Insects are the most numerous class of animals. It is estimated that about 1.5 million insect species live on our planet. However, scientists assume that in fact the number of insect species is approaching 30 million, only they have not yet been described.
Insects are usually terrestrial arthropod creatures. They have 6 segmented legs, and the body consists of segments, separated by notches, hence the name. The body is divided into head, chest and abdomen. And insects do not have an internal skeleton that vertebrates have. But then they have an outer skeleton - cuticleconsisting of a special substance - chitin.
On the insect chest are three pairs of legs, and the majority - and two pairs of wings. And they have a different structure, due to the lifestyle of the insect.
The world of insects is very diverse. Some bugs can glow in the dark like fireflies, others, on the contrary, deftly disguise themselves among the leaves as stick insects.
Where do insects live
Insects live everywhere, including on the bodies of other animals. The woods chose a variety of bark beetles and beetle beetles, fields and vegetable gardens - butterflies, cabbage, human housing - indoor flies.
Gnawing, sucking and other
The eyes and mouth are the most important parts of the body of the insect. The mouthparts of insects are adapted to eating various foods, so they can be gnawing, sucking, licking, piercing-sucking. For example, in the May beetle, grasshopper, dragonfly, gnawing mouthparts, in a mosquito and bug, they are sucking, in butterfly cabbage and other butterflies - sucking.
General characteristics of Lepidoptera
Currently, the class of insects is the most numerous in number of species. In addition, it is the most prosperous group of animals on Earth in terms of the breadth of spatial distribution and ecological differentiation. Insects have a number of common features in the internal structure, but their appearance, development, lifestyle, and other parameters vary greatly.
The division of the class of insects into large systematic categories — subclasses, infraclasses, and detachments — is based on such important features as the structure of the wings, the oral apparatus, and the type of postembryonic development. Additionally, other diagnostic features are used.
Different authors give different systematics to the class, but the number of units, regardless of the source, is quite impressive. The most famous of them are the Dragonfly (Odonata), Tarakanovye (Blattodea), Termites (Isoptera) Kray, Pryvokrylye (Orthoptera), Equoptera (Homoptera), Hemiptera, Hemoptera (Coleoptera), Kryprytrye Kry, and Krykrykrye-Kry (), Copperwing (Coleoptera) , of course, Lepidoptera.
General characteristics of Lepidoptera
Butterflies are one of the most beautiful insects, the order Lepidoptera includes more than 140 (according to some sources 150) thousand species. However, among other insects, this is a rather “young” group, the greatest development of which coincides with the flowering of flowering plants in the Cretaceous period. The lifespan of an imago lasts from several hours, days, to several months. The difference in size in Lepidoptera is stronger than in any other unit. The wingspan of their wings varies from 30 cm in the South American scoop to half a centimeter in eriocrania. Butterflies are most common in tropical latitudes. And in South America, the Far East, Australia live the largest, brightly colored and seemingly interesting butterflies.
So champions on the brightest coloring are the representatives of the South American genus Morho and the Australian sailboat ul. Large (up to 15 - 18 cm), sparkling with blue metal morpho, perhaps, are the dream of any collector. And in terms of flights, the monarch butterfly living in North and Central America and flying from Canada and the northern regions of the United States to the south is best studied.
The structure of an adult insect
Adult insect, or imago, has the following structure. The body of the butterfly consists of three main sections: the head, chest and abdomen. The segments of the head are merged into the total mass, whereas the segments of the chest and abdomen are more or less distinct. The head consists of an acron and 4 segments, the chest of 3, the belly in its entirety contains 11 segments and telson. The head and chest carry the limbs, sometimes only their rudiments retain the belly.
