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87-462: Drosophila melanogaster is a species of fly (an insect of the order Diptera) in the family Drosophilidae . The species is often referred to as the fruit fly or lesser fruit fly , or less commonly the " vinegar fly", " pomace fly", or " banana fly". In the wild, D. melanogaster are attracted to rotting fruit and fermenting beverages, and are often found in orchards, kitchens and pubs. Starting with Charles W. Woodworth 's 1901 proposal of

174-495: A hypoxia treatment experience decreased thorax length, while hyperoxia produces smaller flight muscles, suggesting negative developmental effects of extreme oxygen levels. Circadian rhythms are also subject to developmental plasticity. Light conditions during development affect daily activity patterns in Drosophila melanogaster , where flies raised under constant dark or light are less active as adults than those raised under

261-1156: A 12-hour light/dark cycle. Temperature is one of the most pervasive factors influencing arthropod development. In Drosophila melanogaster temperature-induced developmental plasticity can be beneficial and/or detrimental. Most often lower developmental temperatures reduce growth rates which influence many other physiological factors. For example, development at 25 °C increases walking speed, thermal performance breadth , and territorial success, while development at 18 °C increases body mass, wing size, all of which are tied to fitness. Moreover, developing at certain low temperatures produces proportionally large wings which improve flight and reproductive performance at similarly low temperatures ( See acclimation ). Fly Housefly (Muscidae) (top left) Haematopota pluvialis (Tabanidae) (top right) Ctenophora pectinicornis (Tipulidae) (mid left) Ochlerotatus notoscriptus (Culicidae) (mid right) Milesia crabroniformis (Syrphidae) (bottom left) Holcocephala fusca (Asilidae) (bottom right) Nematocera ( paraphyletic ) (inc Eudiptera ) Brachycera Flies are insects of

348-418: A cluster of spiky hairs (claspers) surrounding the reproducing parts used to attach to the female during mating. Extensive images are found at FlyBase . Drosophila melanogaster can be distinguished from related species by the following combination of features: gena ~1/10 diameter of eye at greatest vertical height; wing hyaline and with costal index 2.4; male protarsus with a single row of ~12 setae forming

435-446: A few hundred, very long (1.76 mm) sperm cells in seminal fluid to the female. Females store the sperm in a tubular receptacle and in two mushroom-shaped spermathecae ; sperm from multiple matings compete for fertilization. A last male precedence is believed to exist; the last male to mate with a female sires about 80% of her offspring. This precedence was found to occur through both displacement and incapacitation. The displacement

522-558: A fully formed adult fruit fly. Males perform a sequence of five behavioral patterns to court females. First, males orient themselves while playing a courtship song by horizontally extending and vibrating their wings. Soon after, the male positions himself at the rear of the female's abdomen in a low posture to tap and lick the female genitalia. Finally, the male curls his abdomen and attempts copulation. Females can reject males by moving away, kicking, and extruding their ovipositor. Copulation lasts around 15–20 minutes, during which males transfer

609-573: A genetic model for several human diseases including the neurodegenerative disorders Parkinson's , Huntington's , spinocerebellar ataxia and Alzheimer's disease . The fly is also being used to study mechanisms underlying aging and oxidative stress , immunity , diabetes , and cancer , as well as drug abuse . The life cycle of this insect has four stages: fertilized egg, larva, pupa, and adult. Embryogenesis in Drosophila has been extensively studied, as its small size, short generation time, and large brood size makes it ideal for genetic studies. It

696-511: A given body mass. As a consequence, endotherms generally rely on higher food consumption, and commonly on food of higher energy content. Such requirements may limit the carrying capacity of a given environment for endotherms as compared to its carrying capacity for ectotherms. Because ectotherms depend on environmental conditions for body temperature regulation, as a rule, they are more sluggish at night and in early mornings. When they emerge from shelter, many diurnal ectotherms need to heat up in

783-526: A greater mating efficiency for experienced males over naïve males. This modification also appears to have obvious evolutionary advantages, as increased mating efficiency is extremely important in the eyes of natural selection . Both male and female D. melanogaster flies act polygamously (having multiple sexual partners at the same time). In both males and females, polygamy results in a decrease in evening activity compared to virgin flies, more so in males than females. Evening activity consists of those in which

870-777: A laboratory known as the Fly Room. The Fly Room was cramped with eight desks, each occupied by students and their experiments. They started off experiments using milk bottles to rear the fruit flies and handheld lenses for observing their traits. The lenses were later replaced by microscopes, which enhanced their observations. Morgan and his students eventually elucidated many basic principles of heredity, including sex-linked inheritance, epistasis , multiple alleles, and gene mapping . D. melanogaster had historically been used in laboratories to study genetics and patterns of inheritance. However, D. melanogaster also has importance in environmental mutagenesis research, allowing researchers to study

