Dioecy

{{Short description|Having distinct male and female organisms}} {{use dmy dates|date=December 2025}} {{Distinguish|Dioicy}}

'''Dioecy''' ({{etymology|grc|''{{wikt-lang|grc|διοικία}}'' ({{grc-transl|διοικία}})|two households}}; adj. '''dioecious''') is a characteristic of species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). '''Dioecious reproduction''' is biparental reproduction. Dioecy has costs, since only the females directly produce offspring. It is a way to prevent self-fertilization and promote allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations. Plants have several other ways to prevent self-fertilization including, for example, dichogamy, herkogamy, and self-incompatibility.

==In zoology== [[File:Physalia.jpg|thumb|''Physalia physalis'', Portuguese man o' war, is a dioecious colonial marine animal; the reproductive medusae within the colony are all of the same sex.<ref>{{cite web |url=http://animaldiversity.ummz.umich.edu/accounts/Physalia_physalis/ |website=Animal Diversity Web |access-date=7 August 2025|last=Kurlansky|first=Mindy B.|year=2002|title=''Physalia physalis''}}</ref>]] {{Further|Gonochorism}}

In zoology, dioecy means that an animal is either male or female, in which case the synonym gonochory is more often used.<ref name="Kliman-2016" /> Most animal species are gonochoric, almost all vertebrate species are gonochoric, and all bird and mammal species are gonochoric.<ref>{{cite journal|author=David, J.R.|year=2001|title=Evolution and development: some insights from evolutionary theory|journal=Anais da Academia Brasileira de Ciências|volume=73|issue=3|pages=385–395|doi=10.1590/s0001-37652001000300008|pmid=11600899|doi-access=free}}</ref> Dioecy may also describe colonies within an animal species, such as the colonies of Siphonophorae (Portuguese man-of-war), which may be either dioecious or monoecious.<ref>{{cite journal |author-last1=Dunn|author-first1= C.W. |author-last2=Pugh|author-first2= P.R. |author-last3=Haddock|author-first3= S.H.D. |author3-link=Steven Haddock |year=2005 |title=Molecular Phylogenetics of the Siphonophora (Cnidaria), with Implications for the Evolution of Functional Specialization |journal=Systematic Biology |volume=54 |issue=6 |pages=916–935 |doi=10.1080/10635150500354837 |pmid=16338764|doi-access= }}</ref>

==In botany== Land plants (embryophytes) differ from animals in that their life cycle involves alternation of generations. In animals, typically an individual produces gametes of one kind, either sperm or egg cells. The gametes have half the number of chromosomes of the individual producing them, so are haploid. Without further dividing, a sperm and an egg cell fuse to form a zygote that develops into a new individual. In land plants, by contrast, one generation – the sporophyte generation – consists of individuals that produce haploid spores rather than haploid gametes. Spores do not fuse, but germinate by dividing repeatedly by mitosis to give rise to haploid multicellular individuals, the gametophytes, which produce gametes. A male gamete and a female gamete then fuse to produce a new diploid sporophyte.{{sfnp|Mauseth|2014|pp=204–205}}

thumb|right|upright=1.3|Alternation of generations in plants: the sporophyte generation produces spores that give rise to the gametophyte generation, which produces gametes that fuse to give rise to a new sporophyte generation.

In bryophytes (mosses, liverworts and hornworts), the gametophytes are fully independent plants.{{sfnp|Mauseth|2014|p=487}} Seed plant gametophytes are dependent on the sporophyte and develop within the spores, a condition known as endospory. In flowering plants, the male gametophytes develop within pollen grains produced by the sporophyte's stamens, and the female gametophytes develop within ovules produced by the sporophyte's carpels.{{sfnp|Mauseth|2014|pp=204–205}}

The sporophyte generation of a seed plant is called "monoecious" when each sporophyte plant has both kinds of spore-producing organ but in separate flowers or cones. For example, a single flowering plant of a monoecious species has both functional stamens and carpels, in separate flowers.{{sfnp|Mauseth|2014|p=218}}

