112-563: Mosquitoes , the Culicidae , are a family of small flies consisting of 3,600 species . The word mosquito (formed by mosca and diminutive -ito ) is Spanish and Portuguese for little fly . Mosquitoes have a slender segmented body , one pair of wings, three pairs of long hair-like legs, and specialized, highly elongated, piercing-sucking mouthparts . All mosquitoes drink nectar from flowers ; females of some species have in addition adapted to drink blood. The group diversified during
224-547: A caribou herd. For a mosquito to transmit disease, there must be favorable seasonal conditions, primarily humidity, temperature, and precipitation. El Niño affects the location and number of outbreaks in East Africa, Latin America, Southeast Asia and India . Climate change impacts the seasonal factors and in turn the dispersal of mosquitoes. Climate models can use historic data to recreate past outbreaks and to predict
336-417: A carrion site, where decomposition likely increased soil nutrient levels and host plant quality. Midges, such as Tokunagayusurika akamusi , form swarms, dancing in the air. Swarming serves multiple purposes, including the facilitation of mating by attracting females to approach the swarm, a phenomenon known as lek mating . Such cloud-like swarms often form in early evening when the sun is getting low, at
448-1236: A family of the true flies (order Diptera) : the Culicidae (from the Latin culex , genitive culicis , meaning "midge" or "gnat"). They are members of the infraorder Culicomorpha and superfamily Culicoidea . The phylogenetic tree is based on the FLYTREE project. Ptychopteromorpha (phantom and primitive crane-flies) [REDACTED] Chironomidae (non-biting midges) [REDACTED] Simulioidea (blackflies and biting midges) [REDACTED] Dixidae (meniscus midges) [REDACTED] Corethrellidae (frog-biting midges) Chaoboridae (phantom midges) [REDACTED] Culicidae [REDACTED] other midges and gnats [REDACTED] all other flies, inc. Brachycera [REDACTED] The two subfamilies of mosquitoes are Anophelinae , containing three genera and approximately 430 species, and Culicinae , which contains 11 tribes, 108 genera and 3,046 species. Kyanne Reidenbach and colleagues analysed mosquito phylogenetics in 2009, using both nuclear DNA and morphology of 26 species. They note that Anophelinae
560-415: A V-formation may conserve 12–20% of the energy they would need to fly alone. Red knots and dunlins were found in radar studies to fly 5 km per hour faster in flocks than when they were flying alone. The birds flying at the tips and at the front are rotated in a timely cyclical fashion to spread flight fatigue equally among the flock members. The formation also makes communication easier and allows
672-426: A blood meal, and avoiding being killed by their vertebrate hosts. The eggs of most mosquitoes are laid in stagnant water, which may be a pond, a marsh, a temporary puddle, a water-filled hole in a tree, or the water-trapping leaf axils of a bromeliad . Some lay near the water's edge while others attach their eggs to aquatic plants. A few, like Opifex fuscus , can breed in salt-marshes. Wyeomyia smithii breeds in
784-419: A blood meal. The mosquito's saliva is transferred to the host during the bite, and can cause an itchy rash . In addition, blood-feeding species can ingest pathogens while biting, and transmit them to other hosts. Those species include vectors of parasitic diseases such as malaria and filariasis , and arboviral diseases such as yellow fever and dengue fever . By transmitting diseases, mosquitoes cause
896-457: A consensus over time. The naming of families is codified by various international bodies using the following suffixes: The taxonomic term familia was first used by French botanist Pierre Magnol in his Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur (1689) where he called the seventy-six groups of plants he recognised in his tables families ( familiae ). The concept of rank at that time
1008-528: A deeper understanding of the behaviour. Early studies of swarm behaviour employed mathematical models to simulate and understand the behaviour. The simplest mathematical models of animal swarms generally represent individual animals as following three rules: The boids computer program, created by Craig Reynolds in 1986, simulates swarm behaviour following the above rules. Many subsequent and current models use variations on these rules, often implementing them by means of concentric "zones" around each animal. In
1120-459: A domestic form and an animal-biting form of the mosquito Aedes aegypti showed that the evolution of preference for human odour is linked to increases in the expression of the olfactory receptor AaegOr4. This recognises a compound present at high levels in human odour called sulcatone . However, the malaria mosquito Anopheles gambiae also has OR4 genes strongly activated by sulcatone, yet none of them are closely related to AaegOr4, suggesting that
1232-446: A family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community for extended periods. The continual publication of new data and diverse opinions plays a crucial role in facilitating adjustments and ultimately reaching
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#17327764941341344-530: A form of parasitism ; in Edward O. Wilson 's phrase "Parasites ... are predators that eat prey in units of less than one." Micropredation is one of six major evolutionarily stable strategies within parasitism. It is distinguished by leaving the host still able to reproduce, unlike the activity of parasitic castrators or parasitoids ; and having multiple hosts, unlike conventional parasites. From this perspective, mosquitoes are ectoparasites , feeding on blood from
1456-434: A host observed by the mosquito allows it to select a host to feed on. This occurs when a mosquito notes the presence of CO 2 , as it then activates odour and visual search behaviours that it otherwise would not use. In terms of a mosquito’s olfactory system, chemical analysis has revealed that people who are highly attractive to mosquitoes produce significantly more carboxylic acids . A human's unique body odour indicates that
1568-507: A loss of alignment in the group appears to increase the randomness of its motion, until an aligned state is again achieved. This noise-induced alignment appears to be an intrinsic characteristic of collective coherent motion. Insect migration is the seasonal movement of insects , particularly those by species of dragonflies , beetles , butterflies , and moths . The distance can vary from species to species, but in most cases these movements involve large numbers of individuals. In some cases
