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95-463: Varroa destructor Varroa jacobsoni Varroa rindereri Varroa underwoodi Varroa is a genus of parasitic mesostigmatan mites associated with honey bees , placed in its own family, Varroidae . The genus was named for Marcus Terentius Varro , a Roman scholar and beekeeper. The condition of a honeybee colony being infested with Varroa mites is called varroosis (also, incorrectly, varroatosis ). Varroa mites, specifically
190-438: A holoparasite such as Cuscuta derives all of its nutrients from another plant. Parasitic plants make up about one per cent of angiosperms and are in almost every biome in the world. All these plants have modified roots, haustoria , which penetrate the host plants, connecting them to the conductive system—either the xylem , the phloem , or both. This provides them with the ability to extract water and nutrients from
285-511: A cause of gastroenteritis , is spread by the fecal–oral route from animals, or by eating insufficiently cooked poultry , or by contaminated water. Haemophilus influenzae , an agent of bacterial meningitis and respiratory tract infections such as influenza and bronchitis , is transmitted by droplet contact. Treponema pallidum , the cause of syphilis , is spread by sexual activity . Viruses are obligate intracellular parasites, characterised by extremely limited biological function, to
380-401: A colony. They involve either estimating the total number of mites in a hive by using a sticky board under a screen bottom board to capture mites falling from the hive or estimating the number of mites per bee with powdered sugar or an ethanol wash. Monitoring for mites with a sticky board can be used to estimate the total number of mites in a colony over 72 hours using the equation: where b
475-472: A contributing factor that leads to colony collapse disorder (CCD). While the exact causes of CCD are not known, infection of colonies from multiple pathogens and interaction of those pathogens with environmental stresses is considered by entomologists to be one of the likely causes of CCD. Most scientists agree there is not a single cause of CCD. Mite populations undergo exponential growth when bee broods are available, and exponential decline when no brood
570-627: A faster rate than their hosts. Classic examples include interactions between vertebrate hosts and tapeworms , flukes , and those between the malaria-causing Plasmodium species, and fleas . Parasites reduce host fitness by general or specialised pathology , that ranges from parasitic castration to modification of host behaviour . Parasites increase their own fitness by exploiting hosts for resources necessary for their survival, in particular by feeding on them and by using intermediate (secondary) hosts to assist in their transmission from one definitive (primary) host to another. Although parasitism
665-595: A hormone or by diverting nutrients. For example, the trematode Zoogonus lasius , whose sporocysts lack mouths, castrates the intertidal marine snail Tritia obsoleta chemically, developing in its gonad and killing its reproductive cells. Directly transmitted parasites, not requiring a vector to reach their hosts, include such parasites of terrestrial vertebrates as lice and mites; marine parasites such as copepods and cyamid amphipods; monogeneans ; and many species of nematodes, fungi, protozoans, bacteria, and viruses. Whether endoparasites or ectoparasites, each has
760-420: A life expectancy of 27 days when brood is present. After the phoretic stage, female mites leave the adult bee and enter brood cells with bee larvae. Drone cells are preferred over workers. These females are called foundress mites, and they bury themselves in brood food provided by worker bees before the cell is capped. Brood cell capping begins egg cell activation for a foundress mite while she emerges to feed on
855-423: A line of bees which uses Varroa -sensitive hygiene to remove reproductive mites. This line is now being distributed to beekeepers to be used as part of their integrated pest management programs. The infestation and subsequent parasitic disease caused by mites in the genus Varroa is called varroosis. Sometimes, the incorrect names varroatosis or varroasis are used. A parasitic disease name must be formed from
950-523: A means by which phoretic mites spread short distances when other bees, including from other hives, visit. They have also been found on larvae of some wasp species, such as Vespula vulgaris , and flower-feeding insects such as the bumblebee , Bombus pensylvanicus , the scarab beetle , Phanaeus vindex , and the flower-fly , Palpada vinetorum . There have not been any indications Varroa mites are able to complete their life cycle on these insects, but instead they become distributed to other areas while
1045-426: A mite is still alive on these insects. Open wounds left by the feeding become sites for disease and virus infections. The mites are vectors for at least five and possibly up to 18 debilitating bee viruses, including RNA viruses such as the deformed wing virus . Prior to the widespread introduction of Varroa mite, honey bee viruses were typically considered a minor issue. Virus particles are directly injected into
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#17328551074201140-836: A parasite employs to identify and approach a potential host are known as "host cues". Such cues can include, for example, vibration, exhaled carbon dioxide , skin odours, visual and heat signatures, and moisture. Parasitic plants can use, for example, light, host physiochemistry, and volatiles to recognize potential hosts. There are six major parasitic strategies , namely parasitic castration ; directly transmitted parasitism; trophically -transmitted parasitism; vector -transmitted parasitism; parasitoidism ; and micropredation. These apply to parasites whose hosts are plants as well as animals. These strategies represent adaptive peaks ; intermediate strategies are possible, but organisms in many different groups have consistently converged on these six, which are evolutionarily stable. A perspective on