The sporophyte generation of seed plants is called ''dioecious'' when each sporophyte plant has only one kind of spore-producing organ, all of whose spores give rise either to male gametophytes, which produce only male gametes (sperm), or to female gametophytes, which produce only female gametes (egg cells). For example, a single flowering plant sporophyte of a fully dioecious species like holly has either flowers with functional stamens producing pollen containing male gametes (staminate or 'male' flowers), or flowers with functional carpels producing female gametes (carpellate or 'female' flowers), but not both.{{sfnp|Mauseth|2014|p=218}}<ref name="Hickey-2001">{{Cite book |last1=Hickey |first1=M. |last2=King |first2=C. |year=2001 |title=The Cambridge Illustrated Glossary of Botanical Terms |publisher=Cambridge University Press |name-list-style=amp}}</ref> There are other, more complex reproductive schemes such as gynodioecy and androdioecy.

Slightly different terms, ''dioicous'' and ''monoicous'', may be used for the gametophyte generation of non-vascular plants, although ''dioecious'' and ''monoecious'' are also used.<ref name="Lepp-2007">{{Cite web |last1=Lepp |first1=Heino |date=2007 |title=Case studies : -oicy: Dioicous, dioecious, monoicous and monoecious |website=Australian Bryophytes |publisher=Australian National Botanic Gardens and Australian National Herbarium |url=https://www.anbg.gov.au/bryophyte/case-studies/-oicy.html |access-date=2021-06-21 }}</ref><ref>{{cite book|author=Stearn, W.T.|year=1992|title=Botanical Latin: History, grammar, syntax, terminology and vocabulary, Fourth edition|publisher=David and Charles}}</ref> A dioicous gametophyte either produces only male gametes (sperm) or produces only female gametes (egg cells). About 60% of liverworts are dioicous.<ref name="Vanderpoorten-2009">{{cite book |vauthors=Vanderpoorten A, Goffinet B |date=2009 |title=Introduction to bryophytes |chapter=Liverworts |publisher=Cambridge University Press |location=Cambridge, UK |isbn=978-0-521-70073-3 }}</ref>{{rp|52}}

Dioecy occurs in a wide variety of plant groups. Examples of dioecious plant species include willows, cannabis and African teak. As its specific name implies, the perennial stinging nettle ''Urtica dioica'' is dioecious,<ref name="Stace-2019">{{cite book|last=Stace|first=C. A.|author-link = Stace, C. A.|year=2019|title=New Flora of the British Isles|edition=Fourth|publisher=C & M Floristics|location = Middlewood Green, Suffolk, U.K.| isbn=978-1-5272-2630-2}}</ref>{{rp|305}} while the annual nettle ''Urtica urens'' is monoecious.<ref name="Stace-2019"/>{{rp|305}} Dioecious flora are predominant in tropical environments.<ref>{{Cite book|last1=Tandon|first1=Rajesh|url=https://books.google.com/books?id=WED2DwAAQBAJ&q=dioecy+tropical+climates&pg=PA179|title=Reproductive Ecology of Flowering Plants: Patterns and Processes|last2=Shivanna|first2=K. R.|last3=Koul|first3=Monika|date=2020-08-07|publisher=Springer Nature|isbn=978-981-15-4210-7|page=179|language=en}}</ref>

