In some of the Hymenoptera a basal subdivision of the femur simulates a second trochanter, but the insertion of the reductor muscle on its base attests that it belongs to the femoral segment, since as shown in the odonate leg, the reductor has its origin in the true second trochanter. Compound eyes fall into two groups: apposition eyes, which form multiple inverted images, and superposition eyes, which form a single erect image. [1]:22–24 Its ventral, or inner, surface is usually membranous and forms the lobe-like epipharynx, which bears mechanosensilla and chemosensilla.[27][28]. Some are plant-eaters, while others prey on small animals, or suck the blood from larger creatures including humans. [1]:41–42 On the head are an insect's compound eyes, its two antennae (they feel and smell things), and its mouth. [31] While Bombardier beetles have well developed, like other carabid beetles, pygidial glands that empty from the lateral edges of the intersegment membranes between the seventh and eighth abdominal segments. The head is the anterior of the three body regions of an adult insect. Not all species of insects have frontal sutures, but in those that do, the sutures split open during ecdysis, which helps provide an opening for the new instar to emerge from the integument. The eggs hatch immediately after being laid, or the flies are ovoviviparous, with the larva hatching inside the mother. The clypeus differs in shape and size, such as species of Lepidoptera with a large clypeus with elongated mouthparts. Gas exchange patterns in insects can range from continuous and diffusive ventilation, to discontinuous gas exchange. In its pure form, it is leathery, but when encrusted in calcium carbonate, it becomes much harder. Muscles arising on the frons are inserted into these sclerites, which distally are hinged to a pair of lingual sclerites. The vannal veins (lV to nV) are the anal veins immediately associated with the third axillary, and which are directly affected by the movement of this sclerite that brings about the flexion of the wings. As the salivary glands produce fluid and carbohydrate-digesting enzymes (mostly amylases), strong muscles in the pharynx pump fluid into the buccal cavity, lubricating the food like the salivarium does, and helping blood feeders, and xylem and phloem feeders. [1]:41–42 When the vannal fold has the usual position anterior to the group of anal veins, the remigium contains the costal, subcostal, radial, medial, cubital, and postcubital veins. With three thoracic and seven or eight abdominal ganglia can be distinguished to that in which all the thoracic and abdominal ganglia are fused to form a composite structure. The remaining antennal segments or flagellomeres are called the flagellum.[17]:8–11. Distally, the vannal veins are either simple or branched. Some insects have only 1 pair of wings. The first section of the alimentary canal is the foregut (element 27 in numbered diagram), or stomodaeum. [26], In mandibulate mouthparts, the labium is a quadrupedal structure, although it is formed from two fused secondary maxillae. Others have sucking mouthparts for example shaped like stylets in bugs and aphids or shaped like a coiled tongue in butterflies and moths. [8] Pumping movements of the body force the air through the system. The cuticle surrounding the veins becomes thickened and more heavily sclerotized to provide strength and rigidity to the wing. In pterygotes, the postocciput forms the extreme posterior, often U-shaped, which forms the rim of the head extending to the postoccipital suture. Some species are in close association with human dwellings and widely found around garbage or in the kitchen. The insect body is divided into three parts: the head, thorax, and abdomen. Insects posses three main body parts : namely Head, thorax, and abdomen. The second axillary presents both a dorsal and a ventral sclerotization in the wing base; its ventral surface rests upon the fulcral wing process of the pleuron. They can produce glue and protective substances for coating eggs or tough coverings for a batch of eggs called oothecae. [1]:22–24 On its inner side, it is membranous and may be produced into a median lobe, the epipharynx, bearing some sensilla. The primary forking takes place near the base of the wing, forming the two principal branches (Cu1, Cu2). Mesally, it articulates anteriorly (f) with the posterior end of the second axillary, and posteriorly (b) with the posterior wing process of the tergum (PNP), or with a small fourth axillary when the latter is present. A Closer Look at the Arthropod Branches a) How many body parts do insects have? Anterior and posterior rotator muscles are inserted on the cardo, and ventral adductor muscles arising on the tentorium are inserted on both cardo and stipes. The mouthparts of adult insects can be of different types. Examples of insect proboscises - True bug (A), Ant (B) and Honeybee (C). How many body parts do these insects have? Female mosquitoes feed on blood (hemophagous) making them disease vectors. Its form is highly variable and often irregular, but the third axillary is the sclerite on which is inserted the flexor muscle of the wing (D). The terminal portion of the ejaculatory duct may be sclerotized to form the intromittent organ, the aedeagus. [55][56] An additional role of the haemolymph in some orders, can be that of predatory defence. The ducts and spermathecae are lined with a cuticle. The larvae of Cyclorrhapha however, tend to have hardly any head capsule at all. This is because the primary axis of the head is rotated 90° to become parallel to the primary axis of the body. Insects are the largest group of animals on Earth. How many main body parts does an insect have? Hardened plates in the exoskeleton are called sclerites, which are subdivisions of the major regions - tergites, sternites and pleurites, for the respective regions tergum, sternum, and pleuron.