1235-618: A parasitic alien species. First used in English in 1539, the word parasite comes from the Medieval French parasite , from the Latinised form parasitus , from Ancient Greek παράσιτος (parasitos) 'one who eats at the table of another' in turn from παρά (para) 'beside, by' and σῖτος (sitos) 'wheat, food'. The related term parasitism appears in English from 1611. Parasitism
1330-432: A phenomenon termed the biotrophy-necrotrophy switch . Pathogenic fungi are well-known causative agents of diseases on animals as well as humans. Fungal infections ( mycosis ) are estimated to kill 1.6 million people each year. One example of a potent fungal animal pathogen are Microsporidia - obligate intracellular parasitic fungi that largely affect insects, but may also affect vertebrates including humans, causing
1425-533: A predator, the European sparrowhawk , giving her time to lay her eggs in the host's nest unobserved. Host species often combat parasitic egg mimicry through egg polymorphism , having two or more egg phenotypes within a single population of a species. Multiple phenotypes in host eggs decrease the probability of a parasitic species accurately "matching" their eggs to host eggs. In kleptoparasitism (from Greek κλέπτης ( kleptēs ), "thief"), parasites steal food gathered by
1520-498: A sample of bees using non-lethal or lethal means. The bees are shaken in a container of either powdered sugar, alcohol, or soapy water to dislodge and count mites. Powdered sugar is generally considered non-lethal to honey bees, but lethal methods such as alcohol can be more effective at dislodging mites. 3% of the colony being infested is considered an economic threshold damaging enough to warrant further management such as miticides, though beekeepers may use other management tactics in
1615-573: A single host-species. Within that species, most individuals are free or almost free of parasites, while a minority carry a large number of parasites; this is known as an aggregated distribution . Trophically -transmitted parasites are transmitted by being eaten by a host. They include trematodes (all except schistosomes ), cestodes , acanthocephalans , pentastomids , many roundworms , and many protozoa such as Toxoplasma . They have complex life cycles involving hosts of two or more species. In their juvenile stages they infect and often encyst in
1710-430: A suitable fungus soon after germinating. Parasitic fungi derive some or all of their nutritional requirements from plants, other fungi, or animals. Plant pathogenic fungi are classified into three categories depending on their mode of nutrition: biotrophs, hemibiotrophs and necrotrophs. Biotrophic fungi derive nutrients from living plant cells, and during the course of infection they colonise their plant host in such
1805-473: A trap for mite removal. Beekeepers can also introduce a frame with drone foundation cells that encourage bees to construct more drone cells. When the drone cells are capped, the frame can be removed to freeze out mites. This labor-intensive process can reduce mite levels by about 50–93%, but if trap cells are not removed early enough before mites emerge, mite populations can spike. This method is only viable in spring and early summer when drones are produced. Heat
1900-502: A trap to remove mites from the hive. Honey bee lines in breeding programs also show partial resistance to Varroa mite through increased hygienic behavior that is being incorporated as an additional management strategy. The adult female mite is reddish-brown in color, while the male is white. Varroa mites are flat, having a button shape. They are 1–1.8 mm long and 1.5–2 mm wide, and have eight legs. Varroa mites lack eyes. These mites have curved bodies that allow them to fit between
1995-1047: A variety of methods to infect animal hosts, including physical contact, the fecal–oral route , free-living infectious stages, and vectors, suiting their differing hosts, life cycles, and ecological contexts. Examples to illustrate some of the many possible combinations are given in the table. social behaviour (grooming) Among the many variations on parasitic strategies are hyperparasitism, social parasitism, brood parasitism, kleptoparasitism, sexual parasitism, and adelphoparasitism. Hyperparasites feed on another parasite, as exemplified by protozoa living in helminth parasites, or facultative or obligate parasitoids whose hosts are either conventional parasites or parasitoids. Levels of parasitism beyond secondary also occur, especially among facultative parasitoids. In oak gall systems, there can be up to five levels of parasitism. Hyperparasites can control their hosts' populations, and are used for this purpose in agriculture and to some extent in medicine . The controlling effects can be seen in
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#17328551074202090-469: A variety of routes. To give a few examples, Bacillus anthracis , the cause of anthrax , is spread by contact with infected domestic animals ; its spores , which can survive for years outside the body, can enter a host through an abrasion or may be inhaled. Borrelia , the cause of Lyme disease and relapsing fever , is transmitted by vectors, ticks of the genus Ixodes , from the diseases' reservoirs in animals such as deer . Campylobacter jejuni ,
2185-474: A way as to keep it alive for a maximally long time. One well-known example of a biotrophic pathogen is Ustilago maydis , causative agent of the corn smut disease. Necrotrophic pathogens on the other hand, kill host cells and feed saprophytically , an example being the root-colonising honey fungi in the genus Armillaria . Hemibiotrophic pathogens begin their colonising their hosts as biotrophs, and subsequently killing off host cells and feeding as necrotrophs,