1680-521: A mosquito's visual search system includes sensitivity to wavelengths from different colours. Mosquitoes are attracted to longer wavelengths, correlated to the colours of red and orange as seen by humans, and range through the spectrum of human skin tones. In addition, they have a strong attraction to dark, high-contrast objects, because of how longer wavelengths are perceived against a lighter-coloured background. Different species of mosquitoes have evolved different methods of identifying target hosts. Study of
1792-488: A neighbour. The shape of these zones will necessarily be affected by the sensory capabilities of a given animal. For example, the visual field of a bird does not extend behind its body. Fish rely on both vision and on hydrodynamic perceptions relayed through their lateral lines , while Antarctic krill rely both on vision and hydrodynamic signals relayed through antennae . However recent studies of starling flocks have shown that each bird modifies its position, relative to
1904-558: A next action, by the same or a different agent. In that way, subsequent actions tend to reinforce and build on each other, leading to the spontaneous emergence of coherent, apparently systematic activity. Stigmergy is a form of self-organization. It produces complex, seemingly intelligent structures, without need for any planning, control, or even direct communication between the agents. As such it supports efficient collaboration between extremely simple agents, who lack any memory, intelligence or even awareness of each other. Swarm intelligence
2016-430: A number of aspects of flock behaviour. In order to gain insight into why animals evolve swarming behaviours, scientists have turned to evolutionary models that simulate populations of evolving animals. Typically these studies use a genetic algorithm to simulate evolution over many generations. These studies have investigated a number of hypotheses attempting to explain why animals evolve swarming behaviours, such as
2128-454: A queen leaving the nest along with some workers to found a colony at a new site, a process akin to swarming in honeybees . The concept of self-propelled particles (SPP) was introduced in 1995 by Tamás Vicsek et al. as a special case of the boids model introduced in 1986 by Reynolds. An SPP swarm is modelled by a collection of particles that move with a constant speed and respond to random perturbations by adopting at each time increment
2240-813: A set of tiny robots that appear to the roaches as other roaches and can thus alter the roaches' perception of critical mass . The robots were also specially scented so that they would be accepted by the real roaches. Locusts are the swarming phase of the short-horned grasshoppers of the family Acrididae . Some species can breed rapidly under suitable conditions and subsequently become gregarious and migratory. They form bands as nymphs and swarms as adults—both of which can travel great distances, rapidly stripping fields and greatly damaging crops . The largest swarms can cover hundreds of square miles and contain billions of locusts. A locust can eat its own weight (about 2 grams) in plants every day. That means one million locusts can eat more than one tonne of food each day, and
2352-492: A simple set of individual interactions. Cockroaches are mainly nocturnal and will run away when exposed to light. A study tested the hypothesis that cockroaches use just two pieces of information to decide where to go under those conditions: how dark it is and how many other cockroaches there are. The study conducted by José Halloy and colleagues at the Free University of Brussels and other European institutions created
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#17327764941342464-482: A source of fascination for children, naturalists and artists. Individual insects seem to do their own thing without any central control, yet the colony as a whole behaves in a highly coordinated manner. Researchers have found that cooperation at the colony level is largely self-organized . The group coordination that emerges is often just a consequence of the way individuals in the colony interact. These interactions can be remarkably simple, such as one ant merely following
2576-400: Is also a scientific stream attempting to model the swarm systems themselves and understand their underlying mechanisms, and an engineering stream focused on applying the insights developed by the scientific stream to solve practical problems in other areas. Swarm algorithms follow a Lagrangian approach or an Eulerian approach. The Eulerian approach views the swarm as a field , working with
2688-410: Is also studied by active matter physicists as a phenomenon which is not in thermodynamic equilibrium , and as such requires the development of tools beyond those available from the statistical physics of systems in thermodynamic equilibrium. In this regard, swarming has been compared to the mathematics of superfluids , specifically in the context of starling flocks (murmuration). Swarm behaviour
2800-519: Is confirmed to be rather basal, but that the deeper parts of the tree are not well resolved. basal spp. [REDACTED] other spp. Aedini [REDACTED] Family (biology) Family ( Latin : familia , pl. : familiae ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy . It is classified between order and genus . A family may be divided into subfamilies , which are intermediate ranks between
2912-432: Is how a fish can choose to join a shoal of animals similar to themselves, given that it cannot know its own appearance. Experiments with zebrafish have shown that shoal preference is a learned ability, not innate. A zebrafish tends to associate with shoals that resemble shoals in which it was reared, a form of imprinting . Other open questions of shoaling behaviour include identifying which individuals are responsible for
3024-766: Is known from Canadian amber from Alberta, Canada, which dates to the Campanian age of the Late Cretaceous, around 79 million years ago. P. burmanicus has been assigned to the Anophelinae , indicating that the split between this subfamily and the Culicinae took place over 99 million years ago. Molecular estimates suggest that this split occurred 197.5 million years ago, during the Early Jurassic , but that major diversification did not take place until
3136-462: Is lost in the Eulerian approach. Ant colony optimization is a widely used algorithm which was inspired by the behaviours of ants, and has been effective solving discrete optimization problems related to swarming. The algorithm was initially proposed by Marco Dorigo in 1992, and has since been diversified to solve a wider class of numerical problems. Species that have multiple queens may have
