What insects lay eggs. All about Russian forests

These photos are from the Flickr photo network and were taken by both amateur and professional photographers.

What these pictures have in common is that they capture tiny life emerging - insect eggs.

1. Egg unknown insect. (c) Picture Esk

Insects typically lay eggs in external environment, however, sometimes the larvae hatch from them while still in the abdomen of the female and are born “alive” from there.

2. Moth eggs. (c) johnhallmen

Insects are characterized by relatively large, yolk-rich eggs.

3. Eggs of an unknown insect. (c) shantaya ~ dannie

4. (c) Gustavo Mazzarollo

Developing in the cavity of the ovariole under the pressure of its walls, the eggs are somewhat elongated in length, thus the insect eggs, which were round in their initial state, are replaced by elliptical ones.

5. Keelewright eggs. (c) linden.g

In butterflies and some bugs, the eggs become rounded for the second time.

6. Stink bug eggs. (c) Nikonian72

Insect eggs vary in shape and size. The largest of them reach 15 mm in length, and the smallest do not exceed 0.05 mm. Sizes vary from 1.35 to 70% of the female’s body length.

7. Eggs laid by the sad diamondback bug. (c) Martin LaBar

Termites lick the eggs and penetrate the shell of the eggs. nutrients contained in saliva, and the egg increases 3-4 times during development.

8. The caterpillar hatches from the egg. (c) "Paul J"

The development of an insect in the egg phase can last from several days (for many flies) to 2-3 weeks.

9. (c) Dean Vuksanovic

In insects that lay eggs in the fall, the duration of the egg phase can reach 6-9 months.

10. (c) toughkidcst

Thanks to polyembryony, each egg of some ichneumon species develops large number larvae.

11. Eggs are predators. (c) Gustavo Mazzarollo

The shell of insect eggs is called chorion; it consists of two layers penetrated by a system of air cavities. Occasionally, a layer of wax and additional cuticle are deposited under the chorion

12. Eggs of stink bugs. (c) Lord V

13. Goldeneye eggs. (c) vega*

14. Eggs of an unknown insect on a gladiolus leaf. (c) Martin Barrett

The eggs of many insects are well protected from moisture loss.

15. Eggs of the bug of the Asopinae family. (c) myriorama

Dung flies lay eggs in animal droppings and provide them with a breathing tube that protrudes above the surface of the droppings and provides the embryo with fresh air.

16. Oak cocoon moth eggs. (c) Joaquim F. P.

17. Egg of a turnip white butterfly or turnip butterfly. (c) Joaquim F. P.

Lacewings, on the other hand, lay their eggs on long, thin stalks to protect them from arthropod predators that feed on the eggs.

18. Little bugs will be born soon. (c) myriorama

Insects are the most numerous and widespread group of animals. The number of species reaches 1.4 million, i.e. significantly more than all other animals combined. On land, insects are distributed everywhere: from the Arctic to Antarctica, high in the mountains, in a wide variety of terrestrial biotopes, and abundantly inhabit fresh waters. Only in the seas are insects rare and live only in the coastal strip. The abundance and wide distribution of insects indicate that these higher arthropods have a perfect organization.

Reproduction of insects.

In insects, only sexual reproduction has been observed. All insects, with few exceptions, are dioecious. In many species, sexual dimorphism is well expressed (for example, males may differ from females in brighter colors, larger sizes, a very complex antenna structure, the presence of different appendages, etc.). High development of the nervous system and advanced methods of movement ensure the meeting of males and females. Fertilization in a minority of species is external-internal, while in the majority it is typically internal.

The male reproductive apparatus consists of two testes, two vas deferens, which pass into the unpaired ejaculatory duct, and accessory glands. In insects with typically internal fertilization, the seed is inserted by the male into the female’s vagina using special copulatory organs.

The female reproductive apparatus consists of two ovaries, two oviducts flowing into the unpaired vagina, accessory glands and the spermatic receptacle. Many insects also have a copulatory bursa and an ovipositor. The ovaries are formed by egg tubes. The anterior ends of the tubes are very thin; as they move towards the oviducts, the eggs become larger and the tubes thicken. The copulatory bursa serves to receive the male copulatory organ and opens into the vagina or independently outward. From the bursa, sperm enter the sperm receptacle, where in some insects they can remain for a very long time (in a bee up to 5 years). As the eggs mature, they are fertilized by sperm from the spermatheca; insects lay them in the soil, on various items, plants, sometimes on other animals. The secretion of the accessory glands glues the eggs, unites them into groups, serves to attach them to substrates, etc. Many species have special ovipositors formed from the rudiments of abdominal legs, which facilitate the placement of eggs to a certain depth in the soil, in plant tissue, in the body of other animals, etc. Some insects experience viviparity.

In insects, the ability to parthenogenesis is quite often observed. It is well known that bees lay some eggs unfertilized and that these eggs always produce larvae that turn into male drones. How does a female bee, having a lifelong supply of sperm in the sperm receptacle, lay either unfertilized or fertilized eggs? It turns out that this happens mechanically and is determined by the different shape and depth of the drone cells of the honeycomb. Drones that develop from unfertilized eggs are distinguished by the fact that they have half the number of chromosomes in their cells. Therefore, during sperm maturation, reduction does not occur.

