Editing Parasitoid (section)

===Hymenoptera===
{{main|Parasitoid wasp}}
[[File:Potter Wasp building mud nest near completion.JPG|thumb|[[Potter wasp]], an idiobiont, building a mud nest; she will [[mass provisioning|provision it]] with paralysed insects, on which she will lay her eggs; she will then seal the nest and provide no further care for her young]]

Within the Hymenoptera, parasitoidism evolved just once, and the many described{{efn|There may be far more species of parasitoid wasp not yet described.}} species of [[parasitoid wasp]]s<ref>{{cite book |title=Hymenoptera of the world : an identification guide to families |date=1993 |publisher=Centre for Land and Biological Resources Research |author1=Goulet, Henri |author2=Huber, John Theodore |isbn=978-0-660-14933-2 |oclc=28024976}}</ref> represent the great majority of species in the order, barring those like the [[ant]]s, [[bee]]s, 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.<ref name=Mills2009/> These often have remarkable life cycles.<ref>{{cite journal |last=Hochberg |first=M. |author2=Elmes, G. W. |author3=Thomas, J. A. |author4=Clarke, R. T. |title=Mechanisms of local persistence in coupled host-parasitoid associations: the case model of Maculinea rebeli and Ichneumon eumerus|year=1996 |volume=351 |issue=1348 |pages=1713–1724 |doi=10.1098/rstb.1996.0153 |journal=Philosophical Transactions of the Royal Society B: Biological Sciences|bibcode=1996RSPTB.351.1713H }}</ref>
They can be classified as either endoparasitic or ectoparasitic according to where they lay their eggs.<ref name="Kapranas2012">{{cite journal |author1=Apostolos, Kapranas |author2=Tena, Alejandro |author3=Luck, Robert F. |title=Dynamic virulence in a parasitoid wasp: the influence of clutch size and sequential oviposition on egg encapsulation |journal=Animal Behaviour |volume=83 |issue=3 |year=2012 |pages=833–838 |doi=10.1016/j.anbehav.2012.01.004|s2cid=54275511 }}</ref> Endoparasitic wasps insert their eggs inside their host, usually as koinobionts, allowing 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.<ref name=Godfray1994/> Most species of wasps attack 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.<ref>{{cite book |author1=Gullan, P. J. |author2=Cranston, P. S. |date=2010 |title=The Insects: An Outline of Entomology |url=https://archive.org/details/insectsoutlineen00pjgu |url-access=limited |publisher=Wiley |edition=4th |pages=[https://archive.org/details/insectsoutlineen00pjgu/page/n388 364], 367 |isbn=978-1-118-84615-5}}</ref><ref name="Gomez, Jose-Maria 2011">{{cite journal | last1=Gomez | first1=Jose-Maria | last2=van Achterberg | first2=Cornelius | year=2011 | title=Oviposition behaviour of four ant parasitoids (Hymenoptera, Braconidae, Euphorinae, Neoneurini and Ichneumonidae, Hybrizontinae), with the description of three new European species | journal=ZooKeys | issue=125 | pages=59–106 | doi=10.3897/zookeys.125.1754| pmid=21998538 | pmc=3185369 | doi-access=free | bibcode=2011ZooK..125U..59V }}</ref><ref name="Quicke Fitton pp. 99–103">{{cite journal | last1=Quicke | first1=D. L. J. | last2=Fitton | first2=M. G. | title=Ovipositor Steering Mechanisms in Parasitic Wasps of the Families Gasteruptiidae and Aulacidae (Hymenoptera) | journal=Proceedings of the Royal Society B: Biological Sciences | publisher=The Royal Society | volume=261 | issue=1360 | date=22 July 1995 | doi=10.1098/rspb.1995.0122 | pages=99–103 | bibcode=1995RSPSB.261...99Q | s2cid=84043987 |quote=The length of the ovipositor compared with the body of the parasitic wasp varies enormously between taxa, from being a fraction of the length of the metasoma to more than 14 times longer than the head and body. (Townes 1975; Achterberg 1986; Compton & Nefdt 1988).}}</ref> 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.<ref name="Achterberg C 1993">Van Achterberg Cornelius; Argaman Q. "Kollasmosoma gen. nov. and a key to the genera of the subfamily Neoneurinae (Hymenoptera: Braconidae)". Zoologische Mededelingen Leiden. 67. (1993):63-74.</ref>

Parasitoid wasps face a range of obstacles to oviposition,<ref name=Godfray1994/> including behavioural, morphological, physiological and immunological defences of their hosts.<ref name="Kapranas2012"/><ref>{{cite journal | last1=Schmidt | first1=O. | last2=Theopold | first2=U. | last3=Strand | first3=M.R. | year=2001 | title=Innate immunity and evasion by insect parasitoids | journal=BioEssays | volume=23 | issue=4| pages=344–351 | doi=10.1002/bies.1049| pmid=11268040 | s2cid=20850885 }}</ref> To thwart this, some wasps inundate their host with their eggs so as to overload its immune system's ability to encapsulate foreign bodies;<ref>{{cite journal |last1=Salt |first1=George | year=1968 | title=The resistance of insect parasitoids to the defense reactions of their hosts | journal=Biological Reviews of the Cambridge Philosophical Society | volume=43 | issue=2| pages=200–232 | doi=10.1111/j.1469-185x.1968.tb00959.x|pmid=4869949 |s2cid=21251615 }}</ref> others introduce a [[Polydnavirus|virus]] which interferes with the host's immune system.<ref>{{cite journal | last1=Summers | first1=M. D. | last2=Dib-Hajj | year=1995 | title=Polydnavirus-facilitated endoparasite protection against host immune defenses | journal=PNAS | volume=92 | issue=1 | pages=29–36 | doi=10.1073/pnas.92.1.29| pmid=7816835 | pmc=42812 | bibcode=1995PNAS...92...29S | doi-access=free }}</ref>
Some parasitoid wasps locate hosts by detecting the chemicals that plants release to defend against insect herbivores.<ref name="Kessler, Andre 2002">{{cite journal | last1=Kessler | first1=Andre | last2=Baldwin | first2=Ian T. | year=2002 | title=Plant Responses to Insect Herbivory: The Emerging Molecular Analysis | journal= Annual Review of Plant Biology  | volume=53 | pages=299–328 | doi=10.1146/annurev.arplant.53.100301.135207| pmid=12221978 }}</ref>