3248-503: Is made by Poli. Researchers in Switzerland have developed an algorithm based on Hamilton's rule of kin selection. The algorithm shows how altruism in a swarm of entities can, over time, evolve and result in more effective swarm behaviour. The earliest evidence of swarm behaviour in animals dates back about 480 million years. Fossils of the trilobite Ampyx priscus have been recently described as clustered in lines along
3360-433: Is no centralized control structure dictating how individual agents should behave, local, and to a certain degree random, interactions between such agents lead to the emergence of intelligent global behaviour, unknown to the individual agents. Swarm intelligence research is multidisciplinary. It can be divided into natural swarm research studying biological systems and artificial swarm research studying human artefacts. There
3472-481: Is short. Different mosquito species favor amphibians , reptiles including snakes , birds , and mammals . For example, Culiseta melanura sucks the blood of passerine birds, but as mosquito numbers rise they attack mammals including horses and humans, causing epidemics of Eastern equine encephalitis virus in North America. Loss of blood from many bites can add up to a large volume, occasionally causing
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3584-501: Is the collective behaviour of decentralized , self-organized systems, natural or artificial. The concept is employed in work on artificial intelligence . The expression was introduced by Gerardo Beni and Jing Wang in 1989, in the context of cellular robotic systems. Swarm intelligence systems are typically made up of a population of simple agents such as boids interacting locally with one another and with their environment. The agents follow very simple rules, and although there
3696-447: Is typically a kilometre or more from the original hive, though some species, e.g., Apis dorsata , may establish new colonies within as little as 500 meters from the natal nest. This collective decision-making process is remarkably successful in identifying the most suitable new nest site and keeping the swarm intact. A good hive site has to be large enough to accommodate the swarm (about 15 litres in volume), has to be well-protected from
3808-530: Is unpredictable, freezing but often warming suddenly in mid-winter, making mosquitoes emerge from pupae in diapause, and then freezing again before they can complete their life cycle. Eggs of temperate zone mosquitoes are more tolerant of cold than the eggs of species indigenous to warmer regions. Many can tolerate subzero temperatures, while adults of some species can survive winter by sheltering in microhabitats such as buildings or hollow trees. In warm and humid tropical regions, some mosquito species are active for
3920-593: The Genera Plantarum of George Bentham and Joseph Dalton Hooker this word ordo was used for what now is given the rank of family. Families serve as valuable units for evolutionary, paleontological, and genetic studies due to their relatively greater stability compared to lower taxonomic levels like genera and species. Swarm Swarm behaviour , or swarming , is a collective behaviour exhibited by entities, particularly animals, of similar size which aggregate together, perhaps milling about
4032-674: The Asteraceae , Rosaceae and Orchidaceae are pollinated by mosquitoes, which visit to obtain sugar-rich nectar . They are attracted to flowers by a range of semiochemicals such as alcohols, aldehydes, ketones, and terpenes. Mosquitoes have visited and pollinated flowers since the Cretaceous period. It is possible that plant-sucking exapted mosquitoes to blood-sucking. Ecologically, blood-feeding mosquitoes are micropredators , small animals that feed on larger animals without immediately killing them. Evolutionary biologists see this as
4144-626: The Bosphorus at migration times. More common species, such as the European honey buzzard , can be counted in hundreds of thousands in autumn. Other barriers, such as mountain ranges, can also cause funnelling, particularly of large diurnal migrants. This is a notable factor in the Central American migratory bottleneck. This concentration of birds during migration can put species at risk. Some spectacular migrants have already gone extinct,
4256-466: The Cretaceous period. Evolutionary biologists view mosquitoes as micropredators , small animals that parasitise larger ones by drinking their blood without immediately killing them. Medical parasitologists view mosquitoes instead as vectors of disease , carrying protozoan parasites or bacterial or viral pathogens from one host to another. The mosquito life cycle consists of four stages: egg , larva , pupa , and adult . Eggs are laid on
4368-594: The Secretary of State for the Colonies , Joseph Chamberlain , who had written that "in view of the possible connection of Malaria with mosquitoes, it is desirable to obtain exact knowledge of the different species of mosquitoes and allied insects in the various tropical colonies. I will therefore ask you ... to have collections made of the winged insects in the Colony which bite men or animals." Mosquitoes are members of
4480-543: The hypopharynx , and the labrum . The labium bends back into a bow when the mosquito begins to bite, staying in contact with the skin and guiding the stylets downwards. The extremely sharp tips of the labrum and maxillae are moved backwards and forwards to saw their way into the skin, with just one thousandth of the force that would be needed to penetrate the skin with a needle, resulting in a painless insertion. Mosquito saliva contains enzymes that aid in sugar feeding, and antimicrobial agents that control bacterial growth in
4592-505: The pupa are merged into a cephalothorax , with the abdomen curving around beneath it. The pupa or "tumbler" can swim actively by flipping its abdomen. Like the larva, the pupa of most species must come to the surface frequently to breathe, which they do through a pair of respiratory trumpets on their cephalothoraxes. They do not feed; they pass much of their time hanging from the surface of the water by their respiratory trumpets. If alarmed, they swim downwards by flipping their abdomens in much
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4704-488: The selfish herd theory the predator confusion effect, the dilution effect, and the many eyes theory. The concept of emergence—that the properties and functions found at a hierarchical level are not present and are irrelevant at the lower levels–is often a basic principle behind self-organizing systems . An example of self-organization in biology leading to emergence in the natural world occurs in ant colonies. The queen does not give direct orders and does not tell