Head. The head is sedentary, free, round shape. Here are strongly developed convex faceted eyes, occupying a significant part of the surface of the head, usually round or oval, surrounded by hairs. In addition to complex compound eyes, sometimes there are two simple ocelli on the vertex behind the antennae. The study of the ability of butterflies to color vision showed that their sensitivity to visible parts of the spectrum varies with their lifestyle. Most perceive the rays in the range of 6500 350 A. Butterflies are particularly active in responding to ultraviolet rays. Butterflies are almost the only animals that perceive the color red. However, due to the lack of pure red flowers in the Central European flora, red is not perceived by hawk moths. Caterpillars of pine silkworm, cabbage moth and willowworm clearly distinguish different parts of the spectrum, reacting to violet rays as white, red is perceived as darkness.
Fig.1. Repnitsa's head, or replica moths (Latin Pieris rapae)
1 - Side view with curled proboscis: B - labyral palp, C - tendril, G - folded proboscis, 2 - front view with curled proboscis: A - facet eye, B - labial palp, C - barb, G - folded proboscis, 3 - side view with unfolded proboscis: B - labyral probe, C - antenna, D - unfolded proboscis
In different groups of butterflies, antennae, or antennas, are of the most diverse forms: filiform, bristle-shaped, clavate, spindle-shaped, pinnate. In males, antennae are usually more developed than in females. Eyes and antennae with olfactory sensillae located on them are the most important sense organs in the butterfly.
Oral apparatus. The mouth apparatus of Lepidoptera arose through the specialization of the usual limbs of arthropods. Absorption and grinding of food. Oral organs of butterflies are no less characteristic feature than the structure of the wings and scales covering them.
In the overwhelming majority of cases, they are represented by a soft proboscis, able to curl up like a clock spring. The basis of this oral apparatus consists of highly elongated internal lobes of the lower jaws, which form the valves of the proboscis. The upper jaws are absent or are represented by small tubercles, the lower lip has also undergone a strong reduction, although its palpi is well developed and consists of 3 segments. The proboscis of the butterfly is very elastic and mobile, it is perfectly adapted to the nourishment of liquid food, which in most cases serves as nectar of flowers. The length of the proboscis of one species or another usually corresponds to the depth of the nectar in those flowers that are visited by butterflies. In some cases, the source of liquid food for Lepidoptera may be the outflow of tree sap, liquid excrement, aphids and other sugary substances. In some butterflies that do not feed, the proboscis may be underdeveloped or completely absent (fine tits, some moths).
Chest. The chest consists of three segments, called the anterior, middle and hind chest. The breast segments carry three pairs of limbs attached between the sternite and the sideplate of each side. The extremities consist of one row of segments in which we distinguish from the base towards the end of the leg: a basin, or thigh, a wide main segment, a swivel, a thigh, the thickest segment of the leg, a tibia, usually the longest of the segments, a foot consisting of different numbers small segments. The last of which ends with one or two claws. There are numerous hairs or setae on the chest, sometimes a tuft forms in the middle of the back, the belly never connects to the breast with a stalk, in females it is generally thicker and equipped with a long ovipositor, in males instead there is a tuft at the end of the abdomen.
Wings. A characteristic feature of insects as a large systematic group is their ability to fly. The flight is carried out with the help of the wings, in most cases there are two pairs of them and they are located on the 2 (mid-chest) and 3 (sub-chest) thoracic segments. The wings are essentially powerful folds of the body wall. Although a fully formed wing has the form of a thin solid plate, it is nonetheless two-layer, the upper and lower layers are separated by a very thin slit, which is a continuation of the body cavity. The wings are laid in the form of bag-like protrusions of the skin, into which the body cavity and the trachea continue. The protrusions flatten dorsoventrally, the hemolymph from them flows into the body, the upper and lower leaflets of the plate approach each other, the soft tissues partially degenerate, and the wing takes the form of a thin membrane.
Fig.2. Greta butterfly (lat. Greta)
The beauty of the butterfly lies in its wings, the variety of their colors. The color scheme provides scales (hence the name of the group Lepidoptera). Scales - amazing invention of nature, which for millions of years faithfully serve butterflies, and now, when people began to study the properties of these amazing structures, can serve us. The scales on the wings are modified hairs. They have a different shape. For example, along the edge of the wing of the Apollo butterfly (Parnassius apollo) there are very narrow scales, which are almost the same as hairs. Towards the middle of the wing, the scales expand, but remain sharp at the ends. And, finally, very close to the base of the wing are wide scales, similar to a hollow sac, attached to the wing by a tiny leg. The scales are arranged in regular rows across the wing: their ends are turned outwards and cover the bases of the following rows.
