Ichneumonidae#Reproduction and oviposition

Insects in the family Ichneumonidae are commonly called ichneumon wasps, or ichneumonids. However, the term ichneumon wasps can refer specifically to the genus Ichneumon within the Ichneumonidae and thus can cause confusion. A group of ichneumonid specialists have proposed Darwin wasps as a better vernacular name for the family.{{Cite journal|last1=Klopfstein|first1=Seraina|last2=Santos|first2=Bernardo F.|last3=Shaw|first3=Mark R.|last4=Alvarado|first4=Mabel|last5=Bennett|first5=Andrew M. R.|last6=Dal Pos|first6=Davide|last7=Giannotta|first7=Madalene|last8=Herrera Florez|first8=Andres F.|last9=Karlsson|first9=Dave|last10=Khalaim|first10=Andrey I.|last11=Lima|first11=Alessandro R.|date=2019|title=Darwin wasps: a new name heralds renewed efforts to unravel the evolutionary history of Ichneumonidae|url=https://entomologicalcommunications.org/index.php/entcom/article/view/ec01006|journal=Entomological Communications|volume=1|pages=ec01006|doi=10.37486/2675-1305.ec01006|doi-access=free|hdl=10141/622809|hdl-access=free}} Less exact terms are ichneumon flies (they are not closely related to true flies) and scorpion wasps due to the extreme lengthening and curving of the abdomen (scorpions are arachnids, not insects).

The name is derived from Latin 'ichneumon', from Ancient Greek ἰχνεύμων (ikhneúmōn, "tracker"), from ἴχνος (íkhnos, "track, footstep"). The name first appeared in Aristotle's "History of Animals", c. 343 BC. Aristotle noted that the ichneumon preys upon spiders, is a wasp smaller than ordinary wasps, and carries its prey to a hole which they lay their larvae inside, and that they seal the hole with mud.{{cite book |author=Aristotle |title=The Complete Aristotle |url=https://books.google.com/books?id=Ts4MCgAAQBAJ&pg=PT1533 |year=2015 |orig-year=343 BC |publisher=Booklassic |isbn=978-963-525-370-8 |page=section 87, chapter 20 |quote=The wasps that are nicknamed 'the ichneumons' (or hunters), less in size, by the way, than the ordinary wasp, kill spiders and carry off the dead bodies to a wall or some such place with a hole in it; this hole they smear over with mud and lay their grubs inside it, and from the grubs come the hunter-wasps. ... The eagle and the snake are enemies, for the eagle lives on snakes; so are the ichneumon and the venom-spider, for the ichneumon preys upon the latter.|author-link=Aristotle }} Aristotle's writing, however, more accurately describes the mud daubers than the true ichneumon wasps, which do not construct mud nests and do not sting.

Adult ichneumonids superficially resemble other wasps. They have a slender waist, two pairs of wings, a pair of large compound eyes on the side of the head and three ocelli on top of the head. Their size varies considerably from a few millimetres to seven or more centimetres.

The ichneumonids have more antennal segments than typical, aculeate wasps (Aculeata: Vespoidea and Apoidea): ichneumonids typically possess 16 or more, while most other wasps have 13 or fewer. Unlike aculeate wasps, which have an ovipositor modified for prey capture and defense, and do not pass their eggs along the stinger, ichneumonid females have an unmodified ovipositor which they use to lay eggs inside or on their host. Ichneumonids generally inject venom along with the egg, but only larger species (some in the genera Netelia and Ophion) with relatively short ovipositors use the ovipositor in defense. Males do not possess stingers or ovipositors in either lineage.

