87-476: The Acariformes , also known as the Actinotrichida , are the more diverse of the two superorders of mites . Over 32,000 described species are found in 351 families , with an estimated total of 440,000 to 929,000 species, including undescribed species . The Acariformes can be divided into two main clades – Sarcoptiformes and Trombidiformes . In addition, a paraphyletic group containing primitive forms,
174-425: A cephalothorax (with no separate head) or prosoma, and an opisthosoma or abdomen. Segmentation has almost entirely been lost and the prosoma and opisthosoma are fused, only the positioning of the limbs indicating the location of the segments. At the front of the body is the gnathosoma or capitulum. This is not a head and does not contain the eyes or the brain, but is a retractable feeding apparatus consisting of
261-408: A prion disease of sheep. The mite Varroa destructor is a serious pest of honey bees , contributing to colony collapse disorder in commercial hives . This organism is an obligate external parasite, able to reproduce only in bee colonies. It directly weakens its host by sucking up the bee's fat, and can spread RNA viruses including deformed wing virus . Heavy infestation causes the death of
348-577: A bad weed when it out-competes cultivated plants. A different group of weeds consists of those that are invasive, introduced, often unintentionally, to habitats to which they are not native but in which they thrive. Without their original competitors, herbivores, and diseases, they may increase and become a serious nuisance. One such plant is purple loosestrife , a native of Europe and Asia where it occurs in ditches, wet meadows and marshes; introduced into North America, it has no natural enemies to keep it in check and has taken over vast tracts of wetlands to
435-577: A colony, generally over the winter. Since 2006, more than 10 million beehives have been lost. Various mites prey on other invertebrates and can be used to control their populations. Phytoseiidae , especially members of Amblyseius , Metaseiulus , and Phytoseiulus , are used to control pests such as spider mites. Among the Laelapidae , Gaeolaelaps aculeifer and Stratiolaelaps scimitus are used to control fungus gnats , poultry red mites and various soil pests. Mites were first observed under
522-522: A few phylogenomic studies have found strong support for monophyly of Acari and a sister relationship between Acariformes and Parasitiformes, although this finding has been questioned, with other studies suggesting that this likely represents a long branch attraction artefact. Mites are tiny members of the class Arachnida ; most are in the size range 250 to 750 μm (0.01 to 0.03 in) but some are larger and some are no bigger than 100 μm (0.004 in) as adults. The body plan has two regions ,
609-419: A means to disperse. The nematodes (eelworms) that attack plants are minute, often too small to be seen with the naked eye, but their presence is often apparent in the galls or "knots" they form in plant tissues. Vast numbers of nematodes are found in soil and attack roots, but others affect stems, buds, leaves, flowers and fruits. High infestations cause stunting, deformation and retardation of plant growth, and
696-439: A million or more species as yet undescribed. The tropical species Archegozetes longisetosus is one of the strongest animals in the world, relative to its mass (100 μg): It lifts up to 1,182 times its own weight, over five times more than would be expected of such a minute animal. A mite also holds a speed record: for its length, Paratarsotomus macropalpis is the fastest animal on Earth. The mites living in soil consist of
783-765: A network of sinuses and most mites lacks a heart, movement of fluid being driven by the contraction of body muscles. But ticks, and some of the larger species of mites, have a dorsal, longitudinal heart. Gas exchange is carried out across the body surface, but many species additionally have between one and four pairs of tracheae . The excretory system includes a nephridium and one or two pairs of Malpighian tubules . Several families of mites, such as Tetranychidae, Eriophyidae, Camerobiidae, Cunaxidae, Trombidiidae, Trombiculidae, Erythraeidae and Bdellidae have silk glands used to produce silk for various purposes. Additionally, water mites (Hydrachnidia) produce long thin threads that may be silk. The sexes are separate in mites; males have
870-532: A nuisance around buildings, roadsides and recreation areas because of its uncomfortably sharp spiny burrs . Disease-causing pathogens such as fungi , oomycetes , bacteria , and viruses can cause damage to crops and garden plants. The term "plant pest", mainly applied to insect micropredators of plants, has a specific definition in terms of the International Plant Protection Convention and phytosanitary measures worldwide. A pest
957-418: A pair of testes in the mid-region of the body, each connected to the gonopore by a vas deferens , and in some species there is a chitinous penis ; females have a single ovary connected to the gonopore by an oviduct , as well as a seminal receptacle for the storage of sperm . In most mites, sperm is transferred to the female indirectly; the male either deposits a spermatophore on a surface from which it