Thus, males (drones) develop from unfertilized eggs, and either females or worker bees develop from fertilized eggs, while the larva develops into a full-fledged queen or worker bee, depending on the quality and abundance of food.

In other insects, parthenogenesis is observed with alternating generations. Aphids are of particular interest in this regard. For example, in the bird cherry-oat aphid, a number of parthenogenetic generations alternate with bisexual ones, and this alternation of generations, like in a number of other aphids, is associated with migration during the life cycle from one plant to another.

Fertilized eggs of the bird cherry-oat aphid are laid by the female in the fall on bird cherry branches and overwinter. These eggs hatch in the spring into wingless female founders, who reproduce parthenogenetically and produce numerous offspring that develop into winged females, the so-called emigrants. The emigrants leave the bird cherry tree and at the beginning of summer fly to the fields, to cereals: oats, rye, etc. Here, the winged female emigrants again parthenogenetically produce a wingless generation of females, which also reproduce parthenogenetically and give birth to a winged generation by the fall, consisting of their winged males and winged females Winged female re-emigrants fly again to the bird cherry tree, where they parthenogenetically produce wingless females, which are fertilized by males arriving here and lay overwintering fertilized eggs.

Parthenogenesis is also known in many other insects. Parthenogenesis is especially interesting in stick insects - curious insects, often completely wingless, belonging to a small order of ghostly insects. In some species of stick insects, parthenogenesis has become the only form of reproduction and males are unknown.

In connection with the question of alternation of generations, the question arises about the life expectancy of successive generations (generation) of a given insect species. The lifespan of one generation of an insect varies greatly. Aphids have several generations within one year, and the life expectancy of each of them is short. Also, two or more generations per year are observed in many other insects (flies, mosquitoes, etc.). Many butterflies have two generations a year - spring and summer or summer and autumn.

However, most insects have one generation per year. Many insects produce one generation over a number of years. Yes, all life cycle The life of the May beetle (oriental) lasts 5 years, the stag beetle also lasts 4-5 years, and the willow wood moth butterfly lasts 2 years. Mayflies, so named because their winged forms soon mate, lay eggs and die after their last molt, actually live much longer. Mayflies, like most metamorphosing insects, spend most of their lives in the larval stages. In some species, 2-3 years pass from the emergence of a young larva from the egg to the emergence of a winged mayfly. An example of the special life expectancy of insects is the American seventeen-year cicada, whose life cycle lasts 17 years.

The number of eggs laid by a female in one clutch can vary greatly. So, a female cockroach lays 16 eggs, which are sealed in a special bag (from the secretions of the accessory glands). The female first carries this package with her and then leaves it somewhere in a secluded place. Housefly lays up to 150 eggs in one clutch; in total, one female lays up to 600 eggs. The queen of a honey bee lays up to 1,000 eggs or more per day, and up to 1,500,000 eggs throughout her life. Female termites lay up to 30,000 eggs per day, or about 10,000,000 over the course of their lives. However, such a high fertility of one female is characteristic of “social” insects, which have the most numerous third caste (except for females and males) - working individuals. For most female insects, an average of 50-150 eggs per clutch can be considered, while the total number of offspring produced by a female depends not only on the number of eggs laid, but also on the number of clutches and on the lifespan of the female.

Development of insects.

Embryonic development.

In the vast majority of insects, eggs are very rich in yolk and have a pronounced centrolecithal type. This means that the nucleus, together with a small amount of protoplasm surrounding it, is placed in the middle and surrounded by a large amount of yolk. On the outside, the egg is covered with a durable chitinous shell - the chorion, under which there is a second - the yolk shell of the egg. At the animal pole, the chorion has an opening - the micropyle, through which sperm penetrate into the egg. The shape of the eggs is often elongated, but, in general, quite varied.

Egg crushing in insects is superficial, which is typical for centrolecithal eggs. The nucleus of a fertilized egg, located in the middle of the egg, divides repeatedly, and the daughter nuclei migrate to the surface of the egg along protoplasmic cords connecting the central portion of the plasma with its peripheral layer. As a result, the surface of the egg under the shell is covered with one layer of cells - the blastoderm. Soon, however, it can be discovered that on one side of the egg, corresponding to the ventral side of the future embryo, the blastoderm cells are much higher. This area forms the so-called germinal band. It is important that the embryo subsequently develops not from the entire blastoderm, but only from the germ strip. Then, due to increased cell division, the middle of this strip sinks, as if invaginating into the yolk, and a groove appears along the germ strip.

This is the beginning of germ layer differentiation. Subsequently, the strip of cells forming the groove is completely detached, and the ectoderm of the embryo closes over this rudiment of endomesoderm. Then a further process of differentiation occurs. An essential feature of the development of an insect egg is that, simultaneously with the process described above, the blastoderm forms a fold along the entire edge around the germ strip, growing from all sides towards the middle of the germ strip. Eventually, the folds growing towards each other converge and grow together, and the germ band is covered by two sheets of cells. These are two embryonic membranes. The outer one is called the serous membrane, the inner one is called the amnion. Between the amnion and the embryo there remains a cavity containing fluid - the amniotic cavity. As a result, the embryo finds itself immersed in the yolk and separated from the external environment not only by the chorion of the egg, but also by the embryonic membranes and the amniotic cavity. Much later, when the embryo is formed up to the development of the rudiments of the limbs, it is freed from the embryonic membranes, moving to the surface of the egg.

