View source for Fig wasp

{{Short description|Group of mostly pollinating insects whose larvae live in figs}}
{{Paraphyletic group
| auto = yes
| name = Fig wasps
| image = Blastophaga_psenes.jpg
| image_caption = ''[[Blastophaga psenes]]'' female
| display_parents = 2
| parent = Chalcidoidea
}}

'''Fig wasps''' are [[wasp]]s of the superfamily [[Chalcidoidea]] which spend their larval stage inside [[ficus|fig]]s. Some are [[pollinator]]s but others simply feed off the plant. The non-pollinators belong to several groups within the superfamily Chalcidoidea, while the pollinators are in the family [[Agaonidae]]. Pollinating fig wasps are all [[gall]]-makers, non-pollinating fig wasps either make their own galls or usurp the galls of other fig wasps; reports of their being [[parasitoid]]s are considered dubious.<ref>Boucek, Z. 1988. Australasian Chalcidoidea (Hymenoptera): a biosystematic revision of genera of fourteen families, with a reclassification of species. C.A.B. International, Wallingford, England. 832 pp.</ref>

== History ==
[[Aristotle]] recorded in his ''[[History of Animals]]'' that the fruits of the wild fig (the [[caprifig]]) contain ''psenes'' (fig wasps); these begin life as grubs (larvae), and the adult ''psen'' splits its "skin" (pupa) and flies out of the fig to find and enter a cultivated fig, saving it from dropping. He believed that the ''psen'' was [[spontaneous generation|generated spontaneously]]; he did not recognise that the fig was reproducing sexually and that the ''psen'' was assisting in that process.<ref name=Leroi244>{{cite book |author=Leroi, Armand Marie |author-link=Armand Marie Leroi |title=The Lagoon: How Aristotle Invented Science |title-link=Aristotle's Lagoon |publisher=Bloomsbury |date=2014 |isbn=978-1-4088-3622-4 |pages=244–247}}</ref>

==Taxonomy==
The fig wasps are a [[polyphyletic]] group, including several unrelated lineages whose similarities are based upon their shared association with figs; efforts are underway to resolve the matter, and remove a number of constituent groups to other families, particularly the [[Pteromalidae]] and [[Torymidae]]. Thus, the number of genera in the family is in flux. The family [[Agaonidae]] has been recently updated to include all the pollinating fig wasps<ref name="Cruaud-etal-2010">{{Harvnb|Cruaud|Jabbour-Zahab|Genson|Cruaud|2010}}</ref> and the subfamily [[Sycophaginae]].<ref name="Heraty-etal-2013">{{Harvnb|Heraty|Burks|Cruaud|Gibson|2013}}</ref>
The remaining taxa such as [[Epichrysomallinae]], [[Sycoecinae]], [[Otitesellinae]], and [[Sycoryctinae]] should be included in the Pteromalidae.<ref name="Heraty-etal-2013"/>

==Morphological adaptations==
[[File:Blastophaga psenes2.png|thumb|upright=1.3<!--width for very low image-->|Female (left, with long ovipositor) and male ''[[Blastophaga psenes]]'']]

Among the Agaonidae, the female is a normal insect, while the males are mostly wingless. The males' only tasks are to mate with the females while still within the fig [[syconium]] (inverted flower) and to chew a hole for the females to escape from the fig interior. This is the reverse of [[Strepsiptera]] and the [[bagworm]], where the male is a normal insect and the female never leaves the host.
The non-pollinating wasps have developed impressive morphological adaptations in order to oviposit eggs inside the fig but from the outside: an extremely long [[ovipositor]].{{Cn|date=June 2021}}

Most figs (more than 600 species) have syconia that contain three types of [[flower]]s: male, short female, and long female. Female fig wasps can reach the ovaries of short female flowers with their ovipositors, but not long female flowers. Thus, the short female flowers grow wasps, and the long flowers only seeds. Contrary to popular belief, ripe figs are not full of dead wasps and the "crunchy bits" in the fruit are only seeds. The fig actually produces an enzyme called [[ficain]] (also known as ficin) which digests the dead wasps and the fig absorbs the nutrients to create the ripe fruits and seeds.<ref>{{Cite web | url=https://askabiologist.asu.edu/figs-without-wasps | title=Figs Without Wasps?| date=2012-10-11}}</ref>  Several commercial and ornamental varieties of fig are [[parthenocarpic]] and do not require pollination to produce (sterile) fruits; these varieties need not be visited by fig wasps to bear fruit.<ref>Roy, D. (2019). Tropical/subtropical fruit crops: Fig. In ''Breeding of fruit crops'' (pp. 113-115). Alpha Science International Ltd.</ref>

