ORANOPOPHINE ORDER - ORTHOPTERA
Orthoptera is one of the most famous groups of insects, not only because everyone knows large grasshoppers and crickets, but also because there are many dangerous agricultural pests among them. From time immemorial, hordes of locusts have been destroying vast areas of crops, leaving bare land behind them. Gardeners are familiar with the bear.
Most orthoptera are large insects, usually with well-developed wings, strong hind legs, and a large head with gnawing jaws. Many orthopterans feed on plant foods (most locusts), some species are omnivores (grasshoppers, crickets, and bears), and among predators there are also predators. The antennae can be long (longer than the body) and shorter (shorter than half the body). On this basis, the orthoptera is divided into 2 suborders - long-billed (Dolichocera) and short-bred (Brachycera).
Orthoptera - insects with incomplete transformation. Larvae emerge from their eggs, which have the same appearance as adult insects, only very small ones. In addition, the larvae have not developed wings. Otherwise, they are an exact copy of their parents and eat the same way as adult insects.
Orthopterans have well-developed organs of vision (two large complex eyes and 3 small eyes) and hearing organs, they can make and perceive sounds using various devices. Grasshoppers sound system (Tettigonio superfamily> Cricket sound system (Gryllo superfamily> Locust (Acr> superfamily)
Orthoptera Order (F. N. Pravdin)
Among the insects with incomplete transformation, orthopterans occupy a special place. This is a very large group, including over 20,000 species, of which more than 700 are found in the USSR. Orthopterans are widespread throughout the globe - from the tropics to the Arctic - and are distinguished by a wide variety of morphological structures and physiological adaptations to very diverse environmental conditions. However, not only this attracts Orthoptera insects. Since ancient times, man has recognized among them many enemies who mercilessly destroy the fruits of his labor. The word "locust" still causes an idea of a great impending danger.
Orthopterans include insects with an elongated body, gnawing mouth organs and a characteristic structure of the chest, aircraft and hind limbs. They have a head with large, usually oval, complex eyes and for the most part 3 eyes, the antennae located on it can be long, exceeding the length of the body (grasshopper, cricket), or short - shorter than half the body (quail, locust). This division in the structure of the antennae is based on the division of Orthoptera into two suborder - long-nosed and short-haired.
The structure of the orthoptera’s chest is specific: the prothorax is highly developed and mobile, and the lateral parts of the pronotum hang downward, forming wide lobes covering the prothorax from the sides. The remaining two sections of the chest are tightly fused with each other. The wings are mostly developed normally, although there are forms with shortened wings and even completely wingless. The wings of the anterior pair are denser and narrower and represent the elytra. Hind wings, or simply wings, wide, webbed with well-developed longitudinal venation. When an insect is planted, they fan-shaped and hide behind the elytra. The hind legs are hopping type with thickened and elongated hips and long legs. Therefore, orthoptera is sometimes called jumping insects (Saltatoria).The abdomen is 10-segmented, elongated, with cerci; from the bottom, it seems to be 8- or 9-segmented, since one or two sternites are reduced. Orthoptera can make and perceive sounds, as they have special sound and hearing aids, the structure of which is different in different suborders.
Suborder Long-winged Orthoptera (Dolichocera, or Ensifera)
Long-winged orthopterans are distinguished primarily by long bristle-shaped antennas that usually exceed body length, the hearing organ, when it is present, is located on the legs of the front legs, the ovipositor is always long. The suborder distinguishes between two superfamily - grasshopper and cricketsx
TOnodule it is easy to distinguish from the other orthopterans in the structure of their legs and the characteristic shape of the female’s ovipositor: the legs on all legs are 4-segmented, and the ovipositor is long, usually laterally compressed, curved in the form of a sickle or saber or xiphoid. The elytra and wings of the grasshoppers are mostly well developed and then reach the apex of the abdomen or even go beyond it. At the same time, at rest, the elytra are folded along the length of the body roof-shaped and cover the wings hidden under them. In some species, the elytra and wings are shortened to varying degrees, and there are completely wingless forms.
The grasshopper's sound apparatus is located on the elytra. At the base of the right elytra is the so-called “mirror” in the form of a rounded thin transparent membrane surrounded by a thick vein that forms a frame. On the left elytra there is also a membrane in the form of a mirror, but it is usually opaque, opaque and rather dense. The vein surrounding it is thick and equipped with small teeth on the underside of the elytra. This characteristic vein is called stridulatory, it acts as a bow, while the “mirror” serves as a resonator when chirping. Chirping is carried out in the following way. The left elytra in a calm state always lies above the right. During chirping, the grasshopper slightly raises and spreads the elytra, and then causes them to vibrate from side to side, as a result of which the cloves of the bow rub against the frame of the “mirror” located on the right elytra. Thanks to the “mirror”, the sound is greatly enhanced and therefore heard from afar. For each species of grasshoppers, the sounds they make are specific. In the vast majority of cases, only males have a sound apparatus, however, there are species of grasshoppers in which females chirp.
The hearing aid is located on the shins of the front legs, it is easy to detect from the outside thanks to two oval membranes located on both sides of the shin and acting as eardrums. In some cases, these membranes are open, although they are located in a small depression, in most species they are covered with chitinous tires, so that only two longitudinal cracks leading to the membranes are visible from the outside. The inner part of the hearing aid has a complex structure consisting of the endings of nerves, sensitive cells, muscles and two branches of the trachea, each of which approaches its eardrum. Due to the air pressure in the trachea, the membranes are always stretched.
Fig. 149. The left front wing and the upper part of the tibia of the front leg of the green grasshopper: 1 - sound apparatus, 2 - cracks leading to the auditory organ
In the summertime, the chirping of grasshoppers is heard everywhere: in meadows, forest edges, forest glades and in gardens. It does not stop even in the evening and at night. However, finding grasshoppers themselves is far from an easy task: they are too well disguised in the greenery of the bushes or in the thickness of the thick grass. This masking is caused by a combination of body shape and its protective coloration. Species living in the grass often have an elongated body and long narrow elytra. The grasshopper Elimaea poaefolia, widespread in the Malay archipelago, has such an elongated body that it resembles the stem of the plant on which it sits. Among tropical grasshoppers, a large number of species are similar to tree leaves.This similarity is achieved due to the strong expansion of the elytra, as well as their specific venation. Depending on the color, they mimic either healthy, or dying and dead leaves. So, for example, on leaf-like wings of Cycloptera elegans there are brown spots resembling leaf damage by parasitic fungi. The elytra shape and color are even more peculiar in Tanusia spp.: The spotting on them imitates the onset of leaf decomposition, and uneven edges give the impression that the leaf is merged or broken off. The leaf-like wings of acridoxenes (Acridoxena hewaniana). Some Indo-Malay grasshoppers living on trees very successfully mimic lichens. For example, javanese satrophilia (Satrophyllia femorata), sitting motionless with the antennae and front legs extended forward, on a tree branch, completely merges with the general background of lichens covering this branch.
Fig. 150. Patronizing similarities with parts of plants in grasshoppers: 1 - Cycloptera elegans, 2 - Tanusia corrupta, 3 - Acridoxena hewaniana, 4 - Satrophyllia femorata (imitation of lichen)
Although grasshoppers, like all orthoptera, have hind legs, that is, with thickened hips, they usually move along branches or in the grass, crawling quickly with all six legs. If the grasshopper is disturbed, it rests against the ends of the legs of the hind legs, and then quickly straightens the legs and makes a leap forward. In this case, winged forms can spread their wings, which in this case serve as a parachute and can significantly increase the jump.
The grasshopper fertilization method is very peculiar: when mating, the male suspends a spermatophore at the end of the abdomen of the female. The spermatophore has a rather complex structure: it consists of the main part - bottle and additional - spermatophilax . The bottle has a narrow neck and two reinforcing blades, it is covered with a shell on top, and its internal cavity, which contains sperm, is divided by a septum into two independent parts. Spermatophilax is a bulky, sticky mass. When mating, the male inserts the neck of the bottle into the female’s genital opening, the bottle and spermatophilax remain outside. After mating, the female begins to eat spermatophilax, due to the viscous consistency of this formation, the eating process is slow and can last several hours. During this time, sperm gradually flows from the vial into the oviduct, after which the female eats the vial. This whole original process is of great biological importance. A spermatophore suspended from the abdomen of a female, equipped with a spermatophilax that makes it heavier, impedes its movement and interferes with egg laying and re-mating. Therefore, its removal is absolutely necessary. At the same time, this process should proceed slowly, otherwise the sperm will not have time to transfer from the vial to the oviduct.
