The oral apparatus consists of three pairs of limbs: upper jaws, lower jaws, lower lip (fused second pair of lower jaws) and upper lip, which is not a limb, but is an outgrowth of chitin. The chitinous protrusion of the bottom of the oral cavity - the tongue or hypopharynx - also belongs to the oral apparatus.

  

  

  

  Depending on the way of feeding, the mouth organs of insects have a different structure. The following types of oral apparatus are distinguished:

  • gnawing-chewing - elements of the oral apparatus look like short hard plates. They are noted in insects that feed on solid plant and animal food (beetles, cockroaches, orthoptera)
  • piercing-sucking - elements of the oral apparatus look like hair-like bristles elongated in length. They are noted in insects that feed on the cell sap of plants or the blood of animals (bugs, aphids, cicadas, mosquitoes, mosquitoes)
  • licking-sucking - the elements of the oral apparatus have the form of tubular formations (in the form of a proboscis). It is noted in butterflies that feed on flower nectar and fruit juice. In many flies, the proboscis is strongly transformed, at least five of its modifications are known, from a piercing-cutting organ in horseflies to a soft "licking" proboscis in flower flies feeding on nectar (or in feeding on liquid parts of manure and falling flies).

  Some species do not feed as adults.

  The structure of the antennae, or tendons, of insects is very diverse - filiform, bristle-like, serrate, comb, clavate, lamellar, etc. Antennae are one pair; they carry the organs of touch and smell, and are homologous to the antennae of crustaceans.

  The senses on the antennae of insects tell them not only the state of the environment, they help to communicate with relatives, find a suitable habitat for themselves and their offspring, as well as food. Females of many insects attract males through smells. Males of the Lesser Night Peacock's Eye can smell the female at a distance of several kilometers. Ants recognize females from their nests by smell. Some species of ants mark their way from the nest to the food source thanks to odorous substances that are secreted from special glands. With the help of antennae, ants and termites smell the smell left by their relatives. If both antennae pick up the odor to the same extent, then the insect is on the right track. Attractants that are secreted by female butterflies ready to mate are usually carried away by the wind.

• Chest insects consists of three segments (prothorax, mesothorax and metathorax), to each of which a pair of legs is attached from the ventral side, hence the name of the class - six-legged. In addition, in higher insects, the chest carries two, less often one pair of wings.

  The number and structure of the limbs are characteristic of the class. All insects have 6 legs, one pair on each of the 3 chest segments. The leg consists of 5 sections: the basin (plow), trochanter, thigh (femur), tibia (tibia) and articulated tarsus (tarsus). Depending on the lifestyle, the limbs of insects can be very modified. Most insects have walking and running legs. In grasshoppers, locusts, fleas and some other species, the third pair of legs is of the jumping type; in the bear, making holes in the soil, the first pair of legs are digging legs. In aquatic insects, for example, the swimming beetle, the hind legs are transformed into rowing, or swimming.

  Digestive system presented

  • The anterior gut, which begins with the oral cavity and subdivides into the pharynx and esophagus, the posterior part of which expands, forming a goiter and chewing stomach (not all). For consumers of solid food, the stomach has thick, muscular walls and carries chitinous teeth or plates from the inside, with the help of which food is crushed and pushed into the middle intestine.

    The salivary glands also belong to the anterior gut (up to three pairs). The secretion of the salivary glands performs a digestive function, contains enzymes, and moistens food. In bloodsucking, it contains a substance that prevents blood clotting. In bees, the secret of one pair of glands is mixed in the goiter with flower nectar and forms honey. In worker bees, the salivary glands, the duct of which opens into the pharynx (pharyngeal), secretes special protein substances ("milk"), which are fed to the larvae, which turn into queens. In caterpillars of butterflies, larvae of caddis flies and hymenoptera, the salivary glands are transformed into silk-separating or spinning glands, producing a silky thread for making a cocoon, protective formations, and other purposes.

  • The midgut at the border with the anterior gut is covered from the inside with glandular epithelium (pyloric outgrowths of the intestine), which secretes digestive enzymes (the liver and other glands are absent in insects). The absorption of nutrients takes place in the midgut.
  • The hindgut takes in undigested food debris. Here water is sucked out of them (this is especially important for desert and semi-desert species). The posterior intestine ends with an anus that leads out excrement.

  

  Excretory organs are represented by malpighian vessels (from 2 to 200), which have the form of thin tubes flowing into the digestive system at the border between the middle and hind intestine, and the fatty body, which performs the function of "accumulation kidneys". The fatty body is a loose tissue located between the internal organs of insects. Has a whitish, yellowish or greenish color. The cells of the fat body absorb metabolic products (uric acid salts, etc.). Further, the products of excretion enter the intestines and, together with excrement, are excreted. In addition, the cells of the fat body store reserve nutrients - fats, proteins and the carbohydrate glycogen. These reserves are spent on the development of eggs during wintering.

