Insects morphology is the study and description of the physical form of insects. The terminology used to describe insects is similar to those used for other arthropods because of their shared evolutionary history. The three physical characteristics of insects separate from other arthropods: they have the body divided into three regions (head, chest, and abdomen), have three pairs of legs, and mouths located outside the capsule of the head. This is the position of the mouth that divides them from their closest relatives, the non-insect hexapods, which include Protura, Diplura, and Collembola.
There are large variations in body structure among insect species. Individuals can range from 0.3 mm (fairyflies) to 30 cm (large owl moths); have no eyes or many; wings that develop well or not at all; and legs are modified to run, jump, swim, or even dig. This modification allows insects to occupy almost every ecological niche on the planet, except the deep and Antarctic sea. This article describes the basic insect body and some major variations of different body parts; in the process it defines many technical terms used to describe the body of insects.
Video Insect morphology
Ringkasan anatomi
Insects, like all arthropods, do not have an interior frame; instead, they have an exoskeleton, a hard outer layer mostly made of chitin that protects and supports the body. Insect body is divided into three parts: head, chest, and abdomen. This head is specific to sensory input and food intake; thorax, which is the anchor point for the legs and wings (if any), is specific to movement; and stomach for digestion, respiration, excretion, and reproduction. Although the general function of the three body regions is the same across all insect species, there is a large difference in the basic structure, with wings, legs, antennas, and mouths varying greatly from group to group.
Maps Insect morphology
External
Exoskeleton
The outer framework of insects, cuticles, consists of two layers; epicuticle, which is a thin outer layer, waxy, waterproof and does not contain chitin, and the underlying layer is called procuticle. It is chitinous and much thicker than epicuticle and has two layers, the outer part is eksokutikel while the inside is the endocuticle. Hard and flexible endoculums are built from many layers of chitin and fibrous proteins, crossed in a sandwich pattern, while their exocutrics are rigid and sclerotized. Exocuticles are greatly reduced in many soft-bodied insects, especially larval stages (eg, caterpillars). Chemically, chitin is a long-chain polymer of N-acetylglucosamine, a derivative of glucose. In an unmodified form, chitin is translucent, supple, resilient and hard enough. In the arthropod, however, it is often modified, becoming embedded in a hardened protein matrix, which forms much of the exoskeleton. In its pure form, it is rough, but when encrusted with calcium carbonate, it becomes much harder. The difference between unmodified and modified forms can be seen by comparing the caterpillar body wall (unmodified) with the beetle (modified).
From the embryonic stage itself, the columnar or cuboid epithelial cell layer raises the external cuticle and the internal basal membrane. The majority of insect material is stored in the endocouple. The cuticle provides muscle support and acts as a protective shield as the insect develops. However, as it can not grow, the external sclerotization part of the cuticle is periodically spilled in a process called "moulting". As the time for moulting approached, most of the exocutorial material was reabsorbed. In moulting, first the old cuticle breaks away from the epidermis (apolisis). Enzymatic fluid is removed between the old cuticle and the epidermis, which separates the exocuticles by digesting the endocryicles and confiscating the material for the new cuticle. When the new cuticle has formed enough, the epicuticle and reduce the exocuticle are shed in ecdysis.
The four main areas of the insect body segment are: dummy or dorsal, sternum or ventral and two pleural or lateral. The hardened slabs in the exoskeleton are called sclerites, which are subdivisions of the principal regions - dikes, sternites and pleurites, for each region of the earth, sternum, and pleuron.
Head
Heads in most insects are covered in hard, very sclerotized, exoskeletal capsule heads. The main exceptions are in species whose larvae are not fully sclerotized, especially some holometabola; but even the least coarse or sclerotised larvae tend to have well-sclerotized head capsules, such as Coleoptera and Hymenoptera larvae. But Cyclorrhapha larvae tend to have almost no head capsule at all.
The head capsule contains most of the major sensory organs, including antennae, oselus, and compound eyes. It also contains the mouth. In adult insects the head capsule does not seem to regenerate, although embryological studies show it consists of six segments that bear the complement of the couple's head, including the mouth, each pair on a particular segment. Each of these pairs occupies one segment, though not all segments in modern insects have a visible appendage.
Of all the orders of insects, Orthoptera most easily displays the greatest features found in insect heads, including stitches and sclerites. Here, the vertex, or apex (dorsal region), lies between compound eyes for insects with hypognathous and opisthognathous heads. In prognathous insects, the vertex is not found between compound eyes, but vice versa, where the octus is usually found. This is because the main axis of the head is turned 90 ° to be parallel to the main axis of the body. In some species, the area is modified and has a different name.
Ecdysial stitches are made of coronal, frontal, and epicranial sutures plus ecdysial and cleavage lines, which vary among different insect species. The ectarsial suture is placed longitudinally on the vertex and separates the epicranial portion of the head to the left and right sides. Depending on the insect, the sutures may come in various forms: such as Y, U, or V. The divergent lines that form ecdysial stitches are called frontal or frontogenal stitches . Not all insect species have frontal stitches, but in those who do, the stitches are open during ecdysis, which helps give the opening for new instars to emerge from the integument.
Frons are part of the head capsule located in the ventrad or anteriad of the vertex. Fron varies in size relative to insects, and in many species the definition of the border is arbitrary, even in some of the taxi of insects that have well-defined capsule heads. However, in most species, the fron is confined anteriorly to the frontoclypeal or epistomal sulcus above the clypeus. The lateral is limited by the fronto-genal sulcus, if any, and the boundary with the vertex, by the ecdysial cleavage line, if visible. If there is a median oselus, generally in fron, although in some insects such as many Hymenoptera, the three oselus appear in the vertex. A more formal definition is that the sclerite from which the pharyngeal muscle muscles appear, but in many contexts as well, does not help. In the anatomy of some taxa, like many Cicadomorpha, the front of the head is quite distinctly differentiated and tends to be broad and sub-vertical; that the median area is generally regarded as fron.
