The wasps (Hymenoptera) are an order of insects, including in the subclass Pterygota (Endopterygota Oligoneoptera) and, as a single order in the section Hymenopteroidea, which includes more than 120,000 species spread throughout the world. The name refers to the membranous wings, and comes from ancient greek ὑμήν (Humen) and membrane πτερόν (pteron): wing. They are divided into two suborders: the Sinf (or Chalastogastra Symphyta), characterized by having the abdomen attached to the chest without restriction, and Apocrita (or Clistogastra Apocrita), more evolved, with distinctly separate thorax from the abdomen. Insects are small, medium and large, terrestrial, winged or wingless, with plumage of varied colors and not consistent with exoskeleton. In some groups, and frequent polymorphism of caste. The Order has been present since the Mesozoic (Lower Jurassic). Morphology of the adult
Cape. The head is generally ipognato, but in some taxonomic groups may also be undershot. It is very mobile, connected by a thin neck to the chest. It has compound eyes and three ocelli (not always present).
antennas. The antennas are varied in shape, sometimes different in the two sexes. Article proximal (stalk) is more or less elongated and the next (pedicel) short and conical. The pedicel is articulated flagellum composed of a greater or lesser number of articles of various shapes, including a number of even several dozens. In general, in advanced forms, the number of distal joints is reduced and the shape is nearly discoidal. The morphology and location of the antennas is an important element of systematic identification.
Mouthparts. The mouthparts are chewing, chewing-chewing-lapping or sucking. In all forms there are the jaws, but often do not perform functions related to food: in many Hymenoptera are used for example to open during flicker the pupal cell or, in endoparasitic species, to open a hole in the integument of the host, others are used for nest building and transporting material used for this purpose. The elements that differ significantly in the mouthparts of the Hymenoptera is the maxillo-labial complex, consisting of the two jaws and the lower lip. Varying in form, the structure of the jaw is typical: It consists of a proximal element, said hinge, and a distal all'ipostoma articulated, sometimes very elongated, said jamb. Jamb articulate the maxillary palp, consisting of 1-6 articles, and more inside the two lobes respectively called galley and Lacinia (in order, from the outside inside). The lower lip is composed, in appearing as a mouth chewing type insects in two parts, one fixed, known PostLab, and a distal mobile prelabio said. The PostLab is divided into two morphological elements, the submento and, more distally, the chin. The prelabio includes an item by pressing said baseline, on which are articulated outside the labial palps and within the lobes. These are divided into two paraglosse, sides, and gloss, central. Overall, the gloss and paraglosse form the ligule.
Chest. The thorax is characterized by a great development compared to the prothorax and mesothorax metathorax, the latter being developed fairly low. A special Hymenoptera Apocrita is its connection with the urite the chest itself, forming a fourth segment propodeum said. The mesonotum is often crossed by two grooves, these grooves or parapsidali notauli (the latter is actually a term used in literature by authors such as Anglo-Saxon plural of notaulus). The notauli not always well defined or even none at all, have a longitudinal course and tend to converge at the rear. Mesoscuto subdivided into three regions, a median or anterior-middle (sometimes interpreted as a hurry) and two lateral or posterior (sometimes interpreted as Scuto proper), containing the wing sclerites (axilla and tegula). The legs are generally surgery type, well developed and robust. Sometimes have morphological adaptations that make them likely to dig or catch prey, carrying supplies. In some cases absent.
Ali. The wings, when present, are four in number and membranous; the front of the rear are more developed. At rest are bent backwards, horizontally, along the back of the abdomen. The morphofunctional most significant element of the wings of Hymenoptera is the device connecting to the front of the rear wing. The posterior margin of the forewings are folded over and hooks the hook this up to it, such hamula placed along the costal margin of hind wings. This apparatus makes the front and rear wings forming a single surface Feather. The robustness of the apparatus of connection may be such that the wings are permanently attached in the resting phase. The venular the wings is an important character for taxonomic purposes in some taxonomic groups. With regard to nomenclature, however, disputes are still open to the interpretation of the wing veins, so in the literature are reported different criteria for classification. These disputes are due to attempts to interpret the veining of the wings of Hymenoptera on different criteria: developmental, anatomical (ratio of ribs and tracheazione) morfoanatomici (ratio longitudinal ribs and basal sclerites). Starting from the elaboration of the Comstock-Needham system, towards the end of the nineteenth century, during the twentieth century have been proposed up to 60 different models. Some derivations proposed by the Comstock-Needham system, other systems regardless of their specific homologies with other orders of insects, others were still trying to extract a summary of the previous theories. The key dispute is the interpretation of the rib media: According to some models this vein would disappear, while others see it as a rib that has a common course with the radio in the proximal and then come in to a distance in the distal region Feather. At present there is no standard universally shared, but the currently most popular approach is to adopt the scheme of Herbert H. Ross in 1936, with later adjustments.