4816-422: The "zone of repulsion", very close to the animal, the focal animal will seek to distance itself from its neighbours to avoid collision. Slightly further away, in the "zone of alignment", the focal animal will seek to align its direction of motion with its neighbours. In the outermost "zone of attraction", which extends as far away from the focal animal as it is able to sense, the focal animal will seek to move towards
4928-468: The Cretaceous. Over 3,600 species of mosquitoes in 112 genera have been described . They are traditionally divided into two subfamilies, the Anophelinae and the Culicinae , which carry different diseases. Roughly speaking, protozoal diseases like malaria are transmitted by anophelines, while viral diseases such as yellow fever and dengue fever are transmitted by culicines. The name Culicidae
5040-404: The ability to solve geometric problems. For example, colonies routinely find the maximum distance from all colony entrances to dispose of dead bodies. A further key concept in the field of swarm intelligence is stigmergy . Stigmergy is a mechanism of indirect coordination between agents or actions. The principle is that the trace left in the environment by an action stimulates the performance of
5152-505: The ants what to do. Instead, each ant reacts to stimuli in the form of chemical scents from larvae, other ants, intruders, food and buildup of waste, and leaves behind a chemical trail, which, in turn, provides a stimulus to other ants. Here each ant is an autonomous unit that reacts depending only on its local environment and the genetically encoded rules for its variety. Despite the lack of centralized decision making, ant colonies exhibit complex behaviours and have even been able to demonstrate
5264-456: The average direction of motion of the other particles in their local neighbourhood. Simulations demonstrate that a suitable "nearest neighbour rule" eventually results in all the particles swarming together, or moving in the same direction. This emerges, even though there is no centralized coordination, and even though the neighbours for each particle constantly change over time. SPP models predict that swarming animals share certain properties at
5376-401: The best solutions. The solutions it finds are called particles . Each particle stores its position as well as the best solution it has achieved so far. The particle swarm optimizer tracks the best local value obtained so far by any particle in the local neighbourhood. The remaining particles then move through the problem space following the lead of the optimum particles. At each time iteration,
5488-447: The best, or closest, food source from several in the vicinity. Such collective decisions are achieved using positive feedback mechanisms. Selection of the best food source is achieved by ants following two simple rules. First, ants which find food return to the nest depositing a pheromone chemical. More pheromone is laid for higher quality food sources. Thus, if two equidistant food sources of different qualities are found simultaneously,
5600-459: The birds to maintain visual contact with each other. Other animals may use similar drafting techniques when migrating. Lobsters , for example, migrate in close single-file formation "lobster trains", sometimes for hundreds of miles. The Mediterranean and other seas present a major obstacle to soaring birds, which must cross at the narrowest points. Massive numbers of large raptors and storks pass through areas such as Gibraltar , Falsterbo , and
5712-418: The blood proteins into free amino acids . These are used in the synthesis of vitellogenin , which in turn is made into egg yolk protein. Mosquitoes have a cosmopolitan distribution , occurring in every land region except Antarctica and a few islands with polar or subpolar climates , such as Iceland , which is essentially free of mosquitoes. This absence is probably caused by Iceland's climate. Its weather
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#17327764941345824-439: The blood separate from anything else in the stomach. Like many Hemiptera that survive on dilute liquid diets, many adult mosquitoes excrete surplus liquid even when feeding. This permits females to accumulate a full meal of nutrient solids. The blood meal is digested over a period of several days. Once blood is in the stomach, the midgut synthesizes protease enzymes, primarily trypsin assisted by aminopeptidase , that hydrolyze
5936-417: The blood; and decrease cytokine production. Females of many blood-feeding species need a blood meal to begin the process of egg development. A sufficiently large blood meal triggers a hormonal cascade that leads to egg development. Upon completion of feeding, the mosquito withdraws her proboscis , and as the gut fills up, the stomach lining secretes a peritrophic membrane that surrounds the blood. This keeps
6048-514: The book's morphological section, where he delved into discussions regarding the vegetative and generative aspects of plants. Subsequently, in French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille was used as a French equivalent of the Latin ordo (or ordo naturalis ). In zoology ,
6160-710: The chance of capture), enhanced foraging success, and higher success in finding a mate. It is also likely that fish benefit from shoal membership through increased hydrodynamic efficiency. Fish use many traits to choose shoalmates. Generally they prefer larger shoals, shoalmates of their own species, shoalmates similar in size and appearance to themselves, healthy fish, and kin (when recognised). The "oddity effect" posits that any shoal member that stands out in appearance will be preferentially targeted by predators. This may explain why fish prefer to shoal with individuals that resemble them. The oddity effect would thus tend to homogenise shoals. One puzzling aspect of shoal selection
6272-537: The cluster. If a scout finds a suitable location, she returns to the cluster and promotes it by dancing a version of the waggle dance . This dance conveys information about the quality, direction, and distance of the new site. The more excited she is about her findings, the more vigorously she dances. If she can convince others they may take off and check the site she found. If they approve they may promote it as well. In this decision-making process, scouts check several sites, often abandoning their own original site to promote
6384-611: The death of livestock as large as cattle and horses . Malaria -transmitting mosquitoes seek out caterpillars and feed on their haemolymph, impeding their development. Most mosquito species are crepuscular , feeding at dawn or dusk, and resting in a cool place through the heat of the day. Some species, such as the Asian tiger mosquito , are known to fly and feed during daytime. Female mosquitoes hunt for hosts by smelling substances such as carbon dioxide (CO 2 ) and 1-octen-3-ol (mushroom alcohol, found in exhaled breath) produced from