2280-570: A western honey bee, it will typically be V. destructor except where V. underwoodi is present, such as in Papua New Guinea. The name "Varroa mite" is typically used as the common name for V. destructor after the species was considered separate from V. jacobsoni . Varroa mite has two distinct genetic strains from when it switched hosts from the Asian honey bee to the western honey bee: Korean and Japanese. The Korean strain that occurred in 1952
2375-498: Is 6–7 days. Males will not leave brood cells and only mate with females present in the brood cell. Adult females can be found feeding both on brood and adult bees. After reaching the adult stage, females will leave the brood cell and enter a phoretic stage where mites attach to adult bees in order to disperse. Mites will feed on adult bees at this time and can be transmitted from bee to bee during this stage. Nurse bees are preferred hosts in order to be moved to new brood cells. Because
2470-544: Is a close relationship between species , where one organism, the parasite, lives on or inside another organism, the host , causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria , sleeping sickness , and amoebic dysentery ; animals such as hookworms , lice , mosquitoes , and vampire bats ; fungi such as honey fungus and
2565-563: Is a kind of symbiosis , a close and persistent long-term biological interaction between a parasite and its host. Unlike saprotrophs , parasites feed on living hosts, though some parasitic fungi, for instance, may continue to feed on hosts they have killed. Unlike commensalism and mutualism , the parasitic relationship harms the host, either feeding on it or, as in the case of intestinal parasites, consuming some of its food. Because parasites interact with other species, they can readily act as vectors of pathogens, causing disease . Predation
2660-675: Is aggregated. Coinfection by multiple parasites is common. Autoinfection , where (by exception) the whole of the parasite's life cycle takes place in a single primary host, can sometimes occur in helminths such as Strongyloides stercoralis . Vector-transmitted parasites rely on a third party, an intermediate host, where the parasite does not reproduce sexually, to carry them from one definitive host to another. These parasites are microorganisms, namely protozoa , bacteria , or viruses , often intracellular pathogens (disease-causers). Their vectors are mostly hematophagic arthropods such as fleas, lice, ticks, and mosquitoes. For example,
2755-403: Is also likely due to its habit of sibling mating. Adult mites feed on both adult bees and bee larvae by sucking on the fat body , an insect organ that stores glycogen and triglycerides with tissue abundant under epidermis and the surrounding internal body cavity. As the fat body is crucial for many bodily functions such as hormone and energy regulation, immunity, and pesticide detoxification,
2850-589: Is also sometimes used as a control method. The mites cannot survive temperatures near 40 °C (104 °F), but brief exposure to these temperatures do not harm honey bees. Devices are marketed intended to heat brood to these temperatures, though the efficacy of many of these products has not been reviewed. Powdered sugar used for estimating mite counts in hives has also been considered for mite management as it or other inert dusts were believed to initiate grooming responses. Long-term studies do not show any efficacy for reducing mite populations. The Asian honey bee,
2945-562: Is available. In 12 weeks, the number of mites in a western honey bee hive can multiply by roughly 12. Mites often invade colonies in the summer, leading to high mite populations in autumn. High mite populations in the autumn can cause a crisis when drone rearing ceases and the mites switch to worker larvae, causing a quick population crash and often hive death. Various management methods are used for Varroa mite integrated pest management to monitor and manage damage to hives. Beekeepers use several methods for monitoring levels of Varroa mites in
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3040-466: Is being actively pursued in bee breeding programs. Researchers have been able to use RNA interference by feeding honey bees mixtures of double-stranded RNA that target expression of several Varroa mite genes, such as cytoskeleton arrangement, transfer of energy, and transcription . This can reduce infestation to 50% without harm to honey bees and is being pursued as an additional control method for Varroa mite. Ectoparasite Parasitism
3135-443: Is by definition not a symbiosis, as the interaction is brief, but the entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Within that scope are many possible strategies. Taxonomists classify parasites in a variety of overlapping schemes, based on their interactions with their hosts and on their life cycles , which can be complex. An obligate parasite depends completely on
3230-645: Is found in the ant Tetramorium inquilinum , an obligate parasite which lives exclusively on the backs of other Tetramorium ants. A mechanism for the evolution of social parasitism was first proposed by Carlo Emery in 1909. Now known as " Emery's rule ", it states that social parasites tend to be closely related to their hosts, often being in the same genus. Intraspecific social parasitism occurs in parasitic nursing, where some individual young take milk from unrelated females. In wedge-capped capuchins , higher ranking females sometimes take milk from low ranking females without any reciprocation. In brood parasitism ,