  Respiratory system- trachea. This is a complex branching system of air tubes that directly deliver oxygen to all organs and tissues. On the sides of the abdomen and chest there are most often 10 pairs of spiracles (stigmas) - holes through which air enters the trachea. Large main trunks (trachea) begin from the stigmas, which branch into smaller tubes. In the chest and anterior part of the abdomen, the trachea are dilated and form air sacs. Tracheas penetrate the entire body of insects, entwine tissues and organs, enter individual cells in the form of tiny branches - tracheoles, through which gas exchange takes place. Carbon dioxide and water vapor are removed to the outside through the tracheal system. Thus, the tracheal system replaces the function of the circulatory system in supplying oxygen to tissues. The role of the circulatory system is reduced to the delivery of digested food to the tissues and the transfer of decay products from the tissues to the excretory organs.

  Circulatory system in accordance with the characteristics of the respiratory system, it is relatively poorly developed, open, consists of a heart and a short unbranched aorta extending from the heart to the head. The colorless fluid circulating in the circulatory system, containing white blood cells, is called hemolymph, in contrast to blood. It fills the body cavity and the gaps between the organs. The heart is tubular, located on the dorsal side of the abdomen. In the heart there are several chambers capable of pulsating, each of which opens a pair of orifices equipped with valves. Through these holes, blood (hemolymph) enters the heart. The pulsation of the heart chambers is caused by the contraction of special pterygoid muscles. Blood moves in the heart from the posterior end to the anterior, then enters the aorta and from it into the head cavity, then washes the tissues and flows through the cracks between them into the body cavity, into the gaps between the organs, from where it enters the heart through special holes (ostia). Insect blood is colorless, or greenish-yellow (rarely red).

  Nervous system reaches an exceptionally high level of development. It consists of the supraopharyngeal ganglion, periopharyngeal connectives, the subopharyngeal ganglion (it was formed as a result of the fusion of three ganglia) and the abdominal nerve chain, which in primitive insects consists of three thoracic ganglia and eight abdominal ganglia. Have higher groups insects, the adjacent nodes of the abdominal nerve chain merge by combining three thoracic nodes into one large node or abdominal nodes into two or three or one large node (for example, in real flies or lamellar beetles).

  The epopharyngeal ganglion, which is often called the brain, is especially complex. It consists of three sections - anterior, middle, posterior, and has a very complex histological structure. The brain innervates the eyes and antennae. In its anterior section, the most important role is played by such a structure as the mushroom bodies - the highest associative and coordinating center of the nervous system. The behavior of insects is very complex, has a clearly expressed reflex nature, which is also associated with significant development of the brain. The subopharyngeal ganglion innervates the mouth organs and the anterior intestine. The pectoral ganglia innervate the organs of movement - the legs and wings.

  Insects are characterized by very complex forms of behavior, which are based on instincts. Particularly complex instincts are characteristic of the so-called social insects - bees, ants, termites.

  Sense organs reach an exceptionally high level of development, which corresponds to a high level of general organization of insects. Representatives of this class have organs of touch, smell, sight, taste and hearing.

  All sense organs are based on the same element - sensilla, consisting of one cell or a group of sensitive receptor cells with two processes. The central process goes to the central nervous system, and the peripheral process goes to the outer part, represented by various cuticular formations. The structure of the cuticular sheath depends on the type of sensory organs.

  The organs of touch are represented by sensitive hairs scattered throughout the body. The olfactory organs are located on the antennae and mandibular palps.

  The organs of vision play a leading role for orientation in the external environment, along with the organs of smell. Insects have simple and compound (faceted) eyes. Compound eyes are made up of a huge number of individual prisms, or ommatidia, separated by an opaque layer. This structure of the eyes gives "mosaic" vision. Higher insects have color vision (bees, butterflies, ant), but it differs from human vision. Insects perceive mainly the short-wavelength part of the spectrum: green-yellow, blue and ultraviolet rays.

  Reproductive organs are in the abdomen. Insects are dioecious organisms, they have a well-expressed sexual dimorphism. Females have developed a pair of tubular ovaries, oviducts, accessory gonads, a seminal receptacle, and often an ovipositor. Males have a pair of testes, vas deferens, ejaculatory canal, accessory gonads, and copulatory apparatus. Insects reproduce sexually, most of them lay eggs, there are viviparous species, their females give birth to live larvae (part of aphids, gadflies, etc.).

  After a certain period of embryonic development, larvae emerge from the laid eggs. Further development of larvae in insects of various orders can occur with incomplete or complete transformation (Table 16).