Experiments have shown that the scaly cover of butterflies has a number of completely amazing properties, for example, good thermal insulation properties, which are most pronounced at the base of the wing. The presence of scaly cover increases the difference between the temperature of the insect and the ambient temperature by 1.5 - 2 times. In addition, wing flakes are involved in the creation of lift. After all, if the butterfly is held in the hands and some of its bright scales remain on the fingers, then the insect will already have great difficulty to flip from place to place.
In addition, as shown by the experiments, the scales dampen the sound vibrations and reduce the vibration of the body during flapping flight. In addition, during the flight, a charge of statistical electricity appears on the insect's wing, and the scales help this charge to “drain” into the external environment. A detailed study of the aerodynamic properties of butterfly scales led to the fact that scientists proposed to create a coating for helicopters, designed in the image and likeness of the scaly cover of the wings of the butterflies. This coating will improve the maneuverability properties of rotary-wing machines. Moreover, such a cover can come in handy for parachutes, yacht sails, and even athletic suits.
The wonderful coloring of the butterflies also depends on their scaly clothing. The membranes of the wings themselves are colorless and transparent, and in the scales there are pigment grains, which cause a wonderful color. Pigments selectively reflect light at a specific wavelength and absorb the rest. In nature, in general, all colors are formed mainly in this way. However, pigments can only reflect 60-70% of the incoming light, and therefore colors due to the presence of pigment are never as bright as they could theoretically be. Therefore, species for which a particularly bright color is vital are “looking for” an opportunity to enhance it. Many types of butterflies in addition to the usual pigment scales, there are special scales, which are called optical. They allow insects to become owners of truly sparkling clothes.
In optical scales, thin-layer interference occurs, the optical effect of which can be observed on the surface of soap bubbles. The lower part of the optical scales is pigmented, the pigment does not transmit light and thus gives a greater brightness to the interference color. Rays of light, passing through the transparent flakes on the wing, are reflected both from their external and internal surfaces. As a result, the two reflections overlap and reinforce each other. Depending on the thickness of the flakes and the refractive index, light is reflected from a certain long wavelength (all other rays are absorbed by the pigment). Butterflies “line up” on the outer surface of their wings thousands of tiny thin-layered mirror mirrors, and each such tiny mirror reflects light of a certain wavelength. The result is a completely stunning effect of reflecting extraordinary brightness.
Fig.3. Butterfly Perelivnitsa willow (Apatura iris)
Record for the brightest colouration are representatives of the South American genus Morho, however, but in the central belt of Russia live butterflies with a wonderful coloration. Best of all, the interference color is noticeable in irile (genus Apatura and Limenitis). From afar, these butterflies seem almost black, but close to cast a pronounced metallic sheen - from bright blue to purple.
Recently it became known that a similar interference effect can be created using different microstructures with unique optical properties. Moreover, the microstructures on the wings differ not only in representatives of different families with similar colors, but also in related species. The study of the subtleties of these effects, using modern technology, is now closely engaged in optical physics from the University of Exter. At the same time, physicists make unexpected discoveries that turn out to be interesting not only for them, but also for biologists studying evolutionary processes.
Interestingly, the biological significance of the bright, variegated colors of the upper side of the wings, which are so often seen in the butterflies, especially in the nymphalides. Their main significance lies in the recognition of individuals of their species at a great distance. Observations show that males and females of such variegated forms are attracted to each other from a distance by coloring, and near there is a final recognition by the smell emitted by androconium.