3325-472: Is higher for Varroa infested bees. Adult mites live and feed under the abdominal plates of adult bees primarily on the underside of the abdominal region on the left side of the bee. Adult mites are more often identified as present in the hive when on top of the adult bee on the thorax, but mites in this location are likely not feeding, but rather attempting to transfer to another bee. Varroa mites have been found on flowers visited by worker bees, which may be
3420-514: Is more hygienic with respect to Varroa mite than western honey bees, which is in part why mite infestations are more pronounced in western honey bee colonies. Efforts also have been made to breed hygienic honey bees heritable behavior traits, such as those with resistance to Varroa mites. Honey bee lines with resistance include Minnesota Hygienic Bees, Russian Honey Bees, and Varroa sensitive hygiene . Hygienic behaviors include workers removing pupae heavily infested with mites, which kills both
3515-504: Is not well-quantified; colonies with this behavior alone do not necessarily result in Varroa mite resistant colonies that can survive without miticide treatments. The efficacy of this behavior can vary between bee lines in comparison studies with Minnesota hygienic bees removing 66% of infested pupae, while Varroa sensitive hygiene bees removed 85% of infested pupae. There are minimal trade-off costs to hives that have this hygienic behavior, so it
3610-664: Is now found worldwide in high frequencies, while the Japanese strain that started around 1957 occurs in similar areas at much lower frequencies. Varroa mite has low genetic diversity, which is typical for an invasive species undergoing a range or host expansion. Varroa mites originally only occurred in Asia on the Asian honey bee , but this species has been introduced to many other countries on several continents, resulting in disastrous infestations of European honey bees. Introduction data prior to 2000
3705-585: Is often unambiguous, it is part of a spectrum of interactions between species , grading via parasitoidism into predation, through evolution into mutualism , and in some fungi, shading into being saprophytic . Human knowledge of parasites such as roundworms and tapeworms dates back to ancient Egypt , Greece , and Rome . In early modern times, Antonie van Leeuwenhoek observed Giardia lamblia with his microscope in 1681, while Francesco Redi described internal and external parasites including sheep liver fluke and ticks . Modern parasitology developed in
3800-419: Is seen in some species of anglerfish , such as Ceratias holboelli , where the males are reduced to tiny sexual parasites , wholly dependent on females of their own species for survival, permanently attached below the female's body, and unable to fend for themselves. The female nourishes the male and protects him from predators, while the male gives nothing back except the sperm that the female needs to produce
3895-402: Is the number of mites found on the sticky board and c is the number of estimated mites in the colony. However, the bee population in a colony also needs to be known to determine what population of mites is tolerable with this method. Mite counts from a known quantity of bees (i.e., 300 bees) collected from brood comb are instead often used to determine mite severity. Mites are dislodged from
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3990-469: Is then carried to a nest, sometimes alongside other prey if it is not large enough to support a parasitoid throughout its development. An egg is laid on top of the prey and the nest is then sealed. The parasitoid develops rapidly through its larval and pupal stages, feeding on the provisions left for it. Koinobiont parasitoids, which include flies as well as wasps, lay their eggs inside young hosts, usually larvae. These are allowed to go on growing, so
4085-654: Is unclear due to confusion with V. jacobsoni . By 2020, V. destructor was confirmed to be present throughout North America excluding Greenland, South America, most of Europe and Asia, and portions of Africa. The species was not present in Australia as well as Oman, Congo, Democratic Republic of Congo, and Malawi. It was suspected to not be present in Sudan and Somalia. Mites were found in 2022 in New South Wales in Australia. Female mites enter brood cells to lay eggs on
4180-689: Is widespread in hives with many of those uses being off-label or in violation of pesticide regulations in various countries. Hop beta acids are lupulones obtained from hop plants and have been used in products marketed for mite control. Resistance to pyrethroids has occurred in the Czech Republic and the UK due to a single amino acid substitution on Varroa mite's genome. Underlying mechanisms for resistance in other pesticides, such as coumaphos, are still unknown. Varroa mites can also be controlled through nonchemical means. Most of these controls are intended to reduce
4275-495: The Port of Newcastle on 22 June 2022 detected an infestation. Eradication is unlikely because no other introduction elsewhere in the world has been eradicated. On 9 November 2023, ABC News reported that researchers have predicted the extinction of feral bees in Australia within three years because of the spreading Varroa mite infestation. Bee-breeding efforts to develop resistance against Varroa are ongoing. The USDA has developed
4370-505: The snubnosed eel is probably a facultative endoparasite (i.e., it is semiparasitic) that opportunistically burrows into and eats sick and dying fish. Plant-eating insects such as scale insects , aphids , and caterpillars closely resemble ectoparasites, attacking much larger plants; they serve as vectors of bacteria, fungi and viruses which cause plant diseases . As female scale insects cannot move, they are obligate parasites, permanently attached to their hosts. The sensory inputs that