Fig. 151. The end of the abdomen of a fertilized female grasshopper Isophya acuminata: 1 - a bottle of spermatophore, 2 - spermatophilax
The nature of the egg laying largely depends on the lifestyle of a particular type of grasshopper. Most carnivorous species that feed on other insects, or species in which food is mixed - animal and vegetable, lay their eggs in the ground, immersing their ovipositor in it. In some cases, the eggs are laid one at a time, in others - in small heaps (5-10 pieces each), fastened with solidifying secretions of the accessory genital glands.
In herbivorous species that are more closely associated in their lives with plants, eggs most often are laid either on the surface of the plant or inside some of its organ. So, for example, a female four-point plate wing (Phaneroptera quadripunctata) lays eggs in the leaf parenchyma (Pl. 29, 1). Getting to the laying, she sits astride the sheet edge, squeezing it from the sides with front and middle legs. Then the female gnaws at the edge of the leaf slightly, bends the abdomen strongly and, holding the base of the ovipositor with the jaws, introduces its wings into the parenchyma at the place where the incision was made.The ovipositor sinks almost completely, and an egg is laid at the bottom of the pocket formed in the tissue.
Common leaftail (Leptophyes albovittata, Tables 29, 2) lays eggs in the cracks of old wood pillars and fences, and another species of this genus (L. punctatissima) lays in cracks in the bark of trees and shrubs. Prickly Wing (Tylopsis lilifolia, Tables 29, 4) places the egg on the stem of the cereals, immersing it behind the leaf sheath. Inhabiting heavily moistened, waterlogged meadows winged swordsman (Conocephalus dorsalis) for laying eggs chooses stems of reed or chytin with a well-developed core, into which he introduces his ovipositor (Tables 29, 3). In our species, grasshopper oviposition usually occurs in the second half of summer, the eggs are elongated, cylindrical or flattened form. The laid eggs overwinter, the larvae hatch in the spring and molt 4-6 times during life. The wing buds appear in the larvae after the first molt in the form of the posterior lower corners of the mesotum and the metanotum drawn down and back; after the third molt, the wing primordia are located on the back, take a triangular shape and longitudinal veins appear on them. After the last molt, fledging occurs.
As a rule, grasshopper larvae and nymphs are similar to adult representatives of this species, differing from them in size and in the absence of normally developed wings. However, there are cases when larvae are very different in appearance from adults. These differences may lie in the structure of the pronotum, the presence of styloid outgrowths on the body, in color and a number of other signs. The most dramatic differences are observed at transformative mimicry. This is the name of the phenomenon in which the larva is characterized by mimicry, which is absent in the imago. In this regard, some African and Indo-Malay leaf-like grasshoppers are particularly interesting, the larvae of which, with their appearance and habits, imitate either ants or racehorse beetles. At Sudanese grasshopper (Eurycorypha fallax) larvae live openly on the leaves and flowers of shrubs, meeting together with the species of ants that they simulate. This imitation is achieved by the nature of the distribution of dark and green pigments on the body. Although the dense and thick body of the larva does not look like the body of an ant, it shows a dark pattern on the light green background of the abdomen, reproducing the narrow "waist" and swollen abdomen typical of ants. At Malay Grasshopper (Leptoderes ornatipennis) younger larvae with their metallic blue coloration and red hips are similar to a racehorse (Collyris tuberculata). Both species are found together, and the nature of their jumps is also very similar.
Fig. 152. Imitation of an ant in the larva of the grasshopper Eurycorypha fallax
Grasshoppers are a group of ancient origin. Their ancestors, apparently, were the so-called primary orthoptera (Protorthoptera) that existed in the Carboniferous period. They had many similarities with grasshoppers, differing from them in a flattened body and hind limbs of a non-jumping type. In the Permian period, typical representatives of grasshoppers appear. In the Tertiary period, some modern genera are formed, such as green grasshoppers (Tettigonia), gray grasshoppers (Decticus) and horse racing (Platycleis).
Fig. 153. Grasshopper Pinegia longipes from the lower sediments of the Permian period (Urals)
Currently, about 70% of grasshoppers are distributed in tropical and subtropical countries. More than 170 species belonging to 3 families inhabit the territory of the Soviet Union.
TO the familyrafidoforide (Rhaphidophoridae) include completely wingless grasshoppers with thin and long antennae and long legs. On the shins of the hind legs sit very elongated spurs, there are no hearing organs. The vast majority of rafidoforids lives in the tropics. A typical native of tropical countries is greenhouse grasshopper (Tachycines asynamorus) - small size (13-18 mm), brownish-gray with dark spots and a silky coating of tiny dense hairs, with very long thin antennae and long legs. The birthplace of this interesting insect is Central China. From here it was brought with plants to the cities of Europe and North America, where it is now found in greenhouses. It leads mainly a night life, hiding in shelters for a day. Can do big jumps - up to 40 cm in height and 1.5 m in length. It feeds on mixed foods - both parts of plants and small insects located on them. It harms ornamental plants: cyclamens, ferns, etc. The female lays from 150 to 900 eggs in the life, from which the larvae hatch after 3-4 months. The development of the latter proceeds within 7 months and, moreover, with an unusually large number of links for grasshoppers - up to 11.
Fig. 154. Rafidoforids: 1 - greenhouse grasshopper (Tachycines asynamorus), 2 - Caucasian cave (Dolichopoda euxina)
On the Black Sea coast of the Caucasus and Western Transcaucasia inhabits caves Caucasian cave (Dolichopoda euxina) - brownish-yellow in color, with the longest antennae, four times the length of the body. This is a representative of the very ancient primary tropical fauna of the Caucasus. It was the cave way of life that allowed this grasshopper to survive to this day, despite the strong changes in the natural environment that took place in the Caucasus.
Familybradyporide (Bradyporidae) - inhabitants of the dry regions of Eurasia and North Africa. The most characteristic feature that makes it possible to distinguish these grasshoppers is the location of the antennae on a spherical convex: head, they attach below the eyes or at the level of their lower edge. The elytra are always greatly shortened and are often hidden under the pronotum. There is always a hearing organ on the shins of the front legs.
Of our representatives, the family is very original in its appearance and biological characteristics. saddle bearer, or grape efippiger (Ephippiger ephippiger, tab. 29, 10). It is relatively small in size (20-30 mm) grasshopper, yellowish or bluish-green color with a blue-black nape. The saddle bearer got its name because of the characteristic structure of the pronotum: it is sharp in the shape of a saddle with a strongly raised back. Rusty-red elytra shortened, almost completely covered by pronotum, no wings. But what is especially interesting is the presence of a sound apparatus in both sexes. Females, as well as: males, are able to chatter. The saddle-shaped pronotum during chirping acts as a horn, amplifying the sound.
More recently, in the feather-grass fescue steppes of the Ciscaucasia, Ukraine and the central regions of Russia, it was often found steppe fat (Bradyporus multituberculatus) - large wingless grasshopper, 6-7 long cm, with a heavy body painted in bronze-black, with two longitudinal yellow stripes on the abdomen (tab. 29, 12). Plowing steppes significantly reduced the range of this species. Now it is a relic of the steppe fauna, preserved only in the Salsk steppes and in some parts of the Ciscaucasia, where virgin steppe areas have survived.
TO the familyreal grasshoppers (Tettigoniidae) refers the vast majority of the species of our grasshoppers. They differ from rafidoforids by the presence of an organ of hearing on the legs of the front legs, and from bradyporids by the fact that their antennae attach above the level of the lower edge of the eyes.
We are widely known green grasshoppers (Tettigonia) - rather large, almost monotonous with long antennae and long, narrow, rather soft elytra, under which well-developed transparent wings, females with a long xiphoid ovipositor, pointed at the apex and slightly bent down are hidden at rest (Table 29, 6-8). More than 10 species of the genus Tettigonia live in the Palearctic, of which 4 are found in the USSR. The most widely distributed among us green grasshopper (T. viridissima): it can be found in all landscape zones, it does not go only to the north.In the forest zone, from the end of July until late autumn, a green grasshopper is often found on the edges of meadows in the grass, and on the edges of forests and gardens - on bushes and trees, artfully masking itself in green foliage. In deserts, it gravitates to river valleys and to the edges of tugai forests; in Central Asia, it penetrates high into the mountains, adhering to gorges with lush grassy vegetation. It feeds on small insects - various dipterous, small butterflies, their caterpillars, etc. When kept in captivity, it exhibits a tendency to cannibalism, eating weaker individuals and larvae of its species. At the same time, a green grasshopper can eat plant foods. So, for example, it sometimes harms vineyards by gnawing buds, eating flowers and leaves. Cases of damage to the leaves of tea, citrus and other plants are known.