About 65% of gymnosperm species are dioecious,<ref>{{Cite journal|date=2018-09-01|title=Sexual systems in gymnosperms: A review|url=https://www.sciencedirect.com/science/article/abs/pii/S1439179117304498|journal=Basic and Applied Ecology|language=en|volume=31|pages=1–9|doi=10.1016/j.baae.2018.05.009|issn=1439-1791|last1=Walas|first1=Łukasz|last2=Mandryk|first2=Wojciech|last3=Thomas|first3=Peter A.|last4=Tyrała-Wierucka|first4=Żanna|last5=Iszkuło|first5=Grzegorz|bibcode=2018BApEc..31....1W |s2cid=90740232|url-access=subscription}}</ref> including ginkgo, all cycads and gnetophytes, most yews, podocarps, and araucarias, and many junipers, but almost all other conifers are monoecious.<ref name="Walas-2018">{{cite journal| vauthors = Walas Ł, Mandryk W, Thomas PA, Tyrała-Wierucka Ż, Iszkuło G |date=2018|title=Sexual systems in gymnosperms: A review|journal=Basic and Applied Ecology|volume=31|pages=1–9|doi=10.1016/j.baae.2018.05.009|bibcode=2018BApEc..31....1W |s2cid=90740232|url=http://eprints.keele.ac.uk/4961/1/29052018_1-s2.0-S1439179117304498-main.pdf}}</ref><ref name=DJ>Dallimore, W., & Jackson, A. B. (1966). ''A Handbook of Coniferae and Ginkgoaceae'' 4th ed. Arnold.</ref> In some species, the situation is mixed; e.g. in ''Araucaria araucana'' and ''Pinus johannis'' most individuals are single-sex, but occasional individuals are monoecious, producing cones of both sexes.<ref name=DJ/><ref name="Mitchell">{{cite book | last1=Mitchell | first1=Alan F. | last2=Mitchell | first2=Alan | title=Alan Mitchell's Trees of Britain | publisher=Whitman Publishing & Distribution Company | date=1996 | isbn=0-00-219972-6 | pages=(34–)36}}</ref><ref>{{cite journal|doi=10.3732/ajb.1200068|title=Sexual stability in the nearly dioecious ''Pinus johannis'' (Pinaceae)|year=2013|last1=Flores-Rentería|first1=Lluvia|last2=Molina-Freaner|first2=Francisco|last3=Whipple|first3=Amy V.|last4=Gehring|first4=Catherine A.|last5=Domínguez|first5=C. A.|journal=American Journal of Botany|volume=100|issue=3|pages=602–612|pmid=23445824}}</ref> In gymnosperms, dioecy and monoecy are strongly correlated with the mode of seed dispersal; monoecious species are mostly wind dispersed (anemophily) and dioecious species animal-dispersed (zoophily).<ref name=Givnish>{{cite journal |author-last1=Givnish|author-first1= TJ |date=1980 |title=Ecological constraints on the evolution of breeding systems in seed plants: dioecy and dispersal in gymnosperms |journal=Evolution |volume=34 |issue=5 |pages=959–972 |doi=10.1111/j.1558-5646.1980.tb04034.x |pmid=28581147 |bibcode=1980Evolu..34..959G |doi-access=free }}</ref>