During the period when the development of the embryo occurs still under the embryonic membranes, differentiation of endoderm and mesoderm is observed. Next, segmentation of the germ band begins. At the same time, the process of formation of internal organs continues until the final formation of the larva.

Postembryonic development.

The development of an insect after emerging from the egg shell, or postembryonic development, occurs differently, which is a characteristic feature of certain systematic groups of insects.

In the lower primary wingless insects, young animals emerge from the eggs, very similar to adults, but, of course, smaller in size. In a few primary wingless insects, young individuals hatched from an egg differ from an adult animal, in addition, in the still incomplete number of abdominal segments, the number of which is replenished during subsequent molts. Thus, an animal emerges from the egg, as if it had not yet completed the formation of its body. A young individual of a primary wingless insect can hardly be called a larva. This is just an underdeveloped young insect. This type of postembryonic development, in which the formation of new segments continues after hatching from the egg, is called anamorphosis. The development of most primary wingless and all winged insects differs in that a young insect or larva emerges from the egg with the full number of segments characteristic of an adult insect of a given species. This type of postembryonic development of an insect is called epimorphosis.

The development of winged insects, in turn, however, can occur in different ways.

Development with incomplete metamorphosis.

This form of postembryonic development is characteristic large group insects belonging to both primary wingless and winged insects, represented in the modern fauna by a significant number of orders. This includes many insects, such as cockroaches, locusts, grasshoppers, bedbugs, termites, etc. In all of these insects, a young animal emerges from the egg, which is also very similar to an adult insect, but unlike some primary wingless insects, it already has a full number of abdominal segments. At the same time, a young insect differs from an adult only in its smaller size, underdevelopment of the reproductive apparatus and the absence of wings. However, some groups of insects have wing rudiments, while others appear after one of the first molts. Examples of this type of development include cockroaches, locusts, etc. Thus, young locusts with outside, with the exception of the absence of wings, are an “adult” miniature.

Further development consists of the growth, development and formation of the missing organs: the reproductive apparatus, wings. This development is associated with periodic molts (from 4-5 to 20 or more molts during life in various insect species). With each molt, the young animal looks more and more like the adult animal. The final molt leads to the hatching of an adult final stage with fully developed wings, capable of flight and reproduction.

The main difference between the larvae is the presence of special larval organs that are not present or are arranged differently in adult animals. Such larval organs are called provisional organs in contrast to the final, or definitive, organs of the adult stage.

If this definition of larval stages is considered correct, then the young age stages of a cockroach, locust, bug, etc. cannot be called larvae. They live in the same conditions as adults and feed similarly to adult insects. Therefore, they do not have provisional larval organs, which are absent in an adult insect, and the existing organs function and are structured in the same way as in a sexually mature individual. Even the rudiments of wings appear at one of the young stages.

When development occurs as described above for cockroaches, grasshoppers, bedbugs, aphids and similar insects in this regard, this type of development is called development with incomplete metamorphosis or hemimetamorphosis, and such insects are called Hemimetabola, or Hemimetamorpha.

A somewhat special position in this regard is occupied by insects belonging to the two most ancient orders: dragonflies and mayflies.

The young stages of these insects are more different from the adult so-called imaginal stage.

True, many of their organs are structured similarly; they always have clear rudiments of wings. But, in addition, they also have some provisional organs. Dragonfly larvae live in water. In this regard, they have a number of adaptations to living conditions in water, which subsequently disappear. Thus, the larvae of the dragonfly - a large rocker and other dragonflies, in addition to moving with the help of their limbs, move by forcefully throwing out water from the hindgut, where the tracheal gills are also located.

Thus, we can say that dragonflies have larval stages that live in water and have provisional organs. The last larval stage differs from the previous ones, if not in external structure, then in behavior, especially in dragonflies. The larvae of this last instar are very lethargic and inactive (they can be found in the reservoir in late spring and early summer). At this time, a more serious restructuring of the organization of the larva occurs: reduction of provisional organs and formation of imaginal ones. This ends with the larva climbing to the surface of the water, and then onto coastal plants, where the last molt occurs. The larval “clothes” emerge into a winged stage that no longer moults.

Thus, mayflies and dragonflies have a larval stage and transformation into an adult. Therefore, they can be classified as a group of insects with semi-metamorphosis. They are distinguished from insects with complete metamorphosis by a smaller degree of difference between the larval and imaginal stages, and most importantly, by the absence of the pupal stage.

Development with complete metamorphosis.

The second form of postembryonic development of winged animals is development with complete metamorphosis, or holometamorphosis. Complete metamorphosis occurs in most insects, and in insects that are higher than others in their organization. Development with complete metamorphosis is characteristic of beetles, fleas, caddis flies, butterflies, flies, mosquitoes, bees, wasps, ants, etc.

The presence of clearly defined four stages: eggs, larvae, pupa and adult - distinguishes complete metamorphosis from hemimetamorphosis.

Insect larvae with complete metamorphosis differ sharply from the imaginal stage. This is explained by the fact that they usually live in different conditions, eat differently and therefore have acquired a significant number of provisional organs.