The clypeus is the sclerite between the face and the labrum, which is dorsally separated from the fron by frontoclypeal stitches in primitive insects. Clypeogenal stitches laterally demarcate the clypeus, with the clypeus being ventralally separated from the labrum by clypeolabral sutures. The clypeus differs in shape and size, such as the Lepidoptera species with large clypeus with an elongated mouth. The cheeks or the veins form a sclerotized area on each side of the head under compound eyes that extend into the gum sutures. Like many other parts that make up the head of an insect, the gene varies between species, with its limits difficult to determine. For example, in dragonflies and damselflies, it is between compound eyes, clypeus, and mouth. Postgena is the immediate region of the posteriad, or posterior or lower in the pterygote insect gein, and forms the lateral and ventral portion of the occipital arch. The occipital arch is a narrow band that forms the posterior edge of the capsule's head curved over the foramen. Subgenal regions are usually narrow, located above the mouth; this area also includes hypostomes and pleurostoma. The vertex extends anteriorly on the base of the antenna as a prominent, pointed, concave rostrum. The posterior wall of the head capsule is penetrated by a large opening, foramen. Through it passes through organ systems, such as nerve wires, esophagus, saliva ducts, and muscles, connecting the head with the thorax.
In the posterior part of the head are occiput, postgena, the occiput foramen, posterior lung hole, sugar, postgenal bridge, hypostomal stitching and bridge, and mandibular, labium, and maxillary. The occipital sutures are also found in Orthoptera species, but not too much in other orders. Where it is found, the occipital suture is a curved groove, horseshoe-shaped at the back of the head, ending in the posterior of each mandible. Postoxipital stitches are landmarks on the posterior surface of the head, and usually near the occipital mandor. In pterygote, postocciput forms an extreme posterior, often U-shaped, which forms the elongated borders of the head to the postoksipital stitch. In pterigots, such as Orthoptera, the occipital foramen and mouth are not separated. Three types of occipital closures, or points below the occipital foramen separating the lower two postgena, are: hypostomal bridges, postgenal bridges, and sugars. Hypostomal bridges are usually found in insects with hypognathous orientation. The postgenal bridge is found in adults of higher species Diptera and aculeate Hymenoptera, whereas sugar is found in some Coleoptera, Neuroptera, and Isoptera, which usually feature prognati-oriented mouth.
Compound eyes and ocelli
Most insects have a pair of large and prominent compound eyes consisting of units called ommatidia (ommatidium, singular), perhaps up to 30,000 in one compound eye, for example, a large dragonfly. This type of eye provides less eye resolution found in vertebrates, but gives a sharp perception of movement and typically has UV and green sensitivity and may have additional peak sensitivity in other areas of the visual spectrum. Often the ability to detect a polarized light E-vector has light polarization. There can also be additional two or three oselus, which help detect low light or small changes in light intensity. The perceived image is a combination of inputs from various ommatidia, located on a convex surface, thus pointing in slightly different directions. Compared with simple eyes, compound eyes have a very large viewing angle and a better acuity than the oselus of the insect's back, but some stemmatal (larvae), such as saw larvae (Tenthredinidae) with 4 degrees of sharpness and very high polarization sensitivity, with compound eye performance.
Because individual lenses are so small, the diffraction effects impose limits on possible resolutions that can be obtained (assuming they do not work as phased arrays). This can only be countered by increasing the size and number of the lens. To see with a resolution that is comparable to our simple eyes, humans will need compound eyes that will each reach the size of their head. The compound eye falls into two groups: the aposition eye, which forms several inverted images, and superposition eyes, which form an erection image. Compound eyes grow on their margins with the addition of a new ommatidia.
Antennae
Antennae, sometimes called "feelers", are flexible supplements located in the head of an insect used to feel the environment. Insects can can feel with their antennae because of the fine feathers (setae) that cover them. However, touch is not the only thing the antenna can detect; many small sensory structures in the antenna allow insects to sense smell, temperature, humidity, pressure, and even potentially feel themselves in space. Some insects, including bees and some groups of flies can also detect sound with their antennae.
The number of segments in the antenna varies greatly among insects, with the higher flies having only 3-6 segments, while the adult cockroach can have more than 140. The general shape of the antenna is also quite varied, but the first segment (attached to the head) is always called scape , and the second segment is called pedicel. The remaining antennal segment or flagellomeres are called flagellum.
Common types of antenna insects are shown below:
Mouthparts
The mouth of the insect consists of the maxilla, labium, and in some species, the mandible. Labrum is a simple, unified sclerite, often called the upper lip, and moves longitudinally, which depends on the clypeus. The mandible (jaw) is a pair of highly sclerotized structures that move at right angles to the body, used to bite, chew, and cut food. Maxillae is a paired structure that can also move at right angles to the body and has a segmented palp. Labium (lower lip) is a longitudinally moving fused structure and has a pair of segmented palps.
The mouth, along with the rest of the head, can be articulated in at least three different positions: prognathous, opisthognathous, and hypognathous. In species with prognathous articulation, the head is positioned vertically parallel to the body, such as the Formicidae species; while in the hypognathous type, the horizontal aligned head is close to the body. An opisthognathous head is positioned diagonally, such as the Blattodea species and some Coleoptera. The mouth varies greatly between insects with different orders, but the two major functional groups are the mandible and haustellate. The Haustellate mouth is used to suck fluid and can be further classified by the presence of stylet, which includes piercing-sucking, wiping, and sucking. The stylets are projection-like needles used to penetrate plant and animal tissues. The stylets and filler tubes form a modified mandible, maxillary, and hypopharyngeal. Mandibulate
- Mandibulate , among the most common in insects, is used to bite and grind solid foods. The
- piercing-pant has a stylet, and is used to penetrate the solid tissue and then suck up the liquid food. The mouth
- Wiping is used to disguise and suck fluids, and does not have a stylet (eg most of Diptera). The mouth
- Siphoning lacks a stylet and is used to suck fluids, and is commonly found among Lepidoptera species.
The mandibular mouth is found in Odonata species, adult neuroptera, Coleoptera, Hymenoptera, Blattodea, Orthoptera, and Lepidoptera. However, most adult Lepidoptera have mouth siphoning, while their larvae (commonly called caterpillars) have lower jaws.
