Editing Parasitoid (section)

== Interactions with humans ==

=== In biological pest control ===
{{Main|Biological pest control}}
[[File:Encarsia formosa, an endoparasitic wasp, is used for whitefly control.jpg|thumb|''[[Encarsia formosa]]'', an endoparasitic [[Aphelinidae|aphelinid]] wasp, bred commercially to control whitefly in [[greenhouse]]s]]

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 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.<ref name="Bale2008">{{cite journal | last1=Bale | first1=J.S | last2=van Lenteren | first2=J.C | last3=Bigler | first3=F | title=Biological control and sustainable food production | journal=Philosophical Transactions of the Royal Society B: Biological Sciences | publisher=The Royal Society | volume=363 | issue=1492 | date=February 2008 | doi=10.1098/rstb.2007.2182 | pmid=17827110 | pages=761–776| pmc=2610108 }}</ref><ref>{{cite web |last1=Legner |first1=Erich F.|title=Economic Gains & Analysis Of Successes In Biological Pest Control |url=http://www.faculty.ucr.edu/~legneref/biotact/bc-5.htm |publisher=University of California, Riverside |access-date=13 February 2018 |archive-url=https://web.archive.org/web/20080623113302/http://www.faculty.ucr.edu/~legneref/biotact/bc-5.htm |archive-date=23 June 2008 |url-status=live}}</ref>

From the point of view of the farmer or horticulturalist, the most important groups are the [[Ichneumon wasp|ichneumonid wasps]], which prey mainly on [[caterpillar]]s of [[butterflies]] and [[moths]]; [[braconid wasp]]s, which attack caterpillars and a wide range of other insects including [[aphid|greenfly]]; [[chalcid wasp|chalcidoid wasps]], which parasitise eggs and larvae of greenfly, [[whitefly]], [[cabbage caterpillar]]s, and [[scale insect]]s; and [[Tachinidae|tachinid flies]], which parasitise a wide range of insects including caterpillars, adult and larval [[beetle]]s, and [[true bugs]].<ref>{{cite web |title=Parasitoid Wasps (Hymenoptera) |url=https://extension.umd.edu/hgic/insects/parasitoid-wasps-hymenoptera |publisher=University of Maryland |access-date=6 June 2016 |archive-date=27 August 2016 |archive-url=https://web.archive.org/web/20160827072031/https://extension.umd.edu/hgic/insects/parasitoid-wasps-hymenoptera |url-status=dead }}</ref> 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.<ref name=smith>{{cite journal |author=Smith, S. M. |date=1996 |title=Biological control with Trichogramma: advances, successes, and potential of their use |journal=Annual Review of Entomology |volume=41 |pages=375–406 |pmid=15012334 |doi=10.1146/annurev.en.41.010196.002111}}</ref><ref>{{cite book |author1=Wajnberg, E. |author2=Hassan, S.A. |title=Biological Control with Egg Parasitoids |publisher=CABI Publishing |year=1994}}</ref>{{-}}

=== Maria Sibylla Merian ===
[[File:Garden Tiger Moth Maria Sibylla Merian.png|thumb|upright|[[Parasitic wasp]]s (centre right) with their [[garden tiger moth]] host, by [[Maria Sibylla Merian]]]]

[[Maria Sibylla Merian]] (1647–1717) was one of the first naturalists to study and depict parasitoids and their insect hosts in her closely-observed paintings.<ref name="Todd2011">{{cite journal |last=Todd |first=Kim |title=Maria Sibylla Merian (1647-1717): an early investigator of parasitoids and phenotypic plasticity |journal=Terrestrial Arthropod Reviews |volume=4 |issue=2 |year=2011 |pages=131–144 |doi=10.1163/187498311X567794}}</ref>

=== Charles Darwin ===

Parasitoids influenced the religious thinking of [[Charles Darwin]],{{efn|Darwin mentions "parasitic" wasps in ''[[On the Origin of Species]]'', Chapter 7, page 218.<ref>''[[On the Origin of Species]]'', Chapter 7, [http://darwin-online.org.uk/content/frameset?pageseq=236&itemID=F373&viewtype=side page 218.]</ref>}} 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 the living bodies of Caterpillars."<ref name=Darwin>{{cite web |url=http://www.darwinproject.ac.uk/entry-2814 | title=Letter 2814&nbsp;— Darwin, C. R. to Gray, Asa, 22 May [1860] |access-date=5 April 2011}}</ref> 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 [[Ichneumonidae|ichneumonid]] wasps.<ref name=Prothero2017>{{cite book |last=Prothero |first=Donald R. |title=Evolution: What the Fossils Say and Why It Matters |url=https://books.google.com/books?id=-LIvDwAAQBAJ&pg=PT85 |year=2017 |publisher=Columbia University Press |isbn=978-0-231-54316-3| pages=84–86}}</ref>

===In science fiction===
{{further|Parasites in fiction|Alien (creature in Alien franchise)}}