In butterfly caterpillars, the worm-like body shape does not in any way resemble the body shape of the imago. In addition to three pairs of short thoracic articulated legs, there are five more pairs of abdominal non-articulated legs, which are not found in the imago. Instead of the sucking mouthparts so characteristic of butterflies, the caterpillar has gnawing mouthparts. On the surface of the body, many caterpillars have skin outgrowths and hairs, which often have poisonous properties. Butterfly caterpillars often have a special coloring - either protective or bright warning.

The larvae are more or less worm-like, having three pairs of legs on the thoracic segments, such as the larvae of many beetles.

Larvae that, in addition to the thoracic articulated limbs, also have false legs on the abdomen. These are butterfly caterpillars and false caterpillars of Hymenoptera sawflies.

Larvae with a clearly differentiated head, but completely lacking thoracic limbs. This includes the larvae of many hymenoptera (bees, ants, etc.), the larvae of many beetles (bark beetles, weevils), and mosquito larvae.

Larvae without heads and without legs, such as fly larvae.

The larval period in the development of insects usually accounts for the majority of their life. During larval life, intensive feeding and growth occur, accompanied by molting.

Along with the last larval molt, pupation occurs.

However, some insects have been found to have not one, but two or more larval stages. Thus, in the blister beetle, or red-headed spandex beetle, a very mobile larva emerges from the egg with a large head, armed with strong mandibles. For further development, the larva must find the egg capsule (egg cocoon) of the locust and penetrate it. Inside the egg capsule, the larva develops into the second larval stage. It is distinguished by a more worm-like shape and very short limbs. The larva lives in an egg capsule, feeding on locust eggs, then it emerges from the egg capsule and, molting, turns into the next stage - a false pupa. This happens at the end of summer. The false pupa is motionless, has almost vestigial limbs and overwinters, and in the spring it develops into a third larval stage, reminiscent of the larvae of many beetles. Then soon the larva pupates.

In this case, the so-called hypomorphosis, or excessive metamorphosis, takes place, which is an adaptation associated with the peculiar nutritional conditions of the larvae, different at different stages.

The pupal stage is very characteristic of complete metamorphosis. This is a non-feeding and usually sedentary stage. Only in some insects, such as mosquitoes, do pupae retain the ability to actively move. Due to the immobility of insect pupae, they are protected in various ways. Pupation often occurs in very secluded places, as is observed in many beetles and other insects. In other insects, the pupae have a protective color (for example, the pupae of many butterflies). Finally, pupae are curled into silky cocoons in many silkworm butterflies, moths, ants, sawflies and other insects.

Fly pupae are covered on top with larval skin. During the last molt, the skin of the last larval instar is not shed, but remains in the form of a cover on the pupa, forming a false cocoon in many flies.

Insect pupae, not counting the protective devices described above (cocoon, larval skin, etc.), are of two types:

A free pupa, characterized by the fact that the head, thoracic limbs and wings, although pressed to the body, are easily distinguishable and are not glued together by frozen secretions of the skin (pupas of beetles, flies, mosquitoes, hymenoptera).

Covered pupa, the pupa of butterflies and some other insects, in which all limbs and wings are covered with a special layer of chitin, which is released during molting and tightens the pupa.

During the pupal period, the formation of organs of the imago occurs, and these processes are associated with changes that begin at the larval stages. In many insects, especially flies, during the larval stages one can clearly see that groups of small embryonic cells appear in certain places of the body and on various organs.

Such buds or discs of cells lie at the base of all limbs, in those places of the chest where wings later form, on various internal organs, for example, on various parts of the intestinal tract (on the salivary glands, on the foregut, middle and hind intestine, etc. ).

These discs grow and increase in size towards the last larval instar. They are protrusions of tissue and are called imaginal discs.

From the imaginal discs, the organs of the adult insect then develop at the pupal stage. Most of the internal organs of the larva undergo complete disintegration, or histolysis, to such an extent that instead of organs, a mush is obtained, which is used in further development only as nutritional material. From the imaginal discs, according to their location, new imaginal organs develop instead of the disintegrated larval organs.

Some larval organs do not undergo decay, and part of the cellular material of these organs is used for the restructuring of these organs (muscles, nerves). The central nervous system and heart are most preserved. Blood circulation, although in a modified form, continues in the pupa. The rudiments of the gonads are completely preserved and further develop. The degree of histolysis of internal organs in the pupal stage varies among various groups insects and, apparently, is expressed to the maximum extent in Hymenoptera and Diptera. Thus, the process occurring in the pupa consists of the replacement of the provisional organs of the larva with imaginal organs developing from the imaginal discs, and the restructuring of the remaining organs of the larva.

There is no doubt that the presence of complete metamorphosis is associated with the highest organization of those groups of insects in which it occurs. They achieve this high organization precisely in the imaginal stage. As a rule, larvae are characterized by a less complex structure. At the same time, the larval period is the most long period in the life of an insect it is a feeding period. The larva, eating a large amount of food, not only grows, but also accumulates reserve nutritional materials, which ensures metamorphosis.

To produce offspring, most insects need to mate with an individual of the opposite sex. Thanks to instinctive reactions to specific smells, colors and sounds, the insect finds suitable partner. This mechanism works in the dark, in dense thickets and over long distances. The fireflies we know do this: wingless females attract males on warm spring evenings with the help of light signals. Other insects provide sound “mating” signals: for example, crickets and grasshoppers charm their partners with their chirping sounds.

Where do insects lay eggs?