Mandibulate
Labrum is the broad lobe that forms the roof of the preoral cavity, hanging from the clypeus in front of the mouth and forming the upper lip. On the inner side, the membrane and can be produced into the median lobe, epipharynx, carries several senses. Labrum is raised from the mandible by two muscles that arise in the head and is inserted medially to the anterior edge of the labrum. It is closed to the mandible partly by two muscles arising in the head and inserted at the posterior lateral margin on two small sclerites, tormae, and, at least on some insects, by the resilin springs on the cuticle at the labrum junction with clypeus. Until now, labrum is generally considered to be associated with the first head segment. However, recent research on embryology, gene expression, and neural supply to the labrum suggests it is innervated by the brain of the tritocerebrum, which is a unified ganglia of the third head segment. It is formed from the fusion of a pair of pair of ancestors found in the third head segment, showing their relationship. The ventral surface, or inside, is usually webbed and forms epipharynx like a lobe, containing mechanosensilla and chemosensilla.
Chewing insects has two jaws, one on each side of the head. The mandible is positioned between the labrum and the maxilla. Mandibles cut and destroy food, and can be used for defense; generally, they have an apical spearhead, and a more basal molar region brings together food. They can be very hard (about 3 in Mohs, or an indentation hardness of about 30 kg/mm 2 ); therefore, many termites and beetles have no physical difficulty in making foams from common metals such as copper, tin, lead, and zinc. Sharp edges are usually strengthened by the addition of zinc, manganese, or rarely, iron, in amounts to about 4% of the dry weight. They are usually the biggest mouth of chewed insects, used for chewing (cutting, tearing, crushing, chewing) food. They open out (to the side of the head) and come together medally. In carnivorous and chewing insects, the mandible can be modified to be more like a knife, whereas in herbivorous chewing insects, they are usually wider and flatter on the opposite face (eg, caterpillar). In the male beetle, the mandible is modified in such a way that it does not serve the function of feeding, but is used to maintain the mating site of another male. In ants, the mandible also functions defensively (especially in the warrior caste). In bull ants, elongated mandibles and toothed, used as a hunt (and defensive).
Located beneath the mandible, couples vomit the maxillae foods during mastication. Maxillae can have hair and "teeth" along their inner margins. On the outer edge, galea is a structure shaped like a cupping or scoop, which lies above the outer edge of the labium. They also have palps, which are used to sense potential food characteristics. Maxillae occupies the lateral position, one on each side of the head behind the mandible. The proximal portion of the maxilla consists of a basal cardo, which has a single articulation with the head, and a flat plate, stipes, depending on cardo. Both cardo and stipes are loosely joined to the head by the membrane so that they are able to move. Distal on the stipes are two lobes, internal lacinea and outer galea, one or both may be absent. More laterally on the stipes is the jointed foot, like a leg consisting of a number of segments; in Orthoptera there are five. The anterior and posterior rotator muscles are inserted into the cardo, and ventral ventilator muscles arising in the tentorium are inserted in cardo and stipes. What arises in stipes is the flexor muscle lacinea and galea and other lacineal flexors appear in the cranium, but both lacinea and galea have extensor muscles. Palp has levator and depressor muscles arising in the stipes, and each palp segment has a single muscle that causes flexion in the next segment.
In the mouth of the lower jaw, the labium is a four-legged structure, although it is formed from two secondary maxims of fused. It can be described as the basis of the mouth. With maxillae, it helps with the manipulation of food during mastication or chewing or, in the unusual case of nymphs nymphs, extends out to reclaim the prey to the head, where the jaw can eat it. Labium has the same structure as the upper jaw, but with the complement of both sides merges with the midline, so they come to form the median plate. The labial basal portion, equivalent to the maxillary cardinal and possibly including the labial part of the sternum, is called postmentum. It can be divided into the proximal submentum and the distal mentum. The distal to the postmentum, and the equivalent of the unified maxillary rule, is prementum. Prementum closes the prefrontal cavity from behind. Terminally, it has four lobes, two inner glosses, and two external paraglains, collectively known as ligula. One or both pairs of lobes may be absent or they can coalesce to form a single median process. A palp appears from each side of the prementum, often into three segments.
Hypopharynx is the median lobe immediately behind the mouth, projecting forward from the back of the preoral cavity; it is the unknown lobe, but may be related to the mandibular segment; in apterygote, earwigs, and nymphal mayflies, hypopharynx has a pair of lateral lobes, superlinguae (singular: superlingua). It divides the cavity into the back feeding pouch, or cibarium, and the ventral saliva where the saliva droplets open. Usually found together with libium. Most of the hypopharynx is membranous, but the adoral face is sclerotized distally, and proximally contains a pair of suspensory suspension extending upwards to end in the lateral wall of the stomodeum. The muscles that arise in fron are inserted into these sclerites, which distal depending on a pair of lingual sclerites. This, in turn, has incorporated into it a pair of antagonistic muscles that appear in tentorium and labium. Various muscles function to swing the hypopharynx forward and back, and in the cockroach, two more muscles run across the hypopharynx and dilate the salivary orifice and expand the salivary.
piercing
The mouth can have many functions. Some insects combine the piercing parts with the fused parts which are then used to penetrate the plant and animal tissues. Female mosquitoes feed on blood (hemophagus) making them disease vectors. The mosquito's mouth consists of a trunk, mandibles in pairs and upper jaw. The maxillae forms a needle-like structure, called a stylet, which is covered by the labium. When the mosquito bites, the upper jaw penetrates the skin and anchor the mouth, thus allowing other parts to be inserted. The labium is like a sheath gliding back, and the remaining mouth passes through its end and enters the network. Then, through hypopharynx, mosquitoes inject saliva, which contains anticoagulants to stop blood from clotting. And finally, the labrum (upper lip) is used to suck blood. Species of the genus Anopheles are characterized by their long palpi (two halves with wide ends), almost reaching the end of the labrum.
Siphoning
The trunk is formed from the maxillary galeae and adaptation is found in some insects to be inhaled. Cibarium or pharyngeal muscle is highly developed and forms a pump. In Hemiptera and many Diptera, which feed on liquids in plants or animals, some components of the mouth are modified to pierce, and the elongated structure is called a stylet. The combined tubular structure is called a trunk, although special terminology is used in several groups.
