beetle |
fly |
top 10 words in brain distribution (in article): plant species animal power seed leaf water food common variety |
top 10 words in brain distribution (in article): type produce size modern time century production term cause popular |
top 10 words in brain distribution (not in article): fruit grow produce tree station flower sugar train line signal |
top 10 words in brain distribution (not in article): vehicle blade iron design wheel engine steel car fuel power |
times more probable under beetle 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under fly (words not in the model) | |
Beetles'" are the group of insects with the largest number of known species. They are placed in the order "'Coleoptera'" (from Greek, "koleos", "sheath"; and, "pteron", "wing", thus "sheathed wing"), which contains more described species than in any other order in the animal kingdom, constituting about 25% of all known life-forms. 40% of all described insect species are beetles (about 350,000 species), and new species are frequently discovered. Estimates put the total number of species, described and undescribed, at between 5 and 8 million. Beetles can be found in almost all habitats, but are not known to occur in the sea or in the polar regions. They interact with their ecosystems in several ways. They often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are prey of various animals including birds and mammals. Certain species are agricultural pests, such as the Colorado potato beetle "Leptinotarsa decemlineata", the boll weevil "Anthonomus grandis", the red flour beetle "Tribolium castaneum", and the mungbean or cowpea beetle "Callosobruchus maculatus", while other species of beetles are important controls of agricultural pests. For example, beetles in the family Coccinellidae ("ladybirds" or "ladybugs") consume aphids, scale insects, thrips, and other plant-sucking insects that damage crops. Description. The name "Coleoptera" was given by Aristotle for the hardened shield-like forewing (coleo= shield+ ptera= wing). Other characters of this group which are believed to be monophyletic include a holometabolous life cycle; having a prothorax that is distinct from and freely articulating with the mesothorax; the meso- and meta-thoracic segments fusing to form a pterothorax; a depressed body shape with the legs on the ventral surface; the coxae of legs recessed into cavities formed by heavily sclerotized thoracic sclerites; the abdominal sternites more sclerotized than the tergites; antennae with 11 or fewer segments; and terminal genitalic appendages retracted into the abdomen and invisible at rest. The general anatomy of beetles is quite uniform, although specific organs and appendages may vary greatly in appearance and function between the many families in the order. Like all insects, beetles' bodies are divided into three sections: the head, the thorax, and the abdomen. When viewed from below, the thorax is that part from which all three pairs of legs and both pairs of wings arise. The abdomen is everything posterior to the thorax. When viewed from above, most beetles appear to have three clear sections, but this is deceptive: on the beetle's upper surface, the middle "section" is a hard plate called the pronotum, which is only the front part of the thorax; the back part of the thorax is concealed by the beetle's wings. Like all arthropods, beetles are segmented organisms, and all three of the major sections of the body are themselves composed of several further segments, although these are not always readily discernible. This further segmentation is usually best seen on the abdomen. Beetles are generally characterised by a particularly hard exoskeleton and hard forewings (elytra). The beetle's exoskeleton is made up of numerous plates called sclerites, separated by thin sutures. This design creates the armoured defences of the beetle while maintaining flexibility. The elytra are not used for flight, but tend to cover the hind part of the body and protect the second pair of wings ("alae"). The elytra must be raised in order to move the hind flight wings. A beetle's flight wings are crossed with veins and are folded after landing, often along these veins, and are stored below the elytra. In some beetles, the ability to fly has been lost. These include the ground beetles (family Carabidae) and some "true weevils" (family Curculionidae), but also some desert and cave-dwelling species of other families. Many of these species have the two elytra fused together, forming a solid shield over the abdomen. In a few families, both the ability to fly and the elytra have been lost, with the best known example being the glow-worms of the family Phengodidae, in which the females are larviform throughout their lives. Beetles have mouthparts similar to those of grasshoppers. Of these parts, the most commonly known are probably the mandibles, which appear as large pincers on the front of some beetles. The mandibles are a pair of hard, often tooth-like structures that move horizontally to grasp, crush, or cut food or enemies (see defence, below). Two pairs of finger-like appendages are found around the mouth in most beetles, serving to move food into the mouth. These are the maxillary and labial palpi. The eyes are compound and may display remarkable adaptability, as in the case of whirligig beetles (family Gyrinidae), in which the eyes are split to allow a view both above and below the waterline. Other species also have divided eyes — some longhorn beetles (family Cerambycidae) and weevils — while many beetles have eyes that are notched to some degree. A few beetle genera also possess ocelli, which are small, simple eyes usually situated farther back on the head (on the vertex). Beetles' antennae