[6]. One or both pairs of lobes may be absent or they may be fused to form a single median process. In Orthoptera, it usually has this position. Species of the genus Anopheles are characterized by their long palpi (two parts with widening end), almost reaching the end of labrum. In the honey bee (Hymenoptera: Apidae: Apis mellifera), the elongated and fused labial glossae form a hairy tongue, which is surrounded by the maxillary galeae and the labial palps to form a tubular proboscis containing a food canal. Where found, the occipital suture is the arched, horseshoe-shaped groove on the back of the head, ending at the posterior of each mandible. 2. [38]:165, The terms profemur, mesofemur and metafemur refer to the femora of the front, middle and hind legs of an insect, respectively. [49]:30–31, The salivary glands (element 30 in numbered diagram) in an insect's mouth produce saliva. Each tube is inwardly concave, thus forming a central tube through which moisture is sucked. In some insects, the legs are specially adapted for jumping. [9], The clypeus is a sclerite between the face and labrum, which is dorsally separated from the frons by the frontoclypeal suture in primitive insects. Cockroaches are generally omnivorous with the exception of the wood-eating species such as Cryptocercus; these roaches are incapable of digesting cellulose themselves, but have symbiotic relationships with various protozoans and bacteria that digest the cellulose, allowing them to extract the nutrients. The stylets and the feeding tube form the modified mandibles, maxilla, and hypopharynx.[24]. The coxa in its more symmetrical form, has the shape of a short cylinder or truncate cone, though commonly it is ovate and may be almost spherical. Many ground-dwelling insects, such as mole crickets (Orthoptera: Gryllotalpidae), nymphal cicadas (Hemiptera: Cicadidae), and scarab beetles (Scarabaeidae), have the tibiae of the forelegs (protibiae) enlarged and modified for digging (fossorial), whereas the forelegs of some predatory insects, such as mantispid lacewings (Neuroptera) and mantids (Mantodea), are specialized for seizing prey, or raptorial. Antennae of different insects are very variable in form and size. [7] In the anatomy of some taxa, such as many Cicadomorpha, the front of the head is fairly clearly distinguished and tends to be broad and sub-vertical; that median area commonly is taken to be the frons. This forces the male to lie on its back in order for its genitalia to remain engaged with those of the female, or the torsion of the male genitals allows the male to mate while remaining upright. [8]:885 The aedeagus can be quite pronounced or de minimis. [1]:69 Air is taken in through spiracles along the sides of the abdomen and thorax supplying the trachea with oxygen as it goes through the lepidopteran's respiratory system. In ants, the mandibles also serve a defensive function (particularly in soldier castes). Spermathecae store sperm for varying periods of time and, along with portions of the oviducts, can control sperm use. rings. Chewing insects have two mandibles, one on each side of the head. It bears 3 pairs of legs (one on each segment) and usually 2 pairs of wings. The fourth axillary sclerite is not a constant element of the wing base. Production of eggs by panoistic ovaries tends to be slower than that by meroistic ovaries. The midgut is short and straight, with the hindgut being longer and coiled. [69] The pupae take various forms, and in some cases develop inside a silk cocoon. When flies mate, the male initially flies on top of the female, facing in the same direction, but then turns round to face in the opposite direction. [38]:163–164, The inflection of the coxal wall bearing the pleural articular surface divides the lateral wall of the basicoxite into a prearticular part and a postarticular part, and the two areas often appear as two marginal lobes on the base of the coxa. [8][1]:22–24, Because the mesothorax and metathorax hold the wings, they have a combined name called the pterothorax (pteron = wing). The trachea of the costal vein is perhaps a branch of the subcostal trachea. The proximal plate (m) is usually attached to the distal arm of the third axillary and perhaps should be regarded as a part of the latter. Each segment is delineated by an intersegmental suture. The vannal region is usually best developed in the hindwing, in which it may be enlarged to form a sustaining surface, as in Plecoptera and Orthoptera. In number, the vannal veins vary from one to 12, according to the expansion of the vannal area of the wing. The tarsus is occasionally fused with the tibia in larval insects, forming a tibiotarsal segment; in some cases it appears to be eliminated or reduced to a rudiment between the tibia and the pretarsus. It divides the cavity into a dorsal food pouch, or cibarium, and a ventral salivarium into which the salivary duct opens. A portion of the vas deferens is often enlarged to form the seminal vesicle, which stores the sperm before they are discharged into the female. [8], The neuroendocrine system is typical of insects. They also have palps, which are used to sense the characteristics of potential foods. Which insect produces honey? The insect's wings and legs are attached to the thorax. [1]:22–24 The cutting edges are typically strengthened by the addition of zinc, manganese, or rarely, iron, in amounts up to about 4% of the dry weight. [48] In addition to the alimentary canal, insects also have paired salivary glands and salivary reservoirs. On the thorax, insects have wings and legs. Part of the Biodiversity Counts Curriculum Collection. By VA It also plays an essential part in the moulting process. Ordinarily, however, a definite number of cross-veins having specific locations occurs. [8], A notable number of species have developed special glands that produce chemicals for deterring predators (see Defense and predation). What is an insect? Insects are able to feel with their antennae because of the fine hairs (setae) that cover them. All insects have six legs (three pairs of … – Urea. In Brachycera, the labellum is especially prominent and used for sponging liquid or semiliquid food. In most species, though, the frons is bordered at its anterior by the frontoclypeal or epistomal sulcus above the clypeus. The lateral ducts are where the eggs leave the body, while the spermatheca is where sperm is stored. In many Diptera, a deep incision of the anal area of the wing membrane behind the single vannal vein sets off a proximal alar lobe distal to the outer squama of the alula. The palp has levator and depressor muscles arising in the stipes, and each segment of the palp has a single muscle causing flexion of the next segment. Segments 8 and 9 bear the genitalia; segment 10 is visible as a complete segment in many "lower" insects but always lacks appendages; and the small segment 11 is represented by a dorsal epiproct and pair of ventral paraprocts derived from the sternum. Continuing with this logic, there is also the mesopleura and metapleura, as well as the mesosternum and metasternum. 4 c. 5 d. 6 3. Over how many orders are there of insects? CO2 diffuses out of the cell into the tracheole. According to current dogma, the archedictyon contained six to eight longitudinal veins. 13. These vesicles are derived from the coxal and trochanteral endites (inner annulated lobes) of the ancestral abdominal appendages. The maxillae occupy a lateral position, one on each side of the head behind the mandibles. [27] Most of the hypopharynx is membranous, but the adoral face is sclerotized distally, and proximally contains a pair of suspensory sclerites extending upwards to end in the lateral wall of the stomodeum. They are the head, the thorax, and the abdomen. Despite "milli" in their name, millipedes do not have 1,000 legs, but common species have anywhere from 36 to 400 legs. However, recent studies of the embryology, gene expression, and nerve supply to the labrum show it is innervated by the tritocerebrum of the brain, which is the fused ganglia of the third head segment. Alternately, the foregut may expand into a very enlarged crop and proventriculus, or the crop could just be a diverticulum, or fluid filled structure, as in some Diptera species. Paternity testing of insects has revealed that some, and probably many, female insects use the spermatheca and various ducts to control or bias sperm used in favor of some males over others. Pumping of the haemolymph occurs by waves of peristaltic contraction, originating at the body's posterior end, pumping forwards into the dorsal vessel, out via the aorta and then into the head where it flows out into the haemocoel. The main structure of an insect's digestive system is a long enclosed tube called the alimentary canal (or gut), which runs lengthwise through the body. Some are tiny, only a few millimeters (less than a quarter of an inch) across, while others can be the size of dinner plates. Situated beneath the mandibles, paired maxillae manipulate food during mastication. In turn, the notum of the prothorax is called the pronotum, the notum for the mesothorax is called the mesonotum and the notum for the metathorax is called the metanotum. Since all winged insects are believed to have evolved from a common ancestor, the archediction represents the "template" that has been modified (and streamlined) by natural selection for 200 million years. In addition, the insect coxa has often an anterior articulation with the anterior, ventral end of the trochantin, but the trochantinal articulation does not coexist with a sternal articulation. Although the general function of the thre… [38], The various movements of the wings, especially in insects that flex their wings horizontally over their backs when at rest, demand a more complicated articular structure at the wing base than a mere hinge of the wing with the body. The sclerite posterior to the suture is called the epimiron (serially, the mesepimiron and metepimiron). There are insects that can fly and others that can swim. [1][57] It is transported around the body by combined heart (posterior) and aorta (anterior) pulsations, which are located dorsally just under the surface of the body. The fourth vein is the radius, which is branched into five separate veins. [8], The reproductive system of females consist of paired ovaries, lateral oviducts, spermatheca, and a genital chamber. The postgena is the area immediately posteriad, or posterior or lower on the gena of pterygote insects, and forms the lateral and ventral parts of the occipital arch. The body of the sclerite articulates laterally with the second axillary. [17]:8–11 However, touch is not the only thing that antennae can detect; numerous tiny sensory structures on the antennae allow insects to sense smells, temperature, humidity, pressure, and even potentially sense themselves in space. Strong neuron connections connect the neurohemal corpora cardiaca to the brain and frontal ganglion, where the closely related median corpus allatum produces juvenile hormone III in close proximity to the neurohemal dorsal aorta. The ejaculatory duct is derived from an invagination of the epidermal cells during development and, as a result, has a cuticular lining. The number of Malpighian tubules possessed by a given insect varies between species, ranging from only two tubules in some insects to over 100 tubules in others. [71] In lepidopteran species, hemolymph is circulated through the veins in the wings by some form of pulsating organ, either by the heart or by the intake of air into the trachea. Like many of the other parts making up the insect's head, the gena varies among species, with its boundaries difficult to establish. In the order Coleoptera, tympanal organs have been described in at least two families. The primitive insect groups use muscles that act directly on the wing structure. In the exoporian type (in Hepialoidea and Mnesarchaeoidea) there are two separate places for insemination and oviposition, both occurring on the same sterna as the monotrysian type, 9/10.