If the upper side of the wings of a nymphalid is always colored brightly, then a different type of coloring is characteristic of their lower side: they are usually cryptic, i.e. Protective. In this regard, two types of folding wings are widespread, widespread in nymphalids, as well as in other families of daytime butterflies. In the first case, the butterfly, being in a resting position, pushes the front wings forward so that their lower surface, which has a protective coloration, is open almost throughout. This type of wings folds, for example, at the C-white caliper (Polygonia C-album). It has a brown-yellow upper side with dark spots and an outer border, the lower side is gray-brown with a white letter “C” on the rear wings, for which it got its name. The motionless sitting butterfly is also inconspicuous due to the irregular angular contour of its wings.
Fig.4. Butterfly Kallima inachus with folded wings
Other species, such as the admiral and burdock, hide the front fenders between the rear wings so that only their tips are visible. In this case, two types of colors are expressed on the lower surface of the wings: that part of the front wings, which is hidden at rest, is brightly colored, the rest of the lower surface of the wings is clearly cryptic.
In some cases, day butterflies are brightly colored and the upper and lower sides of the wings. Such coloring is usually combined with the inedibility of the organism possessing it, therefore it has received the name of warning. On the basis of this feature, butterflies have the ability to mimicry. Mimicry is understood to be similar in color, shape and behavior between two or more insect species. Butterflies mimicry is expressed in the fact that some of the mimicking species are inedible, while others are deprived of protective properties and only “imitate” their protected models. These imitators are Whitefish (Dismorfphia astynome) and perhibris (Perrhybris pyrrha).
Life cycle of Lepidoptera, migratory behavior, role in biocenoses
The structure of mammals, behavior, central nervous system
Features of the birds
Features of lizards
Lepidoptera (or butterflies) is a fairly numerous detachment of insects. It consists of about 150 thousand species. Representatives of Lepidoptera are various butterflies, moths and moths. The main habitats of their habitats are forests, meadows, as well as fields and gardens.
Butterflies are characterized by two pairs of large wings, usually of bright color. The wings are covered with small chitinous multi-colored or colorless scales laid like tile. Hence the name of the unit - Lepidoptera. Scales are modified hairs, they are also on the body.
Обычно у бабочек, ведущих дневной образ жизни (лимонница, капустница и др.), в спокойном состоянии крылья складываются вместе над телом. У ночных чешуекрылых они располагаются крышеобразно (например, у моли).
Яркая окраска крыльев служит бабочкам для распознания представителей своего вида, а также нередко несет защитную от хищников функцию. Так у некоторых чешуекрылых сложенные вместе крылья похожи на листочек, т. е. насекомое маскируется под окружающую среду.
Butterflies life cycle (metamorphosis): butterfly development
Other lepidopterans on the wings have spots that resemble birds' eyes from afar. Such butterflies have warning coloring. Usually, moths have a protective coloration, and they find each other by scent.
Lepidoptera belong to insects with full transformation. Larvae-caterpillars emerge from the eggs, which subsequently pupate, after which a butterfly emerges from the pupa (the adult is an adult, sexually mature stage). Caterpillars usually live longer imago. There are species in which the larva lives for several years, while the butterfly itself lasts about a month.
The caterpillars feed mainly on foliage, have an oral apparatus of the gnawing type. In butterflies, the oral apparatus is of the sucking type, represented by a proboscis coiled up in a spiral tube, which is formed from the lower jaws and the lower lip. Adult lepidopterans most often feed on the nectar of flowers and at the same time pollinate plants. Their long proboscis spins up, and they can penetrate deep into the flower.
Lepidoptera caterpillars, except for three pairs of jointed legs, have a false-leg, representing the outgrowths of the body with suckers or hooks. With their help the larva keeps on leaves and branches, and also creeps. Real legs are most often used to hold food.
The caterpillars in the mouth have silk-secreting glands, secreting a secret that turns into a thin string in the air, from which the larvae spin cocoons when pupated. Some representatives (for example, of the silkworm) thread has value. People get them her silk. Therefore, the silkworm is bred as a pet. Also silk thread, but more coarse, is obtained from the oak silkworm.