6496-421: The deaths of over 725,000 people each year. Like all flies, mosquitoes go through four stages in their life cycles: egg , larva , pupa , and adult . The first three stages—egg, larva, and pupa—are largely aquatic, the eggs usually being laid in stagnant water. They hatch to become larvae , which feed, grow, and molt until they change into pupae . The adult mosquito emerges from the mature pupa as it floats at
6608-467: The density of the swarm and deriving mean field properties. It is a hydrodynamic approach, and can be useful for modelling the overall dynamics of large swarms. However, most models work with the Lagrangian approach, which is an agent-based model following the individual agents (points or particles) that make up the swarm. Individual particle models can follow information on heading and spacing that
6720-697: The elements, receive an optimal amount of sunshine, be some height above the ground, have a small entrance and be capable of resisting ant infestation - that is why tree cavities are often selected. Unlike social insects, swarms of non-social insects that have been studied primarily seem to function in contexts such as mating, feeding, predator avoidance, and migration. Moths may exhibit synchronized mating, during which pheromones released by females initiate searching and swarming behavior in males. Males sense pheromones with sensitive antennae and may track females as far as several kilometers away. Swarm mating involves female choice and male competition. Only one male in
6832-431: The entire year, but in temperate and cold regions they hibernate or enter diapause . Arctic or subarctic mosquitoes, like some other arctic midges in families such as Simuliidae and Ceratopogonidae may be active for only a few weeks annually as melt-water pools form on the permafrost. During that time, though, they emerge in huge numbers in some regions; a swarm may take up to 300 ml of blood per day from each animal in
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#17327764941346944-540: The family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes, disposés dans un ordre naturel (1796). He used families (some of them were not named) in some but not in all his orders of "insects" (which then included all arthropods ). In nineteenth-century works such as the Prodromus of Augustin Pyramus de Candolle and
7056-658: The female to lay more eggs. Both plant materials and blood are useful sources of energy in the form of sugars. Blood supplies more concentrated nutrients, such as lipids , but the main function of blood meals is to obtain proteins for egg production. Mosquitoes like Toxorhynchites reproduce autogenously, not needing blood meals. Disease vector mosquitoes like Anopheles and Aedes are anautogenous , requiring blood to lay eggs. Many Culex species are partially anautogenous, needing blood only for their second and subsequent clutches of eggs. Blood-sucking mosquitoes favour particular host species, though they are less selective when food
7168-495: The genus Toxorhynchites , at up to 18 mm (0.71 in) in length and 24 mm (0.94 in) in wingspan. Those in the genus Aedes are much smaller, with a wingspan of 2.8 to 4.4 mm (0.11 to 0.17 in). Mosquitoes can develop from egg to adult in hot weather in as few as five days, but it may take up to a month. At dawn or dusk, within days of pupating, males assemble in swarms , mating when females fly in. The female mates only once in her lifetime, attracted by
7280-422: The group level, regardless of the type of animals in the swarm. Swarming systems give rise to emergent behaviours which occur at many different scales, some of which are both universal and robust. It has become a challenge in theoretical physics to find minimal statistical models that capture these behaviours. Particle swarm optimization is another algorithm widely used to solve problems related to swarms. It
7392-447: The hind legs or, in some species, simply encountering other individuals causes an increase in levels of serotonin. The transformation of the locust to the swarming variety can be induced by several contacts per minute over a four-hour period. Notably, an innate predisposition to aggregate has been found in hatchlings of the desert locust, Schistocerca gregaria , independent of their parental phase. An individual locust's response to
7504-399: The host, and through visual recognition. The semiochemical that most strongly attracts Culex quinquefasciatus is nonanal . Another attractant is sulcatone . A large part of the mosquito's sense of smell, or olfactory system, is devoted to sniffing out blood sources. Of 72 types of odor receptors on its antennae, at least 27 are tuned to detect chemicals found in perspiration. In Aedes ,
7616-456: The individuals that migrate in one direction may not return and the next generation may instead migrate in the opposite direction. This is a significant difference from bird migration . Monarch butterflies are especially noted for their lengthy annual migration. In North America they make massive southward migrations starting in August until the first frost. A northward migration takes place in
7728-401: The largest swarms can consume over 100,000 tonnes each day. Swarming in locusts has been found to be associated with increased levels of serotonin which causes the locust to change colour, eat much more, become mutually attracted, and breed much more easily. Researchers propose that swarming behaviour is a response to overcrowding and studies have shown that increased tactile stimulation of
7840-859: The many aquatic insects that catch mosquito larvae are dragonfly and damselfly nymphs, whirligig beetles , and water striders . Vertebrate predators include fish such as catfish and the mosquitofish , amphibians including the spadefoot toad and the giant tree frog , freshwater turtles such as the red-eared slider , and birds such as ducks. Emerging adults are consumed at the pond surface by predatory flies including Empididae and Dolichopodidae , and by spiders . Flying adults are captured by dragonflies and damselflies, by birds such as swifts and swallows , and by vertebrates including bats . Mosquitoes are parasitised by hydrachnid mites, ciliates such as Glaucoma , microsporidians such as Thelania , and fungi including species of Saprolegniaceae and Entomophthoraceae . Several flowers including members of
7952-445: The migration such as predation. Many birds migrate in flocks. For larger birds, it is assumed that flying in flocks reduces energy costs. The V formation is often supposed to boost the efficiency and range of flying birds, particularly over long migratory routes. All the birds except the first fly in the upwash from one of the wingtip vortices of the bird ahead. The upwash assists each bird in supporting its own weight in flight, in
