Recently, the number of pests causing damage to gardens and vegetable gardens has increased. In addition, they have become even more aggressive and resistant to poisons.
One of these pests is the cockchafer, which is a type of arthropod. So far no effective remedy has been found against it. Another name for this beetle is Khrushchev. It is called so because of the characteristic crunch that occurs when the pest is destroyed.
Features of the cockchafer
He is considered one of the first heralds of spring. With the arrival of warmer weather, the Khrushchev wakes up from hibernation and goes in search of food. The insect flies very quickly, at a speed of two to three meters per second. Khrushchev is capable of covering about twenty kilometers per day. First, it rises up to a height of 5 to 100 meters, then, after circling above the ground several times, it flies further in a straight line. The interesting thing is that, according to the laws of aerodynamics, this insect should not fly due to the lift coefficient being too low.
Khrushchev always fly in a certain direction. It is impossible to knock them off course. In this regard, scientists even conducted some interesting experiments. Having caught the insect, it was released in another place, after which the cockchafer still returned to the previously chosen route.
These insects can navigate the terrain and the sun. During the flight, the beetle remembers bright objects that serve as a guide. In addition, these insects are susceptible to the influence of magnetic fields.
The rhythm of a beetle's life is determined by the sun. During the day, the insect sits on a tree, hardly moving, and it becomes more active in the evening. The life of the cockchafer is mainly nocturnal; it is at this time of day that it feeds and flies.
Reproduction and lifespan
If a human baby, coming into this world, although it does not copy adults in appearance, still resembles representatives of the human race in proportions and body parts, things are not so with insects.
Khrushchev, for example, appearing in nature from grayish-white eggs that look like beads, are not at all what they become in the end. And only in the process of passing through certain stages of transformations do the organs of the cockchafer and an adult individual is born in the form already described.
And it all starts like this. From the end of May, the female feeds and mates intensively, digs tunnels in the soil and places eggs in them. Then it becomes saturated again and repeats the reproductive cycle, completing it three or even four times per season, after which it dies. The total number of eggs that she manages to lay reaches 70 pieces.
After a month or a little later, larvae, also called furrows, hatch from underground clutches. In appearance, these are unpleasant elongated “somethings”, similar to white caterpillars with sparse hairs, curved and thick, having three pairs of legs and powerful jaws. Such creatures have to spend about three, and sometimes four years in the underworld.
In winter, the furrow, boring into the soil, goes deep into the ground, and by spring it rises higher to be saturated with plant roots all summer. In search of food, the larva is able to move within a day to the distance of a human step and grows over time to a length of five centimeters or more. Then, by the end of the third summer, it turns into a pupa, resembling a beetle in this state, walled up in a bizarre chamber.
Until next spring, this creature remains underground, going through a series of transformations and gradually freeing itself from its puppet shrouds. And in April or May of the next season, the formed individual (imago) makes its way out to a new life.
Finding herself in the aboveground world, driven by hunger, at first she is only concerned with the search for food and intensively strives to satiate herself with young shoots, buds, and leaves. In the adult stage, the beetle will have to survive for about a year, until death. And the full life cycle of Khrushchev is no more than five years.
Appearance of a beetle
There are 24 species of these insects. There is probably no person who does not know what a cockchafer looks like. The least harm to plants comes from representatives of the Caucasian and Oriental species. Western beetles are the biggest nuisance to gardeners and gardeners.
The Western Khrushchev is brownish-yellow in color, with a black chest, red back and legs, and has a mustache with a brown “mace.” The length of the insect is from 25 to 35 millimeters. The larva of the May beetle is often white-yellow in color, fleshy, folded, and has a dark head with two clamping fangs. Beetle eggs are oval and white. The male can be distinguished from the female by the appearance of the back of the abdomen. In male chafers it looks like a long triangular process, which is much shorter in the female. The body of the beetle is covered with a chitinous shell.
The structure of the head of a Khrushchev
The beetle's head has a mouth opening with an upper lip that looks like a transverse plate. The mandibles and lower lip have palps, which are sensory organs.
There are eyes on both sides of the head. The structure of the organ of vision is complex: it consists of a huge number of simple eyes. The beetle's antennae with plates are an organ of smell; with their help, the beetle finds food. The male has a strongly curved “club” at the end of the antennae. The insect's head is unable to turn from side to side.