Many among lepidopteran pests of forests, agricultural fields and gardens. So with a strong reproduction of an oak leafworm and Siberian silkworm, hectares of forests can be destroyed. Caterpillars of the cabbage whitefish feed on cabbage leaves and other cruciferous plants.
Butterflies are arthropods - the most highly developed invertebrate animals. They got their name for the presence of segmented tubular limbs.
Butterfly species: appearance, species, insect structure
Another characteristic feature is the outer skeleton formed by the durable polysaccharide plates - quinine. In arthropods, as a result of the development of a strong outer shell and segmented limbs, a complex system of muscles has been attached, which is attached from the inside to the integument. All movements of their body parts and internal organs are associated with muscles.
3- head with antennae
5, 8, 9- front, middle and hind legs
6, 7- first and second pair of wings
Butterfly body consists of three sections: the head, chest and abdomen. The webbed short and soft neck is bonded to the chest, consisting of three segments that are fixedly connected to each other. Connections are not noticeable. Each of the segments carries a pair of jointed legs. Butterflies have three pairs of legs on the chest. The forelegs of males nymphalides, blue-eyed satyrs are underdeveloped, in females they are more developed, but they are also not used when walking and are always pressed to the chest. In sailboats and fatheads, all legs are developed normally, and the tibia of their front legs are equipped with lobe-shaped formations, which are believed to be used to clean the eyes and antennae. In butterflies, the legs serve mainly for fixing on a certain place and only then for movement. Some butterflies have taste buds on their feet: before such a butterfly touches a sweet solution with a limb, it will not unfold the proboscis and will not start eating.
On the head are the oral apparatus, antennae and eyes. The suction device of the sucking type is a long tubular proboscis, which is not segmented, spirally curled at rest. The lower jaw and the lower lip take part in its formation. Butterflies have no upper jaws. During the meal, the butterfly straightens the long proboscis, plunging it deep into the flower, and sucks the nectar. Adult Lepidoptera use nectar as the main source of food, therefore they are among the main pollinators of flowering plants. All insects and butterflies including a special organ, called Jones, designed to analyze shaking and sound vibrations. With the help of this organ, insects not only assess the state of the physical environment, but also communicate with each other.
Butterflies have perfect nervous system and sense organs, thanks to which they are perfectly oriented in the environment, they quickly react to danger signals. The nervous system, like all arthropods, consists of the pharyngeal ring and the ventral nerve cord. In the head, as a result of the fusion of clusters of nerve cells, the brain forms. This system directs all the movements of the butterfly, except for such involuntary functions as blood circulation, digestion, and respiration. Researchers believe that these functions are controlled by the sympathetic nervous system.
1- allocation organs
2- middle part of the intestine
5 - frontal intestine
6 - large intestine
7- sexual organs
8- nerve ganglion
Circulatory systemlike all arthropods, unlocked. The blood directly washes the internal organs and tissues, being in the body cavity, transferring nutrients to them and carrying harmful substances to the excretion organs. It does not participate in the transport of oxygen and carbon dioxide, that is, in breathing. Its movement is provided by the work of the heart - a longitudinal muscular tube located in the dorsal part above the intestine. The heart, pulsing rhythmically, drives blood to the head end of the body. Reverse blood flow prevents heart valves. When the heart expands, blood enters it from the back of the body through its side openings, fitted with valves that prevent backflow of blood. In the body cavity, in contrast to the heart, blood flows from the front end to the back, and then, entering the heart as a result of its pulsation, again goes to the head.
Respiratory system It is a dense network of branched internal tubes - the trachea, through which air, through the external spiracles, is delivered directly to all internal organs and tissues.
Excretory system - is a bundle of thin tubes, the so-called malpighian vessels located in the body cavity. They are closed at the tops, and the bases open into the intestines. The metabolic products are filtered out over the entire surface of the malpighian vessels, and then inside the vessels they turn into crystals. Then they enter the intestinal cavity and, together with undigested food residues, are excreted from the body. Some harmful substances, especially poisons, accumulate and are isolated in the fatty body.