In the Lepidoptera species, it consists of two tubes held together by a hook and separated for cleaning. Each tube is deeply sunken, thus forming a central tube through which the moisture is sucked. Suction is done through contraction and expansion of the sac on the head. The trunk is rolled under the head when the insect rests, and is only extended during meals. The maxillary palpi is reduced or even vestigial. They are striking and five segments in some families that are more basal, and often folded. The shape and dimensions of the trunk have evolved to provide a wider different species and hence the diet is more favorable. There is an allometric scale relationship between Lepidoptera body mass and the length of the trunk from which an interesting adaptive departure is a very long eagle moth tongue Xanthopan morganii praedicta . Charles Darwin predicted the existence and length of these mothballs before his discovery based on his knowledge of the Madagascar's long-conceived Angraecum sesquipedale .
Sponging
The mouths of insects that feed on fluids are modified in various ways to form a tube through a fluid that can be drawn into the mouth and usually the other through which the saliva passes. Cibarium or pharyngeal muscles are greatly developed to form pumps. In flies that do not perform balancing, the mandible does not exist and the other structure is reduced; the labial palps have been modified to form the labellum, and the maxillary palps are present, albeit occasionally short. In Brachycera, labellum is very prominent and is used to eat liquid or semiliquid food. Labella is a complex structure consisting of many paths, called pseudotracheae, which secrete fluid. Salmon secretions from the labella help dissolve and collect food particles so they are more easily taken by pseudotracheae; this is thought to occur by capillary action. Liquid food is then taken from the pseudotracheae through the food channel to the esophagus.
The mouth of a bee is a type of chewing and chewing. Lapping is a way of feeding where liquid or semiliquid food attached to a damaging organ, or "tongue", is transferred from the substrate to the mouth. In honeybees (Hymenoptera: Apidae: Apis mellifera), labial glazes extend and coalesce into a hairy tongue, surrounded by a maxillary galeae and labial palps to form a tubular trunk containing canal food. At meal time, the tongue is dipped into nectar or honey, which is attached to the hair, then drawn so that the sticking liquid is brought into the space between the galeae and the labial palps. This back and forth sheen movement happens repeatedly. Movement of fluid to the mouth apparently results from the action of the cibaria pump, facilitated by each tongue retraction pushing the liquid up the food channel.
Thorax
Thorax insects have three segments: prothorax, mesothorax, and metathorax. An anterior segment, closest to the head, is prothorax; Its main features are the first pair of legs and the pronotum. The middle segment is mesothorax; Its main features are a pair of second legs and an anterior wing, if any. The third part, posterior, thoracic, abutting abdomen, is a metathorax, which carries a pair of third legs and a posterior wing. Each segment is bounded by intersegmental sutures. Each segment has four base areas. The dorsal surface is called the (or notum) to distinguish it from the abdomen. The two lateral regions are called the pleura (single: pleuron), and the ventral aspect is called the sternum. In turn, the notum of prothorax is called pronotum, notum for mesothorax called mesonotum and notum for metathorax called metanotum. Continuing this logic, there are also mesopleura and metapleura, as well as mesosternum and metasternum.
Thorax buried plates are simple structures in apterygote and in many immature insects, but various modifications in winged adults. Pterothoracic notes each have two main divisions: anterior, posterior and posterior wing pads, postnotum bearings-phrases. Phragmata (single: phragma) is apodem like plate extending inward under antecostal sutures, marking the major intersegmental folds between segments; phragmata provides an attachment for the longitudinal flight muscle. Each alipotum (sometimes confusingly referred to as "notum") can be passed by a stitch marking the position of the internal reinforcement of the back, and usually divides the plate into three areas: the anterior prescutum, the scutum and the smaller posterior scutellum. Lateral pleural sclerites are believed to originate from the subcoxal segment of the ancestral insect legs. The sclerite may be separated, as in a cork, or fused into an almost continuous sclerotic area, as in most winged insects.
Prothorax
Prothorax on the forehead is protected by a large pronotum that extends from the top of the cervix (neck) on the anterior side to cover mesothorax and most metathorax on the posterior side, as well as covering the pleura on the prothorax. The prothorax of the prothorax may be simple in structure and small compared to other notes, but on beetles, mantids, many bugs, and some Orthoptera, expanded pronotum, and in cockroaches, it forms a shield that covers part of the head and mesothorax.
Pterothorax
Because mesothorax and metathorax hold the wings, they have a combined name called pterothorax (pteron = wing). Preface, which goes by different names in different order (for example, tegmina in Orthoptera and elytra in Coleoptera), arises between mesonotum and mesopleura, and the articulate back between metanotum and metapleura. The legs arise from mesopleura and metapleura. Mesothorax and metathorax each have pleural stitches (mesopleural and metapleural stitches) that extend from the base of the wing to the foot coxa. The anterior sclerite to the pleural suture is called episternum (serial, mesepisternum and metepisternum). The posterior sclerite on the stitches is called epimiron (serial, mesepimiron and metepimiron). Spiracles, external organs of the respiratory system, are found in pterothorax, usually one between pro- and mesopleoron, and one between meso- and metapleuron.
The ventral or sternal view follows the same convention, with prosternum under prothorax, mesosternum beneath mesothorax and metasternum under metathorax. Notum, pleura, and sternum of each segment have different sclerits and stitches, vary greatly from order to order, and will not be discussed in detail in this section.
Wing
Most advanced phylogenetically insects have two pairs of wings located in the second and third thorax segments. Insects are the only invertebrates that develop flying abilities, and this has played an important role in their success. Insect flight is not well understood, relies heavily on volatile aerodynamic effects. Primitive insect groups use muscles that act directly on the wing structure. The more advanced groups that make up Neoptera have folded wings, and their muscles work on the thorax wall and induce wings indirectly. These muscles can contract several times for each single nerve impulse, allowing the wings to beat faster than normal.
Insect flight can be very fast, maneuverable, and versatile, possibly because of its changing shape, tremendous control, and variable movement of the insect wing. Insect calls using different flight mechanisms; for example, the butterfly escape can be explained using steady conditions, non-transnational aerodynamics, and thin airfoil theory.