957-456: A length of up to 7 cm (2.8 in), is generally considered to be the largest fly in the world, while the smallest is Euryplatea nanaknihali , which at 0.4 mm (0.016 in) is smaller than a grain of salt. Brachycera are ecologically very diverse, with many being predatory at the larval stage and some being parasitic. Animals parasitised include molluscs , woodlice , millipedes , insects, mammals , and amphibians . Flies are

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1044-405: A meal. For visual course control, flies' optic flow field is analyzed by a set of motion-sensitive neurons. A subset of these neurons is thought to be involved in using the optic flow to estimate the parameters of self-motion, such as yaw, roll, and sideward translation. Other neurons are thought to be involved in analyzing the content of the visual scene itself, such as separating figures from

1131-401: A mobile head, with a pair of large compound eyes , and mouthparts designed for piercing and sucking (mosquitoes, black flies and robber flies), or for lapping and sucking in the other groups. Their wing arrangement gives them great manoeuvrability in flight, and claws and pads on their feet enable them to cling to smooth surfaces. Flies undergo complete metamorphosis ; the eggs are often laid on

1218-744: A season, or even for years, depending on the species and circumstances. Owners of reptiles may use an ultraviolet light system to assist their pets' basking. Ectotherms rely largely on external heat sources such as sunlight to achieve their optimal body temperature for various bodily activities. Accordingly, they depend on ambient conditions to reach operational body temperatures. In contrast, endothermic animals maintain nearly constant high operational body temperatures largely by reliance on internal heat produced by metabolically active organs (liver, kidney, heart, brain, muscle) or even by specialized heat producing organs like brown adipose tissue . Ectotherms typically have lower metabolic rates than endotherms at

1305-441: A sex comb; male epandrial posterior lobe small and nearly triangular; female abdominal tergite 6 with dark band running to its ventral margin; female oviscapt small, pale, without dorsodistal depression and with 12-13 peg-like outer ovisensilla. Drosophila melanogaster flies can sense air currents with the hairs on their backs. Their eyes are sensitive to slight differences in light intensity and will instinctively fly away when

1392-506: A shadow or other movement is detected. Under optimal growth conditions at 25 °C (77 °F), the D. melanogaster lifespan is about 50 days from egg to death. The developmental period for D. melanogaster varies with temperature, as with many ectothermic species. The shortest development time (egg to adult), seven days, is achieved at 28 °C (82 °F). Development times increase at higher temperatures (11 days at 30 °C or 86 °F) due to heat stress. Under ideal conditions,

1479-408: A useful extent. To warm up, reptiles and many insects find sunny places and adopt positions that maximise their exposure; at harmfully high temperatures they seek shade or cooler water. In cold weather, honey bees huddle together to retain heat. Butterflies and moths may orient their wings to maximize exposure to solar radiation in order to build up heat before take-off. Gregarious caterpillars, such as

1566-438: A variety of hosts. The larvae of the shore flies (Ephydridae) and some Chironomidae survive in extreme environments including glaciers ( Diamesa sp., Chironomidae ), hot springs, geysers, saline pools, sulphur pools, septic tanks and even crude oil ( Helaeomyia petrolei ). Adult hoverflies (Syrphidae) are well known for their mimicry and the larvae adopt diverse lifestyles including being inquiline scavengers inside

1653-490: A whole host of other behavioral thermoregulation mechanisms. In contrast to ectotherms, endotherms rely largely, even predominantly, on heat from internal metabolic processes, and mesotherms use an intermediate strategy. As there are more than two categories of temperature control utilized by animals, the terms warm-blooded and cold-blooded have been deprecated as scientific terms. Various patterns of behavior enable certain ectotherms to regulate body temperature to

1740-485: Is Spilomyia longicornis , which is a fly but mimics a vespid wasp. Flies have a mobile head with a pair of large compound eyes on the sides of the head, and in most species, three small ocelli on the top. The compound eyes may be close together or widely separated, and in some instances are divided into a dorsal region and a ventral region, perhaps to assist in swarming behaviour. The antennae are well-developed but variable, being thread-like, feathery or comb-like in

1827-442: Is a holometabolous insect, so it undergoes a full metamorphosis. Their life cycle is broken down into four stages: embryo, larva, pupa, adult. The eggs, which are about 0.5 mm long, hatch after 12–15 hours (at 25 °C or 77 °F). The resulting larvae grow for about four days (at 25 °C) while molting twice (into second- and third-instar larvae), at about 24 and 48 hours after hatching. During this time, they feed on