Insect eggs are usually covered with a durable shell. The stick insect simply leaves them on the ground or rolls them in front of itself. However, most females look for a place for their eggs that is protected from the wind and enemies. The insect instinctively senses what environment the offspring will find themselves in after hatching. favorable conditions and will receive the necessary food. Crickets and grasshoppers dig holes in the ground where they place their eggs. Female mosquitoes leave eggs on the surface of the water. Butterflies and other insects whose larvae are herbivores lay eggs on plants.

Dung beetles bury mammal dung in the ground. Many of the 7,000 species of pillmakers make balls of dung by rolling them away from the dung heap and burying them in a safe place. They feed themselves with these balls, and also supply their offspring with “pills”. For this purpose, they make a hole in the ball and lay eggs there. The hatched larva feeds on such a ball.

Grasshoppers and ichneumon wasps have a long ovipositor, with which they pierce the soil and lay eggs there.

Growths

Some species of wasps lay eggs on oak trees and rose leaves. Gradually they are covered plant tissue. The hatched larvae feed on the creatures inside the growth, grow and pupate. Some species of mosquitoes, flies, aphids, beetles and butterflies also use plants as a “host” to breed. In order for growths to form, the plant tissue must be able to grow when the insect eggs are laid.

How do insects take care of their young?

Some types of insects care about more than just a suitable place for their offspring to hatch. Cockroaches often carry eggs with them in a kind of “bag” on the back of their body. In some species of water bugs, the female lays eggs on the back of the male. He carries the eggs with him, providing a sufficient amount of oxygen and protecting him from fungus. Gravediggers work together to bury a dead mouse or other small animal, raking the soil under the animal's corpse and moving it to the very end of the “cave.” There they lay their eggs, and the female (and sometimes both partners) remains to watch over the offspring, feeding the larvae parts of the dead animal. The care for offspring of termites, ants, and bees and wasps living in colonies is interesting: the offspring remains in the nest until they grow up. Working individuals do not reproduce, returning to their nest throughout their lives.

Female birch bugs guard their eggs. To protect them, they turn their backs to their enemies.

Complete and incomplete metamorphosis of insects

Incomplete metamorphosis of insects

The larvae of cockroaches and grasshoppers, barely emerging from the egg, already resemble adult insects of their species. They are only smaller in size, and their wings and reproductive organs have not yet developed. During growth, these insects do not change that much. In this case, they speak of incomplete transformation. An insect nymph emerging from an egg is very similar to an adult insect; nymphs are larvae that undergo incomplete transformation. In young mayflies and dragonflies, the wings are barely visible, but with each change of shell they become more noticeable.

Complete transformation of insects

The insect develops from an egg, followed by several stages of a caterpillar, which turns into a pupa; then an adult insect hatches from it, thus passing through many stages of transformation. More than four-fifths of all insects develop through the pupal stage. This transformation is called complete. Butterfly pupae are completely different from their parents. In addition to three pairs of legs on the chest, like an adult butterfly, the pupa has five more pairs of legs, with the help of which it moves and holds tightly. The larvae of beetles, flies and bees are also completely different from adult insects. At the end of the larval stage, the insect changes significantly: it no longer accepts food, seeks shelter and enters the next stage: pupation. Butterfly pupae spin a cocoon from long silk threads produced by one of their glands. The pupa only appears motionless from the outside: inside it, significant transformations of the larval organs into the organs of an adult insect take place. The intestines, tracheal system, nervous system and pectoral muscles. The herbivorous wingless creature grows into a nectar-eating flying insect. Depending on the type of insect and conditions environment it emerges from the cocoon after a few days, weeks or months.

This infraorder unites about 100 thousand species. Many of the wasps are beneficial to people because they destroy agricultural pests.

A distinctive feature of riders from other insects

The rider climbs onto the victim, as if he wants to ride it, hence the name, and inserts the eggs directly into the body of the living insect. The larvae develop inside the victim and gradually eat internal organs, develop and destroy their “incubator”.

Groups of riders

The female uses a long ovipositor to lay her eggs inside the caterpillar. After this, the caterpillar remains alive; the “riding” of the rider will not immediately affect its condition.

Ichneumonid parasites lay their eggs in the bodies of larvae living under tree bark.

These riders have very long ovipositors, they can exceed their body length by 7 times. Interestingly, the ovipositor is very thin - no thicker than a hair, so it is extremely difficult for them to drill into wood; such work takes the rider several hours.

Of great interest is how the ephialtes rider drills into the bark of a tree. The female energetically runs along the tree and at the same time knocks on the trunk with her antennae, thus she looks for the larva of the longhorned beetle under the bark. When the female discovers the larva, she bends the ovipositor with a serrated end and begins to drill into the wood with it. During drilling, the ephialtes rises on its hind legs, which are longer than the front ones, higher and higher. When the ovipositor becomes vertical, the rider begins to spin around it like a top. So the female can spin around for about two hours until she lays an egg in the larva.

The benefits of equestrians in agriculture

In different species of ichneumon ichneumon, the number of eggs can range from 15 to 15 thousand. Moreover, it is not at all necessary that the offspring of wasps that lay a small number of eggs will be small, since several thousand larvae can hatch from one egg.

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28.04.2016

One of biological methods natural plant protection in the garden involves the use beneficial insects as natural enemies pests, their study and assistance in settling in the garden and living in it.