File:Female Ichneumon xanthorius (10870689035).jpg|Head (Ichneumon xanthorius). Antennae with many segments

File:Yellow Ichneumon Wasp.jpg|Female Xanthopimpla punctata. Ovipositor longer and more slender than stingers of aculeate wasps

File:Ichneumon wasp (Ichneumonidae sp) female.jpg|Lissonota sp., female
Oxfordshire

Ichneumonids are distinguished from their sister group Braconidae mainly on the basis of wing venation. The fore wing of 95% of ichneumonids has vein 2m-cu (in the Comstock–Needham system), which is absent in braconids. Vein 1rs-m of the fore wing is absent in all ichneumonids, but is present in 85% of braconids. In the hind wing of ichneumonids, vein rs-m joins Rs apical to (or rarely opposite) the split between veins Rs and R1. In braconids, vein rs-m joins basal to this split. The taxa also differ in the structure of the metasoma: about 90% of ichneumonids have a flexible suture between tergites 2 and 3, whereas these tergites are fused in braconids (though the suture is secondarily flexible in Aphidiinae).Sharkey, M.J. (1993), Family Braconidae, pp. 362-394. In: Goulet, H. and J. Huber (eds.). Hymenoptera of the World, an Identification Guide to Families, Agriculture Canada Research Branch Monograph No. 1894E.

Ichneumonids are found on all continents with the exception of Antarctica. They inhabit virtually all terrestrial habitats, wherever there are suitable invertebrate hosts.

The distribution of ichneumonid species richness is subject to ongoing debate. Long believed to be rare in the tropics, and at its most species rich in the temperate region, the family became a classic textbook example of an 'exceptional' latitudinal diversity gradient.{{Cite journal|last=Janzen|first=Daniel H.|date=1981-06-01|title=The Peak in North American Ichneumonid Species Richness Lies Between 38 Degrees and 42 Degrees N|journal=Ecology|language=en|volume=62|issue=3|pages=532–537|doi=10.2307/1937717|issn=1939-9170|jstor=1937717|bibcode=1981Ecol...62..532J }} Recently this belief has been questioned, after the discovery of numerous new tropical species.{{Cite journal | doi=10.1046/j.1365-2656.1998.00198.x| title=Explaining the latitudinal gradient anomaly in ichneumonid species richness: Evidence from butterflies| journal=Journal of Animal Ecology| volume=67| issue=3| pages=387| year=1998| last1=Sime | first1=K. R. | last2=Brower | first2=A. V. Z. | jstor=2647379| doi-access=free| bibcode=1998JAnEc..67..387S}}{{Cite journal | doi=10.1098/rspb.2012.1664| pmid=23034706| title=Unprecedented ichneumonid parasitoid wasp diversity in tropical forests| journal=Proceedings of the Royal Society B: Biological Sciences| volume=279| issue=1748| pages=4694–4698| year=2012| last1=Veijalainen | first1=A.| last2=Wahlberg | first2=N.| last3=Broad | first3=G. R.| last4=Erwin | first4=T. L.| last5=Longino | first5=J. T.| last6=Saaksjarvi | first6=I. E.| pmc=3497088}}{{Cite journal | doi=10.1371/journal.pone.0032101| title=We Know Too Little about Parasitoid Wasp Distributions to Draw Any Conclusions about Latitudinal Trends in Species Richness, Body Size and Biology| journal=PLoS ONE| volume=7| issue=2| pages=e32101| year=2012| last1=Quicke | first1=D. L. J. | pmid=22355411 | pmc=3280234| bibcode=2012PLoSO...732101Q| doi-access=free}}