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1914-409: Is also unique among model organisms in that cleavage occurs in a syncytium . During oogenesis, cytoplasmic bridges called "ring canals" connect the forming oocyte to nurse cells. Nutrients and developmental control molecules move from the nurse cells into the oocyte. In the figure to the left, the forming oocyte can be seen to be covered by follicular support cells. After fertilization of the oocyte,

2001-575: Is attributed to sperm handling by the female fly as multiple matings are conducted and is most significant during the first 1–2 days after copulation. Displacement from the seminal receptacle is more significant than displacement from the spermathecae. Incapacitation of first male sperm by second male sperm becomes significant 2–7 days after copulation. The seminal fluid of the second male is believed to be responsible for this incapacitation mechanism (without removal of first male sperm) which takes effect before fertilization occurs. The delay in effectiveness of

2088-443: Is followed by the name of the gene affected and a description of its phenotype. (Note: Recessive alleles are in lower case, while dominant alleles are capitalised.) Drosophila genes are traditionally named after the phenotype they cause when mutated. For example, the absence of a particular gene in Drosophila will result in a mutant embryo that does not develop a heart. Scientists have thus called this gene tinman , named after

2175-449: Is induced by the DNA damaging agents ultraviolet light and mitomycin C . Females become receptive to courting males about 8–12 hours after emergence. Specific neuron groups in females have been found to affect copulation behavior and mate choice. One such group in the abdominal nerve cord allows the female fly to pause her body movements to copulate. Activation of these neurons induces

2262-547: Is one of the major insect orders and of considerable ecological and human importance. Flies are major pollinators, second only to the bees and their Hymenopteran relatives. Flies may have been among the evolutionarily earliest pollinators responsible for early plant pollination . Fruit flies are used as model organisms in research, but less benignly, mosquitoes are vectors for malaria , dengue , West Nile fever , yellow fever , encephalitis , and other infectious diseases ; and houseflies , commensal with humans all over

2349-421: Is one of the most widely used and genetically best-known of all eukaryotic organisms. All organisms use common genetic systems; therefore, comprehending processes such as transcription and replication in fruit flies helps in understanding these processes in other eukaryotes, including humans . Thomas Hunt Morgan began using fruit flies in experimental studies of heredity at Columbia University in 1910 in

2436-407: Is relatively very small and therefore often ignored, aside from its important eyeless gene. The D. melanogaster sequenced genome of 139.5 million base pairs has been annotated and contains around 15,682 genes according to Ensemble release 73. More than 60% of the genome appears to be functional non-protein-coding DNA involved in gene expression control. Determination of sex in Drosophila occurs by

2523-489: Is sent to a brain region that is a homolog of the hypothalamus and the hypothalamus then controls sexual behavior and desire. Gonadotropic hormones in Drosophila maintain homeostasis and govern reproductive output via a cyclic interrelationship, not unlike the mammalian estrous cycle . Sex peptide perturbs this homeostasis and dramatically shifts the endocrine state of the female by inciting juvenile hormone synthesis in

2610-666: Is served. Flies belonging to the family Tephritidae are also called "fruit flies". This can cause confusion, especially in the Mediterranean, Australia , and South Africa , where the Mediterranean fruit fly Ceratitis capitata is an economic pest. The term " Drosophila ", meaning "dew-loving", is a modern scientific Latin adaptation from Greek words δρόσος , drósos , " dew ", and φιλία , philía , "lover". The term " melanogaster " meaning "black-belly", comes from Ancient Greek μέλας , mélas , “black”, and γᾰστήρ , gastḗr , "belly". Unlike humans ,

2697-440: Is typical of regions of the abyssal ocean and hence can be regarded as homeothermic ectotherms. In contrast, in places where temperature varies so widely as to limit the physiological activities of other kinds of ectotherms, many species habitually seek out external sources of heat or shelter from heat; for example, many reptiles regulate their body temperature by basking in the sun, or seeking shade when necessary in addition to

Drosophila melanogaster - Misplaced Pages Continue

2784-417: Is typically used in research owing to its rapid life cycle, relatively simple genetics with only four pairs of chromosomes , and large number of offspring per generation. It was originally an African species, with all non-African lineages having a common origin. Its geographic range includes all continents, including islands. D. melanogaster is a common pest in homes, restaurants, and other places where food

2871-524: Is widely thought to be a member of Mecopterida , along with Lepidoptera (butterflies and moths), Trichoptera (caddisflies), Siphonaptera (fleas), Mecoptera (scorpionflies) and possibly Strepsiptera (twisted-wing flies). Diptera has been grouped with Siphonaptera and Mecoptera in the Antliophora, but this has not been confirmed by molecular studies. Diptera were traditionally broken down into two suborders, Nematocera and Brachycera , distinguished by