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#17328551148671044-430: A pest is a competitor to humanity. Pests include plants, pathogens, invertebrates, vertebrates, or any organism that harms an ecosystem. Animals are considered pests or vermin when they injure people or damage crops, forestry, or buildings. Elephants are regarded as pests by the farmers whose crops they raid and trample. Mosquitoes and ticks are vectors that can transmit ailments but are also pests because of
1131-404: A pest plant "any plant that, in the local government authority's opinion, is likely to adversely affect the environment of the district, the value of property in the district, or the health, comfort or convenience of the district's inhabitants." An example of such a plant prescribed under this regulation is caltrop, Tribulus terrestris , which can cause poisoning in sheep and goats, but is mainly
1218-448: A range of taxa. Oribatida and Prostigmata are more numerous in soil than Mesostigmata, and have more soil-dwelling species. When soil is affected by an ecological disturbance such as agriculture, most mites (Astigmata, Mesostigmata and Prostigmata) recolonise it within a few months, whereas Oribatida take multiple years. Many mites are parasitic on plants and animals. One family of mites, Pyroglyphidae , or nest mites, live primarily in
1305-542: A small scale, walking is used to access other suitable locations in the immediate vicinity. Some species mount to a high point and adopt a dispersal posture and get carried away by the wind, while others waft a thread of silk aloft to balloon to a new position. Parasitic mites use their hosts to disperse, and spread from host to host by direct contact. Another strategy is phoresy ; the mite, often equipped with suitable claspers or suckers, grips onto an insect or other animal, and gets transported to another place. A phoretic mite
1392-399: A suitable stocking density, and minimizing injury and stress to trees. Pest control in buildings can be approached in several ways, depending on the type of pest and the area affected. Methods include improving sanitation and garbage control, modifying the habitat, and using repellents, growth regulators, traps, baits and pesticides. For example, the pesticide Boron can be impregnated into
1479-518: A thick cuticle or waxy deposits, with the second line of defence being toxic or distasteful secondary metabolites . Mechanical injury to the plant tissues allows the entry of pathogens and stimulates the plant to mobilise its chemical defences. The plant soon seals off the wound to reduce further damage. Plants sometimes take active steps to reduce herbivory. Macaranga triloba for example has adapted its thin-walled stems to create ideal housing for an ant Crematogaster spp., which, in turn, protects
1566-423: Is a plant considered undesirable in a particular situation; the term has no botanical significance. Often, weeds are simply those native plants that are adapted to grow in disturbed ground, the disturbance caused by ploughing and cultivation favouring them over other species. Any plant is a weed if it appears in a location where it is unwanted; Bermuda grass makes a good lawn plant under hot dry conditions but become
1653-561: Is a simple error because phylogenetic software usually fails in handling non dichotomous phylogenies. Consequently, it may be best for the time being to consider each of the three main prostigmatan lineages to be equally distinct from the other two. The oldest fossils of acariform mites are from the Rhynie Chert , Scotland, which dates to the early Devonian , around 410 million years ago The Cretaceous Immensmaris chewbaccei had idiosoma of more than 8 mm (0.31 in) in length and
1740-492: Is any species, strain or biotype of plant, animal, or pathogenic agent injurious to plants or plant products. Worldwide, agricultural pest impacts are increased by higher degrees of interconnectedness. This is due to the increased risk that any particular pest problem anywhere in the world (as a system ) will propagate across the entire system. Plants have developed strategies that they use in their own defence, be they thorns (modified stems) or spines (modified leaves), stings,
1827-440: Is just a hitch-hiker and does not feed during the time it is carried by its temporary host. These travelling mites are mostly species that reproduce rapidly and are quick to colonise new habitats. Mites are tiny and apart from those that are of economic concern to humans, little studied. The majority are beneficial, living in the soil or aqueous environments and assisting in the decomposition of decaying organic material, as part of
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#17328551148671914-491: Is located on the ventral surface between the fourth pair of legs. Some species have one to five median or lateral eyes but many species are blind, and slit and pit sense organs are common. Both body and limbs bear setae (bristles) which may be simple, flattened, club-shaped or sensory. Mites are usually some shade of brown, but some species are red, orange, black or green, or some combination of these colours. Many mites have stigmata (openings used in respiration). In some mites,