About 6% of Angiosperm species are entirely dioecious and about 7% of angiosperm genera contain some dioecious species.<ref name="Renner-1995">{{cite journal|author-last1=Renner|author-first1= S. S. |author-link=Susanne Renner|author-first2=R. E. |author-last2=Ricklefs|year=1995|title=Dioecy and its correlates in the flowering plants|journal=American Journal of Botany|volume=82|issue=5|pages=596–606|doi=10.2307/2445418|jstor=2445418|url=https://epub.ub.uni-muenchen.de/14619/}}</ref> Dioecy is more common in woody plants,<ref>{{citation |author-last1=Matallana|author-first1= G. |author-last2=Wendt|author-first2= T. |author-last3=Araujo|author-first3= D.S.D. |author-last4=Scarano|author-first4= F.R. |year=2005 |title=High abundance of dioecious plants in a tropical coastal vegetation |journal=American Journal of Botany |volume=92 |issue=9 |pages=1513–1519 |doi=10.3732/ajb.92.9.1513 |pmid=21646169 }}</ref> and heterotrophic species.<ref>{{cite journal | author-last1 = Nickrent |author-first1=D.L. |author-last2=Musselman |author-first2=L.J. | year = 2004 | title = Introduction to Parasitic Flowering Plants | url = http://www.apsnet.org/edcenter/intropp/pathogengroups/pages/parasiticplants.aspx | journal = The Plant Health Instructor | doi = 10.1094/PHI-I-2004-0330-01 | access-date = 2017-01-10 | archive-url = https://web.archive.org/web/20161005194620/http://www.apsnet.org/edcenter/intropp/pathogengroups/pages/parasiticplants.aspx | archive-date = 2016-10-05 | url-access = subscription }}</ref> In most dioecious plants, whether male or female gametophytes are produced is determined genetically, but in some cases it can be determined by the environment, as in ''Arisaema'' species.<ref>{{Cite book|last1=Fusco|first1=Giuseppe|url=https://books.google.com/books?id=AKGsDwAAQBAJ&q=gonochorism+sex+determination|title=The Biology of Reproduction|last2=Minelli|first2=Alessandro|date=2019-10-10|publisher=Cambridge University Press|isbn=978-1-108-49985-9|page=329|language=en}}</ref> In the largely monoecious order Fagales, a few species are dioecious or largely so, but with variation; the shrub ''Myrica gale'' is typically dioecious but some individuals are monoecious, and others have been known to change sex from one year to another.<ref name="Blamey">{{cite book | last1=Blamey | first1=Marjorie | last2=Grey-Wilson | first2=C. | title=The Illustrated Flora of Britain and Northern Europe | publisher=Lubrecht & Cramer Limited | publication-place=London | date=1989-01-01 | isbn=0-340-40170-2 | page=52}}</ref><ref name="Streeter">{{cite book | last=Streeter | first=David | title=Flower Guide | publisher=Collins | publication-place=London | date=2010 | isbn=978-0-00-718389-0 | page=98}}</ref>

<gallery mode=packed heights=160px> Ilex aquifolium male HC1.JPG|In dioecious holly, some plants only have 'male' flowers with stamens producing pollen. Ilex aquifolium female HC1.JPG|Other holly plants only have 'female' flowers that produce ovules. Tulip Tulipa clusiana 'Lady Jane' Rock Ledge Flower 2000px.jpg|Each bisexual (perfect) tulip flower has both stamens and carpels. </gallery>

Certain algae, such as some species of ''Polysiphonia'', are dioecious.<ref>Maggs, C.A. and Hommersand, M.H. 1993. ''Seaweeds of the British Isles Volume 1 Rhodophyta Part 3A Ceramiales''. The Natural History Museum, London. {{ISBN|0-11-310045-0}}</ref> Dioecy is prevalent in the brown algae (Phaeophyceae) and may have been the ancestral state in that group.<ref name="Luthringer-2014">{{cite journal |vauthors=LuthringerR, Cormier A, Ahmed S, Peters AF, Cock JM, Coelho, SM |title=Sexual dimorphism in the brown algae |journal=Perspectives in Phycology |volume=1 |date=2014 |issue=1 |pages=11–25 |doi=10.1127/2198-011X/2014/0002 }}</ref>