A very few ichneumonid species lay their eggs in the ground, but the vast majority inject eggs either directly into their host's body or onto its surface, and this may require penetration of substrate around the host, as in wood-boring host larvae that live deep inside of tree trunks, requiring the ichneumon to drill its ovipositor through several centimeters of solid wood (e.g., Megarhyssa species). After hatching, the ichneumonid larva consumes its still living host. The most common hosts are larvae or pupae of Lepidoptera, Coleoptera and Hymenoptera. Some species in the subfamily Pimplinae also parasitise spiders. Hyperparasitoids such as Mesochorinae oviposit inside the larvae of other ichneumonoids. The hosts of some species are agricultural pests, therefore ichneumons are sometimes valuable for biological pest control, but the hosts of most species are unknown; host information has been reviewed and summarized by various researchers, e.g. Aubert,{{cite book |last1=Aubert |first1=Jacques |year=1969 |title=Les Ichneumonides ouest-palearctiques et leurs hotes 1. Pimplinae, Xoridinae, Acaenitinae |trans-title=The Western Palearctic ichneumon wasps and their hosts. 1. Pimplinae, Xoridinae, Acaenitinae |publisher=Laboratoire d'Evolution des Etres Organises |location=Paris |language=fr |oclc=773541612 }}{{page needed|date=March 2016}}{{cite book |last1=Aubert |first1= Jacques François |year=1978 |title=Les Ichneumonides ouest-palearctiques et leurs hotes 2. Banchinae et Suppl. aux Pimplinae |trans-title=The Western Palearctic ichneumon wasps and their hosts. 2. Banchinae and supplement to the Pimplinae |publisher=Laboratoire d'Evolution des Etres Organises |location=Paris & EDIFAT-OPIDA, Echauffour |language=fr |oclc=461814920 }}{{page needed|date=March 2016}}{{cite book |last1=Aubert |first1=Jacques |year=2000 |title=Les Ichneumonides ouest-paléarctiques et leurs hôtes. 3. Scolobatinae (=Ctenopelmatinae) et suppl. aux volumes précédents |trans-title=The West Palaearctic ichneumonids and their hosts. 3. Scolobatinae (= Ctenopelmatinae) and supplements to preceding volumes |series=Litterae Zoologicae |volume=5 |language=fr |oclc=716442080 }}{{page needed|date=March 2016}} Perkins.{{cite book |last1=Perkins |first1=J. F. |year=1959 |title=Ichneumonidae, key to subfamilies and Ichneumoninae – 1 |series=Handbook for the Identification of British Insects |volume=7 (part 2ai) |oclc=704042974 }}{{page needed|date=March 2016}}{{cite book |last1=Perkins |first1=J. F. |year=1960 |title=Hymenoptera: Ichneumonoidea: Ichneumonidae, subfamilies Ichneumoninae 2, Alomyinae, Agriotypinae and Lycorininae |series=Handbook for the Identification of British Insects |volume=7 (part 2aii) |oclc=316445110 }}{{page needed|date=March 2016}} and Townes.{{cite book |last1=Townes |first1=Henry |last2=Momoi |first2=Setsuya |last3=Townes |first3=Marjorie |year=1965 |title=A catalogue and reclassification of the eastern Palearctic Ichneumonidae |series=Memoirs of the American Entomological Institute |volume=5 |oclc=669390657 }}{{page needed|date=March 2016}}

Ichneumonids use both idiobiont and koinobiont strategies. Idiobionts paralyze their host and prevent it from moving or growing. Koinobionts allow their host to continue to grow and develop. In both strategies, the host typically dies after some weeks, after which the ichneumonid larva emerges and pupates.{{Cite journal|last=Gauld|first=Ian D.|date=1988|title=Evolutionary patterns of host utilization by ichneumonoid parasitoids (Hymenoptera: Ichneumonidae and Braconidae)*|journal=Biological Journal of the Linnean Society|volume=35|issue=4|pages=351–377|doi=10.1111/j.1095-8312.1988.tb00476.x|issn=0024-4066}} {{See also|Parasitoid#Basic concepts}}

Adult ichneumonids feed on a diversity of foods, including plant sap and nectar; females of some species also feed on their hosts by sipping body fluids released during oviposition, or even stabbing host and non-host insects to imbibe their body fluids. They spend much of their active time searching, either for hosts (female ichneumonids) or for emerging females (male ichneumonids).{{cite book|chapter-url=https://www.researchgate.net/publication/285831374|doi=10.1017/CBO9780511542220.006|chapter=Food needs of adult parasitoids: Behavioral adaptations and consequences|title=Plant-Provided Food for Carnivorous Insects|pages=137–147|year=2005|last1=Olson|first1=D. M.|last2=Takasu|first2=K.|last3=Lewis|first3=W. J.|isbn=9780521819411}}