2001-458: Is picked up by the female, or he uses his chelicerae or third pair of legs to insert it into the female's gonopore. In some of the Acariformes , insemination is direct using the male's penis. The spermatophora in all mites are aflagellate. The eggs are laid in the substrate , or wherever the mite happens to live. They take up to six weeks to hatch, according to species, with the next stage being
2088-563: Is the Actinedida , but in treatments like the present one, this is split up between the Sarcoptiformes (and formerly the separate Endeostigmata) and Trombidiformes (which contains the bulk of the "Actinedida"), because it appears to be a massively paraphyletic " wastebin taxon ", uniting all Acariformes that are not "typical" Oribatida and Astigmatina . The Trombidiformes present their own problems. The small group Sphaerolichida appears to be
2175-691: Is the case with the emerald ash borer , an insect native to north-eastern Asia, which, since its arrival in North America, has killed millions of ash trees. Another example of a beetle species that exhibits pest behavior are Melolontha Hippocastrani , that cause severe, long-term damage on young trees by feeding on roots. Animals able to live in the dry conditions found in buildings include many arthropods such as beetles, cockroaches, moths, and mites. Another group, including termites , woodworm , longhorn beetles , and wood ants cause structural damage to buildings and furniture. The natural habitat of these
2262-424: Is the decaying parts of trees. The deathwatch beetle infests the structural timbers of old buildings, mostly attacking hardwood , especially oak . The initial attack usually follows the entry of water into a building and the subsequent decay of damp timber. Furniture beetles mainly attack the sapwood of both hard and soft wood , only attacking the heartwood when it is modified by fungal decay. The presence of
2349-723: The Acariformes and the Parasitiformes , which were historically grouped together in the subclass Acari . However, most recent genetic analyses do not recover the two as each other's closest relative within Arachnida, rendering the group non- monophyletic . Most mites are tiny, less than 1 mm (0.04 in) in length, and have a simple, unsegmented body plan. The small size of most species makes them easily overlooked; some species live in water, many live in soil as decomposers , others live on plants, sometimes creating galls , while others are predators or parasites . This last type includes
2436-456: The Endeostigmata , was formerly also considered distinct. The latter is composed of only 10 families of little-studied, minute, soft-bodied mites that ingest solid food, such as fungi , algae , and soft-bodied invertebrates such as nematodes , rotifers , and tardigrades . These clades were formerly considered suborders , but this does not allow for a sufficiently precise classification of
2523-683: The Oribatida need to be split up in two, as the Astigmatina are closer to some of them (e.g. certain Desmonomata ) than the latter are to other "Oribatida". The Trombidiformes are most noted for the economic damage caused by many plant parasite species. All of the most important plant pests among the Acari are trombidiformans, such as spider mites (Tetranychidae) and Eriophyidae . Many species are also predators, fungivores , and animal parasites. Some of
2610-514: The Parasitiformes (sometimes known as Anactinotrichida). Recent genetic research has suggested that Acari is polyphyletic (of multiple origins). A study using molecular data from the mitochondria and nucleus recovered Acariformes as sister to the Solifugae (camel spiders) and Parasitiformes as sister to the Pseudoscorpionida , with other arachnid orders separating these two groupings on
2697-494: The Rhynie Chert , Scotland, which dates to the early Devonian , around 410 million years ago while the earliest fossils of Parasitiformes are known from amber specimens dating to the mid- Cretaceous , around 100 million years ago. Most fossil acarids are no older than the Tertiary (up to 65 mya ). Members of the superorders Opilioacariformes and Acariformes (sometimes known as Actinotrichida) are mites, as well as some of
Acariformes - Misplaced Pages Continue
2784-417: The carbon cycle . Two species live on humans, namely Demodex folliculorum and Demodex brevis ; both are frequently referred to as eyelash mites. The majority of mite species are harmless to humans and domestic animals , but a few species can colonize mammals directly, acting as vectors for disease transmission, and causing or contributing to allergenic diseases. Mites which colonize human skin are
2871-625: The chelicerae , the pedipalps and the oral cavity. It is covered above by an extension of the body carapace and is connected to the body by a flexible section of cuticle . Two-segmented chelicerae is the ancestral condition in Acariformes, but in more derived groups they are single-segmented. And three-segmented chelicerae is the ancestral condition in Parasitiformes, but has been reduced to just two segments in more derived groups. The pedipalps differ between taxa depending on diet; in some species