2958-399: The D. melanogaster homolog of WRN also cause increased physiologic signs of aging, such as shorter lifespan, higher tumor incidence, muscle degeneration, reduced climbing ability, altered behavior and reduced locomotor activity. Meiotic recombination in D. melanogaster appears to be employed in repairing damage in germ-line DNA as indicated by the findings that meiotic recombination

3045-631: The Jurassic , some 180 million years ago. A third radiation took place among the Schizophora at the start of the Paleogene , 66 million years ago. The phylogenetic position of Diptera has been controversial. The monophyly of holometabolous insects has long been accepted, with the main orders being established as Lepidoptera, Coleoptera, Hymenoptera and Diptera, and it is the relationships between these groups which has caused difficulties. Diptera

3132-1071: The Mecopterida , alongside the Mecoptera , Siphonaptera , Lepidoptera and Trichoptera . The possession of a single pair of wings distinguishes most true flies from other insects with "fly" in their names. However, some true flies such as Hippoboscidae (louse flies) have become secondarily wingless. The cladogram represents the current consensus view. Hymenoptera (sawflies, wasps, ants, bees) [REDACTED] Raphidioptera (snakeflies) [REDACTED] Megaloptera (alderflies and allies) [REDACTED] Neuroptera (Lacewings and allies) [REDACTED] Coleoptera (beetles) [REDACTED] Strepsiptera (twisted-wing parasites) [REDACTED] Trichoptera (caddisflies) [REDACTED] Lepidoptera (butterflies, moths) [REDACTED] Diptera [REDACTED] Mecoptera (scorpionflies) [REDACTED] Siphonaptera (fleas) [REDACTED] The first true dipterans known are from

3219-666: The Middle Triassic (around 240 million years ago), and they became widespread during the Middle and Late Triassic . Modern flowering plants did not appear until the Cretaceous (around 140 million years ago), so the original dipterans must have had a different source of nutrition other than nectar . Based on the attraction of many modern fly groups to shiny droplets, it has been suggested that they may have fed on honeydew produced by sap-sucking bugs which were abundant at

3306-676: The Oz character of the same name . Likewise changes in the Shavenbaby gene cause the loss of dorsal cuticular hairs in Drosophila sechellia larvae. This system of nomenclature results in a wider range of gene names than in other organisms. The genome of D. melanogaster (sequenced in 2000, and curated at the FlyBase database) contains four pairs of chromosomes – an X/Y pair, and three autosomes labeled 2, 3, and 4. The fourth chromosome

3393-692: The Strepsiptera . In contrast to the flies, the Strepsiptera bear their halteres on the mesothorax and their flight wings on the metathorax. Each of the fly's six legs has a typical insect structure of coxa, trochanter, femur, tibia and tarsus, with the tarsus in most instances being subdivided into five tarsomeres . At the tip of the limb is a pair of claws, and between these are cushion-like structures known as pulvilli which provide adhesion. Ectotherm Some of these animals live in environments where temperatures are practically constant, as

3480-515: The X:A ratio of X chromosomes to autosomes, not because of the presence of a Y chromosome as in human sex determination. Although the Y chromosome is entirely heterochromatic , it contains at least 16 genes, many of which are thought to have male-related functions. There are three transferrin orthologs, all of which are dramatically divergent from those known in chordate models. A June 2001 study by National Human Genome Research Institute comparing

3567-642: The forest tent caterpillar and fall webworm , benefit from basking in large groups for thermoregulation. Many flying insects, such as honey bees and bumble bees, also raise their internal temperatures endothermally prior to flight, by vibrating their flight muscles without violent movement of the wings. Such endothermal activity is an example of the difficulty of consistent application of terms such as poikilothermy and homeothermy . In addition to behavioral adaptations, physiological adaptations help ectotherms regulate temperature. Diving reptiles conserve heat by heat exchange mechanisms, whereby cold blood from

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3654-409: The mesoderm , and posterior and anterior invagination of endoderm (gut), as well as extensive body segmentation until finally hatching from the surrounding cuticle into a first-instar larva. During larval development, tissues known as imaginal discs grow inside the larva. Imaginal discs develop to form most structures of the adult body, such as the head, legs, wings, thorax, and genitalia. Cells of

3741-426: The microorganisms that decompose the fruit, as well as on the sugar of the fruit itself. The mother puts feces on the egg sacs to establish the same microbial composition in the larvae's guts that has worked positively for herself. Then the larvae encapsulate in the puparium and undergo a four-day-long metamorphosis (at 25 °C), after which the adults eclose (emerge). Drosophila melanogaster, commonly known as