==Life cycle==
{{More citations needed section|date=June 2021}}
[[File:Pleistodontes sp-Female.jpg|thumb|''[[Pleistodontes]]'' sp. female]]
[[File:Ceratosolen capensis op Ficus sur, Jan Celliers Park, a.jpg|thumb|''[[Ceratosolen]]'' species are pollinators of the ''Sycomorus'', ''Sycocarpus'' and ''Neomorphe'' sections of ''[[Ficus]]''.<ref name=zhen>{{cite journal |last1=Zhen |first1=Wen-Quan |last2=Huang |first2=Da-Wei |last3=Xiao |first3=Jin-Hua |last4=Yang |first4=Da-Rong |last5=Zhu |first5=Chao-Dong |last6=Xiao |first6=Hui |title=Ovipositor length of threeApocrypta species: Effect on oviposition behavior and correlation with syconial thickness |journal=Phytoparasitica |date=April 2005 |volume=33 |issue=2 |pages=113–120 |doi=10.1007/BF03029967 |bibcode=2005Phyto..33..113Z |s2cid=35479915 |url=http://www.nhm.ac.uk/resources/research-curation/projects/chalcidoids/pdf_X/ZhenHuXi2005.pdf |access-date=5 October 2015}}</ref>]]
[[File:Apocrypta guineensis, volw-wyfie op F sur, Manie vd Schijff BT, d.jpg|thumb|Non-pollinating [[parasitoid wasp]]s ''[[Apocrypta]]'' ovipositing on ''[[Ficus sur]]'' in South Africa]]

The [[Biological life cycle|life cycle]] of the fig wasp is closely intertwined with that of the fig tree it inhabits. The wasps that inhabit a particular tree can be divided into two groups; [[pollinate|pollinating]] and non-pollinating. The pollinating wasps are part of an obligate nursery pollination [[mutualism (biology)|mutualism]] with the fig tree, while the non-pollinating wasps feed off the plant without benefiting it. The life cycles of the two groups, however, are very similar.

Though the lives of individual species differ, a typical pollinating fig wasp life cycle is as follows. At the beginning of the cycle, a mated mature female pollinator wasp enters the immature "fruit" (actually a stem-like structure known as a [[syconium]]) through a small natural opening (the [[ostiole]]) and [[oviposition|deposits]] her eggs in the cavity. 

Forcing her way through the ostiole, the mated mature female often loses her wings and most of her [[Antenna (biology)|antennae]]. To facilitate her passage through the ostiole, the underside of the female's head is covered with short spines that provide purchase on the walls of the ostiole. 

In depositing her eggs, the female also deposits pollen she picked up from her original host fig. This pollinates some of the female flowers on the inside surface of the fig and allows them to mature. After the female wasp lays her eggs and follows through with pollination, she dies.

After pollination, there are several species of non-pollinating wasps that deposit their eggs before the figs harden. These wasps act as parasites to either the fig or possibly the pollinating wasps. 

As the fig develops, the wasp eggs hatch and develop into [[larva]]e. After going through the pupal stage, the mature male’s first act is to mate with a female - before the female hatches. Consequently, the female will emerge pregnant. The males of many species lack wings and cannot survive outside the fig for a sustained period of time. After mating, a male wasp begins to dig out of the fig, creating a tunnel through which the females escape.

Once out of the fig, the male wasps quickly die. The females find their way out, picking up pollen as they do. They then fly to another tree of the same species, where they deposit their eggs and allow the cycle to begin again.

