Editing Parasitoid (section)

===Basic concepts===
[[File:Pteromalid hyperparasitoid.jpg|thumb|upright|A [[hyperparasitoid]] [[chalcid wasp|chalcidoid wasp]] on the cocoons of its host, a [[braconid wasp]], itself a koinobiont parasitoid of [[Lepidoptera]]]]

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 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 a host that continues to grow larger and avoid predators.<ref name=GullanCranston2010>{{cite book |author1=Gullan, P. J. |author2=Cranston, P. S. |date=2014 |title=The Insects: An Outline of Entomology |publisher=Wiley |edition=5th |isbn=978-1-118-84615-5 |pages=362–370}}</ref>

Primary parasitoids have the simplest parasitic relationship, involving two organisms, the host and the parasitoid. [[Hyperparasitoid]]s 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 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.<ref>{{cite journal |last=Askew |first=R. R. |date=1961 |title=On the biology of the inhabitants of oak galls of Cynipidae (Hymenoptera) in Britain |url=https://www.researchgate.net/publication/238289888 |journal=Transactions of the Society for British Entomology |volume=14 |pages=237–268}}</ref> 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 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 the species. If superparasitism occurs accidentally in normally solitary species the larvae often fight among themselves until only one is left.<ref>{{cite book |author1=Gullan, P. J. |author2=Cranston, P. S. |date=2014 |title=The Insects: An Outline of Entomology |publisher=Wiley |edition=5th |pages=365–369 |isbn=978-1-118-84615-5 }}</ref><ref>{{cite journal  |last=Fisher |first=R. C. |title=A Study in Insect Multiparasitism: I. Host Selection and Oviposition |journal=Journal of Experimental Biology |date=1 June 1961 |volume=38 |issue=2 |pages=267–275 |doi=10.1242/jeb.38.2.267 |url=http://jeb.biologists.org/cgi/reprint/38/2/267.pdf}}</ref>