=== Evolution of dioecy === {{For|evolution in animals|Gonochorism#Evolution}} In plants, dioecy has evolved independently multiple times<ref>{{Cite journal |last1=Bachtrog |first1=Doris |last2=Mank |first2=Judith E. |last3=Peichel |first3=Catherine L. |last4=Kirkpatrick |first4=Mark |last5=Otto |first5=Sarah P. |last6=Ashman |first6=Tia-Lynn |last7=Hahn |first7=Matthew W. |last8=Kitano |first8=Jun |last9=Mayrose |first9=Itay |last10=Ming |first10=Ray |last11=Perrin |first11=Nicolas |date=2014-07-01 |title=Sex Determination: Why So Many Ways of Doing It? |journal=PLOS Biology |volume=12 |issue=7 |article-number=e1001899 |doi=10.1371/journal.pbio.1001899 |issn=1544-9173 |pmc=4077654 |pmid=24983465 |doi-access=free }}</ref> either from hermaphroditic species or from monoecious species. A previously untested hypothesis is that this reduces inbreeding;<ref>{{Cite journal |last1=Sarkar |first1=Sutanu |last2=Banerjee |first2=Joydeep |last3=Gantait |first3=Saikat|date=2017-05-29 |title=Sex-oriented research on dioecious crops of Indian subcontinent: an updated review|journal=3 Biotech|language=en|volume=7|issue=2|page=93|doi=10.1007/s13205-017-0723-8|issn=2190-5738|pmc=5447520|pmid=28555429}}</ref> dioecy has been shown to be associated with increased genetic diversity and greater protection against deleterious mutations.<ref name="Muyle-2021">{{Cite journal |last1=Muyle|first1=Aline|last2=Martin |first2=Hélène|last3=Zemp|first3=Niklaus|last4=Mollion|first4=Maéva |last5=Gallina|first5=Sophie|last6=Tavares|first6=Raquel |last7=Silva|first7=Alexandre|last8=Bataillon|first8=Thomas|last9=Widmer |first9=Alex|last10=Glémin|first10=Sylvain |last11=Touzet|first11=Pascal |date=2021-03-01 |title=Dioecy Is Associated with High Genetic Diversity and Adaptation Rates in the Plant Genus Silene|journal=Molecular Biology and Evolution |volume=38 |issue=3 |pages=805–818|doi=10.1093/molbev/msaa229|issn=0737-4038|pmc=7947750|pmid=32926156}}</ref> Regardless of the evolutionary pathway, the intermediate states need to have fitness advantages compared to monoecy.<ref>{{Cite book|last=Cruzan|first=Mitchell B.|url=https://books.google.com/books?id=nzRtDwAAQBAJ&q=Dioicy+sexual+system&pg=PA377|title=Evolutionary Biology: A Plant Perspective|date=2018-09-11|publisher=Oxford University Press|isbn=978-0-19-088268-6|page=377|language=en}}</ref>

Dioecy evolves due to male or female sterility,<ref>{{Cite book|last1=Atwell|first1=Brian James|url=https://books.google.com/books?id=chWs4ewSzpEC&q=all+botanists+agree+dioecy&pg=PT49|title=Plants in Action: Adaptation in Nature, Performance in Cultivation|last2=Kriedemann|first2=Paul E.|last3=Turnbull|first3=Colin G. N.|date=1999|publisher=Macmillan Education AU|isbn=978-0-7329-4439-1|page=249|language=en}}</ref> though it is unlikely that mutations for male and female sterility occurred at the same time.<ref>{{Cite book|last=Karasawa|first=Marines Marli Gniech|url=https://books.google.com/books?id=prsDCwAAQBAJ&q=evolution+Monoecy|title=Reproductive Diversity of Plants: An Evolutionary Perspective and Genetic Basis|date=2015-11-23|publisher=Springer|isbn=978-3-319-21254-8|page=31|language=en}}</ref> In angiosperms unisexual flowers evolve from bisexual ones.<ref>{{Cite book|last1=Núñez-Farfán|first1=Juan|url=https://books.google.com/books?id=iF70DwAAQBAJ&q=dioecy+consensus&pg=PA177|title=Evolutionary Ecology of Plant-Herbivore Interaction|last2=Valverde|first2=Pedro Luis|date=2020-07-30|publisher=Springer Nature|isbn=978-3-030-46012-9|page=177|language=en}}</ref> Dioecy occurs in almost half of plant families, but only in a minority of genera, suggesting recent evolution.<ref>{{Cite book|last=Reeve|first=Eric C. R.|url=https://books.google.com/books?id=PuCYAgAAQBAJ&q=evolution+of+dioecy&pg=PA616|title=Encyclopedia of Genetics|date=2014-01-14|publisher=Routledge|isbn=978-1-134-26350-9|page=616|language=en}}</ref> For 160 families that have dioecious species, dioecy is thought to have evolved more than 100 times.<ref>{{Cite journal|last=Ainsworth|first=Charles|date=2000-08-01|title=Boys and Girls Come Out to Play: The Molecular Biology of Dioecious Plants|journal=Annals of Botany|volume=86|issue=2|pages=211–221|doi=10.1006/anbo.2000.1201|bibcode=2000AnBot..86..211A |s2cid=85039623 |issn=0305-7364|doi-access=free}}</ref>

