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57-470: See text Oligositini Ashmead, 1904 Poropoeini Girault, 1912 Trichogrammatoidae Foerster, 1856 The Trichogrammatidae are a family of small endoparasitoid wasps in the superfamily Chalcidoidea that include some of the smallest of all insects , with most species having adults less than 1 mm in length, with species of Megaphragma having an adult body length less than 300 μm. Over 840 species are placed in about 80 genera; their distribution

114-399: A certain pattern. Most paralyses caused by nervous-system damage (e.g., spinal cord injuries ) are constant in nature; however, some forms of periodic paralysis , including sleep paralysis , are caused by other factors. Paralysis can occur in newborns due to a congenital defect known as spina bifida . Spina bifida causes one or more of the vertebrae to fail to form vertebral arches within

171-525: A few species are parasitic. The larvae of Epipyropidae feed on Homoptera such as leafhoppers and cicadas, and sometimes on other Lepidoptera. The larvae of Cyclotornidae parasitise first Homoptera and later ant brood. The pyralid moth Chalcoela has been used in biological control of the wasp Polistes in the Galapagos Islands . Parasitism is rare in the Trichoptera (caddisflies), but it

228-401: A host that continues to grow larger and avoid predators. Primary parasitoids have the simplest parasitic relationship, involving two organisms, the host and the parasitoid. Hyperparasitoids are parasitoids of parasitoids; secondary parasitoids have a primary parasitoid as their host, so there are three organisms involved. Hyperparasitoids are either facultative (can be a primary parasitoid or

285-469: A hyperparasitoid depending on the situation) or obligate (always develop as a hyperparasitoid). Levels of parasitoids beyond secondary also occur, especially among facultative parasitoids. In oak gall systems, there can be up to five levels of parasitism. Cases in which two or more species of parasitoids simultaneously attack the same host without parasitizing each other are called multi- or multiple parasitism. In many cases, multiple parasitism still leads to

342-516: A large stalk, growing from the back of the ant's head which subsequently releases ascospores. These spores are too large to be wind dispersed and instead fall directly to the ground where they produce secondary spores that infect ants as they walk over them. O. sinesis , is a parasitoid as well, parasitising ghost moth larvae, killing them within 15-25 days, a similar process to that of O. unilateralis . Host location has been studied in Ormia ochracea ,

399-409: A living host which they eventually kill, typically before it can produce offspring, whereas conventional parasites usually do not kill their hosts, and predators typically kill their prey immediately. Parasitoids can be classified as either endo- or ectoparasitoids with idiobiont or koinobiont developmental strategies. Endoparasitoids live within their host's body, while ectoparasitoids feed on

456-534: A parasitoid tachinid fly that locates their field cricket host acoustically ( phonotaxis ). Preference for the dominant local host species was not explained by DNA analysis. In fact, populations across the southern U.S. were inexplicably closely related, considering rate of range expansion from a presumed Central American origin. A captive population of lab-reared flies were raised on two different host songs ( Gryllus integer or G. lineaticeps ). Responsive adult females overwhelmingly chose their familiar song, indicating

513-399: A range of obstacles to oviposition, including behavioural, morphological, physiological and immunological defences of their hosts. To thwart this, some wasps inundate their host with their eggs so as to overload its immune system's ability to encapsulate foreign bodies; others introduce a virus which interferes with the host's immune system. Some parasitoid wasps locate hosts by detecting

570-454: A wide range of insects including caterpillars, adult and larval beetles , and true bugs . Commercially, there are two types of rearing systems: short-term seasonal daily output with high production of parasitoids per day, and long-term year-round low daily output with a range in production of 4–1000 million female parasitoids per week, to meet demand for suitable biological control agents for different crops. Maria Sibylla Merian (1647–1717)

627-406: Is a deterioration of nerves in the spinal cord, starting in the posterior part of the cord. Affected dogs will become gradually weaker in the hind legs as nerves die off. Eventually, their hind legs become useless. They often also exhibit faecal and urinary incontinence. As the disease progresses, the paresis and paralysis gradually move forward. This disease also affects other large breeds of dogs. It