  Life cycle... Insects are dioecious animals with internal fertilization. By the type of postembryonic development, insects are distinguished with incomplete (in highly organized) and with complete (in higher) metamorphosis (transformation). Complete metamorphosis includes the stages of egg, larva, pupa, and imago.

  In insects with incomplete transformation, a young individual emerges from the egg, which is similar in structure to an adult insect, but differs from it in the absence of wings and underdevelopment of the genitals - a nymph. Often they are called larvae, which is not entirely accurate. Its living conditions are similar to those of adult forms. After several molts, the insect reaches its maximum size and turns into an adult form - an imago.

  In insects with complete transformation, larvae emerge from eggs, which are sharply different in structure (have a worm-like body) and habitat from adult forms; for example, the mosquito larva lives in water, while the imaginal forms live in the air. The larvae grow, go through a series of stages, separated from each other by molts. During the last molt, a stationary stage is formed - the pupa. Pupae do not feed. At this time, metamorphosis occurs, the larval organs undergo decay, and instead of them, the organs of the imago develop. At the end of the metamorphosis, a sexually mature winged individual emerges from the pupa.

  Tab 16. Development of insects	Development type
  	Superorder I. Insects with incomplete transformation	Superorder 2. Insects with complete transformation
  Number of stages	3 (egg, larva, adult insect)	4 (egg, larva, pupa, adult insect)
  Larva	It looks like an adult insect in external structure, lifestyle and nutrition; it is smaller, the wings are absent or incompletely developed	Differs from an adult insect in external structure, lifestyle and nutrition
  Chrysalis	Absent	Yes (in the immobile pupa, histolysis of larval and histogenesis of adult tissues and organs occurs)
  Detachment	Order Orthoptera (Orthoptera)	Order cruel-winged, or beetles (Coleoptera) Order Lepidoptera, or butterflies (Lepidoptera) Order Hymenoptera (Hymenoptera)

  Class overview

  The insect class is divided into more than 30 orders. The characteristics of the main groups are given in table. 17.

  Beneficial insects

  Honeybee, or domestic, bee [show] A family usually lives in the hive, which consists of 40-70 thousand bees, of which one is a queen, several hundred male drones, and all the rest are worker bees. The queen bee is larger in size than the rest of the bees, she has well-developed reproductive organs and ovipositor. Every day, the uterus lays from 300 to 1000 eggs (on average, this is 1.0-1.5 million for a lifetime). Drones are slightly larger and thicker than worker bees, and they do not have wax glands either. Drones develop from unfertilized eggs. Worker bees are underdeveloped females unable to reproduce; their ovipositor has become an organ of defense and attack - a sting. The sting consists of three sharp needles, between them there is a channel for removing the poison formed in a special gland. In connection with the feeding of nectar, the gnawing mouth organs have changed significantly, when they eat they form a kind of tube - the proboscis, through which nectar is absorbed with the help of the muscles of the pharynx. Upper jaw also serve for the construction of honeycombs and other construction work. The nectar is collected in an expanded goiter and turns into honey, which the bee regurgitates into the cells of the honeycomb. There are numerous hairs on the head and chest of the bee, when the insect flies from flower to flower, pollen sticks to the hairs. The bee removes pollen from the body, and it accumulates in the form of a lump, or pollen, in special recesses - baskets on its hind legs. Bees drop pollen into honeycomb cells and cover it with honey. A perga is formed, which the bees feed the larvae. On the last four segments of the bee's abdomen, there are wax glands, which outwardly look like light spots - a mirror. The wax comes out through the pores and solidifies in the form of thin triangular plates. The bee chews these plates with its jaws and builds honeycomb cells from them. The wax glands of a working bee begin to secrete wax on the 3-5th day of its life, reach the greatest development on the 12th-28th day, then decrease and regenerate. In the spring, worker bees begin to collect pollen and nectar, and the queen lays one fertilized egg in each cell of the honeycomb. After three days, larvae hatch from the eggs. The worker bees for 5 days feed them with "milk" - a substance rich in proteins and lipids, which is secreted by the maxillary glands, and then bee bread. After a week, the larva weaves a cocoon inside the cell and pupates. After 11-12 days, a young worker bee emerges from the pupa. For several days she performs various jobs inside the hive - cleans the cells, feeds the larvae, builds honeycombs, and then begins to fly out for a bribe (nectar and pollen). In slightly larger cells, the uterus lays unfertilized eggs, from which drones develop. Their development lasts several days longer than the development of worker bees. The uterus lays fertilized eggs in large queen cells. From them larvae hatch, which the bees feed all the time with "milk". Young queens develop from these larvae. Before the young queen leaves, the old one tries to destroy the queen bee, but the worker bees prevent her from doing it. Then the old queen with some of the worker bees flies out of the hive - swarming takes place. The swarm of bees is usually transferred to a vacant hive. The young queen flies out of the hive together with the drones, and returns after fertilization. The bees have a well-developed epopharyngeal node, or brain, it is distinguished by the strong development of mushroom, or stalked, bodies, with which the complex behavior of bees is associated. Having found flowers rich in nectar, the bee returns to the hive and begins to describe figures on the combs that resemble the number 8; at the same time her abdomen fluctuates. This peculiar dance signals to other bees in which direction and at what distance the bribe is located. The complex reflexes and instincts that determine the behavior of bees are the result of a long historical development; they are inherited. People have been raising bees in apiaries since ancient times. The collapsible frame hive was an outstanding achievement in the development of beekeeping, it was invented by the Ukrainian beekeeper P.I. Prokopovich in 1814. The useful activity of bees is primarily in the cross-pollination of many plants. With bee pollination, the yield of buckwheat increases by 35-40%, sunflower - by 40-45%, cucumbers in greenhouses - by more than 50%. Bee honey is a valuable food product; it is also used for therapeutic purposes in diseases of the gastrointestinal tract, heart, liver, and kidneys. Royal jelly and bee glue (propolis) are used as medicinal products. Bee (wasp) venom is also used in medicine. Beeswax is widely used in various industries - electrical engineering, metallurgy, chemical production. The annual world collection of honey is about 500 thousand tons. [show] The silkworm has been known to people for over 4 thousand years. In nature, it can no longer exist, it is bred in artificial conditions. Butterflies don't feed. Inactive, whitish female silkworms lay 400-700 eggs (the so-called green). Caterpillars are taken out of them in special rooms on racks, which are fed with mulberry leaves. The caterpillar develops within 26-40 days; during this time she sheds four times. An adult caterpillar weaves a cocoon of silk thread, which is produced in its silk-secreting gland. One caterpillar secretes a thread up to 1000 m long. The caterpillar winds this thread around itself in the form of a cocoon, inside which it pupates. A small part of the cocoons are left alive - later butterflies hatch from them, which lay eggs. Most of the cocoons are killed by hot steam or exposure to an ultra-high frequency electromagnetic field (in this case, the pupae inside the cocoons heat up to 80-90 ° C in a few seconds). Then the cocoons are unwound on special machines. More than 90 g of raw silk are obtained from 1 kg of cocoons.