The parasitism pressure exerted by ichneumonids can be tremendous, and they are often one of the major regulators of invertebrate populations.{{cite journal |first1=Gergely |last1=Várkonyi |first2=Ilkka |last2=Hanski |first3=Martin |last3=Rost |first4=Juhani |last4=Itämies |title=Host-Parasitoid Dynamics in Periodic Boreal Moths |journal=Oikos |volume=98 |issue=3 |date=September 2002 |pages=421–30 |jstor=3547182 |doi=10.1034/j.1600-0706.2002.980306.x |bibcode=2002Oikos..98..421V }}{{cite journal |first1=Bradford A. |last1=Hawkins |first2=Howard V. |last2=Cornell |first3=Michael E. |last3=Hochberg |title=Predators, parasitoids, and pathogens as mortality agents in phytophagous insect populations |journal=Ecology |volume=78 |issue=7 |date=October 1997 |pages=2145–52 |jstor=2265951 |doi=10.1890/0012-9658(1997)078[2145:PPAPAM]2.0.CO;2 }} It is quite common for 10-20% or more of a host's population to be parasitised (though reported parasitism rates often include non-ichneumonid parasitoids).{{cite journal |first1=J. |last1=Memmott |first2=H.C.J. |last2=Godfray |first3=I.D. |last3=Gauld |title=The structure of a tropical host-parasitoid community |journal=Journal of Animal Ecology |volume=63 |issue=3 |date=July 1994 |pages=521–40 |id={{INIST|4125431}} |jstor=5219 |doi=10.2307/5219|bibcode=1994JAnEc..63..521M }}{{cite journal |last1=Várkonyi |first1=Gergely |last2=Roslin |first2=Tomas |title=Freezing cold yet diverse: dissecting a high-Arctic parasitoid community associated with Lepidoptera hosts |journal=The Canadian Entomologist |volume=145 |issue=2 |year=2013 |pages=193–218 |doi=10.4039/tce.2013.9 |s2cid=86014193 |url=https://zenodo.org/record/3441232 }}{{Dead link|date=August 2024 |bot=InternetArchiveBot |fix-attempted=yes }}

File:Phytodietus egg.jpg|Phytodietus, egg on Pococera caterpillar

File:Parasite170127-fig S2 ovipositor Pimplinae Zatypota albicoxa.gif|Zatypota albicoxa laying egg on a spider

File:Itoplectis maculator - Wollenberg 2011.ogv|Itoplectis maculator laying eggs in moth cocoons

File:Rhyssa persuasoria - 2014-08-28.webm|Rhyssa persuasoria laying eggs in dead wood, parasitising larvae of beetles or sawflies

File:Therion circumflexum.ogv|Therion circumflexum drinking from damaged edge of leaf

File:Ichneumonidae mating.jpg|Mating ichneumonids

File:Live Tetragnatha montana (RMNH.ARA.14127) parasitized by Acrodactyla quadrisculpta larva (RMNH.INS.593867) - BDJ.1.e992.jpg|Larva of Acrodactyla quadrisculpta parasitising spider

File:Cocoon of an Ichneumoid wasp (Campopleginae) and the empty skin of a caterpillar it had parasitized (8073727904).jpg|Campoplegine pupa, with empty skin of caterpillar it parasitised above it

File:Hercus fontinalis later instar larvae.jpg|Hercus fontinalis larvae feeding on caterpillar

Image:Female ichneumonid wasp in Dominican amber-07.jpg

The taxonomy of the ichneumonids is still poorly known. The family is highly diverse, containing 24,000 described species. Approximately 60,000 species are estimated to exist worldwide, though some estimates place this number at over 100,000. They are severely undersampled, and studies of their diversity typically produce very high numbers of species which are represented by only a single individual.{{Cite journal|last1=Saunders|first1=Thomas E.|last2=Ward|first2=Darren F.|date=2018-04-05|title=Variation in the diversity and richness of parasitoid wasps based on sampling effort|journal=PeerJ|language=en|volume=6|pages=e4642|doi=10.7717/peerj.4642|pmid=29632746|pmc=5889912|issn=2167-8359 |doi-access=free }}{{Cite journal|date=2008-02-01|title=The effectiveness and optimal use of Malaise traps for monitoring parasitoid wasps|journal=Insect Conservation and Diversity|language=en|volume=1|issue=1|pages=22–31|doi=10.1111/j.1752-4598.2007.00003.x|issn=1752-4598|last1=Fraser|first1=Sally E. M.|last2=Dytham|first2=Calvin|last3=Mayhew |first3=Peter J.|doi-access=free}} Due to the high diversity, the existence of numerous small and hard to identify species, and the majority of species being undiscovered, it has proven difficult to resolve the phylogeny of the ichneumonids. Even the relationships between subfamilies are unclear. The sheer diversity also means DNA sequence data is only available for a tiny fraction of the species, and detailed cladistic studies require major computing capacity.