2958-635: The drugstore beetle , the sawtoothed grain beetle and the Indianmeal moth being found worldwide. The insects may be present in the warehouse or maybe introduced during shipping, in retail outlets, or in the home; they may enter packets through tiny cracks or may chew holes in the packaging. The longer a product is stored, the more likely it is to become contaminated, with the insects often originating from dry pet foods. Some mites, too, infest foodstuffs and other stored products. Each substance has its own specific mite, and they multiply with great rapidity. One of
3045-511: The microscope by the English polymath Robert Hooke . In his 1665 book Micrographia , he stated that far from being spontaneously generated from dirt, they were "very prettily shap'd Insects". In 1898, Arthur Conan Doyle wrote a satirical poem, "A Parable", with the conceit of some cheese mites disputing the origin of the round cheddar cheese in which they all lived. The world's first science documentary featured cheese mites , seen under
3132-429: The 10th century Greek monk Tryphon of Constantinople is said to have prayed "Snails, earwigs and all other creatures, hurt not the vines, nor the land nor the fruit of the trees, nor the vegetables ... but depart into the wild mountains." The 11th-century Old English medical text Lacnunga contained charms and spells to ward off or treat pests such as wid smeogan wyrme , " penetrating worms ", in this case requiring
3219-593: The Acari has been relatively little studied, but molecular information from ribosomal DNA is being extensively used to understand relationships between groups. The 18 S rRNA gene provides information on relationships among phyla and superphyla, while the ITS2 , and the 18S ribosomal RNA and 28S ribosomal RNA genes, provide clues at deeper levels. The mite fossil record is sparse, due to their small size and low preservation potential. The oldest fossils of acariform mites are from
3306-609: The ants. Pest ranges are heavily determined by climate . The most common example for the longest time has been rainfall : Although drought stress weakens crop disease resistance , drought also retards contagion and infection; and some variability in precipitation is universal. More recently climate change has been rapidly altering ranges, mostly by pushing them towards the poles (both North and South ). From 1960-2013 ranges have shifted poleward by 2.7 ± 0.8 km (1.68 ± 0.50 mi) per year - albeit with significant differences between taxa . (Especially in
3393-546: The appendages resemble legs while in others they are modified into chelicerae-like structures. The oral cavity connects posteriorly to the mouth and pharynx . Most mites have four pairs of legs (two pairs in Eriophyoidea ), each with six segments, which may be modified for swimming or other purposes. The dorsal surface of the body is clad in hardened tergites and the ventral surface by hardened sclerites ; sometimes these form transverse ridges. The gonopore (genital opening)
3480-474: The beetles only becomes apparent when the larvae gnaw their way out, leaving small circular holes in the timber. Carpet beetles and clothes moths cause non-structural damage to property such as clothing and carpets. It is the larvae that are destructive, feeding on wool, hair, fur, feathers and down. The moth larvae live where they feed, but the beetle larvae may hide behind skirting boards or in other similar locations between meals. They may be introduced to
3567-622: The birth of civilisation. Plagues of locusts caused devastation in the ancient Middle East, and were recorded in tombs in Ancient Egypt from as early as 2470 BC, and in the Book of Exodus in the Bible, as taking place in Egypt around 1446 BC. Homer 's Iliad mentions locusts taking to the wing to escape fire. Given the impact of agricultural pests on human lives, people have prayed for deliverance. For example,
Acariformes - Misplaced Pages Continue
3654-642: The body of honey bees , and Acarapis woodi (family Tarsonemidae ) lives in their tracheae . Hundreds of species are associated with other bees, mostly poorly described. They attach to bees in a variety of ways. For example, Trigona corvina workers have been found with mites attached to the outer face of their hind tibiae. Some are thought to be parasites, while others are beneficial symbionts . Mites also parasitize some ant species, such as Eciton burchellii . Most larvae of Parasitengona are ectoparasites of arthropods, while later life stages in this group tend to shift to being predators. Plant pests include
3741-510: The case of viruses and nematodes which show the opposite trend, toward the equator . This may be due to their lack of airborne dispersal , so their trend conforms with the trend of human-aided dispersal ; or identification difficulties in the field.) In Europe, crop pests are expected to burgeon as the vertebrate predators which control them are expected to be suppressed by future climatic conditions. Together pests and diseases cause up to 40% yield losses every year. The animal groups of
3828-407: The cause of several types of itchy skin rashes, such as gamasoidosis , rodent mite dermatitis , grain itch , grocer's itch , and scabies ; Sarcoptes scabiei is a parasitic mite responsible for scabies, which is one of the three most common skin disorders in children. Demodex mites, which are common cause of mange in dogs and other domesticated animals, have also been implicated in