Beneficial insects

Ladybug

The ladybug is a well-known beneficial insect in the garden. It belongs to the round beetles and, depending on the species, is 4-9 mm long. The most common species is the seven-spotted ladybird. The beetle got its name for the 7 black dots on its red wing covers. But there are also beetles with yellow elytra and black dots, or dark beetles with light spots or without them at all. Also, the number of spots or the pattern of the wings can be varied. In total, we are home to about 70 species of large beetles, of which about 50 species feed on leaf aphids, and the rest feed on oribatid aphids and spider mites. Ladybugs, along with other leaf aphid killers, are essential helpers in the garden.



Adult ladybugs overwinter on open ground, for example, under leaves or dry grass. In the spring, ladybugs lay 10-20 eggs vertically in a group on branches or on inside leaves close to aphid colonies. Larvae from eggs go through 4 stages. They are usually painted dark gray with a yellow or red pattern. At the end of the larval stage, ladybugs begin to pupate and, as a rule, acquire a yellow color. After emerging from the pupa, the beetle needs another 2-3 days before it acquires its final color. It is especially important that both the larvae and the beetles themselves belong to the species predatory insects, feed on aphids.


The well-known seven-spotted ladybug destroys up to 150 aphids per day, smaller species - up to 60. While still larvae, insects devour a total of up to 800 aphids. Thus, a female beetle destroys about 4 thousand adult aphids in her life.

When using ladybug as plant protection, its development cycles should be taken into account.

Stetorus, or tick ladybird

Active spider mite killer. This is a very small, mobile, like mercury, beetle with shiny black elytra, a rounded body shape and a very small size for a beetle - 1-1.5 mm. The larva is small, gray, very mobile. Both beetles and larvae actively feed on mites and their eggs, destroying from 800 to 2000 pests during their lives.

Beetles can be found in places where they accumulate spider mite, most often on raspberries, on back side leaves. There have been cases when, even in production conditions, when raspberries were heavily infested with spider mites, the predator completely exterminated the pest in a few days, and the need for chemical treatment disappeared. On garden plot conditions for stethorus are more favorable, and if, when you detect spider mites, you notice tiny black bugs on the back of the leaves, you don’t have to worry: it will do its job - clear the plants of spider mites quickly and effectively.

By the way, and ladybugs, and stethorus can be collected somewhere else and released in your garden, they take root well.

Osmia

These are fluffy solitary bees - and completely harmless. They bring enormous benefits to the garden. They fly out to collect nectar at air temperatures at which an ordinary domestic bee does not even show its nose from the hive. If you do not have buildings with a thatched roof on your site, we recommend making houses for the osmium. Not only swamp plants, but also banal pieces of wood with drilled holes are suitable as houses. You can also use elderberry branches; inside they have a soft core that must be removed, leaving a hollow tube - a house for osmium.

Osmia settle in the most unexpected places- in the hole from under the old nail, in the cracks. If a house is installed, the osmia will take root, and you will have apples, the garden will be pollinated perfectly.

Bees

Bees are true friends of the garden, as they bring enormous benefits to it. They are the only reliable assistants to agronomists and gardeners. It is known that the vast majority of varieties of apple, pear, plum, cherry, raspberry, and gooseberry are self-sterile, that is, their ovaries cannot be fertilized with their own pollen.
Thus, great benefit bees in the garden bring benefits to humans because, while collecting pollen from flowers, they simultaneously perform cross pollination plants.

bumblebees

Bumblebees are one of the most cold-resistant insects, well adapted to life in the harsh conditions of the north, where other pollinators either cannot live or fly for a short time.

Thanks to their long proboscis, they can extract nectar even from flowers with narrow corollas, thereby collecting pollen from plants inaccessible to other insects.

Bumblebees collect not only nectar, but also pollen from plants. Bumblebees help bring this delicacy to the nest special devices, which are located on the hind legs. But pollen ends up not only in special recesses on the paws. Sometimes dust particles linger on the abdomen and are then transferred to another flower.

Bumblebees can collect pollen and nectar from plants very, very quickly. Biologists have calculated that just one field bumblebee visits 2,634 flowers during a flight lasting 100 minutes. Therefore, bumblebees are rightfully considered the best pollinators of this valuable food plant.

Gallitza

Various species of the gall midge family are better known to amateur gardeners as harmful insects (the larvae of some species develop in plant tissues, causing the formation of galls) than as helping in the fight against pests. The body length of gall midges varies from 1 to 5 mm. Well-known pests in the garden include, for example, the pear gall midge.

Beneficial gall midges feed on the larval stage of aphids. The most important view is Aphidoletes aphidimyza. The female (about 2-3 mm in size) lays 50-60 eggs in one life span of 1 week near the aphid colony. On the 4th-7th day, orange-red larvae hatch. The latter bite the aphids by the legs and inject a paralyzing liquid. The bitten aphid dies and is used by the larva for food. After 2 weeks, the fully formed larva falls to the ground and turns into a cocoon on the ground. After 3 weeks, the second brood hatches, whose larvae spend the winter in a cocoon on the ground and hatch in the spring as adults.

Ground beetle

WITH early spring and up to late autumn in gardens there are quickly escaping beetles - these are predatory ground beetles that destroy eggs, larvae (caterpillars), pupae and adults of many harmful insects. One ground beetle per day can destroy three to five gooseberry moth caterpillars, up to ten sawfly caterpillars, and up to a hundred gall midge larvae.