Extensive catalogues of the ichneumonids include those by Aubert, Gauld,{{cite journal | last1 = Gauld | first1 = I. D. | year = 1976 | title = The classification of the Anomaloninae (Hymenoptera: Ichneumonidae) | journal = Bulletin of the British Museum (Natural History) Entomology | volume = 33 | pages = 1–135 }} Perkins, and Townes.{{cite journal | last1 = Townes | first1 = H. K. | year = 1969a | title = Genera of Ichneumonidae, Part 1 (Ephialtinae, Tryphoninae, Labiinae, Adelognathinae, Xoridinae, Agriotypinae) | journal = Memoirs of the American Entomological Institute | volume = 11 | pages = 1–300 }}{{cite journal | last1 = Townes | first1 = H. K. | year = 1969b | title = Genera of Ichneumonidae, Part 2 (Gelinae) | journal = Memoirs of the American Entomological Institute | volume = 12 | pages = 1–537 }}{{cite journal | last1 = Townes | first1 = H. K. | year = 1969c | title = Genera of Ichneumonidae, Part 3 (Lycorininae, Banchinae, Scolobatinae, Porizontinae) | journal = Memoirs of the American Entomological Institute | volume = 13 | pages = 1–307 }}{{cite journal | last1 = Townes | first1 = H. K. | year = 1971 | title = Genera of Ichneumonidae, Part 4 (Cremastinae, Phrudinae, Tersilochinae, Ophioninae, Mesochorinae, Metopiinae, Anomalinae, Acaenitinae, Microleptinae, Orthopelmatinae, Collyriinae, Orthocentrinae, Diplazontinae) | journal = Memoirs of the American Entomological Institute | volume = 17 | pages = 1–372 }} Due to the taxonomic difficulties involved, however, their classifications and terminology are often confusingly contradictory. Several prominent authors have gone as far as to publish major reviews that defy the International Code of Zoological Nomenclature.{{cite journal | last1 = Oehlke | first1 = J | year = 1966 | title = Die westpaläarktische Arte der Tribus Poemeniini (Hymenoptera, Ichneumonidae) ["The Western Palearctic species of the tribe Poemeniini"]. | journal = Beiträge zur Entomologie | volume = 15 | pages = 881–892 }}{{cite journal | last1 = Oehlke | first1 = J | year = 1967 | title = Westpaläarktische Ichneumonidae 1, Ephialtinae | journal = Hymenopterorum Catalogus | volume = 2 | pages = 1–49 | edition=new }}