4465-965: The 0–2% infestation range to keep mite populations low. Varroa mites can be treated with commercially available acaricides that must be timed carefully to minimize the contamination of honey that might be consumed by humans. The four most common synthetic pesticides used for mite treatments with formulations specific for honey bee colony use are amitraz , coumaphos , and two pyrethroids , flumethrin and tau-fluvalinate , while naturally occurring compounds include formic acid , oxalic acid , essential oils such as thymol and beta acids from hops resin (e.g. lupulone ). Many of these products whether synthetic or naturally produced can negatively affect honey bee brood or queens. These products often are applied through impregnated plastic strips or as powders spread between brood frames. Synthetic compounds often have high efficacy against Varroa mites, but resistance has occurred for all of these products in different areas of
4560-504: The 19th century. In human culture, parasitism has negative connotations. These were exploited to satirical effect in Jonathan Swift 's 1733 poem "On Poetry: A Rhapsody", comparing poets to hyperparasitical "vermin". In fiction, Bram Stoker 's 1897 Gothic horror novel Dracula and its many later adaptations featured a blood-drinking parasite. Ridley Scott 's 1979 film Alien was one of many works of science fiction to feature
4655-704: The Isle of Man and Isle of Colonsay. Because of the lack of varroa in Isle of Man , on February 16, 2015, the EU made a decision that allowed the Isle of Man to block the importation of all bee-related supplies. They were discovered in the United States in 1987, in New Zealand in 2000, and in the United Kingdom in 1992. Australia was free of the mites until a routine inspection at
4750-439: The abdominal segments of adult bees. Host bee species can help differentiate mite species in the genus Varroa ; both V. destructor and Varroa jacobsoni parasitize Apis cerana , the Asian honey bee, but the closely related mite species originally described as V. jacobsoni by Anthonie Cornelis Oudemans in 1904 does not attack Apis mellifera , the western honey bee, unlike V. destructor . Until 2000, V. destructor
4845-458: The agents of ringworm ; and plants such as mistletoe , dodder , and the broomrapes . There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castration , directly transmitted parasitism (by contact), trophically-transmitted parasitism (by being eaten), vector-transmitted parasitism, parasitoidism , and micropredation. One major axis of classification concerns invasiveness: an endoparasite lives inside
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#17328551074204940-696: The air or soil given off by host shoots or roots , respectively. About 4,500 species of parasitic plant in approximately 20 families of flowering plants are known. Species within the Orobanchaceae (broomrapes) are among the most economically destructive of all plants. Species of Striga (witchweeds) are estimated to cost billions of dollars a year in crop yield loss, infesting over 50 million hectares of cultivated land within Sub-Saharan Africa alone. Striga infects both grasses and grains, including corn , rice , and sorghum , which are among
5035-458: The bee's body cavity and mites can also cause immunosuppression that increases infection in host bees. Varroa mites can transmit the following viruses: Deformed wing virus is one of the most prominent and damaging honey bee viruses transmitted by Varroa mites. It causes crumpled deformed wings that resemble sticks and also causes shortened abdomens. There is some evidence that harm from both Varroa mite and associated viruses they transmit may be
5130-449: The bees (e.g., deformed wings , and IAPV ), and accordingly they have been implicated in colony collapse disorder . Research has indicated that alone, neither Varroa mites nor deformed wing virus are particularly deadly, yet together they can pose an incredible risk to colonies. Varroa mites were first discovered in Java about 1904, but are now present in all honey bee populations except
5225-438: The body of the bee and weakens the bee. The species is a vector for at least five debilitating bee viruses, including RNA viruses such as the deformed wing virus (DWV). The Varroa mite is the parasite with possibly the most pronounced economic impact on the beekeeping industry and is one of multiple stress factors contributing to the higher levels of bee losses around the world. Varroa mite has also been implicated as one of
5320-482: The comb wall after the cell is capped. Eggs are approximately 0.2 to 0.3 mm in diameter and cannot be seen without magnification. These eggs hatch into male and female protonymphs that are both transparent white. Immature mites can only feed on capped brood, so the life cycle cannot be completed during broodless periods. Protonymphs molt into deuteronymphs that more closely resemble the curved body of adults before they molt into adults. Development time from egg to adult
5415-864: The deer tick Ixodes scapularis acts as a vector for diseases including Lyme disease , babesiosis , and anaplasmosis . Protozoan endoparasites, such as the malarial parasites in the genus Plasmodium and sleeping-sickness parasites in the genus Trypanosoma , have infective stages in the host's blood which are transported to new hosts by biting insects. Parasitoids are insects which sooner or later kill their hosts, placing their relationship close to predation. Most parasitoids are parasitoid wasps or other hymenopterans ; others include dipterans such as phorid flies . They can be divided into two groups, idiobionts and koinobionts, differing in their treatment of their hosts. Idiobiont parasitoids sting their often-large prey on capture, either killing them outright or paralysing them immediately. The immobilised prey
5510-430: The developing bee and immature mites, and grooming or removal from the brood cell, which increases adult mite mortality. Mites removed from host pupae are at an incorrect life stage to re-infest another pupa. An extended phoretic period in adult female mites has also been noticed. Hygienic behavior is effective against diseases such as American foulbrood or chalkbrood , but the efficacy of this behavior against mites