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684-510: Is a noticeable difference in the antennae. Trichogrammatidae have unique nervous systems resulting from the necessity to conserve space. They have one of the smallest nervous systems , with one particularly diminutive species, Megaphragma mymaripenne , containing as few as 7,400 neurons. They are also the first (and only) known animals which have functioning neurons without nuclei . The neurons develop during pupation with functional nuclei and manufacture enough proteins to last through

741-912: Is depicted as an unending combat between humanity and insect-like extraterrestrial species that tend to parasitise human beings in order to reproduce." The Encyclopedia of Science Fiction lists many instances of "parasitism", often causing the host's death. Paralysis Paralysis is most often caused by damage in the nervous system , especially the spinal cord . Other major causes are stroke , trauma with nerve injury , poliomyelitis , cerebral palsy , peripheral neuropathy , Parkinson's disease , ALS , botulism , spina bifida , multiple sclerosis , and Guillain–Barré syndrome . Temporary paralysis occurs during REM sleep , and dysregulation of this system can lead to episodes of waking paralysis . Drugs that interfere with nerve function , such as curare , can also cause paralysis. Pseudoparalysis ( pseudo- meaning "false, not genuine", from Greek ψεῦδος )

798-676: Is found among the Hydroptilidae (purse-case caddisflies), probably including all 10 species in the Orthotrichia aberrans group; they parasitise the pupae of other trichopterans. Mites of the family Acarophenacidae are ectoparasitoids of insect eggs. Unlike the insect parasitoids, it is the adult stage in Acarophenacidae that acts as a parasitoid. Specifically, adult female mites feed on insect eggs and their body swells up with offspring, which eventually emerge as adults. All known fungi in

855-452: Is one of six major evolutionary strategies within parasitism , distinguished by the fatal prognosis for the host, which makes the strategy close to predation . Among parasitoids, strategies range from living inside the host ( endoparasitism ), allowing it to continue growing before emerging as an adult, to paralysing the host and living outside it ( ectoparasitism ). Hosts can include other parasitoids, resulting in hyperparasitism ; in

912-737: Is parasitoidal on cicadas, locating its host by sound. The Strepsiptera (twisted-wing parasites) consist entirely of parasitoids; they usually sterilise their hosts. Two beetle families, Ripiphoridae (450 species ) and Rhipiceridae , are largely parasitoids, as are Aleochara Staphylinidae ; in all, some 400 staphylinids are parasitoidal. Some 1,600 species of the large and mainly freeliving family Carabidae are parasitoids. A few Neuroptera are parasitoidal; they have larvae that actively search for hosts. The larvae of some Mantispidae , subfamily Symphrasinae, are parasitoids of other arthropods including bees and wasps. Although nearly all Lepidoptera (butterflies and moths) are herbivorous,

969-411: Is similarly far higher than for screening chemicals: 1:30 against 1:5 respectively, since the search for suitable natural enemies can be guided accurately with ecological knowledge. Natural enemies are more difficult to produce and to distribute than chemicals, as they have a shelf life of weeks at most; and they face a commercial obstacle, namely that they cannot be patented. From the point of view of

1026-594: Is the tetrodotoxin of fish species such as Takifugu rubripes , the famously lethal pufferfish of Japanese fugu . This toxin works by binding to sodium channels in nerve cells, inhibiting the cells' proper function. A non-lethal dose of this toxin results in temporary paralysis. This toxin is also present in many other species ranging from toads to nemerteans . Paralysis can be seen in breeds of dogs that are chondrodysplastic . These dogs have short legs, and may also have short muzzles. Their intervertebral disc material can calcify and become more brittle. In such cases,