They hunt at night, so they are rarely seen during the day. Beetles overwinter in the soil.

Ground beetle larvae

Ground beetle larvae feed on eggs of vegetable flies. small insects and their larvae, worms, slugs. These beetles are rarely seen in the garden during the day; they hide in shelters. The length of the ground beetle is up to 4 cm, it is very mobile. Many species cannot fly and are therefore active at night. The color of the ground beetle is very diverse: large black and completely yellow flickering species are known. Adult insects overwinter in the garden in secluded, protected corners, for example, under a house or a woodpile.

Large ground beetles lay 40-60 eggs separately in shallow holes in the ground. The eggs hatch into larvae after a few days and hatch, depending on the species, 2-3 years later to become a pupa. After a pupal period of approximately 2-3 weeks, they hatch into adult (developed) ground beetles. Along with ground beetles, which live mainly on the ground, there are also arboreal and flying species. They feed on small insects and worms and therefore live in rotting organic matter, such as compost.

Ground beetles should be provided with shelter (foliage, sawdust and shavings, small piles of stones), they live in the open ground, sometimes hiding in earthen crevices.

Pesticides are the worst enemy of ground beetles!

Hoverflies

Hoverflies have great value in gardening, since their larvae feed on aphids. Larvae develop in different conditions– in soil, slurry or on plants. Visually, the hoverfly is similar to a wasp; the length of an adult is 8-15 mm. The peculiarity of hoverflies, reflected in their name, is that in flight they can seem to hover in place, while making a sound vaguely reminiscent of the murmur of water.

Egg laying occurs in aphid colonies. Eggs are 1 mm in size, oblong white. The larvae that hatch from the eggs have no legs and move like snails. They are painted white or yellow and look like fly larvae.

To hunt for aphids, hoverflies use their hook-shaped jaws, with which they firmly hold the prey, sucking it out. The development of the larva to the pupal stage lasts 2 weeks. During this time, the larva eats up to 700 aphids. Hoverfly larvae are active mainly at night and go hunting no earlier than dusk. The hoverfly experiences the pupal stage in a shell in the form of a droplet, located near the aphid colony on the leaves or on the ground. Selected species They hatch several generations, most of them up to 5 per year. In some species, females overwinter in the same way as larvae or pupae. The hoverflies themselves feed on flower and honeydew, as well as the secretions of aphids.

Areas with flowering plants are most suitable for hoverflies, but not well-groomed lawns. Hoverflies especially love plants that bloom with yellow flowers.

To overwinter hoverflies, you can leave small wooden boxes filled with dry grass or shavings.

Spiders

Everyone knows these insects with a rounded abdomen and a fused cephalothorax. However, not everyone knows about their role in nature. Most of them are predators. Spiders are found in the soil, under fallen leaves, on herbaceous plants and trees. Often the webs woven by spiders are confused with the webs left by the common spider mite.

Trichogramma

Trichogramma females, 2-3 hours after birth and mating, begin to search for butterfly eggs, and having found them, pierce them with the ovipositor and lay their eggs in them. Depending on the size of the host egg, it can develop from 1 to 60 egg eaters. The duration of development depends primarily on temperature conditions and lasts from 8 days at 30ºС, 11 – at 25ºС, to 53 days at 11ºС. The lifespan of an adult entomophage depends on temperature, humidity and carbohydrate nutrition (2-5 days without food, up to 7-15 days with feeding).

Lacewing and its larvae

The lacewing, along with ladybugs, is an enemy of aphids. In our gardens the most common type is green with yellow eyes. The beetle got its name precisely because of these eyes. An adult has a wingspan of up to 3 cm. Green, oblong insects wear house-shaped, transparent, veined wings, folding them on the lower part of their long body.

The female lays about 20 greenish eggs individually or in groups on the bark or leaves. Larvae hatched from eggs develop depending on weather conditions within 2-3 weeks. Their length is only 7 mm, their jaws are long, sickle-shaped and pointed. The larvae feed on small insects, especially aphids. Individual individuals are capable of destroying up to 500 aphids during development.

After 18 days, the larvae hide in a protected place, wrap themselves and turn into a white round cocoon. After the lacewing emerges from the cocoon, the next generation begins. In total, 2 generations can appear per year. Adults feed, as a rule, on honeydew and pollen, and on occasion do not disdain small insects. The adult lacewing overwinters in secluded corners, so sometimes it can be found in residential areas. During the wintering period, the insect may acquire a yellow or brown color, but in the spring it turns green again.

Creepy Lion

Along with the common lacewing, we also have about 42 species of aphid lions, which, like the lacewing, belong to the true lacewings. One of the most known species has a wingspan (brown with a specific shape) of about 3 cm. Adults and larvae feed on aphids and contribute to the biological balance in the fight against this pest.

Use for targeted biological protection plants in greenhouses and on protected ground was tested and gave good results. For this it is necessary for each square meter place 20 lacewing eggs on the surface, which can be purchased in special biological laboratories.

Riders

The equestrian likes to settle in umbelliferous plants (dill, coriander, cumin, marigold, etc.).