  If it was possible to accurately calculate the harm and benefits of insects for the national economy, then, perhaps, the benefits would significantly exceed the losses. Insects provide cross-pollination of about 150 species of cultivated plants - garden, buckwheat, cruciferous, sunflower, clover, etc. Without insects, they would not produce seeds and would die themselves. The aroma and color of higher flowering plants developed in the process of evolution as special signals to attract bees and other pollinating insects. The sanitary significance of such insects as gravedigger beetles, dung beetles, and some others is great. Dung beetles were specially brought to Australia from Africa, because without them a large amount of manure accumulated on pastures, which interfered with the growth of grass.

  Insects play a significant role in soil formation processes. Soil animals (insects, millipedes, etc.) destroy fallen leaves and other plant debris, assimilating only 5-10% of their mass. However, the excrement of these animals is decomposed by soil microorganisms faster than mechanically crushed leaves. Soil insects, along with earthworms and other soil inhabitants, play a very important role in mixing it. Lacquer bugs from India and Southeast Asia secrete a valuable technical product - shellac, other types of bugs - a valuable natural dye carmine.

  Harmful insects

  Many types of insects damage agricultural and forest crops; in Ukraine alone, up to 3,000 species of pests have been registered.

  [show] In spring, adult beetles eat young leaves of trees (they eat leaves of oak, beech, maple, elm, hazel, poplar, willow, walnut, fruit trees). The females lay their eggs in the soil. Until autumn, the larvae feed on thin roots and humus, hibernate deep in the soil, and the next spring they continue to eat up the roots (mainly of herbaceous plants). After the second wintering in the soil, the larvae begin to feed on the roots of trees and shrubs; young stands with an underdeveloped root system may die as a result of damage. After the third (or fourth) wintering, the larvae pupate. Depending on the geographical latitude of the area and climatic conditions, the development of the May Khrushchev lasts from three to five years. [show] The Colorado potato beetle began to damage potatoes in 1865 in North America in Colorado (hence the name of the pest). After the First World War, it was introduced to Europe and quickly spread east to the Volga and the North Caucasus. Females lay eggs on potato leaves, 12-80 eggs per clutch. Larvae and beetles feed on leaves. For a month, the beetle can eat 4 g, the larva - 1 g of leaves. If we take into account that, on average, a female lays 700 eggs, then already the second generation of one female can destroy 1 ton of potato leaves. The larvae pupate in the soil, and adult beetles overwinter there. In Europe, unlike North America, there are no natural enemies of the Colorado potato beetle that would restrain its reproduction. Common beet weevil [show] Adult beetles devour the seedlings of sugar beet in the spring, sometimes completely destroying the crops. The female lays eggs in the soil, the larvae feed on the roots and roots of sugar beet. At the end of summer, larvae pupate in the soil, young beetles hibernate. Bug harmful turtle [show] The bug is a harmful bug damaging wheat, rye and other cereals. Adult bugs hibernate under fallen leaves in forest belts and bushes. From here in April-May they fly over to winter crops. At first, bugs feed by piercing the stems with their proboscis. Then the females lay 70-100 eggs on the leaves of the cereals. The larvae feed on the cell sap of stems and leaves, and later move to the ovaries and ripening grain. By puncturing the grain, the bug secretes saliva into it, which dissolves proteins. Damage causes drying of grain, a decrease in its germination and deterioration of baking qualities. [show] The forewings are light brown, sometimes almost black. On them - a typical "scoop pattern", represented by a kidney-shaped, round or wedge-shaped spot, edged with a black line. The hind wings are light gray. Antennae in males are weakly combed, in females threadlike. Wingspan 35-45 mm. Caterpillars are earthy gray in color, with a dark head. In autumn, the caterpillar of the winter moth damages (gnaws) mainly the seedlings of winter cereals (hence the name of the pest), to a lesser extent vegetables and root crops; in the southern regions it harms sugar beet. Adult caterpillars hibernate buried in the soil in the fields sown with winter crops. They pupate quickly in spring. The butterflies that emerged from pupae in May fly at night and at dusk. Females lay eggs on millet and row crops - sugar beets, cabbage, onions, etc. and in places with sparse vegetation, so they are often attracted to plowed fields. Caterpillars destroy the sown grains, gnaw the seedlings of plants in the area of ​​the root