Internal
Each wing consists of a thin membrane supported by the venous system. The membrane is formed by two very close layers of the integument, while the vein is formed where the two layers remain separate and the cuticle may be thicker and heavier to sclerotize. In each of the major blood vessels are the nerves and trachea, and, because of the cavity of the veins connected with the hemocoel, hemolymph can flow to the wings. Also, the wing lumen, which is an extension of the hemocoel, contains trachea, nerves, and hemolymph. As the wings develop, the dorsal and ventral layers become very close to most of their area, forming the wing membrane. The remaining area forms a channel, a vein in the future, where nerves and trachea can occur. The cuticle around the vein becomes thickened and heavier sclerotized to give strength and stiffness to the wings. Hair of two types can occur on the wings: microtrichia, small and dispersed irregularly, and macrotrichia, larger, pockets, and may be confined to the veins. The scales of Lepidoptera and Trichoptera are highly modified macrotrichia.
Vena
In some very small insects, the venation may be greatly reduced. In chalcid wasps, for example, only subctos and parts of the radius are present. On the contrary, an increase in venation may occur by branching existing blood vessels to produce additional veins or by the development of additional veins, between the original arteries, such as the Orthoptera wings (grasshoppers and crickets). A large number of cross-veins exist in some insects, and they can form reticulum as in Odonata wings (dragonflies and damselflies) and at the base of forewings Tettigonioidea and Acridoidea (katydids and grasshoppers, respectively).
Archedictyon is the name given to the hypothetical scheme of the proposed wing venation for the first winged insect. It is based on a combination of speculation and fossil data. Because all the winged insects are believed to have evolved from the same ancestors, archediction represents "templates" that have been modified (and simplified) by natural selection for 200 million years. According to the current dogma, archedictyon contains six to eight longitudinal veins. These veins (and their branches) are named according to the system created by John Comstock and George Needham - the Comstock-Needham system:
- Costa (C) - the leading edge of the wing
- Subcosta (Sc) - second longitudinal vein (behind costa), usually not branched
- Radius (R) - the third longitudinal vein, one to five branches reaching the wing limit
- Medium (M) - the fourth longitudinal vein, one to four branches reaching the wing limit
- Cubitus (Cu) - the fifth longitudinal vein, one to three branches reaching the wing limit
- Anal vein (A1, A2, A3) - unbranched veins behind the cubitus
Costa (C) is the main marginal vein in most insects, although the small vein, precosta, is sometimes found above the costa. In almost all of the existing insects, precosta coalesces with the costa; it costs rarely branching because it is on the cutting edge, which is basically linked with the humerus plate. The trachea of ​​the costal vein may be a branch of the subcostal trachea. Located after the costa is the third vein, subcosta, which branches into two separate veins: anterior and posterior. The subcostal base corresponds to the distal end of the first axillary neck. The fourth vein is the radius, which branches into five separate blood vessels. His fingers are generally the strongest wings of the wings. To the center of the wing, the fork becomes the first undivided branch (R1) and the second branch, called the radial sector (Ra), which divides dichotomically into four distal branches (R2, R3, R4, R5). Basically, the fingers are flexibly united with the second axillary anterior end (2Ax).
The fifth vein of wings is media. In the archetype pattern A, the media fork becomes the two main branches, the anterior medium (MA), which is divided into two distal branches (MA1, MA2), and the median sector, or the posterior medium (MP), which has four terminal branches ( M1, M2, M3, M4). In most modern insects, the anterior media has disappeared, and the usual "medium" is a posterior four-pronged medium with a common basal trunk. In Ephemerida, according to the present interpretation of wing venation, both branches of the media are maintained, while in Odonata, the surviving medium is the primitive anterior branch. The media rod is often united with the fingers, but when it occurs as a different vein, its base is related to the distal median plate (m ') or continuous sclerotization with the latter. The cubitus, the sixth vein of the wing, mainly bifurcated. Primary forking occurs near the base of the wing, forming two main branches (Cu1, Cu2). The anterior branches can split into several secondary branches, but usually the branch becomes two distal branches. The second branch of cubitus (Cu2) in Hymenoptera, Trichoptera, and Lepidoptera, was misinterpreted by Comstock and Needham for the first anal. Proximal, the main trunk of cubitus is associated with the distal median plate (m ') of the wing base.
The postcubitus (Pcu) is the first anal of the Comstock and Needham systems. However, postcubitus has an independent wing vein status and should be recognized as such. In the nymph wings, the trachea emerges between the cubital trachea and the tracheal vannal group. In the more mature wings of the more common insects, postcubitus is always associated proximal to the cubitus, and is never closely connected to the flexor sclerite (3Ax) of the wing base. In Neuroptera, Mecoptera, and Trichoptera, postcubitus may be more closely related to the vannal vein, but the base is always free of the latter. Postcubitus is usually not branched; primitive, it bifurcated. The venous veins (lV to nV) are the anal veins directly related to the third axilla, and which are directly affected by this scleritic movement that causes wing flexion. In number, the vannal vein varies from one to 12, according to the expansion of the wing vannal area. Vannal trachea usually arises from a common tracheal trunk in nymphal insects, and the vein is considered a branch of a single anal vein. Distal, venous veins are either simple or branched. The jugal vein (J) of the jugal lobe of the wing is often occupied by irregular veins of tissue, or may be completely membrane; sometimes containing one or two different veins, the first jugal vein, or arcuate vein, and the second jugal vein, or the cardinal vein (2J).
- C-Sc cross-veins - runs between costa and subcosta
- R cross-veins - runs between branches of adjacent radius
- R-M cross-veins - runs between radius and media
- M-Cu cross-veins - run between media and cubitus
All wing veins are subject to secondary forking and union by cross-veins. In some orders of insects, blood vessels are numerous, all venational patterns into tissues adjacent to branched veins and veins. Usually, however, the exact number of cross-vein that has a specific location occurs. The more constant cross-shell is the cross-vein humerus (h) between the costa and subcosta, the radial cross-vein (r) between R and the first fork Rs, cross-vein (s) between the two forks R8, median cross- ) between M2 and M3, and mediocubital cross-vein (m-cu) between the media and cubitus.