3828-570: The order Diptera , the name being derived from the Greek δι- di- "two", and πτερόν pteron "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced mechanosensory organs known as halteres , which act as high-speed sensors of rotational movement and allow dipterans to perform advanced aerobatics. Diptera is a large order containing more than 150,000 species including horse-flies , crane flies , hoverflies , mosquitoes and others. Flies have

3915-548: The thorax , bears the wings and contains the flight muscles on the second segment, which is greatly enlarged; the first and third segments have been reduced to collar-like structures, and the third segment bears the halteres , which help to balance the insect during flight. The third tagma is the abdomen consisting of 11 segments, some of which may be fused, and with the 3 hindmost segments modified for reproduction. Some Dipterans are mimics and can only be distinguished from their models by very careful inspection. An example of this

4002-827: The Brachycera includes broader, more robust flies with short antennae. Many nematoceran larvae are aquatic. There are estimated to be a total of about 19,000 species of Diptera in Europe, 22,000 in the Nearctic region, 20,000 in the Afrotropical region, 23,000 in the Oriental region and 19,000 in the Australasian region. While most species have restricted distributions, a few like the housefly ( Musca domestica ) are cosmopolitan. Gauromydas heros ( Asiloidea ), with

4089-1403: The Nematocera. The construction of a phylogenetic tree has been the subject of ongoing research. The following cladogram is based on the FLYTREE project. Ptychopteromorpha (phantom and primitive crane-flies) [REDACTED] Culicomorpha (mosquitoes, blackflies and midges) [REDACTED] Blephariceromorpha (net-winged midges, etc) [REDACTED] Bibionomorpha (gnats) [REDACTED] Psychodomorpha (drain flies, sand flies, etc) [REDACTED] Tipulomorpha (crane flies) [REDACTED] Stratiomyomorpha (soldier flies, etc) [REDACTED] Xylophagomorpha (stink flies, etc) [REDACTED] Tabanomorpha (horse flies, snipe flies, etc) [REDACTED] Nemestrinoidea [REDACTED] Asiloidea (robber flies, bee flies, etc) [REDACTED] Empidoidea (dance flies, etc) [REDACTED] Aschiza (in part) Phoroidea (flat-footed flies, etc) [REDACTED] Syrphoidea (hoverflies) [REDACTED] Hippoboscoidea (louse flies, etc) [REDACTED] Muscoidea (house flies, dung flies, etc) [REDACTED] Oestroidea (blow flies, flesh flies, etc) [REDACTED] Acalyptratae (marsh flies, etc) [REDACTED] Flies are often abundant and are found in almost all terrestrial habitats in

4176-482: The abdomen. The black portions of the abdomen are the inspiration for the species name ( melanogaster = "black-bellied" ). The brick-red color of the eyes of the wild type fly are due to two pigments: xanthommatin, which is brown and is derived from tryptophan , and drosopterins, which are red and are derived from guanosine triphosphate . They exhibit sexual dimorphism ; females are about 2.5 mm (0.10 in) long; males are slightly smaller. Furthermore, males have

4263-519: The antennae and the maxillary palps bear the main olfactory receptors, while the gustatory receptors are in the labium, pharynx, feet, wing margins and female genitalia, enabling flies to taste their food by walking on it. The taste receptors in females at the tip of the abdomen receive information on the suitability of a site for ovipositing. Flies that feed on blood have special sensory structures that can detect infrared emissions, and use them to home in on their hosts, Many blood-sucking flies can detect

4350-479: The body temperature. Such variation in body temperature is called poikilothermy , though the concept is not widely satisfactory and the use of the term is declining. In small aquatic creatures such as Rotifera , poikilothermy is practically absolute, but other creatures (like crabs ) have wider physiological options at their disposal, and they can move to preferred temperatures, avoid ambient temperature changes, or moderate their effects. Ectotherms can also display

4437-905: The copulation of others). This behavior is sensitive to environmental conditions, and females copulate less in bad weather conditions. D. melanogaster males exhibit a strong reproductive learning curve. That is, with sexual experience, these flies tend to modify their future mating behavior in multiple ways. These changes include increased selectivity for courting only intraspecifically, as well as decreased courtship times. Sexually naïve D. melanogaster males are known to spend significant time courting interspecifically, such as with D. simulans flies. Naïve D. melanogaster will also attempt to court females that are not yet sexually mature, and other males. D. melanogaster males show little to no preference for D. melanogaster females over females of other species or even other male flies. However, after D. simulans or other flies incapable of copulation have rejected