8064-566: The most notable being the passenger pigeon . During migration the flocks were a mile (1.6 km) wide and 300 miles (500 km) long, taking several days to pass and containing up to a billion birds. The term "shoal" can be used to describe any group of fish, including mixed-species groups, while "school" is used for more closely knit groups of the same species swimming in a highly synchronised and polarised manner. Fish derive many benefits from shoaling behaviour including defence against predators (through better predator detection and by diluting
8176-779: The ocean floor. The animals were all mature adults, and were all facing the same direction as though they had formed a conga line or a peloton . It has been suggested they line up in this manner to migrate, much as spiny lobsters migrate in single-file queues; it has also been suggested that the formation is the precursor for mating, as with the fly Leptoconops torrens . The findings suggest animal collective behaviour has very early evolutionary origins. Examples of biological swarming are found in bird flocks , fish schools , insect swarms , bacteria swarms , molds, molecular motors , quadruped herds and people. The behaviour of social insects (insects that live in colonies , such as ants, bees, wasps and termites) has always been
8288-587: The outside of their hosts, using their piercing mouthparts, rather than entering their bodies. Unlike some other ectoparasites such as fleas and lice , mosquitoes do not remain constantly on the body of the host, but visit only to feed. A 2023 study suggested that Libanoculex intermedius found in Lebanese amber , dating to the Barremian age of the Early Cretaceous, around 125 million years ago
8400-534: The particle swarm optimiser accelerates each particle toward its optimum locations according to simple mathematical rules . Particle swarm optimization has been applied in many areas. It has few parameters to adjust, and a version that works well for a specific applications can also work well with minor modifications across a range of related applications. A book by Kennedy and Eberhart describes some philosophical aspects of particle swarm optimization applications and swarm intelligence. An extensive survey of applications
8512-424: The pheromone trail to the better one will be stronger. Ants in the nest follow another simple rule, to favor stronger trails, on average. More ants then follow the stronger trail, so more ants arrive at the high quality food source, and a positive feedback cycle ensures, resulting in a collective decision for the best food source. If there are two paths from the ant nest to a food source, then the colony usually selects
8624-423: The pheromones emitted by the male. As a species that need blood for the eggs to develop, the female finds a host and drinks a full meal of blood. She then rests for two or three days to digest the meal and allow her eggs to develop. She is then ready to lay the eggs and repeat the cycle of feeding and laying. Females can live for up to three weeks in the wild, depending on temperature, humidity, their ability to obtain
8736-689: The pitchers of pitcher plants , its larvae feeding on decaying insects that have drowned there. Oviposition , egg-laying, varies between species. Anopheles females fly over the water, touching down or dapping to place eggs on the surface one at a time; their eggs are roughly cigar-shaped and have floats down their sides. A female can lay 100–200 eggs in her lifetime. Aedes females drop their eggs singly, on damp mud or other surfaces near water; their eggs hatch only when they are flooded. Females in genera such as Culex , Culiseta , and Uranotaenia lay their eggs in floating rafts. Mansonia females in contrast lay their eggs in arrays, attached usually to
8848-491: The ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae , but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family— or whether a described family should be acknowledged— is established and decided upon by active taxonomists . There are not strict regulations for outlining or acknowledging
8960-480: The risk of vector-borne disease, based on an area's forecasted climate. Mosquito-borne diseases have long been most prevalent in East Africa, Latin America, Southeast Asia, and India . An emergence in Europe was observed early in the 21st century. It is predicted that by 2030, the climate of southern Great Britain will be suitable for transmission of Plasmodium vivax malaria by Anopheles mosquitoes for two months of
9072-606: The same basic behavioural and ecological syndrome, often referred to as "legionary behaviour", and may be an example of convergent evolution . The successful techniques used by ant colonies have been studied in computer science and robotics to produce distributed and fault-tolerant systems for solving problems. This area of biomimetics has led to studies of ant locomotion, search engines that make use of "foraging trails", fault-tolerant storage and networking algorithms . In temperate climates, honey bees usually form swarms in late spring. A swarm typically contains about half
9184-604: The same spot or perhaps moving en masse or migrating in some direction. It is a highly interdisciplinary topic. As a term, swarming is applied particularly to insects, but can also be applied to any other entity or animal that exhibits swarm behaviour. The term flocking or murmuration can refer specifically to swarm behaviour in birds, herding to refer to swarm behaviour in tetrapods , and shoaling or schooling to refer to swarm behaviour in fish. Phytoplankton also gather in huge swarms called blooms , although these organisms are algae and are not self-propelled
9296-437: The same way a glider can climb or maintain height indefinitely in rising air. Geese flying in a V formation save energy by flying in the updraft of the wingtip vortex generated by the previous animal in the formation. Thus, the birds flying behind do not need to work as hard to achieve lift. Studies show that birds in a V formation place themselves roughly at the optimum distance predicted by simple aerodynamic theory. Geese in
9408-403: The same way as the larvae. If undisturbed, they soon float up again. The adult emerges from the pupa at the surface of the water and flies off. Both male and female mosquitoes feed on nectar , aphid honeydew, and plant juices, but in many species the females are also blood-sucking ectoparasites . In some of those species, a blood meal is essential for egg production; in others, it just enables