The blood vessels of the wings of insects are characterized by the placement of concave, as seen in the dragonflies (ie, concave is "bottom" and convex is "up"), which alternates regularly and with their branching; every time a venous fork there is always an interpolated vein from the opposite position between the two branches. The concave vein will branch off into two concave veins (with interpolated veins being convex) and regular vein changes are maintained. The wing veins seem to fall into a wavy pattern according to whether they have a tendency to fold up or down when the wings are relaxed. The basal shaft of the convex vein, but each fork is distal to the anterior convex branch and the posterior concave branch. Thus, the costa and subcosta are considered as convex and concave branches of the first primary vein, Rs is the concave branch of the radius, the posterior medium of the concave branch of the media, Cu1 and Cu2 each convex and concave, whereas the first primitive and vannal postcubitus has branches convex anterior and posterior sunken branches. The convex or concave nature of blood vessels has been used as evidence in determining the identity of the remaining distal branches of the modern insect vein, but has not been consistently proven for all wings.
Fields
The wing area is limited and divided by the fold line, where the wings can fold, and the flexion lines, which flex during the flight. Between flexion and folding lines, fundamental differences are often blurred, since fold lines can allow flexibility or otherwise. Two constants, found in almost all insect wings, are claval (flexural line) and jugal folds (or fold lines), forming variable and unsatisfactory boundaries. Wing folding can be very complicated, with transverse folding occurring on the back skin of Dermaptera and Coleoptera, and on some insects, the anal area can be folded like a fan. The four distinct areas found on the wings of insects are:
- Remigium
- Anal area (vannus)
- Frugal area
- Axilla area
- Alula
Most veins and veins occur in the anterior area of ​​the remigium, which is responsible for most flights, supported by the thoracic muscle. The posterior part of the remigium is sometimes called the clavus; the other two posterior areas are anal and sparing areas. When the vannal folds have an anterior position in the anal vein group, the remigium contains the costal, subcostal, radial, medial, cubital, and postcubital veins. In the flexed wing, the remigium rotates posteriorly at the flexible basal connection of the radius with the second axillary, and the medocular base of the mediocubital plane folds medial in the axillary region along the basal plica (bf) between the median (m, m ') plate of the wing base.
Vannus is limited by the vannal fold, which usually occurs between postcubitus and the first vannal vein. In Orthoptera, it usually has this position. However, in Blattidae, the only folds in this wing section are located just before postcubitus. In Plecoptera, the vannal folds are posteriorly postcubitus, but proximal across the first venous vein base. In crickets, the vannal fold is located just behind the first venous vein (lV). Small variations in the actual position of the vannal fold, however, do not affect the unity of vannal vein action, controlled by the flexor sclerite (3Ax), in wing flexion. In most hindwings of Orthoptera, a secondary venous dividend forms a rib in the vannal fold. Vannus is usually triangular, and its blood vessels usually spread from the third axilla like a fan rib. Some venous veins can be branched, and the secondary vein may alternate with the primary veins. The vannal area is usually best developed in hindwing, where it can be enlarged to form a supporting surface, as in Plecoptera and Orthoptera. A very similar expansion to the fan on the back of Acrididae is clearly a vannal area, since their veins are all supported on the third axillary sclerite at the wing base, although Martynov (1925) considers most of the fan areas in Acrididae to the jugal region of the wing. The true jugum acridid ​​wing is represented only by the small membrane (Ju) mesad of the last vein vein. The higher jugum is developed in some other Orthoptera, such as in Mantidae. In most of the higher insects with narrow wings, the vannus becomes reduced, and the vannal fold is lost, but even in such cases, the bent wings may bend along the line between postcubitus and the first venous vein.
The area of ​​jugal, or neala, is the area of ​​the wing which is usually a small proximal membrane area to the base of the vannus reinforced by some small, irregular vein thickening such as; but when it develops well, it is a different part of the wings and may contain one or two blood vessels. When the jugal region of the front wing is developed as a free lobe, it projects under the humerial angle of hindwing and thus serves to unite the two wings together. In the Jugatae group of Lepidoptera, it has a long lobe like a finger. The region of jugal is called neala ("new wing") because it is clearly a secondary and newly developed part of the wing.
Additional areas containing axillary sclerite have, in general, a triangular side shape not equal in length. The base of the triangle (a-b) is the wing hinge with the body; apex (c) is the distal end of the third axillary sclerite; the longer side of the anterior to the top. The d point on the anterior side of the triangle marks the articulation of the radial vein with the second axillary sclerite. The line between d and c is the basal plica (bf), or the wing folds at the base of the mediocubital plane.
At the posterior angle of the wing base in some Diptera there are a pair of membranous lobes (squamae, or calypteres) known as alula. Alula develops well in house flies. The outer squash (c) emerges from the base of the wing behind the third axillary sclerite (3Ax) and apparently represents the frugal lobe of another insect (A, D); Larger inner squam (d) emerges from the posterior scutellar edge of the wing-bearing segment of the column and forms a protective canopy, such as the hood of the dumbbell. In the bent wing, the outer skuama of alula is reversed over the inner skuama, the latter unaffected by the wing movement. In many of the Diptera, a deep incision from the rectal region of the wing membrane behind a single vannal vein triggers the distal proximal alpha lobe to the outside of the alula.
Joints
Various wing movements, especially on insects that flex their wings horizontally over their backs during breaks, demand a more complex articular structure at the base of the wing rather than just wing hinges with the body. Each wing is attached to the body by the membranous basal region, but the articular membrane contains a number of small articular sclerites, collectively known as pteralia. The pteryia includes the anterior humerus plate at the base of the costal vein, a group of armpits (Ax) associated with the subcostal, radial, and vannal veins, and two undetermined median plates (m, m ') at the base of the mediocubital region. Axilla is specifically developed only on wing-flexing insects, where they are the flexor mechanism of the wing operated by flexor muscles arising in the pleuron. Characteristics of the wing base is also a small lobe on the anterior edge of the proximal articular region to the humerus plate, which, in the prohibition of some insects, develops into a large, flat flap, such as scale, tegula, overlap of the wing base. Posterior, articular membranes often form considerable lobes between the wings and the body, and their margins are generally thickened and wavy, giving the appearance of a ligament, called axillary axillary, mesial continuously with posterior marginal scutellar folds of wing plate plate.