3915-437: The commercially destructive Varroa parasite of honey bees , as well as scabies mites of humans. Most species are harmless to humans, but a few are associated with allergies or may transmit diseases. The scientific discipline devoted to the study of mites is called acarology . The mites are not a defined taxon, but is used for two distinct groups of arachnids, the Acariformes and the Parasitiformes . The phylogeny of
4002-455: The cooling systems of power and desalination plants which draw their water from the sea. Many of the animals that we regard as pests live in our homes. Before humans built dwellings, these creatures lived in the wider environment, but co-evolved with humans, adapting to the warm, sheltered conditions that a house provides, the wooden timbers, the furnishings, the food supplies and the rubbish dumps. Many no longer exist as free-living organisms in
4089-416: The damage done by molluscs becomes of greater significance. Terrestrial molluscs need moist environments; snails may be more noticeable because their shells provide protection from desiccation, while most slugs live in soil and only come out to feed at night. They devour seedlings, damage developing shoots and feed on salad crops and cabbages, and some species tunnel into potatoes and other tubers. A weed
4176-408: The difficulty of examining entire trees, and the certainty that pesticides would damage many forest organisms other than the intended pests. Forest integrated pest management therefore aims to use a combination of prevention, cultural control measures, and direct control (such as pesticide use). Cultural measures include choosing appropriate species, keeping competing vegetation under control, ensuring
4263-428: The disease rickettsialpox . House dust mites , found in warm and humid places such as beds, cause several forms of allergic diseases, including hay fever , asthma and eczema , and are known to aggravate atopic dermatitis . Among domestic animals , sheep are affected by the mite Psoroptes ovis which lives on the skin, causing hypersensitivity and inflammation. Hay mites are a suspected reservoir for scrapie ,
4350-494: The distress caused by their bites. Grasshoppers are usually solitary herbivores of little economic importance until the conditions are met for them to enter a swarming phase , become locusts and cause enormous damage. Many people appreciate birds in the countryside and their gardens, but when these accumulate in large masses, they can be a nuisance. Flocks of starlings can consist of hundreds of thousands of individual birds, their roosts can be noisy and their droppings voluminous;
4437-715: The droppings are acidic and can cause corrosion of metals, stonework, and brickwork as well as being unsightly. Pigeons in urban settings may be a health hazard, and gulls near the coast can become a nuisance, especially if they become bold enough to snatch food from passers-by. All birds are a risk at airfields where they can be sucked into aircraft engines. Woodpeckers sometimes excavate holes in buildings, fencing and utility poles, causing structural damage; they also drum on various reverberatory structures on buildings such as gutters, down-spouts, chimneys, vents and aluminium sheeting. Jellyfish can form vast swarms which may be responsible for damage to fishing gear, and sometimes clog
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#17328551148674524-630: The exclusion of native species. In forestry, pests may affect various parts of the tree, from its roots and trunk to the canopy far overhead. The accessibility of the part of the tree affected may make detection difficult, so that a pest problem may already be far advanced before it is first observed from the ground. The larch sawfly and spruce budworm are two insect pests prevalent in Alaska and aerial surveys can show which sections of forest are being defoliated in any given year so that appropriate remedial action can be taken. Some pests may not be present on
4611-764: The fibres of cellulose insulation to kill self-grooming insects such as ants and cockroaches. Clothes moths can be controlled with airtight containers for storage, periodic laundering of garments, trapping, freezing, heating and the use of chemicals. Traditional mothballs deter adult moths with strong-smelling naphthalene ; modern ones use volatile repellents such as 1,4-Dichlorobenzene . Moth larvae can be killed with insecticides such as permethrin or pyrethroids . However, insecticides cannot safely be used in food storage areas; alternative treatments include freezing foods for four days at 0 °F (−18 °C) or baking for half an hour at 130 °F (54 °C) to kill any insects present. Pests have attracted human attention from
4698-560: The general collection. There are over four thousand species of cockroach worldwide, but only four species are commonly regarded as pests, having adapted to live permanently in buildings. Considered to be a sign of unsanitary conditions, they feed on almost anything, reproduce rapidly and are difficult to eradicate. They can passively transport pathogenic microbes on their body surfaces, particularly in environments such as hospitals, and are linked with allergic reactions in humans. Various insects attack dry food products, with flour beetles ,