== Coevolution ==
{{main article|Reproductive coevolution in Ficus}}

The fig–wasp [[Mutualism (biology)|mutualism]] originated between 70 and 90 million years ago as the product of a unique evolutionary event.<ref>{{Harvnb|Machado|Jousselin|Kjellberg|Compton|2001}}</ref><ref name="Cook-Rasplus">{{Harvnb|Cook|Rasplus|2003}}</ref><ref name="Herre-etal-2008">Herre et al. (2008)</ref> Since then, [[reproductive coevolution in Ficus|cocladogenesis and coadaptation on a coarse scale between wasp genera and fig sections]] have been demonstrated by both morphological and molecular studies.<ref name="Herre-etal-2008" /><ref>{{Harvnb|Molbo|Machado|Sevenster|Keller|2003}}</ref> This illustrates the tendency towards coradiation of figs and wasps.<ref name="Herre-etal-2008" /> Such strict cospeciation should result in identical [[phylogenetic tree]]s for the two lineages<ref name="Cook-Rasplus" /> and recent work mapping fig sections onto molecular phylogenies of wasp genera and performing statistical comparisons has provided strong evidence for cospeciation at that scale.<ref name="Cook-Rasplus" />

Groups of genetically well-defined pollinator wasp species [[coevolution|coevolve]] in association with groups of genetically poorly defined figs.<ref name="Machado-etal-2005">Machado C.A., Robbins N., Gilbert M.T.P., Herre E.A. Critical review of host specificity and this coevolutionary implications in the fig/fig-wasp mutualism. (2005). ''Proc. Of the National Acad. Of Sci. of the U.S.A''.102(1), 6558-6565. doi: 10.1073/pnas.0501840102</ref> The constant hybridization of the figs promotes the constant evolution of new pollinator wasp species. [[Host switch]]ing and pollinator host sharing may contribute to the incredible diversity of figs and fig wasp species like ''[[Pegoscapus]]'' as they result in hybridization and introgression''.''<ref name="Machado-etal-2005" />

==Genera==
Fig wasps genera and classification according to the various publications:<ref name="Cruaud-etal-2010"/><ref name="Heraty-etal-2013"/><ref>{{Harvnb|Cruaud|Jabbour-Zahab|Genson|Kjellberg|2011}}</ref><ref name=BurksEtAl>{{Cite Q|Q115923766|doi-access=free}}</ref>
{{div col|colwidth=25em}}
*'''[[Agaonidae]]'''
**[[Agaoninae]]
***''[[Agaon]]''
***''[[Alfonsiella]]''
***''[[Allotriozoon]]''
***''[[Blastophaga]]''
****''[[Blastophaga psenes]]''
***''[[Courtella]]''
***''[[Deilagaon]]''
***''[[Dolichoris]]''
***''[[Elisabethiella]]''
***''[[Eupristina]]''
***''[[Nigeriella]]''
***''[[Paragaon]]''
***''[[Pegoscapus]]''
***''[[Platyscapa]]''
***''[[Pleistodontes]]''
***''[[Waterstoniella]]''
***''[[Wiebesia]]''
**[[Kradibiinae]]
***''[[Ceratosolen]]''
***''[[Kradibia]]''
**[[Tetrapusiinae]]
***''[[Tetrapus]]''
*[[Epichrysomallidae]]
**''[[Acophila]]''
**''[[Asycobia]]''
**''[[Camarothorax]]''
**''[[Epichrysomalla]]''
**''[[Eufroggattia]]''
**''[[Herodotia (wasp)|Herodotia]]''
**''[[Lachaisea]]''
**''[[Meselatus]]''
**''[[Neosycophila]]''
**''[[Odontofroggatia]]''
**''[[Parapilkhanivora]]''
**''[[Sycobia]]''
**''[[Sycobiomorphella]]''
**''[[Sycomacophila]]''
**''[[Sycophilodes]]''
**''[[Sycophilomorpha]]''
**''[[Sycotetra]]''
*'''[[Pteromalidae]]'''
**[[Colotrechinae]]
***''[[Podvina]]''
**[[Pteromalinae]]
***''[[Adiyodiella]]''
***''[[Apocrypta]]''
***''[[Arachonia]]''
***''[[Bouceka]]''
***''[[Comptoniella]]''
***''[[Critogaster]]''
***''[[Crossogaster]]''
***''[[Diaziella]]''
***''[[Dobunabaa]]''
***''[[Eujacobsonia]]''
***''[[Ficicola]]''
***''[[Gaudalia]]''
***''[[Grandiana]]''
***''[[Grasseiana]]''
***''[[Hansonita]]''
***''[[Lipothymus]]''
***''[[Marginalia (wasp)|Marginalia]]''
***''[[Micranisa]]''
***''[[Micrognathophora]]''
***''[[Otitesella]]''
***''[[Parasycobia]]''
***''[[Philocaenus]]''
***''[[Philosycus]]''
***''[[Philosycella]]''
***''[[Philotrypesis]]''
***''[[Philoverdance]]''
***''[[Robertsia]]''
***''[[Seres (wasp)|Seres]]''
***''[[Sycoecus]]''
***''[[Sycoscapter]]''
***''[[Walkerella]]''
***''[[Watshamiella]]''
**[[Sycophaginae]]
***''[[Anidarnes]]''
***''[[Eukoebelea]]''
***''[[Idarnes]]''
***''[[Pseudidarnes]]''
***''[[Sycophaga]]''
*'''[[Ormyridae]]'''
***''[[Ormyrus]]''
*'''[[Eurytomidae]]'''
***''[[Bruchophagus]]''
***''[[Eurytoma]]''
***''[[Ficomila]]''
***''[[Syceurytoma]]''
***''[[Sycophila]]''
*'''[[Torymidae]]'''
***''[[Megastigmus]]''
***''[[Physothorax]]''
***''[[Torymus]]''
{{div col end}}