The articular sclerites, or pteralia, from the wing-base of the wing-stretch insects and their relationship with the wing body and veins, shown diagrams, are as follows:
- The humerus plate
- First Axillary
- Second Axillary
- Third Axilla
- Fourth Root
- Median plates ( m , m ')
The humerus plate is usually a small sclerite on the anterior edge of the wing base, can be moved and articulated with the base of the costal veins. Odonates have their enlarged humerus plates, with two muscles arising from the episternum inserted into the humeral plate and two of the epimeron edges inserted into the axillary plate.
The first axillary sclerite (lAx) is the anterior hinge plate of the wing base. The anterior portion is supported on the anterior process of the wing notes of the bergum (ANP); the posterior part articulates with the margin of the obstruction. The antler end of the sclerite is generally produced as a slender arm, the apex which (e) is always associated with the subcostal vein base (Sc), though not united with the latter. The scleritic body articulates laterally with a second axillary. The second axillary sclerite (2Ax) is more variable in shape than the first axilla, but its mechanical relationship is no less certain. It is tilted hinge to the outer edge of the first axillary body, and the radial (R) vein is always flexibly attached to the anterior end (d). The second axilla presents the dorsal and ventral sclerotization at the base of the wing; Its ventral surface rests on the pleural fulcral wing process. Therefore, the second axillary is the most important sclerite of the wing base, and specifically manipulates the radial vein.
The third axillary sclerite (3Ax) is located in the posterior part of the articular area of ​​the wing. The shape is highly variable and often irregular, but the third axillary is the sclerite which is inserted by the flexor muscle of the wing (D). Mesally, it articulates anteriorly (f) with the posterior end of the second axillary, and posterior (b) with the posterior wing process of the bonded (PNP), or with the fourth axillary when the latter is present. Distally, the third armpit is prolonged in a process always associated with the base of the venous group in the anal region of the wing, hereinafter called venous vein (V). Therefore, the third axis is usually the posterior hinge plate of the base of the wing and is the active sclerit of the flexor mechanism, which directly manipulates the vannal vein. The flexor muscle contraction (D) revolves in the third axle of the articulation (b, f), and thus raises the distal arms; this movement produces wing flexion. The fourth axillary sclerite is not a constant element of wing base. Currently, it is usually a small plate that interferes between the third axilla and the posterior signature wing process, and may be a separate part of the latter.
The median plates (m, m ') are also sclerites that are not so clearly distinguished as special plates such as the three main axillaries, but they are important elements of the flexor apparatus. They are located in the median region of the distal wing base to the second and third axilla, and are separated from each other by a slash (bf), which forms a prominent prominent fold during the wing flexion. The proximal plate (m) is usually attached to the third distal arm of the armpit and may be considered part of the last. The distal plate (m ') is less always present as a distinct sclerite, and can be represented by the general sclerotization of the base of the mediocubital field of the wing. When blood vessels in these areas differ at their base, they are associated with the outer median plate.
Merge, fold and other features
In many species of insects, the front and rear wings are combined together, which increases the aerodynamic efficiency of the flight. The most common coupling mechanisms (eg, Hymenoptera and Trichoptera) are small hooks on the hindwing front margin, or "hamuli", which lock forward, keeping them together (hamulate coupling). In some other insect species (eg, Mecoptera, Lepidoptera, and some Trichoptera) the frugal lobes of the introduction include a portion of the hindwing (thin clutch), or a wider overlapping margin of wings (amplexiform coupling), or feather feathers rear, or frenulum, hooks under retaining structures or retinalucum on the front wing.
At rest, the wing is held behind in most insects, which may involve longitudinal longitudinal wings folding and sometimes also transverse. Folding sometimes occurs along the line of flexion. Although folded lines can be transverse, such as on the back of beetles and earwigs, they usually co-exist with the wing base, allowing adjacent wing sections to be folded above or below each other. The most common fold line is the jugal crease, located just behind the third anal vein, though, most Neoptera have jugal folds just behind the 3A vein on the front wing. Sometimes also present in hindwings. Where the anal area of ​​a large hindwing, as in Orthoptera and Blattodea, this whole section can be folded beneath the anterior portion of the wing along the vannal folds slightly in posterior to the claval strain. In addition, in Orthoptera and Blattodea, the anus area is folded like a fan along the veins, the anal veins become convex, at the top of the folds, and the concave access basin. Whereas claval and jugal fold indentations may be homologous in different species, vannal folds vary in positions in different taxa. The folding is produced by the muscle that arises in the pleuron and is inserted into the third axillary sclerite such that when contracting, the sclerite revolves around its articulation point by the process of the posterior notepad and the second axillary sclerite.
As a result, the third axle third sclerital distal arm rotates upward and inwards, so that the position is completely reversed. The anal veins are articulated with this sclerite in such a way that when moving they are carried with it and become bent over the backs of insects. The same muscle activity in flight affects the power output of the wings and is therefore also important in flight control. In orthopteroid insects, the elasticity of the cuticle causes the vannal area of ​​the wings to fold along the vein. As a result, energy is spent to open up this area when the wings are moved into flight positions. In general, wing extensions may result from muscle contractions attached to basalar sclerite or, to some insects, to the subalar sclerite.
Legs
Typical and usually segments of the insect legs are divided into coxa, one trochanter, femur, tibia, tarsus, and pretarsus. Coxa in its more symmetrical shape, has a short or cut cylindrical cone shape, although it is generally oval and may be almost spherical. The proximal end of coxa is connected by a submascinal base stitch that forms an internal ridge, or basicosta, and forms a marginal flange, coxomarginale, or basicoxite. The base pad strengthens the base of the coxa and is generally enlarged on the outer wall to provide insertion to the muscle; in the mesial half of coxa, however, is usually weak and often confluent with the coxal margin. The trochanteral muscle that takes their origin in coxa is always attached distally to the basics. Coxa is attached to the body by the articular membrane, corium coxal, which surrounds the base. These two articulations may be the main dorsal and ventral articular points of the subcoxo-coxal hinge. In addition, coxa insects often have anterior articulation with the anterior, ventral end of trochantin, but the trochantinal articulation does not coexist with the sternum articulation. The pleural articular surface of coxa is borne on mesial inflection of the coxal wall. If coxa can be moved only on pleural articulation, the coxal articular surface is usually infected to a sufficient depth to provide levers to the abductor muscles inserted on the outer edge of the coxal base. The distal coxa contains anterior and posterior articulation with trochanters. Coxa's outer walls are often marked with longitudinal stitches from the base to anterior trochanteral articulation. In some insects, the coxal stitches fall in line with pleural stitches, and in such cases coxa seems to be divided into two parts corresponding to episternum and epimeron pleuron. Coxal stitches do not exist in many insects.