General characteristics of the class
They live in soil, water, plant tissues, animals and humans.
Fertility:
- queen bee - 1,500,000 eggs in her entire life (lives 5 years).
- termite queen - 10,000,000 eggs per life (lives 10 years).
Benefit:
- pollinate plants;
- destroy field pests;
- gardens and vegetable gardens.
Harm:
- blood-sucking (affect milk yield);
- carry pathogens from animals to humans (lice - typhus, relapsing fever; mosquitoes - malaria; flies - eye diseases).
Types of mouthparts:
- gnawing - beetles, cockroaches, grasshoppers;
- sucking - butterflies;
- piercing - mosquito;
- licking - fly;
- gnawing-licking - bees, gadflies, wasps, bumblebees, hornets.
Vision is complex (faceted). A person distinguishes about 60 individual colors; bees see yellow, blue-green, blue, ultraviolet (butterflies see red).
The shape of objects is distinguished - predatory (dragonflies, tyrs...); social (ants, bees, wasps).
The sense of smell is on the antennae (butterfly - 2-3 km).
Taste organ on the mouth parts (jaws, lips, palps). Just like humans, they distinguish between sweet, sour, salty, and bitter.
Sense organs are well developed and provide insects with great information about the external environment.
Circulatory system
Like other arthropods, this insect has an open circulatory system. With the flow of blood in the body cavity, internal organs and tissues receive nutrients. The movement of blood is provided by the heart, which pulsates and drives it to the head end of the body. Its reverse flow is impossible due to the heart valves. When the heart expands, blood enters it from the back of the body. The side openings of the central organ of the circulatory system have valves that prevent the reverse flow of blood. This biological fluid does not participate in the respiratory process.
Other types of mouthparts
Filter type
The described varieties belong to the main types of mouthparts, however, among smaller and less numerous orders there are also other modifications. For example, some aquatic larvae, in particular the larvae of many midges (Simuliidae), develop a kind of fan on their heads designed to filter microorganisms. Based on the mechanism of operation, this type of apparatus is called filtering. [4]
Cutting and sucking type
Horseflies (Tabanidae) and some other dipterans have a cutting-sucking type of mouthparts: the mandibles are elongated into sharp blades, and the maxillae are elongated into long piercing stylets. Both pairs of jaws cut and pierce the integument of the body of mammals, causing bleeding from the wound. This blood is collected by a sponge-like structure on the lower lip and delivered to the apex of the hypopharynx. The epipharynx and hypopharynx are tightly adjacent to each other, creating a tube through which blood rises into the esophagus. [4]
Tubular-sucking type
Adult Lepidoptera feed on nectar and other liquid food. It is absorbed through a long proboscis formed by the galea and maxillae folded together. The result is a tube that opens into the esophagus. This type of structure is called the tubular-sucking type of mouthparts. [4]
How the cockchafer reproduces. Stages of development
The female cockchafer can reproduce 2-3 weeks after it emerges from the pupa. After mating, she buries herself in the ground, where she lays eggs. After this, she again goes in search of a male, and the process of laying eggs is repeated. The whole action can happen up to four times, after which the female dies.
Egg
The eggs that the female lays are off-white in color. Their width is 0.2 cm, length - 0.3 cm. At first the eggs are soft, then they harden. Their development occurs from 24 to 50 days.
Larva
It is thick and curved, and has a light color. The cockchafer larva has a round head, light yellow or brown color and three pairs of legs. Can reach 65 mm in length.
Doll
The pupa is yellowish in color, is usually located in the ground, in a “cradle”, and is similar in appearance to an adult beetle, but its wings are shorter. The length of the pupa reaches 0.25 cm. This developmental phase lasts from two to four weeks.
Modifications of the oral apparatus
In different groups of insects, the oral apparatus has been modified to better absorb different types of food in different ways. The most specialized and varied types of mouthparts are listed below; they are chosen to demonstrate the richness of the forms assumed by homologous parts and the different ways in which they are used. There are also many other types, and they often represent transitional stages between the types we are considering here. [4]
The type of mouthparts is a systematic character at the order level. In smaller taxa, there are usually no differences in this character: as a rule, only some individual structural features are found. [2]
Gnawing mouthparts
1 – Structural diagram 2 – Mouthparts of the beetle Prionus californicus from the longhorned beetle family
Designations in both pictures: VG - upper lip, NG - lower lip, HF - upper jaws, LF - lower jaws.