The chirping of a green grasshopper can be heard during the day, in the afternoon and in the evening; it does not cease even in the dark until 2–3 a.m. In the morning, the green grasshopper takes a “sun bath”. He lies on his side, substituting his body for the sunlight falling on him and from time to time turning over to the other side. Mating in a green grasshopper lasts about 45 minutes. After 15 minutes, the male begins to chatter again. Eating by a female spermatophore can last 15 hours. She lays eggs one at a time, laying them so tightly that they are glued together with each other 2, 3 or 4. The process of laying eggs is apparently quite difficult, as can be judged by the fact that the female breathes, and the number of eggs laid by it reaches 70-100. The eggs lie in the soil until spring, when larvae hatch from them. They are also green in color with a brown or blackish stripe on the dorsal side.
Two other species of this genus found in the European part are similar to a green grasshopper both in appearance and in lifestyle. songwriter grasshopper (Tettigonia cantans) and tailed grasshopper (T. caudata). A singing grasshopper lives in a forest zone. It differs by shorter and wide elytra, not extending beyond the top of the hips of the hind legs. A tailed grasshopper is found in the south of the European part of the USSR, reaching Western Siberia. It has the same long wings as the green, extending beyond the top of the hips of the hind legs, but the ovipositor always protrudes beyond the top of the elytra. The fourth species of the genus Tettigonia found in the USSR is Ussuri green grasshopper (T. ussuriana) is distributed in the Ussuri Territory, inhabiting the region of mixed and broad-leaved forests of the Far East.
It is as widespread as the green grasshopper, and our gray grasshopper (Decticus verrucivorus, pl. 29, 9). This is also a large species, painted in a light or dark green color with a large number of brown spots, often quite brown with even darker spots. The gray grasshopper does not tolerate shading and therefore usually settles in brightly sunlit dry meadows, forest glades and other open places. If disturbed, he takes off low and then hides in the grass again. The gray grasshopper is also omnivorous and in captivity prone to cannibalism. Near Moscow, chirping begins in the second half of June. The male proceeds to him a week after winging. The female begins to lay eggs a week after mating. The number of eggs laid on the ground is on average about 50.
Very peculiar steppe (Saga pedo, pl. 29, 11). This is one of our largest grasshoppers, 6-8 long cm, almost or completely wingless, with an elongated, slender body of green or yellowish color, with two bright stripes extending along the lower edge of the pronotum and on the sides of all abdominal segments. Dyba is a typical representative of the steppe fauna. In the USSR, it is found in the steppes of the European part and Northern Kazakhstan and in the adjacent parts of Western Siberia. In its habits, the steppe hawk resembles a praying mantis rather than a grasshopper. For hours, she can sit motionless, with outstretched legs, in the grass or on a bush, waiting for her victims, whom she catches with her front legs.Its victims are rather large insects - locusts, crickets, bugs and bugs. Another biological feature of this insect is curious: males are extremely rare, and therefore reproduction occurs, obviously, by the parthenogenetic pathway.
Cricket, unlike grasshoppers, have 3-segmented tarsi, long flexible cerci and a thin straight ovipositor (in females), which is usually spear-shaped at the end. Only the bear (family Gryllotalpidae) has no ovipositor.
The elytra of the crickets at rest lie flat on the dorsal surface of the body, with the left always covered by the right. This is associated with the features of the sound apparatus, which although similar in structure to the sound apparatus of grasshoppers, differs from the latter in greater complexity and a different arrangement of components: the stridulation vein, which performs the function of a bow, is located on the right elytra, and the vein about which it rubs, reproducing the sound is on the left. In general, this entire apparatus is more developed and occupies a much larger area on the elytra than grasshoppers. It exists only in males, and in each species it is different in structure and reproduced sounds. There are 6 types of cricket chirping: invocative, mating, chirping after mating, aggressive chirping at the meeting of males, chirping associated with the sudden disappearance of the female, and in some species - “identification” signal. However, the "repertoire" of the form usually consists of fewer songs. The most ancient type of song is probably marital singing.
In some species of crickets, both elytra and wings can be underdeveloped or even completely absent. There are frequent cases when the degree of development of the aircraft is not the same for different individuals of the same species and gender. In those cases when the hind wings are developed normally, they fold fan-shaped and at rest in the form of bundles protrude from under the elytra.
The crickets' hearing aids are of the same type as grasshoppers, and are also located on the legs of the front legs.
In the USSR there are about 45 species of crickets, most of which are the familycrickets (Gryllidae). A representative of this family can serve widely distributed in central and southern parts of Europe, Central Asia and North Africa. field cricket (Gryllus campestris). This is one of our largest species, with a length of 2-2.6 cm. It is black with brown elytra, at the base of which there is one orange spot, the hips of the hind legs below are bright red. In the south, his chirping can be heard already in early summer. The singing male sits at the entrance to his hole, if disturbed, he immediately hides in it. Mink is an oblique stroke, not wider than a finger and about a finger long. The entrance to the hole is closed by a bunch of grass. If another male approaches the mink, then a fight begins between them. Both rush at each other, hit with their thick heads, and each tries to bite his opponent. The defeated opponent is eaten by the winner, although usually the field cricket eats plant foods.
Fig. 155. Field Cricket (Gryllus campestris)
The chirping of a male attracts a female. During mating, the male suspends a spermatophore from the female abdomen, which is very similar to the spermatophore of grasshoppers, but differs in the absence of spermatophilax. A few days after mating, the female begins to lay eggs, for which she immerses the ovipositor in the ground, holding it completely sheer. One female can lay up to 500-600 eggs. About a month later, young crickets hatch from them, very similar to adults and differ mainly in small size and lack of wings. After the second molt, they begin to dig small holes, before the start of winter, another or one molt occurs. The last molt, after which an adult cricket is formed, occurs in the spring, approximately in May.
In homes may occur house cricket (Gryllus domesticus). It is smaller, 1.6-2 long cmstraw-yellow with brown stripes.During the day he hides in crevices and creeps out of these shelters for the most part only at night in search of food consisting of various garbage of plant origin. Males chirp in the evening and at night. The development of house cricket takes place throughout the year. Apparently, he does not have a clear confinement of the egg-laying period to any particular season, since at any time of the year you can find different stages of its development. Outside of human settlements, in the wild, house cricket is found only in deserts.
Very peculiar stem crickets (family Oecanthidae) with a yellowish or greenish tender body, flat, wide elytra, almost entirely occupied by the organ of chirping, and thin long legs. These are southern forms associated with landscapes of steppes and deserts. Stem crickets spend most of their time on plants that they feed on. During the day they hide under the leaves, the loud chirping of their males is heard in the evening and at night. Females lay eggs in the stems of plants, here the eggs remain lying throughout the winter, and only in spring young crickets hatch from them. The laying of eggs in the stems spoils the young shoots, which then quickly dry out. When meeting in cultivated fields, stem crickets can be harmful to agricultural plants. So, in the southern part of the Ussuri region Far Eastern stem cricket (Oecanthus longicaudus) harms soybeans and sugar beets, common stem cricket (O. pellucens) damages vineyards and tobacco plantations in the steppe regions, and Turanian stem cricket (O. turanicus) during the years of mass breeding harms cotton, sesame seeds and other crops in Transcaucasia and Central Asia.
Completely devoid of wings and sound apparatus very small, only 2-5 long mmwith ovoid or rounded body and large cerci ants crickets (family Myrmecophilidae), living under the stones in the nests of ants. In the USSR, they are represented by 5 species. The most well-studied lifestyle in common ant (Myrmecophilus acervorus). This cricket can be found in the underground anthills of various ants. Here he feeds not only on the remnants of stocks made by the owners, but can destroy their eggs and larvae. It is characteristic that females are able to breed parthenogenetically. Eggs are laid in the ground and flow from spring to autumn. During the season, one female can lay up to 49 eggs.