Abdomen. The abdomen is sessile or pedunculated, consisting of 10 uriti, of which the latter are more or less modified and reduced. In Apocrita there is a marked difference in the morphology of the abdomen in front. In addition to the shift of the I urite in the thoracic region to form the propodeum, show a narrowing of the Apocrita urite II or II and III, called the petiole. Sometimes the petiole is very long, sometimes reduced in length to make the abdomen secondarily sessile. The part of the abdomen below the petiole, composed of III or IV urite on, is called gastro.
ovipositor. The ovipositor is formed by the VIII and IX urosternite. These sternites form of sheets, such valviferi, of which the first pair consists of two formations laminar side. Between the two pairs of valviferi emerge VALVE, VALVE separate respectively the first, second and third VALVE. The first merged to form a sheath as it moves up the second VALVE. The first and second VALVE sclerificate are strongly and form a body piercing Terebras said. The third VALVE are larger and less sclerificate and embrace the Terebras. An important distinction concerns the role played by Terebras:
In Hymenoptera Terebrantia the genital opening is stationed at the base and dell'ovopositore Terebras is used effectively as well as body piercing ovipositor. In
Hymenoptera aculeata is deployed in front of the genital opening and Terebras has lost its original function. The ovipositor retracts into the abdomen and everted, assuming the function of organ of defense or offense. In these wasps the sting is called Terebras or sting.
juveniles. The Hymenoptera are holometabolous insects or hypermetabolic. The larvae are grouped into two types.
Larvae with independent living. Included in this type eruciformi larvae, which look similar to caterpillars of the Lepidoptera. These larvae exoskeleton have a strong, well-differentiated head with chewing mouthparts well developed, they move through three pairs of thoracic legs and abdominal pseudozampe 6-8 pairs of these from the second urite. Included in this way with the larvae flat base, adapted to living as miners in plant tissues. Larvae
not equipped with independent living. Included in this type larvae carrying out their development within a nest or as endoparasites within a host. Have a marked morphological simplification, with soft exoskeleton, head slightly distinct or not differentiated, simplified mouthparts, the absence of visual organs and bodies in movement. There is a marked morphological heterogeneity the first larval stage, to distinguish a dozen different larval forms. The pupae are generally
exar, that is, with appendages free, and adectiche, that is, not articulated jaws. Are formed within the host or the nest, or outdoors, near the host. Are immobile and do not feed.
Reproduction. The Hymenoptera reproduce both anfigonica with which females are produced for both parthenogenetic, in which males are produced. The fact that males are haploid favors altruism. The parasite is common forms polyembryony.
Power. In Hymenoptera are represented various diets. Under the scheme feed the wasps are important in three different aspects: Several species, especially common among primitive Hymenoptera are phytophagous. Among the pests include, in particular forms fillofaghe, carpofaghe, antofaghe, spermatofaghe, and palinofaghe xylophagous. The Terebrantia include parasitic species of great interest because it is often useful as auxiliaries in the biological control. Other species, among Aculeate, are mostly predators, but their role in agro-systems is sometimes controversial. Among the insects including bees are of fundamental importance as pollinators. Their diet is based mostly on pollen as a protein source, sugar and liquid (nectar, honeydew secondarily, etc.). as an energy source. Therefore play a vital ecological role for the reproduction of plants pollinating insects.
Ethology. Most of the Hymenoptera lead a solitary life, but in this order shows the most advanced and complex forms of social structure and more interesting from the standpoint of ethology. Companies may monoginiche (ruled by a queen) or polygyny (more females). Other interesting examples from the ethological point of view are found in various forms of symbiosis is mutualistic or parasitic.
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