The large number of species in Ichneumonidae may be due to the evolution of parasitoidism in Hymenoptera, which occurred approximately 247 million years ago.{{Cite journal|last1=Peters|first1=Ralph S.|last2=Krogmann|first2=Lars|last3=Mayer|first3=Christoph|last4=Donath|first4=Alexander|last5=Gunkel|first5=Simon|last6=Meusemann|first6=Karen|last7=Kozlov|first7=Alexey|last8=Podsiadlowski|first8=Lars|last9=Petersen|first9=Malte|date=2017-04-03|title=Evolutionary History of the Hymenoptera|journal=Current Biology|volume=27|issue=7|pages=1013–1018|doi=10.1016/j.cub.2017.01.027|pmid=28343967|doi-access=free|bibcode=2017CBio...27.1013P |hdl=2434/801122|hdl-access=free}}{{Cite journal|last1=Heraty|first1=John|last2=Ronquist|first2=Fredrik|last3=Carpenter|first3=James M.|last4=Hawks|first4=David|last5=Schulmeister|first5=Susanne|last6=Dowling|first6=Ashley P.|last7=Murray|first7=Debra|last8=Munro|first8=James|last9=Wheeler|first9=Ward C.|title=Evolution of the hymenopteran megaradiation|journal=Molecular Phylogenetics and Evolution|volume=60|issue=1|pages=73–88|doi=10.1016/j.ympev.2011.04.003|pmid=21540117|year=2011|bibcode=2011MolPE..60...73H |url=http://www.escholarship.org/uc/item/2f33z9mz|archive-date=2020-06-22|access-date=2019-06-28|archive-url=https://web.archive.org/web/20200622084050/https://escholarship.org/uc/item/2f33z9mz|url-status=live}} Ichneumonidae is the basal branch of Apocrita, which together with Orussoidea makes up the lineage in which parasitoidism in Hymenoptera evolved, and some ichneumonids are thought to have been in stasis for millions of years and closely resemble the common ancestor in which parasitoidism evolved. This common ancestor was likely an Ectoparasitoid woodwasp that parasitized wood-boring beetle larvae in trees.{{Cite journal|last1=Pennacchio|first1=Francesco|last2=Strand|first2=Michael R.|date=2005-12-06|title=Evolution of developmental strategies in parasitic Hymenoptera|journal=Annual Review of Entomology|volume=51|issue=1|pages=233–258|doi=10.1146/annurev.ento.51.110104.151029|pmid=16332211|issn=0066-4170}} However, this has been disputed as early fossil ichneumonoids (such as Praeichneumonidae, Tanychorinae, Eoichneumoninae, and Protorhyssalinae) have ovipositors that are only a few millimeters long. Therefore, it has been proposed that they make unlikely candidates for parasitoids of wood-boring hosts. The family has existed since at least the Early Cretaceous ({{circa}} 125 mya),{{Cite journal|last=Kopylov|first=D. S.|date=January 2009|title=A new subfamily of ichneumonids from the Lower Cretaceous of Transbaikalia and Mongolia (Insecta: Hymenoptera: Ichneumonidae)|journal=Paleontological Journal|language=en|volume=43|issue=1|pages=83–93|doi=10.1134/S0031030109010092|bibcode=2009PalJ...43...83K |s2cid=83827172|issn=0031-0301}}{{Cite journal|last=Kopylov|first=D. S.|date=March 2010|title=Ichneumonids of the subfamily Tanychorinae (Insecta: Hymenoptera: Ichneumonidae) from the Lower Cretaceous of Transbaikalia and Mongolia|journal=Paleontological Journal|language=en|volume=44|issue=2|pages=180–187|doi=10.1134/S0031030110020097|bibcode=2010PalJ...44..180K |s2cid=83902440|issn=0031-0301}} but probably appeared already in the Jurassic (c. 181 mya), soon after the appearance of its major host groups.{{Cite journal|last1=Spasojevic|first1=Tamara|last2=Broad|first2=Gavin R.|last3=Sääksjärvi|first3=Ilari E.|last4=Schwarz|first4=Martin|last5=Ito|first5=Masato|last6=Korenko|first6=Stanislav|last7=Klopfstein|first7=Seraina|title=Mind the Outgroup and Bare Branches in Total-Evidence Dating: a Case Study of Pimpliform Darwin Wasps (Hymenoptera, Ichneumonidae)|journal=Systematic Biology|year=2021|volume=70|issue=2|pages=322–339|language=en|doi=10.1093/sysbio/syaa079|pmid=33057674|pmc=7875445|doi-access=free}} It diversified during the Oligocene.