Fig. 156. Crickets: 1 - brownie (Gryllus domesticus), 2 - common stem (Oecanthus pellucens), 3 - common ant-species (Myrmecophilus acervorus)
Underground lead the little bears (family Gryllotalpidae), which differ sharply from all other crickets with a very large pronotum, comparatively short antennae, only slightly extending beyond the pronotum, and strongly modified forelegs, perfectly adapted for digging and moving in the ground. By the perfection of the adaptation, the front limb of the bear is not inferior to the front leg of the mole, hence the Latin name of this animal comes from: Gryllotalpa - "cricket-mole". In the digging limb of the bear, the thigh and lower leg are greatly expanded, while the tarsus is shortened and attached to the side of the lower leg, on which there are 4 black teeth. Of the 3 species found in the USSR, the bear is widespread in the Palearctic common bear (Gryllotalpa glyllotalpa).
Her large body, length 3.5-5 cm, dark brown above, and brown yellow below, it seems silky due to a dense cover of small golden hairs, wings are developed normally and in a calm state protrude from under short elytra in the form of bundles bent downwards.
Under natural conditions, the bear usually settles in the floodplains of the rivers, where the soil is always quite moist. However, it can often be found in gardens and orchards, and here it does great harm, damaging the root system of many cultivated plants, including corn, potatoes, cucumbers, and in Central Asia - cotton and rice.
During the day, the bears remain underground, and in the evening, after dark, they come to the surface of the earth, and sometimes they fly into the light.Males chirp in the dark, although they can make sounds even during the day, being underground, but these sounds are much shorter and weaker compared to long and sharp night draft trills. It is characteristic that females can also chirp.
The bear’s food is mixed; when kept in captivity, they readily eat both the underground organs of plants and animals, such as earthworms, larvae of ladybirds and dragonflies.
During the breeding season, the cubs arrange a complex system of moves located near the root system of wild and cultivated plants. On the bald patches formed as a result of this activity at a depth of 5-10 cm from the surface of the bear in the middle of summer, it arranges large uterine chambers, having the form of a spherical nest, with a diameter of 5-10 cm. In mid-summer, up to 600 eggs or young bear hatching from them can be found in such a nest. In the European part of the USSR, the bear is distributed almost throughout the territory, reaching in the north to the Leningrad region. Therefore, the duration of postembryonic development in her is not the same in different areas. In the south, it apparently develops during the year, while in the north, development is delayed to 2-2 1 /2 years. During this time, up to 8-9 links can occur. Younger larvae are very nimble and jump well. In the summer, the bears dig their passages shallow underground, but for the winter, both larvae and adults dig long passages located at an angle of 45-60 ° to the surface and go to great depths - up to 25 (larvae) and even up to 60 cm (adults). Another biological feature of the bear is interesting: since floodplain meadows, where it usually lives, are flooded with water in spring, the insect is well adapted to swimming, and can freely swim over water-flooded spaces.
Fig. 157. European Bear (Gryllotalpa gryllotalpa) (1) and Common Quail (Tridactylus variegatus) (2)
Suborder Short-winged Orthoptera (Brachycera, or Caelifera)
In contrast to the long-winged orthoptera, the representatives of this suborder have relatively short antennas that never reach the length of the body. The suborder distinguishes between two superfamily - quail and locusts.
Triperst called small insects, 4-9 long mmreminiscent of the appearance of little bears. This similarity is expressed in the same body configuration and in the structure of the front legs, which, like the bear, are adapted for digging. However, it is enough to look at these insects a little more closely to make sure that the thirsts belong to another systematic group, namely, the short-banded orthoptera. This is evidenced by the structure of the head, which has a distinct mustache, consisting of only 10 segments.
The elytra of the quail is short, horny, the wings can be either longer or shorter than the elytra, with an opaque front edge and numerous radially diverging veins. The structure of the hind legs is very peculiar: they are hopping, with wide flattened hips and thin, slightly curved legs. On both sides of the tibia there are spines having the appearance of lobes, and two short and two long spurs sit on its apex. The paw of the hind leg consists of only one more or less elongated finger-shaped segment located between the long spurs of the tibia, which gave reason to call these insects "quail". Abdomen 9-10-segmented, bearing on top two pairs of elongated appendages, of which the upper, 2-segmented, is a cerci. The thirds have neither a sound nor a hearing aid; the females of our species also lack an ovipositor.
In the USSR, there are only 4 species belonging to the same genus (Tridactylus), distributed mainly in the subtropics. Our species are known from the Caucasus, from Central Asia and Kazakhstan, as well as from the steppe regions of the European part of the USSR and Western Siberia. They usually live on the sandy banks of rivers and other bodies of water. In saline deserts are found near depressions, where water is stored for a long time.
An example is common thirst (Tridactylus variegatus), widespread in the steppes and deserts of Eurasia. It can be found on sandbanks, where, using the front legs and jaws, he digs minks in the moist sand. Under such conditions, quail can sometimes be found in bulk. They quickly jump from one place to another on the sunlit surface of sand or in a sparse grass cover. Trippers are predators that feed on small insects and earthworms.
Locust make up the largest group among orthoptera. They are easily distinguished from grasshoppers and crickets by short antennae, not exceeding the length of half the body, short female ovipositor, and very specific organs of sound and hearing. In contrast to the locust tarsi, the locust tarsi of the hind legs are 3-segmented, the number of antennae segments can reach 28, the cerci are not segmented in the form of conical protrusions, and the female always has an ovipositor.
Like grasshoppers and crickets, locusts are recognized musicians in the insect world. To verify this, it’s enough to go out to any meadow or forest edge in the summer, in the daytime their chirping clearly clogs the “singing” of grasshoppers due to the fact that at the same time a large number of copies can chatter.
The locust sound system is located on the hips of the hind legs and elytra. Usually, a long row of tubercles or capitate cones stretches along the inner surface of the thigh, and one of the elytra veins is thicker than the others. Quickly moving the thigh, the insect conducts these tubercles along the vein, as a result of which abrupt jerking sounds are heard. These sounds can be reproduced even on a dead insect, if you quickly move his hips, pressing them to the elytra. The distance between the tubercles can be unequal: in some species, the tubercles at the base of the thigh are more often than in its upper part. This achieves a different pitch of the sound produced. In some cases, as is the case with cracking fire (Psophus stridulus), on the thigh there is a smooth edging, and tubercles are located on the anterior vein of the wing. This species and some others may make sounds of a different nature on the fly. When flying, they crack loudly, reproducing a sound resembling the crackle of a wooden rattle. The mechanism of this sound is not entirely clear, but, obviously, it is associated with the features of venation of the wings: usually at the “rattles” several longitudinal veins of the wings are strongly flattened.
It is known that the same locust may have several different “songs”. At winged skate (Chorthippus longicornis) an ordinary "song" consists of 4-14 identical syllables, separated by pauses, and sounds something like this: tsre-tsre-tsre-tsre-tsre. The rhythm of the song may vary slightly depending on the warming of the air: the higher the temperature, the greater the frequency of the rhythm. However, in addition to the main song, the short-winged skate has three more sound options that differ in rhythm frequency, number and sound of syllables. You can distinguish between a "song of the opponent", "recruiting" and "copulation" songs. The first of them occurs when the male hears the song of another male - "rival", the second - when meeting a female, and the third - when mating.
Tympanic organs are placed near the locusts on the sides of the first abdominal segment, behind the spiracle located on it. They are rounded or slit-like holes, tightened by a transparent eardrum. The eardrum is framed by a chitinous thickening, slightly overlapping it in front and behind. From the inside, a large air sac of the tracheal system is attached to the membrane, which supports it in a taut state. Apparently, two special muscles are also involved in the tension of the membrane.
Fig. 158. Tympanic organ of the locust: 1 - membrane, 2 - nerve
In locusts, the shape of the body and the color of its integument is in very close agreement with the behavior of the insect and reflects the characteristics of the environment in which this or that species was currently forming and inhabiting. This combination of morphological, biological and physiological properties of the species, which is in accordance with the environment, is called life form (tab.thirty). The life forms of the locusts can be combined into two classes: the inhabitants of plants, or phytophiles, and the inhabitants of open areas on the surface of the soil, or geophiles.