5605-409: The energy that would have gone into reproduction into host and parasite growth, sometimes causing gigantism in the host. The host's other systems remain intact, allowing it to survive and to sustain the parasite. Parasitic crustaceans such as those in the specialised barnacle genus Sacculina specifically cause damage to the gonads of their many species of host crabs . In the case of Sacculina ,
5700-491: The evolutionary options can be gained by considering four key questions: the effect on the fitness of a parasite's hosts; the number of hosts they have per life stage; whether the host is prevented from reproducing; and whether the effect depends on intensity (number of parasites per host). From this analysis, the major evolutionary strategies of parasitism emerge, alongside predation. Parasitic castrators partly or completely destroy their host's ability to reproduce, diverting
5795-444: The family Cuculidae , over 40% of cuckoo species are obligate brood parasites, while others are either facultative brood parasites or provide parental care. The eggs of some brood parasites mimic those of their hosts, while some cowbird eggs have tough shells, making them hard for the hosts to kill by piercing, both mechanisms implying selection by the hosts against parasitic eggs. The adult female European cuckoo further mimics
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#17328551074205890-693: The honey bee population or the use of Organic Acids such as Oxalic Acid which is harmful to the mite but not the honey bee. Best results are obtained during periods of low or no brooding given the difficulty of applying medication to the brood, and is often dispersed through a small vaporiser to distribute the acid within the hive. Commercial treatments such as Apistan and Apivar are commonly used as well. The genus Varroa contains these species: Some honey bees strains have been bred to be resistant to Varroa , through Varroa sensitive hygiene (VSH) behavior, enabling them to detect reproducing varroa mites and diseased pupae within capped cells, which are then uncapped and
5985-424: The host and parasitoid develop together for an extended period, ending when the parasitoids emerge as adults, leaving the prey dead, eaten from inside. Some koinobionts regulate their host's development, for example preventing it from pupating or making it moult whenever the parasitoid is ready to moult. They may do this by producing hormones that mimic the host's moulting hormones ( ecdysteroids ), or by regulating
6080-442: The host to complete its life cycle, while a facultative parasite does not. Parasite life cycles involving only one host are called "direct"; those with a definitive host (where the parasite reproduces sexually) and at least one intermediate host are called "indirect". An endoparasite lives inside the host's body; an ectoparasite lives outside, on the host's surface. Mesoparasites—like some copepods , for example—enter an opening in
6175-422: The host's body and remain partly embedded there. Some parasites can be generalists, feeding on a wide range of hosts, but many parasites, and the majority of protozoans and helminths that parasitise animals, are specialists and extremely host-specific. An early basic, functional division of parasites distinguished microparasites and macroparasites. These each had a mathematical model assigned in order to analyse
6270-453: The host's body; an ectoparasite lives outside, on the host's surface. Like predation, parasitism is a type of consumer–resource interaction , but unlike predators , parasites, with the exception of parasitoids, are much smaller than their hosts, do not kill them, and often live in or on their hosts for an extended period. Parasites of animals are highly specialised , each parasite species living on one given animal species, and reproduce at
6365-656: The host's endocrine system. A micropredator attacks more than one host, reducing each host's fitness by at least a small amount, and is only in contact with any one host intermittently. This behavior makes micropredators suitable as vectors, as they can pass smaller parasites from one host to another. Most micropredators are hematophagic , feeding on blood. They include annelids such as leeches , crustaceans such as branchiurans and gnathiid isopods, various dipterans such as mosquitoes and tsetse flies , other arthropods such as fleas and ticks, vertebrates such as lampreys , and mammals such as vampire bats . Parasites use
6460-425: The host. A parasitic plant is classified depending on where it latches onto the host, either the stem or the root, and the amount of nutrients it requires. Since holoparasites have no chlorophyll and therefore cannot make food for themselves by photosynthesis , they are always obligate parasites, deriving all their food from their hosts. Some parasitic plants can locate their host plants by detecting chemicals in
6555-477: The host. The parasitism is often on close relatives, whether within the same species or between species in the same genus or family. For instance, the many lineages of cuckoo bees lay their eggs in the nest cells of other bees in the same family. Kleptoparasitism is uncommon generally but conspicuous in birds; some such as skuas are specialised in pirating food from other seabirds, relentlessly chasing them down until they disgorge their catch. A unique approach
6650-423: The hosts suffer increased parental investment and energy expenditure to feed parasitic young, which are commonly larger than host young. The growth rate of host nestlings is slowed, reducing the host's fitness. Brood parasites include birds in different families such as cowbirds , whydahs , cuckoos , and black-headed ducks . These do not build nests of their own, but leave their eggs in nests of other species . In