1083-423: Is voluntary restriction or inhibition of motion because of pain, incoordination, orgasm, or other cause, and is not due to actual muscular paralysis. In an infant, it may be a symptom of congenital syphilis . Pseudoparalysis can be caused by extreme mental stresses, and is a common feature of mental disorders such as panic anxiety disorder . Paralysis can occur in localised or generalised forms, or it may follow

1140-466: Is worldwide. Their fossil record extends back to the Eocene aged Baltic amber . The Trichogrammatidae have 3-segmented tarsi , without strigil on the foretarsus. The abdomen is broadly jointed to the metathorax and is penetrated by a muscle-bearing mesophragma. Its forewings are fringed by marginal cilia and are larger than its hindwings . They are not strong fliers and are generally moved through

1197-750: The Hymenoptera , where the ichneumons and many other parasitoid wasps are highly specialised for a parasitoidal way of life. There are parasitoids, too, in the Diptera , Coleoptera and other orders of endopterygote insects . Some of these, usually but not only wasps, are used in biological pest control . The 17th-century zoological artist Maria Sibylla Merian closely observed parasitoids and their hosts in her paintings. The biology of parasitoidism influenced Charles Darwin 's beliefs and has inspired science fiction authors and scriptwriters to create numerous parasitoidal aliens that kill their human hosts, such as

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1254-460: The Lepidoptera , Coleoptera , Hemiptera , Hymenoptera and Diptera . As such, many species are among the more important biological control agents known, attacking many pest insects. Endoparasitoid In evolutionary ecology , a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism

1311-586: The alien species in Ridley Scott 's 1979 film Alien . The term "parasitoid" was coined in 1913 by the Swedo-Finnish writer Odo Reuter , and adopted in English by his reviewer, the entomologist William Morton Wheeler . Reuter used it to describe the strategy where the parasite develops in or on the body of a single host individual, eventually killing that host, while the adult is free-living. Since that time,

1368-1035: The phylogenetic tree ; groups containing parasitoids are shown in boldface, e.g. Coleoptera , with the number of times parasitoidism evolved in the group in parentheses, e.g. (10 clades) . The approximate number (estimates can vary widely) of parasitoid species out of the total is shown in square brackets, e.g. [2,500 of 400,000]. Raphidioptera Megaloptera Neuroptera (net-winged insects) (1 clade) [c. 15 of 6,000] Coleoptera (beetles) (10 clades) [c. 2,500 of 400,000] [REDACTED] Strepsiptera (twisted-wing parasites) [600 of 600] [REDACTED] Symphyta Orussoidea (parasitic wood wasps) [75 of 75] [REDACTED] Apocrita (wasp-waisted insects) [c. 50,000 of 100,000] [REDACTED] Diptera (true flies) (21 clades) [c. 17,000 of 125,000] [REDACTED] Mecoptera Siphonaptera Trichoptera (caddis flies) (1 clade) [c. 10 of 14,500] Lepidoptera (butterflies, moths) (2 clades) [c. 40 of 180,000] [REDACTED] Within

1425-412: The 'death bite'. This approach is so fine-tuned it causes the ant to bite down on the part of the leaf most optimal for the fungus to fruit; the adaxial leaf midrib. In fact, it has been found that in specific circumstances, the time of the death bite is synchronised to solar noon. As much as 40% of the ant's biomass is fungal hyphae at the moment of the death bite. After the ant dies, the fungus produces

1482-754: The Hymenoptera, parasitoidism evolved just once, and the many described species of parasitoid wasps represent the great majority of species in the order, barring those like the ants , bees , and Vespidae wasps that have secondarily lost the parasitoid habit. The parasitoid wasps include some 25,000 Ichneumonoidea , 22,000 Chalcidoidea , 5,500 Vespoidea , 4,000 Platygastroidea , 3,000 Chrysidoidea , 2,300 Cynipoidea , and many smaller families. These often have remarkable life cycles. They can be classified as either endoparasitic or ectoparasitic according to where they lay their eggs. Endoparasitic wasps insert their eggs inside their host, usually as koinobionts, allowing