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4524-419: The corpus allatum. D. melanogaster is often used for life extension studies, such as to identify genes purported to increase lifespan when mutated . D. melanogaster is also used in studies of aging . Werner syndrome is a condition in humans characterized by accelerated aging. It is caused by mutations in the gene WRN that encodes a protein with essential roles in repair of DNA damage. Mutations in

4611-444: The development time at 25 °C (77 °F) is 8 + 1 ⁄ 2 days, at 18 °C (64 °F) it takes 19 days and at 12 °C (54 °F) it takes over 50 days. Under crowded conditions, development time increases, while the emerging flies are smaller. Females lay some 400 eggs (embryos), about five at a time, into rotting fruit or other suitable material such as decaying mushrooms and sap fluxes . Drosophila melanogaster

4698-404: The differences in antennae. The Nematocera are identified by their elongated bodies and many-segmented, often feathery antennae as represented by mosquitoes and crane flies. The Brachycera have rounder bodies and much shorter antennae. Subsequent studies have identified the Nematocera as being non-monophyletic with modern phylogenies placing the Brachycera within grades of groups formerly placed in

4785-431: The different families. The mouthparts are adapted for piercing and sucking, as in the black flies, mosquitoes and robber flies, and for lapping and sucking as in many other groups. Female horse-flies use knife-like mandibles and maxillae to make a cross-shaped incision in the host's skin and then lap up the blood that flows. The gut includes large diverticulae , allowing the insect to store small quantities of liquid after

4872-405: The early embryo (or syncytial embryo ) undergoes rapid DNA replication and 13 nuclear divisions until about 5000 to 6000 nuclei accumulate in the unseparated cytoplasm of the embryo. By the end of the eighth division, most nuclei have migrated to the surface, surrounding the yolk sac (leaving behind only a few nuclei, which will become the yolk nuclei). After the 10th division, the pole cells form at

4959-456: The early sunlight before they can begin their daily activities. In cool weather the foraging activity of such species is therefore restricted to the day time in most vertebrate ectotherms, and in cold climates most cannot survive at all. In lizards, for instance, most nocturnal species are geckos specialising in "sit and wait" foraging strategies. Such strategies do not require as much energy as active foraging and do not require hunting activity of

5046-405: The effects of specific environmental mutagens. There are many reasons the fruit fly is a popular choice as a model organism: Genetic markers are commonly used in Drosophila research, for example within balancer chromosomes or P-element inserts, and most phenotypes are easily identifiable either with the naked eye or under a microscope. In the list of a few common markers below, the allele symbol

5133-451: The female fruit fly and are present in the early stages of embryo development. They determine the embryo's main features and early development. For example, the gene called Bicoid regulates the formation of the embryo's anterior end, and its absence leads to an embryo lacking a head. Zygotic genes: These genes are activated in later stages of embryo development when the fruit fly embryo begins to produce its own genetic products. For example,

5220-493: The female to cease movement and orient herself towards the male to allow for mounting. If the group is inactivated, the female remains in motion and does not copulate. Various chemical signals such as male pheromones often are able to activate the group. Also, females exhibit mate choice copying . When virgin females are shown other females copulating with a certain type of male, they tend to copulate more with this type of male afterwards than naïve females (which have not observed

5307-489: The flies participate other than mating and finding partners, such as finding food. The reproductive success of males and females varies, because a female only needs to mate once to reach maximum fertility. Mating with multiple partners provides no advantage over mating with one partner, so females exhibit no difference in evening activity between polygamous and monogamous individuals. For males, however, mating with multiple partners increases their reproductive success by increasing

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5394-749: The flies, principally in the family Cecidomyiidae (gall midges). Many flies (most importantly in the family Agromyzidae) lay their eggs in the mesophyll tissue of leaves with larvae feeding between the surfaces forming blisters and mines. Some families are mycophagous or fungus feeding. These include the cave dwelling Mycetophilidae (fungus gnats) whose larvae are the only diptera with bioluminescence. The Sciaridae are also fungus feeders. Some plants are pollinated by fungus feeding flies that visit fungus infected male flowers. The larvae of Megaselia scalaris (Phoridae) are almost omnivorous and consume such substances as paint and shoe polish. The Exorista mella (Walker) fly are considered generalists and parasitoids of

5481-409: The fruit fly and human genome estimated that about 60% of genes are conserved between the two species. About 75% of known human disease genes have a recognizable match in the genome of fruit flies, and 50% of fly protein sequences have mammalian homologs . An online database called Homophila is available to search for human disease gene homologues in flies and vice versa. Drosophila is being used as