In 1999, the extant ichneumonids were divided into 39 subfamilies,Wahl, David (1999): [http://iris.biosci.ohio-state.edu/catalogs/ichneumonids/ Classification and Systematics of the Ichneumonidae (Hymenoptera)] {{webarchive|url=https://web.archive.org/web/20080725073724/http://iris.biosci.ohio-state.edu/catalogs/ichneumonids/ |date=2008-07-25 }}. Version of 1999-JUL-19. Retrieved 2008-JUN-18.{{cite web|last1=Wahl|first1=David|last2=Gauld|first2=Ian|url=http://www.amentinst.org/GIN/|website=Genera Ichneumonorum Nearcticae|title=American Entomological Institute|publisher=The American Entomological Institute|access-date=9 August 2017|archive-date=9 June 2017|archive-url=https://web.archive.org/web/20170609113951/http://www.amentinst.org/GIN/|url-status=live}} whose names and definitions have varied considerably. In 2019, combined morphological and molecular phylogenetic analysis of the family resulted in the following 41 subfamilies being recognized, in addition to the extinct Labenopimplinae.

{{div col}}

• Acaenitinae {{small|Townes, 1950}}
• Adelognathinae {{small|Thomson, 1888}}
• Agriotypinae {{small|Haliday,1838}}
• Anomaloninae {{small|Viereck, 1918}} (= Anomalinae)
• Ateleutinae {{small|Townes, 1970}} (previously part of Cryptinae)
• Banchinae {{small|Townes, 1951}}
• Brachycyrtinae {{small|Viereck, 1919}} (previously part of Phrudinae)
• Campopleginae {{small|Förster, 1869}} (= Porizontinae)
• Claseinae {{small|Porter, 1998}}
• Collyriinae {{small|Cushman, 1924 }}
• Cremastinae {{small|Förster, 1869}}
• Cryptinae {{small|Kirby, 1837}} (= Gelinae, Hemitelinae, Phygadeuontinae)
• Ctenopelmatinae {{small|Förster, 1869}} (= Scolobatinae)
• Cylloceriinae {{small|Wahl, 1990 }} (sometimes included in Microleptinae)
• Diacritinae {{small|Townes, 1965 }} (sometimes included in Pimplinae)
• Diplazontinae {{small|Viereck, 1918}}
• Eucerotinae {{small|Seyrig, 1934}} (sometimes included in Tryphoninae)
• Hybrizontinae (= Paxylommatinae) (sometimes placed in own family)
• Ichneumoninae {{small|Latreille, 1802}} (includes Alomyini)
• Labeninae {{small|Ashmead,1900}} (= Labiinae)
• Labenopimplinae (extinct)
• Lycorininae (sometimes included in Banchinae)
• Mesochorinae {{small|Forster, 1869}}
• Metopiinae {{small|Forster, 1869}}
• Microleptinae {{small|Townes, 1958 }}
• Neorhacodinae (sometimes included in Banchinae)
• Nesomesochorinae {{small|Ashmead, 1905 }}
• Ophioninae {{small|Shuckard, 1840}}
• Orthocentrinae {{small|Förster, 1869}} (sometimes included in Microleptinae)
• Orthopelmatinae {{small|Schmiedeknecht, 1910}}
• Oxytorinae {{small|Thomson, 1883}}
• Pedunculinae {{small|Porter, 1998 }}
• Phygadeuontinae (previously part of Cryptinae)
• Pimplinae {{small|Wesmael, 1845}} (= Ephialtinae)
• Poemeniinae {{small|Smith & Shenefelt, 1955 }} (sometimes included in Pimplinae)
• Rhyssinae {{small|Morley, 1913}} (sometimes included in Pimplinae)
• Sisyrostolinae (sometimes included in Phrudinae)
• Stilbopinae {{small|Townes & Townes, 1949}} (excluding Notostilbops)
• Tatogastrinae {{small|Wahl, 1990}} (sometimes included in Microleptinae)
• Tersilochinae {{small|Schmiedeknecht, 1910}} (includes Neorhacodinae and part of Phrudinae)
• Tryphoninae {{small|Shuckard, 1840}}
• Xoridinae {{small|Shuckard, 1840}}

{{div col end}}

Famous ichneumonologists include:

• Jacques Aubert
• Carl Gustav Alexander Brischke
• Peter Cameron
• Arnold Förster
• Johann Ludwig Christian Gravenhorst
• Alexander Henry Haliday
• Gerd Heinrich
• August Emil Holmgren
• Joseph Kriechbaumer
• Thomas Ansell Marshall
• Henry Keith Townes
• Constantin Wesmael