1539-584: The Lepidoptera, 10 times or more in Coleoptera, and no less than 21 times among the Diptera. These are all holometabolous insects ( Endopterygota , which form a single clade ), and it is always the larvae that are parasitoidal. The metamorphosis from active larva to an adult with a different body structure permits the dual lifestyle of parasitic larva, freeliving adult in this group. These relationships are shown on

1596-439: The air by the prevailing winds. Their fore wings are typically somewhat stubby and paddle-shaped, with a long fringe of hinged setae around the outer margin to increase the surface area during the downstroke. Males of some species are wingless, and mate with their sisters inside the host egg in which they are born, dying without ever leaving the host egg. It has short antennae , with the sockets low on its face and are elbowed at

1653-521: The best-known is the Xenomorph in Ridley Scott 's 1979 film Alien , which runs rapidly through its lifecycle from violently entering a human host's mouth to bursting fatally from the host's chest. The molecular biologist Alex Sercel, writing in Signal to Noise Magazine , compares "the biology of the [ Alien ] Xenomorphs to parasitoid wasps and nematomorph worms from Earth to illustrate how close to reality

1710-514: The biology of these aliens is and to discuss this exceptional instance of science inspiring artists". Sercel notes that the way the Xenomorph grasps a human's face to implant its embryo is comparable to the way a parasitoid wasp lays its eggs in a living host. He further compares the Xenomorph life cycle to that of the nematomorph Paragordius tricuspidatus which grows to fill its host's body cavity before bursting out and killing it. Alistair Dove, on

1767-415: The case of oak galls , up to five levels of parasitism are possible. Some parasitoids influence their host's behaviour in ways that favour the propagation of the parasitoid. Parasitoids are found in a variety of taxa across the insect superorder Endopterygota , whose complete metamorphosis may have pre-adapted them for a split lifestyle, with parasitoid larvae and free-living adults. Most are in

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1824-444: The chance of recovery declines rapidly, since with continued pressure, the spinal cord tissue deteriorates and dies. Another type of paralysis is caused by a fibrocartilaginous embolism. This is a microscopic piece of disc material that breaks off and becomes lodged in a spinal artery. Nerves served by the artery will die when deprived of blood. The German Shepherd Dog is especially prone to developing degenerative myelopathy . This

1881-753: The chemicals that plants release to defend against insect herbivores. The true flies ( Diptera ) include several families of parasitoids, the largest of which is the Tachinidae (some 9,200 species ), followed by the Bombyliidae (some 4,500 species ), along with the Pipunculidae and the Conopidae , which includes parasitoidal genera such as Stylogaster . Other families of flies include some protelean species. Some Phoridae are parasitoids of ants. Some flesh flies are parasitoids: for instance Emblemasoma auditrix

1938-440: The concept has been generalised and widely applied. A perspective on the evolutionary options can be gained by considering four questions: the effect on the reproductive 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, proposed by K. D. Lafferty and A. M. Kunis,

1995-403: The death of one or more of the parasitoids involved. If multiple parasitoids of the same species coexist in a single host, it is called superparasitism . Gregarious species lay multiple eggs or polyembryonic eggs which lead to multiple larvae in a single host. The end result of gregarious superparasitism can be a single surviving parasitoid individual or multiple surviving individuals, depending on

2052-461: The decrease in muscle contraction. In invertebrates, this clearly indicates that, e.g., Microbracon (wasp genus) venom causes paralysis of the neuromuscular system by acting at a presynaptic site. Philanthus venom inhibits both the fast and slow neuromuscular system at identical concentrations. It causes a decrease in the frequency of the miniature potentials without affecting their amplitude significantly. In some species of wasp , to complete

2109-435: The disc may rupture, with disc material ending up in the spinal canal, or rupturing more laterally to press on spinal nerves. A minor rupture may only result in paresis , but a major rupture can cause enough damage to cut off circulation. If no signs of pain can be elicited, surgery should be performed within 24 hours of the incident, to remove the disc material and relieve pressure on the spinal cord . After 24 hours,