4785-401: The greatest importance as agricultural pests are (in order of economic importance) insects , mites , nematodes and gastropod molluscs . Insects are responsible for two major forms of damage to crops. First, there is the direct injury they cause to the plants as they feed on the tissues; a reduction in leaf surface available for photosynthesis, distortion of growing shoots, a diminution of
4872-527: The home in any product containing animal fibres including upholstered furniture; the moths are feeble fliers but the carpet beetles may also enter houses through open windows. Furniture beetles, carpet beetles and clothes moths are also capable of creating great damage to museum exhibits, zoological and botanical collections, and other cultural heritage items. Constant vigilance is required to prevent an attack, and newly acquired items, and those that have been out on loan, may need quarantining before being added to
4959-417: The human skin disease rosacea , although the mechanism by which demodex contributes to the disease is unclear. Ticks are well known for carrying diseases, such as Lyme disease and Rocky Mountain spotted fever . Chiggers are known primarily for their itchy bite , but they can also spread disease in some limited circumstances, such as scrub typhus . The house-mouse mite is the only known vector of
5046-526: The microscope; the short film was shown in London's Alhambra music hall in 1903, causing a boom in the sales of simple microscopes. Pest (organism) A pest is any organism harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environment for their own purposes and are intolerant of other creatures occupying
5133-583: The mites and is abolished in more modern treatments; the Endeostigmata are variously considered to form a suborder on their own (the old view) or are included mainly in the Sarcoptiformes, thus making both groups monophyletic . The superfamily Eriophyoidea , traditionally considered members of the Trombidiformes, have been found to be basal mites in genomic analyses, sister to the clade containing Sarcoptiformes and Trombidiformes. Another group often mentioned
5220-559: The most ancient lineage among them. However, the Prostigmata are variously subdivided into the Anystina and Eleutherengona , and Eupodina . The delimitation and interrelationships of these groups are entirely unclear; while most analyses find one of the latter two, but not the other to be a subgroup of the Anystina; neither of these mutually contradicting hypotheses is very robust; possibly this
5307-435: The most conspicuous species of free-living mites are the relatively large and bright red velvet mites, that belong to the family Trombidiidae . Oribatid mites and to a much lesser extent others are a source of alkaloids in poison frogs (namely small species like the strawberry poison-dart frog Oophaga pumilio ). Such frogs raised without these oribatids in their diets do not develop the strong poisons associated with them in
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#17328551148675394-662: The most damaging is the flour mite , which is found in grain and may become exceedingly abundant in poorly stored material. In time, predatory mites usually move in and control the flour mites. The control of pests in crops is as old as civilisation. The earliest approach was mechanical, from ploughing to picking off insects by hand. Early methods included the use of sulphur compounds, before 2500 BC in Sumeria. In ancient China, insecticides derived from plants were in use by 1200 BC to treat seeds and to fumigate plants. Chinese agronomy recognised biological control by natural enemies of pests and
5481-612: The most diverse and successful of all invertebrate groups. They have exploited a wide array of habitats , and because of their small size go largely unnoticed. They are found in freshwater (e.g. the water mites or Hydrachnidia ) and saltwater (most Halacaridae ), in the soil, in forests, pastures, agricultural crops, ornamental plants, thermal springs and caves. They inhabit organic debris of all kinds and are extremely numerous in leaf litter. They feed on animals, plants and fungi and some are parasites of plants and animals. Some 48,200 species of mites have been described, but there may be
5568-680: The nematodes can transmit viral diseases from one plant to another. When its populations are high, the potato cyst nematode can cause reductions of 80% in yield of susceptible potato varieties. The nematode eggs survive in the soil for many years, being stimulated to hatch by chemical cues produced by roots of susceptible plants. Slugs and snails are terrestrial gastropod molluscs which typically chew leaves, stems, flowers, fruit and vegetable debris. Slugs and snails differ little from each other and both do considerable damage to plants. With novel crops being grown and with insect pests having been brought more under control by biological and other means,