== Museum collections ==
One of the world's major fig wasp collections resides in [[Leeds Museums & Galleries|Leeds Museums and Galleries]]' [[Leeds Discovery Centre|Discovery Centre]],<ref>{{Cite web|title=Natural Science – Leeds Museums and Galleries|url=https://museumsandgalleries.leeds.gov.uk/about-us/collections/natural-science/|access-date=19 August 2020|website=Leeds Museums and Galleries}}</ref> and was collected by Dr. Steve Compton.<ref>{{Cite web|last=Compton|first=Steve|title=Dr Steve Compton|url=https://biologicalsciences.leeds.ac.uk/school-of-biology/staff/49/dr-steve-compton|access-date=19 August 2020}}</ref><ref>{{Cite journal|last=Compton|first=S|title=Host-parasitoid relationships within figs of an invasive fig tree: a fig wasp community structured by gall size|journal=Insect Conservation and Diversity|year=2018|volume=11|issue=4|pages=341–351|doi=10.1111/icad.12282|s2cid=89701549|url=http://eprints.whiterose.ac.uk/139055/1/Host-parasitoid%20relationships%20within%20figs%20of%20an%20invasive%20fig%20tree.pdf}}</ref>

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==Further reading==
*{{cite magazine |last1=Crair |first1=Ben |title=Love the Fig - Annals of Technology |url=https://www.newyorker.com/tech/annals-of-technology/love-the-fig <!-- |access-date=8 June 2023 --> |magazine=[[The New Yorker]] |date=10 August 2016}}
*{{cite book |last1=Shanahan |first1=Mike |title=Gods, Wasps and Stranglers: The Secret History and Redemptive Future of Fig Trees |date=1 November 2016 |publisher=Chelsea Green Publishing |isbn=978-1-60358-715-0}}
*{{cite journal |last1=Janzen |first1=Daniel H. |title=How to be a Fig |journal=[[Annual Review of Ecology and Systematics]] |date=November 1979 |volume=10 |issue=1 |pages=13–51 |doi=10.1146/annurev.es.10.110179.000305 |url=http://fission.sas.upenn.edu/caterpillar/index.php?action=retrieve&article=Janzen%2C1979figs.pdf |access-date=8 June 2023 |jstor=2096784 |bibcode=1979AnRES..10...13J |quote= researchgate/234150391}}

== External links ==
{{Commons|Fig wasp|Fig wasp}}
* [http://morphbank.net/Browse/ByImage/index.php?keywords=&tsnKeywords=agaonidae&spKeywords=&viewKeywords=whole+body&localityKeywords=&listField1=imageId&orderAsc1=DESC&listField2=&orderAsc2=ASC&listField3=&orderAsc3=ASC&numPerPage=20&goTo=&resetOffset=&activeSubmit=2 Images of fig wasps on Morphbank, a biological image database]

{{Hymenoptera|2}}

[[Category:Agaonidae]]
[[Category:Chalcidoidea]]
[[Category:Insect common names]]