2166-456: The eggs or larvae of their host, but some attack adults. Oviposition depends on finding the host and on evading host defences; the ovipositor is a tube-like organ used to inject eggs into hosts, sometimes much longer than the wasp's body. Hosts such as ants often behave as if aware of the wasps' presence, making violent movements to prevent oviposition. Wasps may wait for the host to stop moving, and then attack suddenly. Parasitoid wasps face

2223-530: The extraordinarily fast range expansion of O. ochracea, as well as the presence and power of learning in parasitoids. Parasitoids are among the most widely used biological control agents. Classic biological pest control using natural enemies of pests (parasitoids or predators) is extremely cost effective, the cost/benefit ratio for classic control being 1:250, but the technique is more variable in its effects than pesticides; it reduces rather than eliminates pests. The cost/benefit ratio for screening natural enemies

2280-414: The farmer or horticulturalist, the most important groups are the ichneumonid wasps , which prey mainly on caterpillars of butterflies and moths ; braconid wasps , which attack caterpillars and a wide range of other insects including greenfly ; chalcidoid wasps , which parasitise eggs and larvae of greenfly, whitefly , cabbage caterpillars , and scale insects ; and tachinid flies , which parasitise

2337-428: The genera Cordyceps and Ophiocordyceps are endoparasitic. One of the most notable fungal parasitoids is O. unilateralis which infects carpenter ants by breaching the ant's exoskeletons via their spores and growing in the ant's hemocoel as free living yeast cells. Eventually the yeast cells progress to producing nerve toxins to alter the behaviour of the ant causing it to climb and bite onto vegetation, known as

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2394-399: The hive. About 10% of described insects are parasitoids, in the orders Hymenoptera , Diptera , Coleoptera , Neuroptera , Lepidoptera , Strepsiptera , and Trichoptera . The majority are wasps within the Hymenoptera; most of the others are Dipteran flies. Parasitoidism has evolved independently many times: once each in Hymenoptera, Strepsiptera, Neuroptera, and Trichoptera, twice in

2451-410: The host from outside. Idiobiont parasitoids prevent further development of the host after initially immobilising it, whereas koinobiont parasitoids allow the host to continue its development while feeding upon it. Most ectoparasitoids are idiobiont, as the host could damage or dislodge the external parasitoid if allowed to move and moult . Most endoparasitoids are koinobionts, giving them the advantage of

2508-406: The host to continue to grow (thus providing more food to the wasp larvae), moult, and evade predators. Ectoparasitic wasps deposit theirs outside the host's body, usually as idiobionts, immediately paralysing the host to prevent it from escaping or throwing off the parasite. They often carry the host to a nest where it will remain undisturbed for the wasp larva to feed on. Most species of wasps attack

2565-435: The host's behaviour. Among the parasitic wasps, Glyptapanteles modifies the behaviour of its host caterpillar to defend the pupae of the wasps after they emerge from the caterpillar's body. The phorid fly Apocephalus borealis oviposits into the abdomen of its hosts, including honey bees , causing them to abandon their nest, flying from it at night and soon dying, allowing the next generation of flies to emerge outside

2622-549: The infant, which allows the spinal cord to protrude from the rest of the spine. In extreme cases, this can cause spinal cord function inferior to the missing vertebral arches to cease. This cessation of spinal cord function can result in paralysis of lower extremities. Documented cases of paralysis of the anal sphincter in newborns have been observed when spina bifida has gone untreated. While life-threatening, many cases of spina bifida can be corrected surgically if operated on within 72 hours of birth. Ascending paralysis presents in

2679-423: The junction of the scape and pedicel . The scape is held in a facial scrobe. The flagellum consists of 1 or 2 annuli and the flagellar segments vary between genera but do not exceed 7 in female antennae. The funicle never exceeds 2 segments and may be absent. The clava consists of 1 to 5 segments. The male antennae are usually similar to those of females but in some genera (e.g., Ufens, Trichogramma ) there