collar, and eat leaves. Very voracious. If 10 caterpillars live on 1 m 2 of crops, then they destroy all plants and "bald patches" appear in the fields. At the end of July, they pupate; in August, butterflies of the second generation emerge from the pupae, which lay eggs on weeds on stubble or winter seedlings. One female winter moth can lay up to 2000 eggs. In Ukraine, during the growing season, two generations of the winter moth develops. [show] One of our most common butterflies. The upper side of the wings is white, the outer corners are black. Males have no black spots on the front wings; females have 2 black round spots and 1 club-shaped spot on each wing. The hind wings of both males and females are the same - white, with the exception of a black wedge-shaped spot at the anterior margin. The underside of the hind wings is of a characteristic yellowish-green color. Wingspan up to 60 mm. The body of the cabbage is covered with dense, very short hairs, giving it a velvety appearance. The variegated coloring of the caterpillars is a warning about inedibility. Caterpillars are bluish-green, with yellow stripes and small black dots, the abdomen is yellow. In cabbage butterflies caterpillars, the poisonous gland is located on the lower surface of the body, between the head and the first segment. Defending themselves, they regurgitate a green gruel from their mouths, to which they also mix the secretions of the poisonous gland. This discharge is a pungent, bright green liquid, with which the caterpillars try to smear the attacking enemy. For small birds, a dose of a few of these animals can be lethal. Swallowed cabbage caterpillars are the cause of death of domestic ducks. People who collected these insects with their bare hands happened to end up in the hospital. The skin on the hands was reddened, inflamed, the hands were swollen and itchy. Cabbage butterflies fly in the afternoon in May-June and with a short break throughout the second half of summer and autumn. They feed on the nectar of flowers. Eggs are laid in heaps of 15-200 eggs on the underside of a cabbage leaf. In total, the butterfly lays up to 250 eggs. Young caterpillars live in groups, scrape off the pulp of cabbage leaves, while older ones eat out all the pulp of the leaf. If 5-6 caterpillars feed on a cabbage leaf, then they eat it whole, leaving only large veins. For pupation, caterpillars crawl onto surrounding objects - a tree trunk, a fence, etc. During the growing season, two or three generations of cabbage whites develop. Cabbage is common in the European part of the former USSR; this pest is not in Siberia, since butterflies cannot withstand severe winter frosts. The harm caused by cabbage is very great. Often, many hectares of cabbage are completely destroyed by this pest. The flights of butterflies are interesting. With strong breeding, butterflies gather in large masses and fly over considerable distances. [show] Willow tree borer - Cossus cossus (L.) Willow woodworm damages the bast and wood of poplars, willows, oaks, other deciduous trees and fruit species. Butterflies appear in nature from the end of June, mainly in July, and depending on the geographic location, in some places even before mid-August. They fly slowly in the late evening. The years lasts a maximum of 14 days. During the day, they sit in a characteristic pose with a slanting chest on the lower part of the trunk. Females lay eggs in groups of 15-50 pieces in cracks in the bark, on damaged places, cancerous wounds of the trunks at heights of up to 2 m. Caterpillars hatch after 14 days. First, they jointly eat away the bast tissue. On older trees with thick bark in the lower part of the trunk, the caterpillars eat out separate long, incorrectly passing, oval passages in cross section only after the first wintering. The walls of the passages are destroyed by a special liquid and are brown or black. On thinner trunks with smooth bark, caterpillars penetrate the wood earlier, usually within a month after hatching. Caterpillar splinters and excrement are pushed out through the bottom opening. At the end of the growing season, when the leaves fall off, feeding of caterpillars stops, which hibernate in the passages until the period of foliage blooming, that is, until April - May, when the caterpillars continue to feed in separate passages again until autumn, hibernate once more and finish feeding. They pupate either at the end of the circular path, where they will prepare an air hole, closed with chips, or in the ground, near the damaged trunk in a cocoon of chips. The pupal stage lasts 3-6 weeks. Before departure, the pupa with the help of spines protrudes halfway out of the flight hole or out of the cocoon so that the butterfly can more easily leave the exuvium. Generation is maximum two years. The willow woodworm is distributed throughout Europe, mainly in the middle and southern parts. It is found throughout the forest