6745-472: The intermediate host. When the intermediate-host animal is eaten by a predator, the definitive host, the parasite survives the digestion process and matures into an adult; some live as intestinal parasites . Many trophically transmitted parasites modify the behaviour of their intermediate hosts, increasing their chances of being eaten by a predator. As with directly transmitted parasites, the distribution of trophically transmitted parasites among host individuals
6840-471: The intestinal infection microsporidiosis . Protozoa such as Plasmodium , Trypanosoma , and Entamoeba are endoparasitic. They cause serious diseases in vertebrates including humans—in these examples, malaria, sleeping sickness, and amoebic dysentery —and have complex life cycles. Many bacteria are parasitic, though they are more generally thought of as pathogens causing disease. Parasitic bacteria are extremely diverse, and infect their hosts by
6935-441: The large blue butterfly, Phengaris arion , its larvae employing ant mimicry to parasitise certain ants, Bombus bohemicus , a bumblebee which invades the hives of other bees and takes over reproduction while their young are raised by host workers, and Melipona scutellaris , a eusocial bee whose virgin queens escape killer workers and invade another colony without a queen. An extreme example of interspecific social parasitism
7030-567: The largest group is the parasitoid wasps in the Hymenoptera. The phyla and classes with the largest numbers of parasitic species are listed in the table. Numbers are conservative minimum estimates. The columns for Endo- and Ecto-parasitism refer to the definitive host, as documented in the Vertebrate and Invertebrate columns. A hemiparasite or partial parasite such as mistletoe derives some of its nutrients from another living plant, whereas
7125-460: The larva. She will lay a single unfertilized egg after feeding to produce a male mite. After laying this egg, fertilized eggs to produce females are laid approximately once a day. Both the mother and nymphs will feed on the developing pupa. Unless multiple foundress mites are present in a cell, mating occurs between siblings when they reach the adult stage. Once females mate, they are unable to receive additional sperm. Varroa mite's genetic bottleneck
7220-537: The marine worm Bonellia viridis has a similar reproductive strategy, although the larvae are planktonic. Examples of the major variant strategies are illustrated. Parasitism has an extremely wide taxonomic range, including animals, plants, fungi, protozoans, bacteria, and viruses. Parasitism is widespread in the animal kingdom, and has evolved independently from free-living forms hundreds of times. Many types of helminth including flukes and cestodes have complete life cycles involving two or more hosts. By far
7315-446: The mite population to a manageable level, not to eliminate the mites completely. Screened bottom boards are used both for monitoring and can modestly reduce mite populations by 11–14%. Mites which fall from the comb or bees can land outside the hive instead landing on a solid bottom board that would allow them to easily return to the nest. Varroa infest drone cells at a higher rate than worker brood cells, so drone cells can be used as
7410-589: The mite's consumption of the fat body weakens both the adult bee and the larva. Feeding on fat body cells significantly decreases the weight of both the immature and adult bee. Infested adult worker bees have a shorter lifespan than ordinary worker bees, and they furthermore tend to be absent from the colony far more than ordinary bees, which could be due to their reduced ability to navigate or regulate their energy for flight. Infested bees are more likely to wander into other hives and further increase spread. Bees will occasionally drift into other nearby hives, but this rate
7505-575: The multiple causes of colony collapse disorder . Management of this pest focuses on reducing mite numbers through monitoring to avoid significant hive losses or death. 3% of bees infested in a hive is considered an economic threshold where damage is high enough to warrant additional management. Miticides are available, though some are difficult to time correctly while avoiding harm to the hive, and resistance has occurred for others. Screened bottom boards on hives can be used for both monitoring and mite removal, and drone comb that mites prefer can be used as
7600-407: The next generation. Adelphoparasitism, (from Greek ἀδελφός ( adelphós ), brother ), also known as sibling-parasitism, occurs where the host species is closely related to the parasite, often in the same family or genus. In the citrus blackfly parasitoid, Encarsia perplexa , unmated females may lay haploid eggs in the fully developed larvae of their own species, producing male offspring, while
7695-425: The nurse bee spends more time around the drone brood (i.e., male bees) rather than the worker brood, many more drones are infected with the mites. These phoretic females can also be transmitted to other hives through bee contact or hive equipment transfer. The phoretic stage can last for 4.5–11 days during brood production periods or up to five to six months when no brood is present in winter months. Female mites have
7790-417: The point where, while they are evidently able to infect all other organisms from bacteria and archaea to animals, plants and fungi, it is unclear whether they can themselves be described as living. They can be either RNA or DNA viruses consisting of a single or double strand of genetic material ( RNA or DNA , respectively), covered in a protein coat and sometimes a lipid envelope. They thus lack all