Coxal wall inflection with pleural articular surface divides the lateral wall of basicoxite into prearticular and postarticular parts, and two areas often appear as two marginal lobes on the base of coxa. The posterior lobe is usually larger and is called a meron. The meron can be greatly enlarged by the distal extension in the posterior coxa wall; in Neuroptera, Mecoptera, Trichoptera, and Lepidoptera, the meron is so large that the coxa seems to be divided into anterior parts, called "coxa genuina," and meron, but the meron never includes the posterior trochantic articulation region, and the limiting path is always part of the sutura basic. A coxa with an enlarged meron has an appearance similar to one divided by a coxal suture that falls in line with pleural stitches, but the two conditions are substantially different and should not be confused. Meron reached the extreme of his departure from the usual conditions in Diptera. In some of the more common flies, such as in Tipulidae, the middle foot platform appears as a large coxa lobe leading upward and posterior to the coxal base; in the higher members of the order it becomes completely separate from the coxa and forms a lateral mesothorax wall plate.
Trochanter is a basal segment of telopodite; it's always a small segment in the legs of insects, free to move with horizontal hinges on the coxa, but more or less fixed to the base of the femur. When driven on the femur, the trochantero femoral hinges are usually vertical or oblique in the vertical plane, providing little movement of production and reduction in joints, although only the reducing muscles are present. In Odonata, both nymphs and adults, there are two trochanteral segments, but they can not be moved to one another; the second contains the reductor muscle of the femur. The usual single-trochanteral segment of insects, therefore, may represent two trochanters of other arthropods that converge into one clear segment, since it is unlikely that the primary coxotrochanteral hinge has been lost from the foot. In some Hymenoptera subdivisions the basal femur simulates the second trochanter, but the insertion of the reducing muscle at its base proves that the femur is derived from the femoral segment, because as shown in the odonate leg, the reductant has its origin in the true second trochanter.
The thigh bone is the third segment of the insect's leg, usually the longest and strongest part of the limb, but varies in size from the large rear femur of Orthoptera jump to a very small segment as it is present in many forms of larvae. The femoral volume is generally correlated with the size of the tibial muscle contained therein, but is sometimes enlarged and modified in form for other purposes rather than accommodating the tibial muscles. Tibia is characteristically a slender segment of adult insects, only slightly shorter than the femur or femur and combined trochanters. The proximate end forms a more or less different head bent toward the femur, a device that allows the tibia to be bent near the lower surface of the femur.
The term profemur, mesofemur and metaphoric refers to the femora from the front, middle and back of the insect, respectively. Similarly, protibias, mesotibia and metatibia refer to tibiae front, middle and back legs.
The insect tarsus corresponds to the second segment of the back of the general extremity arthropod, which is a segment called propodit in Crustacea. Adult insects are generally divided into two to five subsegments, or tarsomers, but in Protura, some Collembola, and most holometabolous insect larvae retain primitive shapes from simple segments. Adult insect tarsus subsegments are usually free to move from one another by the infected connective membrane, but the tarsus never has intrinsic muscle. The adult pterygote insect tarsus has fewer than five subsegments may be special by the loss of one or more subsegments or by a combination of adjacent subsegements. In the Acrididae tarsi, long basalt pieces clearly consist of three combined tarsoms, leaving the fourth and fifth. The basal tarsomere is sometimes conspicuously striking and distinguished as basitarsus. On the lower surface of the tarsal subsystem in certain Orthoptera there are small pads, tarsal pulvilli, or euplantulae. Tarsus sometimes coalesce with the tibia in larval insects, forming a tibiotarsal segment; in some cases seems to be eliminated or reduced to abnormalities between the tibia and pretarsus.
For most thighbones and tibia is the longest leg segment but variations in the length and robustness of each segment relate to their function. For example, gressorial and cursorial, or the type of insect walking and running respectively, usually have femora and tibiae develop well on all legs, whereas insect jumps (asinators) such as grasshoppers have developed metaphoremic and metatibiae disproportionately. In aquatic beetle (Coleoptera) and insects (Hemiptera), tibia and/or tarsi of one or more pairs of legs are usually modified for swimming (natatorial) with long and slender hair rims. Many insects that live on the ground, such as mole crickets (Orthoptera: Gryllotalpidae), nymphal crickets (Hemiptera: Cicadidae), and scarab beetles (Scarabaeidae), have a tibia of the forefoot (protibiae) enlarged and modified to dig, front of some predatory insects, such as mantispid lacewings (Neuroptera) and mantids (Mantodea), devoted to capture prey, or raptorial. The tibia and basal tarsomere of each honey bee honey are modified for collection and transport of pollen.
Abdomen
The basic plan of adult insect stomach usually consists of 11-12 segments and less strongly sclerotized than head or chest. Each abdominal segment is represented by sclerotized, sternum, and possibly pleurite. Terga separate from each other and from sterna or pleura adjacent to the membrane. Spirulata is located in the pleural area. Variations of this basic plan include merging terga or terga and sterna to form a continuous back or stomach shield or a cone tube. Some insects contain sclerite in the pleural area called laterotergite. Ventral sclerites are sometimes called laterosternites. During the embryonic stages of many insects and postembryonic stages of primitive insects, 11 stomach segments are present. In modern insects there is a tendency towards reducing the number of abdominal segments, but the primitive number 11 is maintained during embryogenesis. The variation in the number of abdominal segments is quite large. If the Apterygota is considered an indication of the basic plan for the pterygote, confusion of government: the adult Protura has 12 segments, the Collembola has 6. The orthopteran Acrididae family has 11 segments, and the Zoraptera fossil specimen has a 10-segment stomach.
Generally, the first seven stomach segments of an adult (pregenital segment) are similar in structure and do not have a complement. However, apterygote (bristletails and silverfish) and many mature water insects have a stomach complement. Apterygote has a pair of styles; a serial basis homologous to the distal portion of the thoracic leg. And, mesal
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