Reproductive system females consists of two ovaries, in which the formation of eggs. The ovaries, passing into the tubular oviducts, the bases merge into a single unpaired oviduct, along which mature eggs are brought out. In the reproductive system of the female there is a seminal receptacle - a reservoir into which the male spermatozoa enter. Mature eggs can be fertilized by these sperm. Male reproductive organs are two testes that enter the seed canals, which are combined into an unpaired ejaculating channel that serves to remove sperm.
Butterfly squad, or lepidoptera
Lepidoptera are the largest group of insects of the type of arthropod animals. A characteristic feature of all representatives of the order of butterflies - scaly multi-colored cover of the body and wings. These scales are nothing more than modified hairs. They have a different color, can be complex and fancy drawings. These patterns serve as a disguise that hides an insect or signals inedibility. For most species, the drawings on the wings have an identifying character so that individuals of the same species can recognize each other.
Another identifying feature of the butterfly squad is the sucking oral apparatus in the form of a long tubular proboscis. For food, the butterfly pushes a long proboscis, plunges it deep into the flower and sucks nectar.
The main source of food for the order of butterflies is the nectar of flowers, so they are considered the main pollinators of flowering plants. There is an opinion that with the appearance of flowers on Earth, butterflies appeared.
Everyone knows that butterflies are night and day. These insects pass in the process of development of a complete transformation. At first they lay eggs, the larvae hatch from them, completely different from adult individuals. This is a caterpillar. With the help of the salivary glands, the caterpillars secrete saliva and silk threads. It is from them that the caterpillars weave a cocoon for the pupa. The caterpillar will turn into it after passing a few molts. After a while, an adult butterfly (imago) flies out of the pupa. Imago's longest life expectancy is a few months.
Food for caterpillars are plants. But some species can be called predators and parasites. The main food of adult butterflies is nectar, juice of plant or animal origin. In some species of butterflies, the proboscis is not developed at all, they do not feed, therefore they live for several hours or days.
The annual development cycle of the butterfly is different, depending on the species. Most often in the year butterflies give one generation. There are species that give and two or three generations per year.
Lepidoptera may have sizes from 2 mm to 15 cm. The smallest butterfly is the mole-baby that lives on the Canary Islands. The largest species is the Maacka sailing vessel, which is common in Europe.
Like other insects, butterflies have a belly, head and chest. The outer skeleton is a durable chitinous cover. Butterflies have two pairs of wings with modified hair-scales. It is with these scales that the wings acquire a pattern and color. Butterflies can fly long distances. These insects are of two sexes.
Troops of insects: butterfly, winged, two-winged, fleas
Today there are about 150,000 species of scaly, which inhabit all continents except Antarctica. Tropical areas are rich in especially brightly colored butterflies. In addition to butterflies, there are several similar groups of insects: horned, double-winged, and flea. We offer to meet with the main representatives of each unit:
- Equal-winged. There are more than 30,000 species. These include cicadas, whiteflies, listoblushki, worms, aphids, gall midges, scale insects. All of them are sucking insects that feed on plant sap. They have a piercing-sucking mouth like a proboscis. Why are they called equiplaned? Nature endowed them with two pairs of transparent wings - front and rear.
- Diptera. A million species belong to this order. They originated more than 100 million years ago. Everyone knows the bites of mosquitoes and annoying flies. They have the presence of the front pair of wings. Their rear wings can be called small appendages - halters, maintaining balance during the flight.
- Fleas. There are more than 1000 species. These are small insects without wings and with flattened sides. Flea size - from 1 to 5 mm. They have a big belly and legs, but a small chest and head. They have a slippery and smooth body, dotted with bristles and hairs. All this in order to make it easier to move through the fur of animals inhabited by fleas. An adult flea is a bloodsucker that parasitizes birds and mammals.
Lepidoptera are of great importance in nature and human life. After all, butterflies perfectly pollinate plants. Many large butterflies, such as the Machaon, Apollo, simply fascinate with its beauty. They become exhibits of many entomological collections.