5568-485: The fruit fly, has been a significant model organism in embryonic development research. Many of its genes that regulate embryonic development and their mechanisms of action have been crucial in understanding the fundamental principles of embryonic development regulation in many multicellular organisms, including humans. Here are some important genes regulating embryonic development in Drosophila melanogaster and their modes of action: Maternal genes: These genes are encoded in

5655-527: The genetic diversity of their offspring. This benefit of genetic diversity is an evolutionary advantage because it increases the chance that some of the offspring will have traits that increase their fitness in their environment. The difference in evening activity between polygamous and monogamous male flies can be explained with courtship. For polygamous flies, their reproductive success increases by having offspring with multiple partners, and therefore they spend more time and energy on courting multiple females. On

5742-467: The gradient. For example, the Hedgehog morphogen regulates the differentiation of segments and segment identity in the fruit fly embryo. These genes and their modes of action form a complex regulatory network that guides the embryonic development of Drosophila melanogaster. They influence cell differentiation, segment formation, and axial patterning in the embryo, ultimately leading to the development of

5829-527: The ground using motion parallax. The H1 neuron is responsible for detecting horizontal motion across the entire visual field of the fly, allowing the fly to generate and guide stabilizing motor corrections midflight with respect to yaw. The ocelli are concerned in the detection of changes in light intensity, enabling the fly to react swiftly to the approach of an object. Like other insects, flies have chemoreceptors that detect smell and taste, and mechanoreceptors that respond to touch. The third segments of

5916-482: The hunchback gene regulates the formation of segments in the embryo. Homeotic genes: This gene family regulates segmentation and axial patterning in development. They act as regulatory factors that determine cell fate in embryonic development. For example, the gene called Antennapedia regulates the formation of anterior limbs in the embryo. Morphogens: These are molecules that form gradients in embryonic development and regulate cell fate depending on their position in

6003-763: The imaginal disks are set aside during embryogenesis and continue to grow and divide during the larval stages—unlike most other cells of the larva, which have differentiated to perform specialized functions and grow without further cell division. At metamorphosis, the larva forms a pupa , inside which the larval tissues are reabsorbed and the imaginal tissues undergo extensive morphogenetic movements to form adult structures. Biotic and abiotic factors experienced during development will affect developmental resource allocation leading to phenotypic variation , also referred to as developmental plasticity. As in all insects, environmental factors can influence several aspects of development in Drosophila melanogaster . Fruit flies reared under

6090-485: The incapacitation mechanism is believed to be a protective mechanism that prevents a male fly from incapacitating his own sperm should he mate with the same female fly repetitively. Sensory neurons in the uterus of female D. melanogaster respond to a male protein, sex peptide , which is found in semen. This protein makes the female reluctant to copulate for about 10 days after insemination . The signal pathway leading to this change in behavior has been determined. The signal

6177-431: The larval food-source and the larvae, which lack true limbs, develop in a protected environment, often inside their food source. Other species are ovoviviparous , opportunistically depositing hatched or hatching larvae instead of eggs on carrion , dung, decaying material, or open wounds of mammals. The pupa is a tough capsule from which the adult emerges when ready to do so; flies mostly have short lives as adults. Diptera

6264-581: The males' advances, D. melanogaster males are much less likely to spend time courting nonspecifically in the future. This apparent learned behavior modification seems to be evolutionarily significant, as it allows the males to avoid investing energy into futile sexual encounters. In addition, males with previous sexual experience modify their courtship dance when attempting to mate with new females—the experienced males spend less time courting, so have lower mating latencies, meaning that they are able to reproduce more quickly. This decreased mating latency leads to

6351-419: The nests of social insects. Some brachycerans are agricultural pests, some bite animals and humans and suck their blood, and some transmit diseases. Flies are adapted for aerial movement and typically have short and streamlined bodies. The first tagma of the fly, the head, bears the eyes, the antennae , and the mouthparts (the labrum, labium, mandible, and maxilla make up the mouthparts). The second tagma,

6438-406: The neural ganglia , and concentration of nerve tissue in the thorax, a feature that is most extreme in the highly derived Muscomorpha infraorder. Some flies such as the ectoparasitic Nycteribiidae and Streblidae are exceptional in having lost their wings and become flightless. The only other order of insects bearing a single pair of true, functional wings, in addition to any form of halteres, are

6525-637: The nuclei that have made a mistake detach from their centrosomes and fall into the centre of the embryo (yolk sac), which will not form part of the fly. The gene network (transcriptional and protein interactions) governing the early development of the fruit fly embryo is one of the best understood gene networks to date, especially the patterning along the anteroposterior (AP) and dorsoventral (DV) axes (See under morphogenesis ). The embryo undergoes well-characterized morphogenetic movements during gastrulation and early development, including germ-band extension , formation of several furrows, ventral invagination of