zone of the European part of Russia, in the Caucasus, in Siberia, as well as in the Far East. Known in western and northern China and Central Asia. The front wings of the butterfly are from gray-brown to dark gray with a "marble" pattern and vague gray-white spots, as well as dark transverse wavy lines. The hindwings are dark brown with matte dark wavy lines. The chest is dark from above, whitish to the abdomen. The dark abdomen has light rings. The male has a wingspan of 65-70 mm, the female - from 80 to 95 mm. The abdomen of the female is terminated by a retractable, well-visible ovipositor. The caterpillar is cherry-red immediately after hatching, later meat-red. The head and occipital plate are black shining. An adult caterpillar is 8-11 cm (most often 8-9 cm), then it is yellowish meat-colored, brown on top with a purple tint. The yellow-brown occipital plate has two dark spots. The airway is brown. The egg is oval-longitudinal, light brown with black stripes, dense, 1.2 mm in size. Many insects, especially those with a piercing-sucking mouth apparatus, carry pathogens of various diseases. Malaria plasmodium [show] Plasmodium malaria, the causative agent of malaria, enters the human bloodstream when bitten by an anopheles mosquito. Back in the 30s of the XX century. in India annually over 100 million people fell ill with malaria, in the USSR in 1935 9 million malaria cases were registered. In the last century, malaria was eradicated in the Soviet Union, and the incidence in India dropped sharply. The center of the incidence of malaria has moved to Africa. Theoretical and practical recommendations for the successful fight against malaria in the USSR and neighboring countries were developed by V.N.Beklemishev and his students. The nature of damage to plant tissues depends on the structure of the pest's oral apparatus. Insects with gnawing oral organs gnaw off or eat away parts of the leaf blade, stem, root, fruit, or make passages in them. Insects with a piercing-sucking mouth apparatus pierce the integumentary tissues of animals or plants and feed on blood or cell sap. They cause direct harm to a plant or animal, and also often carry pathogens of viral, bacterial and other diseases. Annual losses in agriculture from pests are about 25 billion rubles, in particular, damage from harmful insects in our country annually averages 4.5 billion rubles, in the USA - about 4 billion dollars. Dangerous pests of cultivated plants in Ukraine include about 300 species, in particular beetles, larvae of click beetles, bear, bread beetles, Colorado potato beetles, common beet weevil, turtles, meadow and stem moths, winter and cabbage scoops , hawthorn, unpaired silkworm, ringed silkworm, apple moth, American white butterfly, beet root aphid, etc. Fight against harmful insects To combat harmful insects, a comprehensive system of measures has been developed - preventive, including agro- and forestry, mechanical, physical, chemical and biological. Preventive measures consist in compliance with certain sanitary and hygienic standards that prevent the mass reproduction of harmful insects. In particular, timely cleaning or disposal of waste, garbage helps to reduce the number of flies. Drainage of swamps leads to a decrease in the number of mosquitoes. Compliance with the rules of personal hygiene (washing hands before eating, thoroughly washing fruits, vegetables, etc.) is also of great importance. Agrotechnical and forestry measures, in particular weed control, correct crop rotation, correct soil preparation, the use of healthy and sedimentary material, pre-sowing seed cleaning, well-organized care of cultivated plants, create unfavorable conditions for the mass reproduction of pests. Mechanical measures consist in the direct destruction of harmful insects by hand or with the help of special devices: flycatchers, adhesive tapes and jars, trapping grooves, etc. In winter, in the gardens, they remove from the trees and burn the wintering nests of the hawthorn and goldtail caterpillars. Physical measures - the use of some physical factors to kill insects. Many moths, beetles, dipterans fly to the light. With the help of special devices - light traps - you can timely find out about the appearance of some pests and begin to fight them. To disinfect citrus fruits infected with Mediterranean fruit flies, they are refrigerated. Barn pests are destroyed using high frequency currents. Therefore, integrated pest control is of particular importance, providing for a combination of chemical, biological, agrotechnical and other methods of plant protection with the maximum use of agrotechnical and biological methods. Integrated control methods provide for chemical treatments only in the outbreaks that threaten a sharp increase in the number of pests, and not a continuous treatment of all areas. With the tsnlya nature protection provides for the widespread use of biological plant protection.