5655-506: The nests of birds and other animals. These mites are largely parasitic and consume blood , skin and keratin . Dust mites , which feed mostly on dead skin and hair shed from humans instead of consuming them from the organism directly, evolved from these parasitic ancestors. Ticks are a prominent group of mites that are parasitic on vertebrates, mostly mammal and birds, feeding on blood with specialised mouthparts. Parasitic mites sometimes infest insects. Varroa destructor attaches to
5742-441: The open for brief periods as adults, primarily to mate and disperse. The import and export of timber has inadvertently assisted some insect pests to establish themselves far from their country of origin. An insect may be of little importance in its native range, being kept under control by parasitoid wasps, predators, and the natural resistance of the host trees, but be a serious pest in a region into which it has been introduced. This
5829-425: The order Oribatida are very ancient and likely arose 400-300 million years ago. In some parthenogenetic species that undergo automixis (a kind of self-fertilization that retains meiosis ) sexual reproduction has re-emerged. Eriophyidae , plant parasites , e.g. Acalitus essigi (redberry mite) Mite Mites are small arachnids (eight-legged arthropods ). Mites span two large orders of arachnids,
5916-532: The outside world, and can therefore be considered to be domesticated. The St Kilda house mouse rapidly became extinct when the last islander left the island of St Kilda, Scotland in 1930, but the St Kilda field mouse survived. Plants may be considered pests, for example, if they are invasive species or weeds . There is no universal definition of what makes a plant a pest. Some governments, such as that of Western Australia, permit their authorities to prescribe as
6003-413: The phylogenetic tree, as shown below. Palpigradi False scorpions [REDACTED] Ixodida (ticks) [REDACTED] Parasitic mites, inc. Varroa [REDACTED] Trombidiformes (chiggers, velvet mites, etc) [REDACTED] Sarcoptiformes (dust & fur mites, etc) [REDACTED] Camel spiders [REDACTED] other Arachnids including spiders and scorpions However,
6090-452: The plant from herbivores. In addition to providing housing, the plant also provides the ant with its exclusive food source in the form of food bodies located on the leaf stipules. Similarly, several Acacia tree species have developed stout spines that are swollen at the base, forming a hollow structure that provides housing for ants which protect the plant. These Acacia trees also produce nectar in nectaries on their leaves as food for
6177-417: The plant's growth and vigour, and the wilting of shoots and branches caused by the insects' tunneling activities. Secondly there is the indirect damage, where the insects do little direct harm, but either transmit or allow entry of fungal, bacterial or viral infections. Although some insects are polyphagous, many are restricted to one specific crop, or group of crops. In many cases it is the larva that feeds on
6264-456: The plant, building up a nutritional store that will be used by the short-lived adult; sawfly and lepidopteran larvae feed mainly on the aerial portions of plants while beetle larvae tend to live underground, feeding on roots, or tunnel into the stem or under the bark. The true bugs, Hemiptera , have piercing and sucking mouthparts and live by sucking sap from plants. These include aphids , whiteflies and scale insects . Apart from weakening
6351-442: The plant, they encourage the growth of sooty mould on the honeydew the insects produce, which cuts out the light and reduces photosynthesis, stunting the plant's growth. They often transmit serious viral diseases between plants. The mites that cause most trouble in the field are the spider mites . These are less than 1 mm (0.04 in) in diameter, can be very numerous, and thrive in hot, dry conditions. They mostly live on
6438-631: The plants and from the indirect consequences of the fungal, bacterial or viral infections they transmit. Plants have their own defences against these attacks but these may be overwhelmed, especially in habitats where the plants are already stressed, or where the pests have been accidentally introduced and may have no natural enemies. The pests affecting trees are predominantly insects, and many of these have also been introduced inadvertently and lack natural enemies, and some have transmitted novel fungal diseases with devastating results. Humans have traditionally performed pest control in agriculture and forestry by
6525-407: The roots or the aerial parts of plants and transmit viruses. Some examples are the big bud mite that transmits the reversion virus of blackcurrants , the coconut mite which can devastate coconut production, and the cereal rust mite which transmits several grass and cereal viruses. Being exceedingly minute, many plant mites are spread by wind, although others use insects or other arthropods as
6612-431: The same space when their activities impact adversely on human objectives. Thus, an elephant is unobjectionable in its natural habitat but a pest when it tramples crops. Some animals are disliked because they bite or sting; wolves , snakes , wasps , ants , bed bugs , fleas and ticks belong in this category. Others enter the home; these include houseflies, which land on and contaminate food; beetles, which tunnel into