9520-451: The search for a host takes place in two phases. First, the mosquito flies about until it detects a host's odorants; then it flies towards them, using the concentration of odorants as its guide. Mosquitoes prefer to feed on people with type O blood , an abundance of skin bacteria, high body heat, and pregnant women. Individuals' attractiveness to mosquitoes has a heritable , genetically controlled component. The multitude of characteristics in
9632-468: The shorter path. This is because the ants that first return to the nest from the food source are more likely to be those that took the shorter path. More ants then retrace the shorter path, reinforcing the pheromone trail. Army ants , unlike most ant species, do not construct permanent nests; an army ant colony moves almost incessantly over the time it exists, remaining in an essentially perpetual state of swarming. Several lineages have independently evolved
9744-429: The six or seven animals directly surrounding it, no matter how close or how far away those animals are. Interactions between flocking starlings are thus based on a topological , rather than a metric, rule. It remains to be seen whether this applies to other animals. Another recent study, based on an analysis of high-speed camera footage of flocks above Rome and assuming minimal behavioural rules, has convincingly simulated
9856-419: The skin, creating large cues for mosquitoes as it increases the attractiveness of an odour blend, imitating a "healthy" human odour. Infected individuals produce larger amounts of aldehydes heptanal , octanal , and nonanal . These compounds are detected by mosquito antennae. Thus, people infected with malaria are more prone to mosquito biting. Contributing to a mosquito's ability to activate search behaviours,
9968-403: The somewhat similar Chironomid midges hold these legs forwards. Anopheles mosquitoes can fly for up to four hours continuously at 1 to 2 km/h (0.62 to 1.24 mph), traveling up to 12 km (7.5 mi) in a night. Males beat their wings between 450 and 600 times per second, driven indirectly by muscles which vibrate the thorax. Mosquitoes are mainly small flies; the largest are in
10080-571: The spring. How the species manages to return to the same overwintering spots over a gap of several generations is still a subject of research; the flight patterns appear to be inherited, based on a combination of the position of the sun in the sky and a time-compensated Sun compass that depends upon a circadian clock that is based in their antennae. Approximately 1800 of the world's 10,000 bird species are long-distance migrants. The primary motivation for migration appears to be food; for example, some hummingbirds choose not to migrate if fed through
10192-415: The spring. The monarch is the only butterfly that migrates both north and south as the birds do on a regular basis. But no single individual makes the entire round trip. Female monarchs deposit eggs for the next generation during these migrations. The length of these journeys exceeds the normal lifespan of most monarchs, which is less than two months for butterflies born in early summer. The last generation of
10304-716: The sugar meal. For a mosquito to obtain a blood meal, it must circumvent its vertebrate host's physiological responses. Mosquito saliva blocks the host's hemostasis system, with proteins that reduce vascular constriction , blood clotting , and platelet aggregation, to ensure the blood keeps flowing. It modulates the host's immune response via a mixture of proteins which lower angiogenesis and immunity ; create inflammation ; suppress tumor necrosis factor release from activated mast cells ; suppress interleukin (IL)-2 and IFN-γ production; suppress T cell populations; decrease expression of interferon −α/β, making virus infections more severe; increase natural killer T cells in
10416-545: The summer enters into a non-reproductive phase known as diapause and may live seven months or more. During diapause, butterflies fly to one of many overwintering sites. The generation that overwinters generally does not reproduce until it leaves the overwintering site sometime in February and March. It is the second, third and fourth generations that return to their northern locations in the United States and Canada in
10528-503: The superior site of another scout. Several different sites may be promoted by different scouts at first. After some hours and sometimes days, a preferred location eventually emerges from this decision-making process. When all scouts agree on the final location, the whole cluster takes off and swarms to it. Sometimes, if no decision is reached, the swarm will separate, some bees going in one direction; others, going in another. This usually results in failure, with both groups dying. A new location
10640-518: The swarm—typically the first—will successfully copulate. Females maximize fitness benefits and minimize cost by governing the onset and magnitude of pheromone deployed. Too little pheromone will not attract a mate, too much allows less fit males to sense the signal. After copulation, females lay the eggs on a host plant. Quality of host plant may be a factor influencing the location of swarming and egg-laying. In one case, researchers observed pink-striped oakworm moths ( Anisota virginiensis ) swarming at
10752-532: The target is actually a human host rather than some other living warm-blooded animal (as the presence of CO 2 shows). Body odour, composed of volatile organic compounds emitted from the skin of humans, is the most important cue used by mosquitoes. Variation in skin odour is caused by body weight, hormones, genetic factors, and metabolic or genetic disorders. Infections such as malaria can influence an individual’s body odour. People infected by malaria produce relatively large amounts of Plasmodium -induced aldehydes in
10864-960: The tip of a bush, on a hilltop, over a pool of water, or even sometimes above a person. The forming of such swarms is not out of instinct, but an adaptive behavior – a "consensus" – between the individuals within the swarms. It is also suggested that swarming is a ritual , because there is rarely any male midge by itself and not in a swarm. This could have formed due to the benefit of lowering inbreeding by having males of various genes gathering in one spot. The genus Culicoides , also known as biting midges, have displayed swarming behavior which are believed to cause confusion in predators. Cockroaches leave chemical trails in their feces as well as emitting airborne pheromones for mating. Other cockroaches will follow these trails to discover sources of food and water, and also discover where other cockroaches are hiding. Thus, groups of cockroaches can exhibit emergent behaviour , in which group or swarm behaviour emerges from