Material from the site. Beekeeping encyclopedia

Insects- a class of invertebrate arthropods that arose about 410 million years ago. According to the traditional classification, together with millipedes, they belong to the trachea-breathing subtype. The name of the class comes from the verb "to cut" (to scribble) and is a tracing paper from the French " insecte"(Latin insectum, cf. Greek ἔντομον with the same meaning), meaning "notched animal." The body of insects is covered with a chitinized cuticle, which forms an exoskeleton, and consists of three sections: head, chest and abdomen. In many groups of insects, the second and third segments of the chest bear a pair of wings. There are three pairs of legs, and they are attached to the thoracic region. The body sizes of insects are from 0.2 millimeters to 30 centimeters or more.

The science of insects is called entomology.

Taxonomy

Latin name Insecta is formally authored by Carl Linnaeus by virtue of the rules of the International Code of Zoological Nomenclature, according to which the release date of the 10th edition of Linnean's "System of Nature" () is the initial priority date for all names of zoological taxa. The rules of the International Code of Zoological Nomenclature apply to typified names of species, genera, families and intermediate names, but for such untyped names as Insecta, they do not apply. As a result, the scientific literature has used the name "Insecta" for a wide variety of taxa. Initially, since the time of Aristotle, this name referred to terrestrial arthropods (six-legged, arachnids and others), but not to crustaceans. Linnaeus placed crustaceans in class Insecta, so that Insecta according to Linnaeus approximately corresponds to the current taxon Arthropoda(arthropods). J. B. Lamarck referred to the class Insecta some winged insects. Other authors used the title "Insecta" in one sense or another, intermediate between Linnean and Lamarckian. The most traditional is the use of the title "Insecta"(William Alford Leach, 1815) - in the sense of six-legged; but also in modern scientific literature the name "Insecta" used in at least three or four different meanings. Term Hexapoda used as another designation Insecta, especially in cases where primitive wingless insects ( Apterygota) are not considered true insects. In the old world and Russian literature "insects" is most often called a group in a wide range, including primary wingless insects and all Pterygota(sometimes the name is also used Hexapoda). In the modern sense, the class Insecta is accepted in a narrower volume. Two-tailed, collembolans and insects are either opposed by scientists to insects, forming a separate class Entognatha, or are considered separate classes.

Number of species

As of August 2013, scientists have described 1,070,781 biological species of insects, including 17,203 fossil species. Estimates of the true total number of insect species range from about 2 to about 8 million. At least 7000-7500 new species of insects are described annually. Among the four dozen modern and extinct orders, the 5 largest are distinguished: coleoptera (392 415 species), Diptera (160 591), Lepidoptera (158 570), Hymenoptera (155 517), and Hemiptera (104 165).

External structure

The insect body is divided into three segmented sections: head, chest and abdomen... Each segment is subdivided into four parts - the upper half-ring is called tergite, the lower semiring is called sternite, side walls - plerites... When designating the relative position of body parts and organs by the term "dorsal" ( dorsalis) denote the upper side of the body, and "ventral" ( ventralis) - the bottom side. The mesosome is also distinguished (in ants from three thoracic segments and the first abdominal segment of the propodeum) and the metasome (stalk and abdomen).

A distinctive feature of insects is the presence of a chitinous exoskeleton, which is the outer cover of the body and limbs. The cuticle covering the body forms a dense outer exoskeleton, but in some cases it is soft and thin. A solid external skeleton creates a number of advantages: it protects the body from mechanical stress, drying out and others, and increases resistance to deformation. It also has a number of disadvantages (for example, high energy consumption associated with molting). The exoskeleton is subdivided into separate shields - sclerites (sclerites), connected by thinner sections of the cuticle. The surface of the integument usually bears all sorts of outgrowths, folds, spines, scales, bristles, small hairs - hetoids... The cuticle also includes mobile skin hairs - hats.