Table 30. Locust life forms: 1-3 true hortobionts: 1 - steppe ridge (Euchorthippus pulvinatus), 2 - acrida (Acrida bicolor), 3 - tropidopol (Tropidopola longicornis), 4 - herbivorous hortobiont of Konofim Dirsch (Conophyma dirschi), 5 6 - tamnobionts: 5 - Egyptian filly (Anacridium aegyptium), 6 - large saxaul humpback (Dericorys albidula), 7, 8 - open geophiles: 7 - blue-winged filly (Oedipoda coerulescens), 8 - hermit (Sphasciatusus oct petrobiont saksetaniya (Saxetania cultricollis), 10, 11 psammobionts: 10 - common gerbil (Hyalorrhipis clausi), 11 - slender thin-spur (Leptopternis gracilis), 12, 13 - herpetobionts: 12 - Paratettix bolivar i, 13 - Tetrix depressa
Among phytophiles, hortobionts and tamnobionts are distinguished. Real hortobionts (Tables 30, 1-3) live in the thickness of the grass cover and feed mainly on cereals. They have a slender elongated body, often with a beveled forehead, the ratio between the width and height of the body in its widest part (w / h index) is always below unity. In some cases, the body can be so elongated and devoid of wings that it takes on a rod-shaped shape, as is the case with the South American rod-shaped filly (Cephalocoema lineata). The integument of the body of hortobionts is smooth, devoid of a rough sculpture and painted the color of green or dry grass, often with longitudinal stripes along the body. The wings are usually colorless, less often painted in pale pinkish or greenish tones. Hortobionts are widespread in meadows, in the steppes and savannahs, i.e., where grassy plants predominate. A typical representative of hortobionts can serve steppe horse (Euchorthippus pulvinatus), widespread in the feather grass steppes of Europe and Asia. Among hortobionts, many species are pests of agriculture.
Fig. 159. Rod-shaped filly (Cephalocoema lineata)
Some hortobionts prefer not to eat cereals, but broad-leaved herbaceous plants, they are called herbivores hortobionts. This includes species of wingless fillies. konofim (Conophyma, tab. 30, 4), widespread in the mountains of Central Asia, and a number of other forms. Herbivorous hortobionts have a stockier body and a head with a sheer forehead. It is characteristic that their upper jaw is adapted for grinding and chewing soft leaves.
In some cases, there are species that, although they live in the thickness of the grass, do not avoid open spaces on the surface of the soil, as some do krestavichki (Dociostaurus). Such locusts are called optional hortobionts. In their behavior and body shape, they are transitional to geophiles.
Unlike hortobionts associated with grassy vegetation, tamnobionts (Tables 30, 5, 6) live on shrubs and trees. Adaptations to this lifestyle are primarily expressed in the specific structure of the extremities: they have asymmetry in the arms of the legs of the hind legs, on the inside of which the spikes are longer than the spikes of the outer row, claws located on the legs of the claws, between which there is a strongly developed sucker, can be asymmetric. Some tamnobionts are closely related to certain plant species. For instance, large saxaul humpback (Dericorys albidula), like some other species of this genus, is associated with saxaul. In the sandy deserts of Central Asia during the years of mass reproduction of this insect, it can severely damage saxaul.
Table 30. Locust life forms: 1 - 3 true hortobionts: 1 - steppe horse (Euchorthippus pulvinatus), 2 - acrida (Acrida bicolor), 3 - tropidopol (Tropidopola longicornis), 4 - herbivorous hortobiont of Konofim Dirsch (Conophyma dirschi) 6 - tamnobionts: 5 - Egyptian filly (Anacridium aegyptium), 6 - large saxaul humpback (Dericorys albidula)
The second class of life forms is geophiles - includes locusts, usually living on the surface of the soil, climbing plants only during feeding. It distinguishes between open geophiles and hiding geophiles (herpetobionts) Open geophiles (tab.30, 7, 8), unlike hortobionts, have a more flattened body with a w / h index rising to unity and higher, they are always poorly developed, and sometimes there are no suckers between the claws. The integument of open geophiles is dense, wrinkled, often covered with tubercles. The color of their body and elytra is always protective and corresponds to the general background on which they are found. The hind wings are often brightly colored, with dark, eye-catching bandages. This combination of elytra and wing stains is closely related to the behavior of open geophiles. You can come very close to a sitting insect and not notice it, it is so well camouflaged. And suddenly, completely unexpectedly, it flies right under my feet, attracting attention to itself with the bright flags of its open wings. Having quickly flown some distance, the insect also suddenly lands on the ground and again disappears from the eyes. Some geophilic species are capable of making rattling sounds during flight, as various rattles (Bryodema, Angara cris), rattling fire, some hermitages (Sphingonotus), etc. make flying. Brightly colored geophilic locusts attract attention with their movement, coloring and sound, but, as soon as they sit down, they disappear from the stalker's eyes, clearly disorienting him.
The high cryptic nature of the color of the outer covers is easily explained by the phenomenon homochromia, expressed in the fact that with the development of larvae of the same species on different backgrounds, their color will vary greatly and ultimately in each case to some extent correspond to the background. This is proved by special experiments conducted with various locusts, including with blue-winged filly (Oedipoda coerulescens). The specimens of this species brought up under experimental conditions imitated the color of the soil on which they grew, acquiring a black, reddish, or gray shade, respectively.
Open geophiles are mainly inhabitants of deserts and semi-deserts, representatives of this group, found in the steppes or in the forest zone, prefer open, well-heated places with sparse vegetation on rock outcrops, salt marshes, pebbles along river banks, etc.
Among open geophiles, they are especially distinguished petrobionts ipsammobionts. Petrobionts, or stone-lovers, live on rocky areas, most often on mountain slopes. They have more sharply than other geophiles, expressed density and sculptural cover. The body is very wide and shortened, valky, pronotum usually high, in some cases with a strongly elevated keel, as is the case, for example, in Saxony (Saxetania, tab. 30, 9), widespread in the northern mountains of Iran and Afghanistan, and here in Kopet-Dag and some other mountain systems of Central Asia. Petrobionts usually have a reduced aircraft, and movements are very slow. But cryptic coloring is very well expressed and always reflects the specifics of the background of rocky slopes.
Other adaptations of psammobionts (Tables 30, 10, 11) - inhabitants of sand massifs, especially vividly represented in sand deserts. They primarily include species gerbil (Hyalorrhipis) and fine spurs (Leptopternis). Their coloring well imitates the general tone and specific granularity of a sandy substrate. Their adaptations to their habitat are peculiar: at psammobionts the spurs on the shins of the hind legs are very elongated, which facilitates the repulsion of the hopping on the loose sand.
In contrast to open geophiles, herpetobionts (Tables 30, 12, 13) are forms that live on the surface of the soil occupied by sparse grass cover, leaf litter, or other plant debris. They can also be found on wet sand along the banks of water bodies. They are very demanding on increased hydration. Usually these are small forms with a fusiform body, narrowed from the posterior thorax back and forth, painted in protective, often grayish tones. Typical representatives of herpetobionts are species of a specific family jumpers, or tetrigide (Tetrigidae).
Table 30. Locust life forms: 7, 8 — open geophiles: 7 — blue-winged filly (Oedipoda coerulescens), 8 — desert hermit (Sphingonotus octofasciatus), 9 — saxetania petrobiont (Saxetania cultricollis), 10, 11-psammobionnae: 10 — common spp. (Hyalorrhipis clausi), 11 - slender thin-spur (Leptopternis gracilis), 12, 13 - herpetobionts: 12 - Paratettix bolivari, 13 - Tetrix depressa
All locusts common in the USSR have one generation in a year, most of them wintering in the egg phase. However, there are species that give 2-3 generations during the year. For locusts, as well as for other orthopterans, spermatophore fertilization is typical, spermatophores have the form of either vesicular reservoirs with a long hatching tubular part, or rounded cylinders. During mating, which lasts for several (up to 20) hours, the male introduces spermatophores with sperm into the female genital tract.
The overwhelming majority of species lays eggs in the surface layer of the soil, digging in it with the help of a short course of four ovipositor eggs. At the same time, the female deeply immerses the strongly stretched abdomen in the ground and releases a portion of eggs suspended in a special foamy liquid. These foamy discharge, hardening, often cement the particles of the earth surrounding the masonry, as a result of which the so-called egg capsule, which is a capsule, often with hard, earthy walls, inside which eggs are placed. In some cases, the capsules may be covered with a special lid. In general, the structure of egg capsules, the number of eggs contained in them, and the number of egg capsules laid by the female are different for different species. For example, in many species the grass (Stenobothrus) the walls of the egg capsule are encrusted with their own excrement. Only some hortobionts lay their eggs on plants or inside their organs. Short-winged Zelenchuk (Euthystira brachyptera), for example, places a small egg between leaves near the roots of a plant or in fallen leaves, unpaired zelenchuk (Chrysochraon dispar) lays eggs in the stems of raspberries and other plants.