10976-619: The trail left by another ant. Yet put together, the cumulative effect of such behaviours can solve highly complex problems, such as locating the shortest route in a network of possible paths to a food source. The organised behaviour that emerges in this way is sometimes called swarm intelligence , a form of biological emergence . Individual ants do not exhibit complex behaviours, yet a colony of ants collectively achieves complex tasks such as constructing nests, taking care of their young, building bridges and foraging for food. A colony of ants can collectively select (i.e. send most workers towards)
11088-495: The two species have evolved to specialise in biting humans independently. Female mosquito mouthparts are highly adapted to piercing skin and sucking blood. Males only drink sugary fluids, and have less specialized mouthparts. Externally, the most obvious feeding structure of the mosquito is the proboscis, composed of the labium , U-shaped in section like a rain gutter , which sheaths a bundle (fascicle) of six piercing mouthparts or stylets. These are two mandibles , two maxillae ,
11200-475: The under-surfaces of waterlily pads. Clutches of eggs of most mosquito species hatch simultaneously, but Aedes eggs in diapause hatch irregularly over an extended period. The mosquito larva's head has prominent mouth brushes used for feeding, a large thorax with no legs, and a segmented abdomen . It breathes air through a siphon on its abdomen, so must come to the surface frequently. It spends most of its time feeding on algae , bacteria, and other microbes in
11312-441: The water surface. Mosquitoes have adult lifespans ranging from as short as a week to around a month. Some species overwinter as adults in diapause . Mosquitoes have one pair of wings, with distinct scales on the surface. Their wings are long and narrow, while the legs are long and thin. The body, usually grey or black, is slender, and typically 3–6 mm long. When at rest, mosquitoes hold their first pair of legs outwards, whereas
11424-464: The water surface; they hatch into motile larvae that feed on aquatic algae and organic material . These larvae are important food sources for many freshwater animals, such as dragonfly nymphs , many fish, and some birds. Adult females of many species have mouthparts adapted to pierce the skin of a host and feed on blood of a wide range of vertebrate hosts, and some invertebrates , primarily other arthropods . Some species only produce eggs after
11536-434: The water's surface layer. It dives below the surface when disturbed. It swims either by propelling itself with its mouth brushes, or by jerkily wriggling its body. It develops through several stages, or instars , molting each time, after which it metamorphoses into a pupa . Aedes larvae, except when very young, can withstand drying; they go into diapause for several months if their pond dries out. The head and thorax of
11648-522: The way animals are. By extension, the term "swarm" is applied also to inanimate entities which exhibit parallel behaviours, as in a robot swarm , an earthquake swarm , or a swarm of stars. From a more abstract point of view, swarm behaviour is the collective motion of a large number of self-propelled entities . From the perspective of the mathematical modeller, it is an emergent behaviour arising from simple rules that are followed by individuals and does not involve any central coordination. Swarm behaviour
11760-453: The winter. Also, the longer days of the northern summer provide extended time for breeding birds to feed their young. This helps diurnal birds to produce larger clutches than related non-migratory species that remain in the tropics. As the days shorten in autumn, the birds return to warmer regions where the available food supply varies little with the season. These advantages offset the high stress, physical exertion costs, and other risks of
11872-400: The workers together with the old queen, while the new queen stays back with the remaining workers in the original hive. When honey bees emerge from a hive to form a swarm, they may gather on a branch of a tree or on a bush only a few meters from the hive. The bees cluster about the queen and send out 20–50 scouts to find suitable new nest locations. The scouts are the most experienced foragers in
11984-591: The year, and that by 2080, the same will be true for southern Scotland. Dengue fever , too, is spreading northwards with climate change. The vector, the Asian tiger mosquito Aedes albopictus , has by 2023 established across southern Europe and as far north as much of northern France, Belgium, Holland, and both Kent and West London in England. Mosquito larvae are among the commonest animals in ponds, and they form an important food source for freshwater predators . Among
12096-412: Was developed in 1995 by Kennedy and Eberhart and was first aimed at simulating the social behaviour and choreography of bird flocks and fish schools. The algorithm was simplified and it was observed to be performing optimization. The system initially seeds a population with random solutions. It then searches in the problem space through successive generations using stochastic optimization to find
12208-416: Was first simulated on a computer in 1986 with the simulation program boids . This program simulates simple agents (boids) that are allowed to move according to a set of basic rules. The model was originally designed to mimic the flocking behaviour of birds, but it can be applied also to schooling fish and other swarming entities. In recent decades, scientists have turned to modeling swarm behaviour to gain
12320-589: Was introduced by the German entomologist Johann Wilhelm Meigen in his seven-volume classification published in 1818–1838. Mosquito taxonomy was advanced in 1901 when the English entomologist Frederick Vincent Theobald published his 5-volume monograph on the Culicidae. He had been provided with mosquito specimens sent in to the British Museum (Natural History) from around the world, on the 1898 instruction of
12432-488: Was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera , which is far from how the term is used today. In his work Philosophia Botanica published in 1751, Carl Linnaeus employed the term familia to categorize significant plant groups such as trees , herbs , ferns , palms , and so on. Notably, he restricted the use of this term solely within
12544-513: Was the oldest known mosquito. However its identification as a mosquito is disputed, with other authors considering it to be a chaoborid fly instead. Three other unambiguous species of Cretaceous mosquito are known. Burmaculex antiquus and Priscoculex burmanicus are known from Burmese amber from Myanmar, which dates to the earliest part of the Cenomanian age of the Late Cretaceous, around 99 million years ago. Paleoculicis minutus ,
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