Common earwig

The common earwig, which belongs to the order Leatherwing, is well known to gardeners and gardeners. The body length is 3.5-5 mm, the front wings are solid, the hind wings are membranous. There are also wingless forms. Its claws located in the back of the body are impressive. The earwig hunts mainly at dusk and at night, and during the day it hides in dark narrow crevices.

By destroying harmful insects such as dahlia woodlice, the earwig can damage tender young dahlia plants.

In spring and autumn, the female lays up to 100 eggs in a hole, which she digs herself, guards them and takes care of her offspring - first about the eggs, and later about the larvae. Earwigs overwinter in shelters - in the bark of trees, cracks in buildings, in soil, in flower pots filled with small shavings or some other material, such as moss.

Can be used as shelters flower pots filled with wood shavings, moss or hay. Such pots are placed between vegetable crops or hung on trees.

Pots should be cleaned out in the winter and refilled in the spring.

Digging in tree trunk circles trees contributes to the normal functioning of the insect. Earwigs often also seek refuge for the winter under trees, in their fallen leaves.

Bedbugs

The predatory bug belongs to the class of weevils. His various types have specific power sources. For some it is the juice of some plant, for others it is insects. The gardener is interested, first of all, in the latter, which, among other things, destroy aphids. These include soft-bodied and false bugs, among which some species feed primarily on spider mites.

Flower bugs are small predatory insects 3-4 mm long. At one time, the female lays up to 8 eggs, mainly along the edges of the leaves. During the year, bedbugs hatch 2 generations, and in areas with a warm climate even 3. Predatory bugs overwinter as adults. More large species Flower bugs also feed on gall midge larvae.

How to attract insects to the garden?

If we take a lot of beneficial insects from somewhere and release them into the garden, the effect will only be short-term. It is much more important that beneficial insects take root in the garden. To do this you need to create for them suitable conditions. First of all, it is a food supply and places for sheltering and breeding of beneficial insects.




To reproduce and increase the species composition of beneficial insects, including predatory insects (entomophages), it is important to take into account their characteristics:

Predatory insects are attracted to flowering plants, not pests (phytophages);
- predatory insects are used for reproduction and destroy the type of “host”, i.e., the pest on which they themselves developed.

So, beneficial insects are attracted to the garden by flowering plants (flowering weeds), not pests.

The presence of natural nectar-bearing flowers in the garden and lawns, even in small quantities, allows predatory insects to carry out extra food in the stages of reproduction. Moreover, some predatory insects are able to reproduce effectively only by combining feeding on nectar or honeydew and insect prey. Therefore, the presence of flowering weeds, even in fields where agricultural crops are grown, at a level below the economic threshold of harmfulness, increases the effectiveness of predatory insects and is considered appropriate.

There must always be a number of different pests in the garden in order for beneficial insects to survive.




Specialized predatory insects look for their “master”, i.e., the pest no matter how large it is. Therefore, once again, there should always be a certain number of different pests in the garden, no matter how paradoxical it sounds! Typically, plants are planted in the hedges around the garden on which pests develop and predatory insects survive. Only in this case can they prevent pest outbreaks. Polyphagous predatory insects show interest in a particular type of pest only when its numbers are high, so they are usually late.

Therefore, a diversity of predatory insect species is necessary for sustainable pest control. And to expand the species composition and reproduction of predatory insects, their nectar-bearing food plants should be sown. These are typically asteraceous umbelliferous and paniculate plants whose many small flowers provide multiple sources of nectar and together form a habitat for beneficial insects, including bees, and butterflies.

Plants that Attract Beneficial Insects

Tansy

The advantage of tansy is that the infusion of tansy leaves repels Colorado potato beetle. I’ll add on my own that abundant tansy herbage is good for use in composts. This compost does not harbor mole cricket and chafer larvae.

Decoctions of tansy leaves and flowers contain many different vitamins and essential substances, improve the taste of kvass and dough, and jam is made from the flowers.

Chamomile

A perennial plant attractive to wasps and flies. During the flowering period it is covered with many yellow flowers.

Lemon marigolds

Attract small wasps and spiders. Seedlings are planted in the ground when the danger of frost has passed.

Caraway

Attracts sly bugs, spiders, small wasps, hoverflies and lacewings during the flowering period. Its aromatic seeds are used in baking and for making marinades.

Dill fragrant

Attracts ladybugs, hoverflies, small wasps and spiders.

Buckwheat

It is an effective soil-forming plant that increases the content organic matter when plowing.

Honey plant

Attracts not only pollinating bees, but also flies, ladybugs, hoverflies, and predatory bugs.

Spearmint

Used to make refreshing tea and as a fragrance. Mint is attractive to flies and spiders.




Many types of legumes have the ability to attract beneficial insects, for example: crimson clover, creeping clover, vetch. They provide beneficial insects with constant food and moisture and enrich the soil with nitrogen.

To ensure availability throughout the season flowering plants, attractive to beneficial insects, you need to start with those that bloom earlier, for example, with buckwheat, which will be replaced by fragrant dill. You should immediately plant marigolds and calendula so that they bloom in mid-summer. You should grow tansy, sweet clover and navel, which bloom for a long time from year to year.

The goal of using beneficial insects is not to completely destroy pests, but to control their numbers.

By creating conditions that combine a favorable environment for beneficial insects and decorativeness, a natural balance can be achieved between the number of harmful and beneficial insects.