6699-404: The second half of the 19th century, starting with the vedalia beetle against cottony cushion scale . All these methods have been refined and developed since their discovery. Forest pests inflict costly damage, but treating them is often unaffordable, given the relatively low value of forest products compared to agricultural crops. It is also generally impossible to eradicate forest pests, given
6786-564: The six-legged larvae. After three moults, the larvae become nymphs, with eight legs, and after a further three moults, they become adults. Longevity varies between species, but the lifespan of mites is short compared to many other arachnids. Mites occupy a wide range of ecological niches . For example, Oribatida mites are important decomposers in many habitats. They eat a wide variety of material including living and dead plant and fungal material, lichens and carrion; some are predatory , though no oribatid mites are parasitic . Mites are among
6873-477: The so-called spider mites (family Tetranychidae ), thread-footed mites (family Tarsonemidae ), and the gall mites (family Eriophyidae ). Among the species that attack animals are members of the sarcoptic mange mites (family Sarcoptidae ), which burrow under the skin. Demodex mites (family Demodecidae ) are parasites that live in or near the hair follicles of mammals , including humans. Being unable to fly, mites need some other means of dispersal. On
6960-505: The stigmata are associated with peritremes: paired, tubular, elaborated extensions of the tracheal system. The higher taxa of mites are defined by these structures: Mite digestive systems have salivary glands that open into the preoral space rather than the foregut. Most species carry two to six pairs of salivary glands that empty at various points into the subcheliceral space. A few mite species lack an anus: they do not defecate during their short lives. The circulatory system consists of
7047-455: The tree all year round, either because of their life cycle or because they rotate between different host species at different times of the year. In forestry, pests may affect various parts of the tree, from its roots and trunk to the canopy far overhead. The larvae of wood-boring beetles , for example, are notorious for spending years excavating tunnels under the bark of trees, leading to significant structural damage. These larvae only emerge into
7134-448: The underside of leaves and puncture the plant cells to feed, with some species forming webbing. They occur on nearly all important food crops and ornamental plants, both outdoors and under glass, and include some of the most economically important pests. Another important group of mites is the gall mites which affect a wide range of plants, several mite species being major pests causing substantial economic damage to crops. They can feed on
7221-470: The use of pesticides ; however, other methods exist such as mechanical control , and recently developed biological controls . A pest is any living thing which humans consider troublesome to themselves, their possessions, or the environment. Pests can cause issues with crops, human or animal health, buildings, and wild areas or larger landscapes. An older usage of the word "pest" is of a deadly epidemic disease, specifically plague . In its broadest sense,
7308-686: The varying of planting time to reduce pests before the first century AD. The agricultural revolution in Europe saw the introduction of effective plant-based insecticides such as pyrethrum , derris , quassia , and tobacco extract. The phylloxera (a powdery mildew ) damage to the wine industry in the 19th century resulted in the development of resistant varieties and grafting , and the accidental discovery of effective chemical pesticides, Bordeaux mixture (lime and copper sulphate ) and Paris Green (an arsenic compound), both very widely used. Biological control also became established as an effective measure in
7395-442: The wild. Acariformes species appear to have evolved from a sexual ancestor and the primary manner of reproduction during the course of evolution has been sexual reproduction . However, within the super order Acariformes, parthenogenetic species have arisen numerous times during the course of evolution. In contrast to the commonly held view that parthenogenetic lineages are short lived, four species-rich parthenogenetic clusters of
7482-402: The woodwork; and other animals that scuttle about on the floor at night, like rats and cockroaches , which are often associated with unsanitary conditions. Agricultural and horticultural crops are attacked by a wide variety of pests, the most important being rodents , insects , mites , nematodes and gastropod molluscs . The damage they do results both from the direct injury they cause to
7569-615: Was the largest fossil acariform mite and also the largest erythraeoid mite ever recorded. The Sarcoptiformes ingest solid food, being mainly microherbivores, fungivores and detritivores . Some Astigmatina – the Psoroptidia – have become associated with vertebrates and nest-building insects . These include the well known house dust mites , scab mites and mange mites, stored product mites, feather mites and some fur mites. The relationships between their main groups are not well-resolved and subject to revision. In particular it appears as if
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