Fig. 160. Egg-capsules: on the left is a migratory locust (Locusta migratoria), on the right is a thick-headed grassy species (Stenobothrus lineatus)
The development of the embryo begins immediately after the laying of the eggs, but then in most of our species it stops even before the onset of cold weather and resumes in the spring after overwintering, so there is embryonic diapause. Locust hatching begins in the spring after snow melts and the soil warms up sufficiently. The larva emerging from the egg has a worm-like shape. It has a special short-term functioning organ - a pulsating bubble, with the help of which it spreads soil particles and, making worm-like movements, comes to its surface, where it immediately molts and turns into a larva of the first age. Hatching larvae first have a milky-white body color, and then, after 2-3 hours, they darken. Now they are already similar to adult locusts, differing from them in smaller sizes, the absence of wings and a reduced number of antennae segments (no more than 13). Sometimes they have wing buds in the form of slightly drawn lower posterior posterior angles.
Larval development, depending on the type of locust and environmental conditions, lasts 30-40 days. During this time, the larvae molt 4-5 times, and with each molt the size of the body and wing primordia increase, and the number of antennae segments increases. In second-instar larvae, wing primordia are already clearly visible in the lower posterior corners of the mid- and metanotum, but there are still no veins on them, the number of antennal segments increases to 15-17, and sometimes to 18-19. In third-instar larvae, the wing primordia extend even more and the veins are clearly distinguished on them. The fourth-instar larvae are characterized by the arrangement of wing primordia on the back in the form of triangular lobes not exceeding the length of the pronotum, of which the inner pair (elytra rudiments) are shorter and narrower than the wings. The number of antennae segments continues to increase, reaching in some cases up to 22.In the larva of the last (fifth) age, both pairs of primordia reach the same length, which is either equal to the length of the pronotum or already exceeds it.
Fig. 161. Development of a migratory locust
Among locusts, many species are dangerous pests of agriculture, as a result of which people have long paid attention to them. Locusts were already depicted on murals and papyrus painted in ancient Egypt 3,000 years before our era, and descriptions of the disasters caused by it in Egypt, Libya and Palestine date back to 1490-904 BC.
The locust issue has not lost its relevance at the present time, since on all continents these insects cause enormous damage to agriculture annually. Suffice it to say that in the 23 western states of the United States, from 1925 to 1949, annual locust losses exceeded $ 31 million. The high harmfulness of these insects is due primarily to the fact that some locust species are capable of periodically producing outbreaks of mass reproduction.
In 1928, a special Locust Control Center was established in London, which has now become a scientific organization of international importance. Here, the laws of mass reproduction of the most important species of harmful locusts are studied and new methods for combating them are developed. Since 1961, by agreement with the Food and Agriculture Organization of the United Nations (FAO UN), a special desert locust information service has been organized at the Anti-Locust Center. Her responsibilities include the scientific processing of various information about this pest coming from all over the world.
It has long been customary to divide the harmful locusts into herd, otherwise called locusts, and non-horsemen, who are called filly. Herd species (migratory locusts, Moroccan locusts, desert locusts, or Schistocercia, red locusts, etc.) live hidden during mass breeding, grouping in swords (accumulations of larvae) or flocks (clusters of adults).
All locusts to one degree or another are characterized by various types of migration, expressed in the form of transitions or flights. Hortobionts regularly perform vertical migrations, moving up and down plants in the morning and evening, and often in the daytime. Geophiles do horizontal migrations all day long, flying from one place to another. Locusts also migrate from the areas where they feed to places convenient for laying eggs. However, migratory instincts are especially developed in herd species, in which active transitions and flights are carried out by swifts and flocks over long distances. Both larvae and adult locusts usually spend the night on the upper parts of plants, where they are at night in a state of cold numbness. After sunrise, as the air warms up, the larvae become active and concentrate on illuminated areas of the soil or sometimes on plants, forming the so-called "sun coils". These are dense clusters of motionlessly sitting larvae in which each individual is closely pressed against neighboring ones. Primary “sun coils” are formed by larvae hatching from one egg-pod. As soon as the body temperature of the individuals together rises above 40 ° C, the waders disperse and foot migration begins, which stops in the evening when the larvae again fall into a state of rest. In the hot time of the day, if the body temperature of the insect rises above 50 ° C, a daytime period of thermal depression sets in, in which a state of relative rest is also observed.
In the years of mass reproduction, swarms are formed so large that the area they occupy can reach hundreds and thousands of hectares. During the period of larval development, swools are always in a state of migratory activity, moving from hatching places to areas with more favorable conditions of temperature, humidity and nutrition. As a result, herd locusts can travel very long distances during larval life - up to 30 Km and more, as is the case, for example, in the Asian locust.It is characteristic that the swarm movement has a certain direction and is usually carried out in the direction opposite to the direction of the wind. Optimum conditions for movement are created with a slight wind (3-5 m / s) with gusty or strong winds exceeding 10 m / s, swarm movement stops.
After locust inspiration, its movements take the form of migration flights, when flocks fly over a distance of several tens of kilometers per day. It is characteristic that the direction of movement of the flock is in very close connection with the direction of the wind. So, in light wind (up to 1 m / s) flocks of Asian locusts usually fly in the wind, with an increase in wind strength to 5 m / s Locusts take off with great difficulty, and the flight itself is carried out at an acute angle to the direction of the wind. Flights can be carried out not only during the day, but in some cases at night, however, the flight speed decreases dramatically: during the day, Asian locusts fly 30-40 Km, and at night no more than 15 Km, Over the entire period of movement, a flock can fly away from its nest for 200-300 or more kilometers. Desert locusts fly even further: in 1954, small flocks of this species from North West Africa reached the British Isles, flying more than 2,400 Km over the open sea. Significantly lower migratory capacity of the Italian Prus and the Moroccan locusts, which fly off from hatching areas for shorter distances, measured in tens of kilometers.
As it was established by B.P. Uvarov, in the herd locusts, a very peculiar phenomenon of the so-called phase variability is observed, the essence of which is the change in the appearance and physiological functions of the insect depending on the degree of crowding and other conditions in the development process. With high crowding, developing individuals of this species arise herd phase, and with development in a sparse population - solitary. These phases are primarily well distinguished by external signs. So, in individuals of the migratory locust of the herd phase, the median keel of the pronotum in the profile is straight or even slightly concave, while in a single phase of the same species it is arched. The larvae of the herd phase have a motley body color, in which black and orange colors are combined; in larvae of a single phase, the body color is in harmony with the surrounding background and is more often monochromatic green (Tables 31, 2, 3).
It is believed that the more common is the state of a single phase, in which individuals live dispersed in the area, and the population density in this case is very low. The transition to the herd phase is due to a sharp increase in the population, leading to the coexistence of larvae in the form of large swarms. Such concentrations in a single phase are observed primarily in the event of a change in the conditions of existence, for example, with a lack of moisture, leading to drying out of the vegetation. At the same time, migration to places with more favorable conditions occurs, where green vegetation is still preserved.
Such forced concentration leads to a very close contact of individuals forming a swarm. This contact is not only through the organs of vision and smell, but also, most importantly, through the organs of touch. Larvae exchange touches of antennas and jerks of their hind legs, which ultimately leads to the emergence of a special conditioned reflex - the herd reflex. Herd habits increase with age, and the larvae tend to maintain them, even when isolated from the swarm.
Herd lifestyle increases the excitability of the nervous system and changes the direction of metabolism in the body. With a large accumulation of locusts, females are excited by other individuals not only mechanically, due to direct contact, but also by a chemically special hormone - pheromone, secreted by skin cells over the entire surface of the male’s body. The same pheromone in the desert locust determines the characteristic yellow color of mature males. Interestingly, a similar color can be obtained artificially by increasing the CO content in air.2 up to 3-4% (by volume).