6612-455: The other hand, monogamous flies only court one female, and expend less energy doing so. While it requires more energy for male flies to court multiple females, the overall reproductive benefits it produces has kept polygamy as the preferred sexual choice. The mechanism that affects courtship behavior in Drosophila is controlled by the oscillator neurons DN1s and LNDs. Oscillation of the DN1 neurons

6699-481: The posterior end of the embryo, segregating the germ line from the syncytium. Finally, after the 13th division, cell membranes slowly invaginate, dividing the syncytium into individual somatic cells. Once this process is completed, gastrulation starts. Nuclear division in the early Drosophila embryo happens so quickly, no proper checkpoints exist, so mistakes may be made in division of the DNA. To get around this problem,

6786-405: The raised concentration of carbon dioxide that occurs near large animals. Some tachinid flies (Ormiinae) which are parasitoids of bush crickets , have sound receptors to help them locate their singing hosts. Diptera have one pair of fore wings on the mesothorax and a pair of halteres , or reduced hind wings, on the metathorax . A further adaptation for flight is the reduction in number of

6873-532: The same intensity. From another point of view, sit-and-wait predation may require very long periods of unproductive waiting. Endotherms cannot, in general, afford such long periods without food, but suitably adapted ectotherms can wait without expending much energy. Endothermic vertebrate species are therefore less dependent on the environmental conditions and have developed a higher variability (both within and between species) in their daily patterns of activity. In ectotherms, fluctuating ambient temperatures may affect

6960-568: The second largest group of pollinators after the Hymenoptera (bees, wasps and relatives). In wet and colder environments flies are significantly more important as pollinators. Compared to bees, they need less food as they do not need to provision their young. Many flowers that bear low nectar and those that have evolved trap pollination depend on flies. It is thought that some of the earliest pollinators of plants may have been flies. The greatest diversity of gall forming insects are found among

7047-400: The sex and physical appearance of fruit flies is not influenced by hormones . The appearance and sex of fruit flies is determined only by genetic information. Female fruit flies are substantially larger than male fruit flies, with females having bodies that are up to 30% larger than an adult male. Wild type fruit flies are yellow-brown, with brick-red eyes and transverse black rings across

7134-461: The skin picks up heat from blood moving outward from the body core, re-using and thereby conserving some of the heat that otherwise would have been wasted. The skin of bullfrogs secretes more mucus when it is hot, allowing more cooling by evaporation. During periods of cold, some ectotherms enter a state of torpor , in which their metabolism slows or, in some cases, such as the wood frog , effectively stops. The torpor might last overnight or last for

7221-606: The time, and dipteran mouthparts are well-adapted to softening and lapping up the crusted residues. The basal clades in the Diptera include the Deuterophlebiidae and the enigmatic Nymphomyiidae . Three episodes of evolutionary radiation are thought to have occurred based on the fossil record. Many new species of lower Diptera developed in the Triassic , about 220 million years ago. Many lower Brachycera appeared in

7308-405: The use of this species as a model organism , D. melanogaster continues to be widely used for biological research in genetics , physiology , microbial pathogenesis , and life history evolution . D. melanogaster was the first animal to be launched into space in 1947. As of 2017, six Nobel Prizes have been awarded to drosophilists for their work using the insect. Drosophila melanogaster

7395-473: The world apart from Antarctica. They include many familiar insects such as house flies, blow flies, mosquitoes, gnats, black flies, midges and fruit flies. More than 150,000 have been formally described and the actual species diversity is much greater, with the flies from many parts of the world yet to be studied intensively. The suborder Nematocera include generally small, slender insects with long antennae such as mosquitoes, gnats, midges and crane-flies, while

7482-607: The world, spread foodborne illnesses . Flies can be annoyances especially in some parts of the world where they can occur in large numbers, buzzing and settling on the skin or eyes to bite or seek fluids. Larger flies such as tsetse flies and screwworms cause significant economic harm to cattle. Blowfly larvae, known as gentles , and other dipteran larvae, known more generally as maggots , are used as fishing bait , as food for carnivorous animals, and in medicine in debridement , to clean wounds . Dipterans are holometabolans , insects that undergo radical metamorphosis. They belong to

7569-415: Was found to be effected by sociosexual interactions , and is connected to mating-related decrease of evening activity. D. melanogaster remains one of the most studied organisms in biological research, particularly in genetics and developmental biology. It is also employed in studies of environmental mutagenesis. D. melanogaster was among the first organisms used for genetic analysis , and today it

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