[[File:Paisley Abbey "Xenomorph" Gargoyle (10317339143) (cropped).jpg|thumb|left|A 1990s [[gargoyle]] at [[Paisley Abbey]], Scotland, resembling a [[Alien (creature in Alien franchise)|Xenomorph]]<ref>{{cite web |last1=Budanovic |first1=Nikola |title=An explanation emerges for how the 12th century Paisley Abbey in Scotland could feature a gargoyle out of the film "Alien" |url=https://www.thevintagenews.com/2018/03/10/alien-gargoyle/ |publisher=The Vintage News |access-date=17 June 2018 |date=10 March 2018}}</ref> parasitoid from the film ''[[Alien (film)|Alien]]''<ref>{{cite web |title='Alien' gargoyle on ancient Paisley Abbey |url=https://www.bbc.co.uk/news/uk-scotland-glasgow-west-23810979 |publisher=[[British Broadcasting Corporation]] |access-date=17 June 2018 |date=23 August 2013}}</ref>]]

Parasitoids have inspired [[science fiction]] authors and screenwriters to create terrifying [[Parasites in fiction|parasitic alien species]] that kill their human hosts.<ref name=Moisseeff2014>{{cite book |last1=Moisseeff |first1=Marika |author-link=Marika Moisseeff |title=Aliens as an Invasive Reproductive Power in Science Fiction |url=https://hal.archives-ouvertes.fr/hal-00935705 |website=HAL Archives-Ouvertes |date=23 January 2014|pages=239–257 |publisher=Polis, Sofia }}</ref> One of the best-known is the [[Alien (creature in Alien franchise)|Xenomorph]] in [[Ridley Scott]]'s 1979 film ''[[Alien (film)|Alien]]'', which runs rapidly through its lifecycle from violently entering a human host's mouth to bursting fatally from the host's chest.<ref name="Pappas2012">{{cite web |last1=Pappas |first1=Stephanie |title=5 Alien Parasites and Their Real-World Counterparts |url=https://www.livescience.com/20624-5-alien-parasites-real-inspiration.html |publisher=Live Science |date=29 May 2012}}</ref><ref>{{cite web |last1=Williams |first1=Robyn |last2=Field |first2=Scott |title=Behaviour, Evolutionary Games and .... Aliens |url=http://www.abc.net.au/science/kelvin/files/s223.htm |publisher=Australian Broadcasting Corporation |access-date=30 November 2017 |date=27 September 1997}}</ref><ref name=Guardian2009>{{cite web |title=The Making of Alien's Chestburster Scene |date=13 October 2009 |work=[[The Guardian]] |url=https://www.theguardian.com/film/2009/oct/13/making-of-alien-chestburster |access-date=29 May 2010| archive-url=https://web.archive.org/web/20100430221033/http://www.guardian.co.uk/film/2009/oct/13/making-of-alien-chestburster| archive-date=30 April 2010 | url-status=live}}</ref> The molecular biologist Alex Sercel, writing in ''Signal to Noise Magazine'', compares "the biology of the [''Alien''] Xenomorphs to parasitoid wasps and [[Nematomorpha|nematomorph worms]] from Earth to illustrate how close to reality the biology of these aliens is and to discuss this exceptional instance of science inspiring artists".<ref name=Sercel2017>{{cite web |last1=Sercel |first1=Alex |title=Parasitism in the Alien Movies |url=http://www.signaltonoisemag.com/allarticles/2017/5/19/parasitism-in-the-alien-movies |archive-url=https://web.archive.org/web/20170705023131/http://www.signaltonoisemag.com/allarticles/2017/5/19/parasitism-in-the-alien-movies |url-status=usurped |archive-date=5 July 2017 |publisher=Signal to Noise Magazine |date=19 May 2017}}</ref> 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.<ref name=Sercel2017/> [[Alistair Dove]], on the science website ''Deep Sea News'', writes that there are multiple parallels with parasitoids, although in his view, there are more disturbing life cycles in real biology. Dove stated that the parallels include the placing of an embryo in the host; its growth in the host; the resulting death of the host; and [[Heterogamy|alternating generations]], as in the [[Digenea]] (trematodes).<ref name="Dove2011">{{cite web |last1=Dove |first1=Alistair |title=This is clearly an important species we're dealing with |url=http://www.deepseanews.com/2011/05/this-is-clearly-an-important-species-were-dealing-with/ |publisher=Deep Sea News |date=9 May 2011}}</ref> The social anthropologist [[Marika Moisseeff]] argues that "The parasitical and swarming aspects of insect reproduction make these animals favoured [[Villain|villains]] in [[Cinema of the United States|Hollywood]] science fiction. The battle of culture against nature is depicted as an unending combat between humanity and insect-like extraterrestrial species that tend to parasitise human beings in order to reproduce."<ref name=Moisseeff2014/> ''[[The Encyclopedia of Science Fiction]]'' lists many instances of "parasitism", often causing the host's death.<ref>{{cite encyclopedia|title=Parasitism and Symbiosis |url=http://www.sf-encyclopedia.com/entry/parasitism_and_symbiosis |encyclopedia=[[The Encyclopedia of Science Fiction]] |date=10 January 2016}}</ref>