2736-475: The living bodies of Caterpillars." The palaeontologist Donald Prothero notes that religiously minded people of the Victorian era , including Darwin, were horrified by this instance of evident cruelty in nature, particularly noticeable in the ichneumonid wasps. Parasitoids have inspired science fiction authors and screenwriters to create terrifying parasitic alien species that kill their human hosts. One of

2793-402: The lower limbs before the upper limbs. It can be associated with: Ascending paralysis contrasts with descending paralysis , which occurs in conditions such as botulism . Many animal species use paralyzing toxins to capture prey, evade predation, or both. In stimulated muscles, the decrease in frequency of the miniature potentials runs parallel to the decrease in postsynaptic potential, and to

2850-543: The major evolutionary strategies of parasitism emerge, alongside predation. Parasitoidism, in the view of R. Poulin and H. S. Randhawa, is one of six main evolutionary strategies within parasitism , the others being parasitic castrator , directly transmitted parasite, trophically transmitted parasite, vector -transmitted parasite, and micropredator. These are adaptive peaks , with many possible intermediate strategies, but organisms in many different groups have consistently converged on these six. Parasitoids feed on

2907-419: The parasitoidal fluke's life cycle in its definitive host . Similarly, as strepsipteran parasitoids of ants mature, they cause the hosts to climb high on grass stalks, positions that are risky, but favour the emergence of the strepsipterans. Among pathogens of mammals, the rabies virus affects the host's central nervous system , eventually killing it, but perhaps helping to disseminate the virus by modifying

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2964-417: The reproductive cycle, the female wasp paralyses a prey item such as a grasshopper and places it in her nest. In the species Philanthus gibbosus , the paralysed insect (most often a bee species) is coated in a thick layer of pollen. The adult P. gibbosus then lays eggs in the paralysed insect, which is devoured by the larvae when they hatch. A well-known example of a vertebrate-produced paralyzing toxin

3021-691: The science website Deep Sea News , writes that there are multiple parallels with parasitoids, though there are in his view more disturbing life cycles in real biology. In his view, the parallels include the placing of an embryo in the host; its growth in the host; the resulting death of the host; and alternating generations , as in the Digenea (trematodes). The social anthropologist Marika Moisseeff argues that "The parasitical and swarming aspects of insect reproduction make these animals favoured villains in Hollywood science fiction. The battle of culture against nature

3078-493: The short lifespans of the adults. Before emerging as an adult, the nuclei are destroyed, allowing the wasp to conserve space by making the neurons smaller. Even without nuclei (which contain the DNA , essential for manufacturing proteins to repair damage in living cells), the neurons can survive because the proteins manufactured as a pupa are sufficient. Trichogrammatids parasitize the eggs of many different orders of insects, notably

3135-483: The species. If superparasitism occurs accidentally in normally solitary species the larvae often fight among themselves until only one is left. In another strategy, some parasitoids influence the host's behaviour in ways that favour the propagation of the parasitoid, often at the cost of the host's life. A spectacular example is the lancet liver fluke , which causes host ants to die clinging to grass stalks, where grazers or birds may be expected to eat them and complete

3192-468: The use of a learned, auditory search image. This phenotypic plasticity allows such a highly specialized parasitoid to avoid overspecialization disasters. Interestingly, when receptive females only heard silence the night before testing for preference, they chose the host songs equally, 50/50. This capacity for learning and use of search images paired with a highly specialized morphology and lifestyle (eg. tympana tuned to host sound cues, larviparous) supports

3249-471: Was one of the first naturalists to study and depict parasitoids and their insect hosts in her closely-observed paintings. Parasitoids influenced the religious thinking of Charles Darwin , who wrote in an 1860 letter to the American naturalist Asa Gray : "I cannot persuade myself that a beneficent and omnipotent God would have designedly created parasitic wasps with the express intention of their feeding within

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