7885-535: The population movements of the host–parasite groupings. The microorganisms and viruses that can reproduce and complete their life cycle within the host are known as microparasites. Macroparasites are the multicellular organisms that reproduce and complete their life cycle outside of the host or on the host's body. Much of the thinking on types of parasitism has focused on terrestrial animal parasites of animals, such as helminths. Those in other environments and with other hosts often have analogous strategies. For example,
7980-559: The pupae removed. Varroa destructor Varroa destructor , the Varroa mite , is an external parasitic mite that attacks and feeds on honey bees and is one of the most damaging honey bee pests in the world. A significant mite infestation leads to the death of a honey bee colony, usually in the late autumn through early spring. Without management for Varroa mite, honey bee colonies typically collapse within 2 to 3 years in temperate climates. These mites can infest Apis mellifera ,
8075-402: The species Varroa destructor , are recognised as the biggest pest to honeybees worldwide due to their ability to transmit diseases such as deformed wing virus (or DWV) to larval or pupating bees, resulting in death or severe deformity of the pupae. Varroa mites feed off the fat body tissue of adult, pupal , and larval honey bees, and may carry viruses that are particularly damaging to
8170-736: The taxonomic name of the parasite and the suffix -osis as provided in the Standardised Nomenclature by the World Association for the Advancement of Veterinary Parasitology. For example, the World Organisation for Animal Health (OIE) uses the name varroosis in the OIE Terrestrial Manual. The chemical treatment of Varroa mites in common beehives typically use an alcohol wash which causes significant consequential damage to
8265-466: The testes of over two-thirds of their crab hosts degenerate sufficiently for these male crabs to develop female secondary sex characteristics such as broader abdomens, smaller claws and egg-grasping appendages. Various species of helminth castrate their hosts (such as insects and snails). This may happen directly, whether mechanically by feeding on their gonads, or by secreting a chemical that destroys reproductive cells; or indirectly, whether by secreting
8360-403: The tropics, however effectively cheat by taking carbon from a fungus rather than exchanging it for minerals. They have much reduced roots, as they do not need to absorb water from the soil; their stems are slender with few vascular bundles , and their leaves are reduced to small scales, as they do not photosynthesize. Their seeds are small and numerous, so they appear to rely on being infected by
8455-506: The usual machinery of the cell such as enzymes , relying entirely on the host cell's ability to replicate DNA and synthesise proteins. Most viruses are bacteriophages , infecting bacteria. Parasitism is a major aspect of evolutionary ecology; for example, almost all free-living animals are host to at least one species of parasite. Vertebrates, the best-studied group, are hosts to between 75,000 and 300,000 species of helminths and an uncounted number of parasitic microorganisms. On average,
8550-585: The way that the CHV1 virus helps to control the damage that chestnut blight , Cryphonectria parasitica , does to American chestnut trees, and in the way that bacteriophages can limit bacterial infections. It is likely, though little researched, that most pathogenic microparasites have hyperparasites which may prove widely useful in both agriculture and medicine. Social parasites take advantage of interspecific interactions between members of eusocial animals such as ants , termites , and bumblebees . Examples include
8645-414: The western honey bee, and Apis cerana , the Asian honey bee. Due to very similar physical characteristics, this species was thought to be the closely related Varroa jacobsoni prior to 2000, but they were found to be two separate species after DNA analysis. Parasitism of bees by mites in the genus Varroa is called varroosis . The Varroa mite can reproduce only in a honey bee colony. It attaches to
8740-471: The world's most important food crops. Orobanche also threatens a wide range of other important crops, including peas , chickpeas , tomatoes , carrots , and varieties of cabbage . Yield loss from Orobanche can be total; despite extensive research, no method of control has been entirely successful. Many plants and fungi exchange carbon and nutrients in mutualistic mycorrhizal relationships. Some 400 species of myco-heterotrophic plants, mostly in
8835-495: The world. Pyrethroids are used because a concentration that will kill mites has relatively low toxicity to honey bees. Compounds derived from plants have also been assessed for mite management. Thymol is one essential oil with efficacy against mites, but can be harmful to bees at high temperatures. Other essential oils such as garlic, oregano, and neem oil have had some efficacy in field trials, though most essential oils that have been tested have little to no effect. Essential oil use
8930-404: Was actually research on V. destructor . Other Varroa species V. underwoodi and V. rindereri can also parasitize honey bee species and can be distinguished from V. destructor and V. jacobsoni with slight differences in body size and setae characteristics, though each of the four species within the Varroa genus have similar physical characteristics. If a Varroa species is found on
9025-414: Was thought to be V. jacobsoni and resulted in some mislabeling in the scientific literature. The two species cannot be easily distinguished with physical traits and have 99.7% similar genomes, so DNA analysis is required instead. Because the more virulent and damaging species V. destructor could not be distinguished at the time, most pre-2000 research on western honey bees that refers to V. jacobsoni
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