The color of the body and its parts in insects is very diverse. Distinguish between structural and pigment coloration. Structural is associated with some specific features of the surface structure of the cuticle (microscopic ribs, plates, scales, etc.), which create the effects of interference, diffraction and dispersion of light - metallic shiny shades. Pigment coloration is due to pigments that are often found in the cuticle, less often in the cells of the hypodermis or fat body. Many insects have a combination of the two. Most insect species have very vivid patterns on various parts of their body. Mostly brightly colored insects with daytime activity, confined to plant substrates. Many species that move along the soil surface or have night activity are characterized by a uniform and predominantly dark body coloration. Coloring can be one-color or consisting of a combination of several colors, mainly two or three, less often - a larger number of colors. On the general background, there may be spots, stripes or any other pattern.

Respiratory system

Sense organs

Insects, like other multicellular organisms, have many different receptors, or sensilla, that are sensitive to certain stimuli. Insect receptors are very diverse. Insects have mechanoreceptors (auditory receptors, proprioceptors), photoreceptors, thermoreceptors, chemoreceptors. With their help, insects capture the energy of radiation in the form of heat and light, mechanical vibrations, including a wide range of sounds, mechanical pressure, gravity, the concentration of water vapor and volatile substances in the air, and many other factors. Insects have a developed sense of smell and taste. Mechanoreceptors are trichoid sensilla that perceive tactile stimuli. Some sensilla can pick up the slightest vibrations of air around the insect, while others signal the position of body parts relative to each other. Air receptors perceive the speed and direction of air currents in the vicinity of the insect and regulate the flight speed.

Vision

Insect color vision can be dichromatic (ants, bronze beetles) or trichromatic (bees and some butterflies). At least one species of butterfly has tetrachromatic vision. There are insects that are able to distinguish colors with only one (upper or lower) half of the faceted eye (four-spotted dragonfly). For some insects, the visible part of the spectrum is shifted to the shortwave side. For example, bees and ants do not see the red color (650-700 nm), but distinguish part of the ultraviolet spectrum (300-400 nm). Bees and other pollinating insects can see ultraviolet patterns on flowers that are hidden from human vision.

Hearing

The perception of sounds transmitted through a solid substrate is carried out in insects by vibroreceptors located in the shins of the legs near their articulation with the thigh. Many insects are highly sensitive to the shaking of the substrate they are on. The perception of sounds through air or water is carried out by phonoreceptors. Diptera perceive sounds with the help of Johnston's organs. The most complex auditory organs of insects are tympanic organs... The number of sensilla in one tympanic organ varies from 3 (some butterflies) to 70 (locust) and even up to 1500 (in song cicadas).

Many insects are ectotherms (animals for which the environment is a source of heat), while others can be endotherms (independently produce heat inside their body by biochemical processes). It is more correct to describe endothermic insects as heterotherms, because they are not entirely endothermic. When heat is produced, different parts of the insect's body can have different temperatures, for example, moths produce heat in their chests for flight, but their abdomen is relatively unheated.

Features of behavior

Intraspecific communication

Contact signals

Scout bees can communicate to their family members through a special dance the path to the found source of food. Bees are dancing in the dark, inside the hive. Carl von Frisch deciphered the language of bee dancing, who received in 1973 for his work in this area Nobel Prize... An important role is played by contact signals (touching the antennas) during trophallaxis.

Pheromones

Pheromones are used by insects for a wide variety of purposes. They elicit a response in individuals of the same species. There are two functional groups of pheromones: releasers and primers. Release pheromones elicit an immediate behavioral response. They are widespread in insects, mediate sexual behavior, the formation of clusters, the distribution of individuals in space at a high population density of one species. The most important are the sex pheromones, which make it easier for males and females to meet. Pheromones-primers induce slow reactions and, by promoting physiological changes, either inhibit or excite behavioral responses.

Orientation in space

The most important means of orientation for many insects are visual and sound stimuli and smells. Honeybees use Sun orientation to direct other individuals in their hive towards the nectar source (bees' circular and wagging dances). Having the ability to orient themselves along the plane of polarization of light, insects can determine the position of the Sun in cloudy weather. Bees and wasps orient themselves, remembering the location of their nest relative to the surrounding objects (trees, shrubs, stones, etc.). Before leaving, many solitary wasps circle over the nest, memorizing the main milestones on the way to it. In the case of bees, if you move the hive to the side at a distance of less than one meter, then the bees returning with a bribe look for it in the same place and do not immediately find it in a new one.

Ecology

Relationship with other organisms

In the course of long evolution, insects have formed a variety of