Gnawing type
Typical owners of the gnawing apparatus can be locusts and lepidopteran larvae - caterpillars. [4]
This type of organization is primary. It is this variant that contains the most complete set of oral parts - the upper lip and three pairs of oral limbs: mandibles (upper jaw), maxilla (lower jaw) and labium (lower lip). [2]
The leading role in food intake is played by the upper jaws, which bite off and crush the substrate, and the remaining oral parts help swallow it, pushing the pieces into the esophagus. [4]
Sucking mouthparts
1 – Structure diagram 2 – Mouthparts of a butterfly
Designations in both pictures: VG - upper lip, NG - lower lip, LF - lower jaws (proboscis).
Sucking type
This type of oral apparatus is found only in representatives of Lepidoptera.
Its main part is called the proboscis, which is a modified pair of lower jaws. The upper and lower lips look like plates located above and below the proboscis, and butterflies do not have upper jaws at all. [3]
Nutrition is carried out as follows. At rest, the proboscis is curled under the head, and during feeding it expands into a long tube that can penetrate inside the corolla of the flower. The insect sucks in nectar through this tube. [3]
Licking mouthparts
Licking type
The licking type of mouthparts is common among flies.
Its main part is the hypertrophied lower lip. It is modified and, with the participation of reduced structures of the remaining oral parts, forms a proboscis. [2]
During feeding, the proboscis is immersed in liquid food, which rises into the esophagus through capillary tubes. Flies are also capable of absorbing soluble nutrient substrates by first secreting a drop of saliva on them and then sucking up the resulting liquid. [4]
Piercing-sucking mouthparts
1 – Structural diagram, 2 – Oral apparatus of the mosquito Culex tarsalis.
Designations in both pictures: VG - upper lip, NG - lower lip.
Piercing-sucking type
This modification of the oral apparatus is found in aphids, scale insects, mosquitoes, bedbugs and other insects that feed on the juices of plants, other representatives of their class or the blood of animals.
In the piercing-sucking apparatus, the upper lip and both pairs of jaws are transformed into a needle with a lumen inside, and the lower jaw is modified and surrounds this needle in the form of a case, forming another version of the proboscis. [4]
To take food, the insect presses its proboscis against the integumentary tissues of a plant or animal, and then inserts a needle into its tissue and sucks juices into the esophagus. [4]
Gnawing-licking mouthparts
1 – Structural diagram 2 – Mouthparts of a honey bee.
Designations in both pictures: VG - upper lip, NG - lower lip, HF - upper jaws, LF - lower jaws.
Gnawing-licking type
The gnawing-licking type is characteristic of Hymenoptera.
The upper lip and upper jaws of bees and wasps are almost the same in structure as in a typical gnawing apparatus, and the maxillae and labium have been transformed into a retractable groove-like organ. [4]
Feeding occurs by lowering the latter into the nectaries of flowers. Through the smallest channels in its thickness, saliva descends, and dissolved food moves upward. [4]
Stages of development
In the first summer, the larvae eat humus and grass roots. In winter, it hides 1.5 meters into the ground, and with the arrival of spring it moves closer to the root system of plants.
The two-year-old larva feeds on the roots of a young tree. In the third year, it reaches a size of five to six centimeters; now it can even gnaw the roots of adult trees. In the fourth year of life, the larva transforms into a pupa, and two months later it becomes a beetle.
In winter, the beetles are in suspended animation; with the arrival of spring warmth, the May beetle begins its flight.
What does Khrushchev eat?
In spring, when the air warms up to a temperature of +10°C and above, the cockchafer flies out. The insect causes enormous damage to fruit trees, damaging leaves, flowers, and ovaries. Apple, plum, cherry, and walnut trees suffer more than other trees. In addition, the May beetle can eat the needles and foliage of various shrubs. The only things he doesn't eat are lilac and ash leaves. Having destroyed the foliage in one area, the beetle flies to another.
The larvae damage the roots and trunks of plants and vegetable crops.