are primarily organs of smell, but may also be used to feel out a beetle's environment physically. They may also be used in some families during mating, or among a few beetles for defence. Antennae vary greatly in form within the Coleoptera, but are often similar within any | True flies'" are insects of the Order "'Diptera'" (=two, and "pteron"= wing), possessing a single pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax. The presence of a single pair of wings distinguishes true flies from other insects with "fly" in their name, such as mayflies, dragonflies, damselflies, stoneflies, whiteflies, fireflies, alderflies, dobsonflies, snakeflies, sawflies, caddisflies, butterflies or scorpionflies. Some true flies have become secondarily wingless, especially in the superfamily Hippoboscoidea, or among those that are inquilines in social insect colonies. Diptera is a large order, containing an estimated 240,000 species of mosquitos, gnats, midges and others, although under half of these (about 120,000 species) have been described. It is one of the major insect orders both in terms of ecological and human (medical and economic) importance. The Diptera, in particular the mosquitoes (Culicidae), are of great importance as disease transmitters, acting as vectors for malaria, dengue, West Nile virus, yellow fever, encephalitis and other infectious diseases. Classification. There are two generally accepted suborders of Diptera. The Nematocera are usually recognized by their elongated bodies and feathery antennae as represented by mosquitoes and crane flies. The Brachycera tend to have a more roundly proportioned body and very short antennae. A more recent classification has been proposed in which the Nematocera is split into two suborders, the Archidiptera and the Eudiptera, but this has not yet gained widespread acceptance among dipterists. Most of the Muscomorpha are further subdivided into the Acalyptratae and Calyptratae based on whether or not they have a calypter (a wing flap that extends over the halteres). Beyond that, considerable revision in the taxonomy of the flies has taken place since the introduction of modern cladistic techniques, and much remains uncertain. The secondary ranks between the suborders and the families are more out of practical or historical considerations than out of any strict respect for phylogenetic classifications (some modern cladists tend to spurn the use of Linnaean rank names). Nearly all classifications in use now, including this article, contain some paraphyletic groupings; this is emphasized where the numerous alternative systems are most greatly at odds. See list of families of Diptera. Dipterans belong to the group Mecopterida, that also contains Mecoptera, Siphonaptera, Lepidoptera (butterflies and moths) and Trichoptera. Inside it, they are sometimes classified closely together with Mecoptera and Siphonaptera in the superorder Antliophora. Evolution. Diptera are usually thought to derive from Mecoptera or a strictly related group. First true dipterans are known from the Middle Triassic, becoming widespread during the Middle and Late Triassic . Flies in culture. Flies have often been used in mythology and literature to represent agents of death and decay, such as the Biblical fourth plague of Egypt, or portrayed as nuisances (e.g., in Greek mythology, Myiagros was a god who chased away flies during the sacrifices to Zeus and Athena, and Zeus sent a fly to bite the horse Pegasus causing Bellerophon to fall back to Earth when he attempted to ride to Mount Olympus), though in a few cultures the connotation is not so negative (e.g., in the traditional Navajo religion, Big Fly is an important spirit being). Emily Dickinson's poem "I Heard a Fly Buzz When I Died" also makes reference to flies in the context of death. Not surprisingly, in art and entertainment, flies are also used primarily to introduce elements of horror or the simply mundane; an example of the former is the 1958 science fiction film "The Fly" (remade in 1986), in which a scientist accidentally exchanges parts of his body with those of a fly. Examples of the latter include trompe l'oeil paintings of the fifteenth century such as "Portrait of a Carthusian" by Petrus Christus, showing a fly sitting on a fake frame , a 2001 art project by Garnet Hertz in which a complete web server was implanted into a dead fly, and various musical works (such as Yoko Ono's album "Fly", U2's song "The Fly," Dave Matthews' song "The Fly" and Béla Bartók's "From the Diary of a Fly"). The ability of flies to cling to almost any surface has also inspired the title of "Human Fly" for stunt performers whose stunts involve climbing buildings, including both real life and fictional individuals. Aside from the fictional and conceptual role flies play in culture, there are practical roles that flies can play (e.g., flies are reared in large numbers in Japan to serve as pollinators of sunflowers in greenhouses), especially the maggots of various species. Maggots. Some types of maggots found on corpses can be of great use to forensic scientists. By their stage of development, these maggots can be used to give an indication of the time elapsed since death, as well as the place the organism died. Maggot species can be identified through the Use of DNA in forensic entomology. The size of the house fly maggot is 10–20 mm (⅜–¾ in). At the height of the summer season, a generation of flies (egg to adult) may be produced in 12–14 days. Other types of maggots are bred commercially, as a popular bait in angling, and a food for carnivorous pets such as reptiles or birds. Maggots have been used in medicine to clean out necrotic wounds , and in food production, particularly of cheeses (casu marzu). |