Characteristic changes also occur in the activity of the endocrine glands, including the so-called adjacent bodies - special paired glands located in the head behind the brain and topographically associated with the aorta. Experiments with migratory locusts showed that if larvae of the fourth or fifth age with clearly expressed signs of the herd phase transplant adjacent bodies of a single locust, then after molting a green color characteristic of a single phase appears. However, at the same time, increased respiration intensity and mobility, typical of the larvae and imago of the stag phase, remain. It should be noted that the accumulation of dark pigments in the outer integument of individuals leading a herd lifestyle leads to the absorption of solar energy and an increase in body temperature.
The crowding of individuals in swarms and flocks also affects the fecundity of the locusts, lowering it. In laboratory conditions, the offspring of migratory locusts raised in isolation, the fertility of females reaches 1000-1200 eggs, while in the offspring of the herd phase it is only 300 eggs. At the same time, the offspring of the herd phase of the migratory locust, schistocercia and red locust are distinguished by larger sizes and greater ability to survive starvation. This is of great adaptive importance, since in areas of overpopulation, larvae fall into more difficult living conditions.
Thus, the herd of locusts should be considered as a complex of useful devices that ensure the existence of the species in the peculiar conditions of an arid climate, where insects that do not have these devices cannot save large offspring.
Locust species, having a wide range covering various landscape zones, populate different habitats (stations) in different parts of their distribution area. The following regularity was revealed: in the northern part of its range, such species inhabit drier (xerophytic) stations; as they move south, they sequentially move to wetter habitats - first to mesophytic (with medium moisture), and then to hygrophytic (very moist) . For example, migratory locusts in the central chernozem region and in the south of Western Siberia live on sandy areas, and in the deserts of Central Asia and Kazakhstan - on the banks of rivers, lakes and seas in reed beds. The Italian prus in the south of the forest zone settles on Cretaceous outcrops with sparse vegetation, and in Central Asia - in river valleys, oases and foothills, which is why it is called an oasis pruss there. This phenomenon is called principle of zonal change of stations (principle G. Ya. Bey-Bienko). It is mainly explained by the specifics of the temperature and humidity conditions in various zones.
The vast majority of locusts are inhabitants of hot countries: over 50% of known species inhabit the tropics and subtropics. In the USSR, up to 485 species belonging to 5 families are known.
Tetrigides, or jumpers (family Tetrigidae), - one of the smallest locusts with a dark body, painted the color of the earth, and a characteristic pronot elongated at the back in a long process, covering the abdomen from above. If they have elytra, they are very short, in the form of small lobes. The wings are normally developed. Tetrigids do not chatter and are devoid of hearing. In the tropics, tetrigids are represented by a wide variety of species, while we have less than 30. The biology of these locusts is quite peculiar. These are all herpetobionts that live in moist meadows, forest edges, along the banks of water bodies. Constantly jumping near the water, they can fall into it, and some species in these cases are able to swim and even dive.
Being immigrants from the tropics, tetrigides are distinguished by a peculiar rhythm of development. In our conditions, they winter in the form of larvae or adult insects. Some species may have 2-3 generations per year.
Eumastacides (family Eumastacidae) are characteristic of the forest regions of the tropical zone. In our country, they are found only in Central Asia, where they are represented by 16 species belonging to 3 genera (Clinomastax, Phytomastax, Gomphomastax).These are small or medium-sized wingless locusts, 1-2.5 long cm, with a short head and a laterally compressed body, do not chatter and are devoid of a hearing aid. They live in mountainous terrain and can penetrate high into the mountains - up to 3000-4000 m. Mostly tamnobionts, preferring to stay on shrubs (caragana, wild rose, juniper) or shrubs. An example is Phytomastax robusta, who lives in the mountains of Kazakhstan (Zailiysky Alatau) and Kyrgyzstan (Kungey Alatau) at high altitudes, from 1800 m and higher. On gravelly slopes it keeps on wormwood and some shrubs.
Representatives of the original familypamphagide (Pamphagidae) are distributed throughout Africa, as well as in the desert and mountainous regions of southern Europe, Western, Middle and Central Asia, reaching the Far East. Within the USSR there are about 50 species.
Pamphagids are large locusts with very dense rough outer covers. They are characterized by a specific structure of the hips of the hind legs, the outer surface of which does not have feathery sites located between the keels. A sound apparatus is usually found even in wingless forms.
By way of life, all the pamphagids we meet or typical geophiles, or specialized inhabitants of a rocky substrate - petrobionts. The first of them are distributed mainly on the wide plains of deserts and semi-deserts. They are very mobile and have well-developed wings. In Central Asia you can often find trinhus (Thrinchus) - characteristic endemic of the Central Asian deserts. They live in clay-pebble and rocky areas in the valleys and foothills. Trinchuses are distinguished by a powerful, stocky dark-colored body and greenish or bluish wings with a dark band in the middle. They are very mobile: if you frighten off an insect sitting on the ground, it quickly flies to another place, making a throw at 5-10 m.
Inhabitant in Kyzylkum desert trinchus (Thrinchus desertus) has adapted to the conditions of a sandy desert and has a number of features characteristic of psammobionts. He has a more slender body with dark longitudinal stripes on a white background and elongated spurs that help push off from the loose substrate when jumping.
Petrobiont species of pamphagids live on rocky slopes in the mountains of the Caucasus and Central Asia. Most of them are completely devoid of wings and have a clumsy, gross body. A typical petrobiont is Saxony (Saxetania cultricollis), widespread in Iran (North and Central Khorasan), as well as in some mountain ranges of Central Asia (Kopet-Dag, Kugitang, Gissar range). This is a wingless species of large sizes, 2.5-6 long cm, with a sharply arched median keel of the pronotum, Body color, then gray, then darkish, harmonizes well with the general background of the rocky substrate, a bright, intensely blue color appears only on the inner side of the legs of the hind legs. Apparently, this is a kind of "identification tag", facilitating the meeting of the male with the female. Saksetania lives on the rocky slopes of mountains with sparse vegetation. She is very slow, makes small jumps, and therefore is not able to move long distances.
Pyrgomorphids (family Pyrgomorphidae) are widely represented in the tropics, while only 3 species are found within the USSR. From pamphagids they are easily distinguished by a conical head with a strongly sloping forehead. Of our representatives widespread desert pyrgomorph (Pyrgomorpha conica), which lives in deserts and semi-deserts of Kazakhstan, Central Asia and Transcaucasia. It is relatively small (1.5-2 cm), with an elongated body, well-developed elytra and wings, and a very characteristic head with xiphoid antennae and crown, protruding forward like a duck nose. It occurs in the form of two color forms - grayish yellow and green. It is kept in grassy cover, often choosing a place near rivers and other water bodies, and in the mountains there are bottoms and slopes of ravines rich in streams and springs.
Real locusts (family Acrididae) can be easily distinguished from all the families considered above.They primarily differ from tetrigides and eumastacid by the presence of a sound apparatus, in addition to the absence of those signs that are specific to these families. At the same time, they have a completely different sculpture than the pamphagids and pyromorphids from the hind surface of the hips of the hind legs - in the form of feathery platforms correctly located between the keels. This family is rich in species: in the fauna of the USSR, it accounts for about 80% of the currently known species.
Fig. 162. Locusts, 1 - Tetrix tenuicornis, 2 - Phytomastax robusta, 3 - Pyrgomorpha conica
The body shape of true locusts varies greatly depending on the species belonging to a particular life form. In fact, almost all life forms are expressed in this family, excluding only herpetobionts and petrobionts.
Among the species common in the USSR, over 100 to one extent or another can harm crops. Of these, herd forms are the most dangerous - migratory locust, moroccan locust, italian prus and Turanian, as well as flying over some years from Iran and Afghanistan desert locust (tab. 31, 1-6).
Migratory Locust (Locusta migratoria) - large insect, up to 6 cm long, grayish or olive-brown, with small spots, pronotum with a sharp median keel, hips of hind legs inside the main part bluish-black, tibia of hind legs yellowish or red. The difference between the herd and single phases is discussed above. In the USSR, migratory locusts are found in southern Ukraine, in the Ciscaucasia, in the lower Volga, in the southern regions of Western Siberia, in Kazakhstan and Central Asia. To the south outside of our country, it is distributed to southern Africa, Australia and New Zealand.