The perceived cruelty of the ichneumonids troubled philosophers, naturalists, and theologians in the 19th century, who found the parasitoid life cycle inconsistent with the notion of a world created by a loving and benevolent God.{{cite web |url=http://www.stephenjaygould.org/library/gould_nonmoral.html |title=Nonmoral Nature |access-date=2011-04-05 |archive-url=https://web.archive.org/web/20151117022650/http://www.stephenjaygould.org/library/gould_nonmoral.html |archive-date=2015-11-17 |url-status=dead }} Charles Darwin found the example of the Ichneumonidae so troubling that it contributed to his increasing doubts about the nature and existence of a Creator. In an 1860 letter to the American naturalist Asa Gray, Darwin wrote:

I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of Caterpillars, or that a cat should play with mice.{{cite web |url=http://www.darwinproject.ac.uk/entry-2814 |title=Letter 2814 — Darwin, C. R. to Gray, Asa, 22 May [1860] |access-date=2011-04-05 |archive-date=2023-01-14 |archive-url=https://web.archive.org/web/20230114162534/https://www.darwinproject.ac.uk/letter/DCP-LETT-2814.xml |url-status=live }}

File:Megarhyssa greenei female.jpg|Megarhyssa greenei female

File:2-Morphology-of-head.png|Morphology of the head and its processes: (А) head capsule; (В) antenna; (С) mandibleTereshkin, A. (2009): Illustrated key to the tribes of subfamilia Ichneumoninae and genera of the tribe Platylabini of world fauna (Hymenoptera, Ichneumonidae). Linzer biol. Beitr. 41/2: 1317-1608. [http://tereshkin.info/39.pdf PDF] {{Webarchive|url=https://web.archive.org/web/20180410114635/http://tereshkin.info/39.pdf |date=2018-04-10 }}

File:3-Morphology-of-thotax.png|Morphology of the thorax (D)

File:4-Morphology-of-abdomen-and.png|Morphology of the abdomen and processes of the thorax: (E) front wing; (F) leg III; (G) abdomen of female

• Checklist of UK recorded Ichneumonidae

{{Reflist|refs=

{{Cite journal

| title = Phylogeny of the subfamilies of Ichneumonidae (Hymenoptera)

| date = 2021

| last1 = Bennett | first1 = A.M.R.

| last2 = Cardinal | first2 = S.

| last3 = Gauld | first3 = I.D.

| last4 = Wahl | first4 = D.B.

| journal = Journal of Hymenoptera Research

| volume = 71

| pages = 1–156

| url = https://jhr.pensoft.net/article/32375/list/9/

| doi = 10.3897/jhr.71.32375

| doi-access = free

}}

}}

{{subject bar|auto=y|d=y|Insects}}

• [http://delta-intkey.com/britin/hym/www/ichneumo.htm Long Family Description] Many illustrations from John Curtis British Entomology
• [https://web.archive.org/web/20070927182621/http://www.faunaeur.org/full_results.php?id=11277 Fauna Europaea]
• [http://www.waspweb.org/Ichneumonoidea/Ichneumonidae/Classification/index.htm Ichneumonidae:Classification of afrotropical ichneumonid wasps]. Extensive use of images.
• [http://eol.org/pages/703/media Family Ichneumonidae at EOL] Comprehensive taxonomic resource and image database
• [http://www.landcareresearch.co.nz/science/plants-animals-fungi/animals/invertebrates/systematics/hymenoptera/ichneumonidae/ichneumonidae-image-gallery Images of Ichneumonidae species in New Zealand]
• [http://www.rutkies.de/bienen-3/ W.Rutkies] {{Webarchive|url=https://web.archive.org/web/20190215175906/http://www.rutkies.de/bienen-3/ |date=2019-02-15 }} Images. Authority id.
• [http://www.amentinst.org/GIN/morphology.php Genera Ichneumonorum Nearctica]. Morphology of Ichneumonidae

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Category:Apocrita families

Category:Taxa named by Pierre André Latreille