On this vast territory, locust breaks up into 7 subspecies, of which two are found in the USSR - Central Russian and Asian Migratory Locust. Central Russian locusts live in the forest and forest-steppe zones of the European part of the USSR, and breed in mass in hot and dry years. The greatest danger is represented by the Asian locust, whose permanent nests are located in the floodplains of the lower reaches of such large rivers as the Volga, Ural, Don, Terek, Amu Darya, Syr Darya, as well as along the shores of large lakes - Balkhash, Alakol and Zaysan. Here she prefers wetlands with dense reed beds. Under these conditions, in the second half of summer, Asian locusts lay eggs on the outskirts of reed massifs. In spring, the larvae hatch quite late - in the first half of May, they develop within 35-40 days, after which fledging occurs. The speed of movement of the swarm depends on the age of the larvae: in larvae of the third and fourth ages, it reaches 6-7 m per minute, at the fifth - up to 10-12 m. During the movement, the kulig sometimes have to cross over water bodies - swamps, channels, river branches. There are cases when locust larvae crossed over such large rivers as Kuma and Syr Darya.
Fig. 163. Schematic map of the main centers of mass breeding of herd locusts in the USSR and the paths of locusts entering the USSR from neighboring countries
A flock of adult locusts flies at a speed of 10-15 Km 80-120 flies per hour and per day Km. Therefore, despite the limited size of the permanent nesting sites, Asian locusts can spread over long distances and live in new places inhabited by it for several years in a row, going through its characteristic development here. Of all our locusts, Asian locusts are the most gluttonous. It is estimated that each instance of it during its life eats 300 g of green food. The offspring of one female locust during the summer destroys as much feed as would be enough for two sheep. Swarms and flocks of this insect within 1 - 2 hours can destroy hundreds and thousands of hectares of crops. Reed is a favorite food of Asian locusts in places of its hatching. During movement, it harms many plants, preferring cultivated and wild grasses. The older the locusts, the more crowded and, in addition to cereals, it can cause great harm to cabbage, watermelons, sunflowers and other plants.
Moroccan locust (Dociostaurus maroccanus) is distributed in Central Asia, Kazakhstan, the Caucasus, Transcaucasia, Crimea, and outside the USSR - in the countries surrounding the Mediterranean Sea, in Iran and Afghanistan. It is much smaller than the migratory locust, reaches a length of 22-38 mm, reddish yellow, with dark spots, a light cruciform pattern on the pronotum, pinkish or yellowish hips and red legs of the hind legs.
Egg-laying areas of Moroccan locusts are localized mainly in the desert zone - in the foothills and lower part of the mountain slopes, not higher than 1800 m. These are usually dry areas with loamy and loamy gray soils, the vegetation of which is mainly ephemeral plants - viviparous bluegrass, desert sedge, etc. Under such conditions, the number of laid egg capsules can reach 1,500, or even 6,000 per 1 m 2. In Central Asia, the larvae hatch in late March - early April, and the entire larval development period does not exceed 25-35 days. After 3-10 days after fledging, mating and egg laying begins. At this time, Moroccan locusts migrate during the day, flying from egg-laying to low, well-moistened areas with abundant vegetation where it feeds. Moroccan locusts damage many plants, but are especially harmful to cotton, cereals, alfalfa, garden and melon crops. It has been established that the main condition conducive to its mass reproduction is the loss of spring rainfall in the amount of about 100 mm during the development of overwintered eggs and hatching of larvae.
The Prussians several species of locusts belonging to the genus Calliptamus are called. These are medium sized insects with a length of 14.5-48 mm, with a stocky body painted in brownish-red tones, elytra gray with dark spots, the wings of most species are pink. Most dangerous to agriculture italian prus (C. italicus) and turanian prus (C. turanicus). They are easily distinguished by the color of the hind legs: on the Italian prus, the hips on the inside are pink with 2 incomplete black bandages, the tibia are pink or red, the hips of the Turanian prus are monochromatic, yellow or gray on the inside, without dark bandages, and the legs are yellowish on the outside and pale inside -orange (tab. 31, 14.15).
Table 31. Harmful locusts: 1 - migratory locust (Locusta migratoria), 2, 3 - its larvae (2 - single, 3 - herd phases), 4 - Moroccan locust (Dociostaurus maroccanus), 5 - Italian Pruss (Calliptamus italicus), 6 - desert locust (Schistocerca gregaria), 7 - atbasarca (Dociostaurus kraussi), 8-10 - Siberian filly (Gomphocerus si-biricus): 8, 9 - male, 10 - female, 11 - white-breasted filly (Chorthippus albomarginatus) - Turkmen filly (Ramburiella turcomana), 13 - black-striped filly (Oedaleus decorus), 14 - foot of the Italian prus, 15 - foot of the Turanian prus
Table 31. Harmful locusts: 1 - migratory locust (Locusta migratoria), 2, 3 - its larvae (2 - single, 3 - herd phases), 4 - Moroccan locust (Dociostaurus maroccanus), 5 - Italian Pruss (Calliptamus italicus), 6 - desert locust (Schistocerca gregaria), 7 - atbasarca (Dociostaurus kraussi), 8-10 - Siberian filly (Gomphocerus sibiricus): 8.9 - male, 10 - female, 11 - white-breasted filly (Chorthippus albomarginatus), 12 - filly (Ramburiella turcomana), 13 - black-striped filly (Oedaleus decorus), 14 - foot of the Italian prus, 15 - foot of the Turanian prus
The Turanian Prus lives in Central Asia and Kazakhstan. The Italian Prus is much more widespread and in the USSR harms crops in the middle Volga region, in the south of the European part and in Western Siberia, the Caucasus, Central Asia and Kazakhstan. Thus, both of these species are found in the southern regions of Kazakhstan and Central Asia, but their behavior is different here. The Italian Prus is most dangerous in the area of irrigated agriculture, where it mainly harms industrial crops, the Turanian Prus lives mainly on the dry land and harms cereal crops. Prus larvae hatch in mid-May, and their development lasts for 40-45 days.
Desert locust, or schistocerca (Schistocerca gregaria), larger than migratory locusts and reaches a length of 6 cm. The newly winged individuals are pinkish in color, later they turn yellow, the elytra are in dark spots, and the wings are completely colorless. Permanent habitats of schistocerci are found in the subtropical and tropical zones of Africa, Arabia, India and Pakistan. Due to its huge MOBILITY and ability to long-distance flights, it can survive in hot desert areas, although it would seem that the conditions for its reproduction are unfavorable here.The fact is that females lay their eggs after rains in the sand or loose soil. During a short incubation period, lasting 12-15 days, young larvae hatch, the development of which lasts 5-6 weeks. During this period, they find juicy plant foods in the desert, due to the fact that after the rains there is plant vegetation. The adult schistocerca is better adapted to tolerate dry air and high temperatures. However, for puberty, she also needs juicy green food.
The sheltered herd phase of the desert locust can spread over thousands of kilometers. So, in October 1954, its small flocks flying from North West Africa reached the British Isles, flying more than 2,400 Km above the sea. Average flight altitude does not exceed 600 mhowever, from airplanes in some cases its flocks were recorded at an altitude of 2000 m. It is known that individual instances, rising to 6000 mflew to the glaciers of Kenya.
From the Indian and Arabian foci, the schistocercus reaches Iran and Afghanistan, where it forms temporary foci of reproduction. Of these countries, desert locusts can fly into the Soviet Union. In 1929, huge flocks of schistocerci entered Central Asia, where they spread over an area of over 1.5 million hectares and caused great damage to agriculture. In 1928 and 1930, she flew to Transcaucasia. In 1962, a schistocercus at the junction of the borders of the USSR, Iran and Afghanistan invaded the territory of Turkmenistan, having a common front of a length of about 160 Km. The flight lasted from March to May. At the same time, she laid down her egg capsules on an area of about 40 thousand hectares. It is characteristic that the new generation, after fledging, flew back south.
In addition to herd locusts, non-herd ones can also cause significant damage to agriculture, and certain types of grasshoppers are harmful in different landscape zones. So, in the forest-steppe and in the northern part of the steppe regions of Siberia, the Urals and Northern Kazakhstan, significant harm can be caused Siberian (Gomphocerus sibiricus) and white-striped (Chorthippus albomarginatus) filly, in the southern steppes of Kazakhstan - atbasarka (Dociostaurus kraussi), in the conditions of Central Asian rainfed - Turkmen (Ramburiella turcomana) and black stripe (Oedaleus decorus) mares and other species (tab. 31, 7-13).