In the family Caricaceae, dioecy is likely the ancestral system.<ref>{{Cite book|last=Mitra|first=Sisir|url=https://books.google.com/books?id=7zX8DwAAQBAJ&dq=trioecy&pg=PA161|title=The Papaya: Botany, Production and Uses|date=2020-09-01|publisher=CABI|isbn=978-1-78924-190-7|page=161|language=en}}</ref>

==== From monoecy ==== Dioecious flowering plants can evolve from monoecious ancestors that had flowers containing both functional stamens and functional carpels.<ref name="Bawa-1980" /> Some authors argue monoecy and dioecy are related.<ref name="Batygina-2019">{{Cite book|last=Batygina|first=T. B.|url=https://books.google.com/books?id=4VOWDwAAQBAJ&q=monoecy&pg=PA43|title=Embryology of Flowering Plants: Terminology and Concepts, Vol. 3: Reproductive Systems|date=2019-04-23|publisher=CRC Press|isbn=978-1-4398-4436-6|page=43|language=en}}</ref>

In the genus ''Sagittaria'', since there is a distribution of sexual systems, it has been postulated that dioecy evolved from monoecy<ref>{{Cite book|last1=Wilson|first1=Karen L.|url=https://books.google.com/books?id=YzQBUQqLS0YC&q=Monoecy&pg=PA264|title=Monocots: Systematics and Evolution: Systematics and Evolution|last2=Morrison|first2=David A.|date=2000-05-19|publisher=Csiro Publishing|isbn=978-0-643-09929-6|page=264|language=en}}</ref> through gynodioecy mainly from mutations that resulted in male sterility.<ref name="EEB-2016">{{Cite book|url=https://books.google.com/books?id=_r4OCAAAQBAJ&q=evolution+of+Monoecy&pg=RA1-PA478|title=Encyclopedia of Evolutionary Biology|date=2016-04-14|publisher=Academic Press|isbn=978-0-12-800426-5|volume=2|language=en}}</ref>{{rp|478}} However, since the ancestral state is unclear, more work is needed to clarify the evolution of dioecy via monoecy.<ref name="EEB-2016" />{{rp|478}}

==== From hermaphroditism ==== Dioecy usually evolves from hermaphroditism through gynodioecy but may also evolve through androdioecy,<ref>{{Cite journal|last1=Perry|first1=Laura E.|last2=Pannell|first2=John R.|last3=Dorken|first3=Marcel E.|date=2012-04-19|title=Two's Company, Three's a Crowd: Experimental Evaluation of the Evolutionary Maintenance of Trioecy in Mercurialis annua (Euphorbiaceae)|journal=PLOS ONE|language=en|volume=7|issue=4|article-number=e35597|doi=10.1371/journal.pone.0035597|issn=1932-6203|pmc=3330815|pmid=22532862|bibcode=2012PLoSO...735597P |doi-access=free}}</ref> through distyly<ref>{{Cite book|last=Leonard|first=Janet L.|url=https://books.google.com/books?id=0rWZDwAAQBAJ&q=evolution+of+Monoecy&pg=PA91|title=Transitions Between Sexual Systems: Understanding the Mechanisms of, and Pathways Between, Dioecy, Hermaphroditism and Other Sexual Systems|date=2019-05-21|publisher=Springer|isbn=978-3-319-94139-4|page=91|language=en}}</ref> or through heterostyly.<ref name="Muyle-2021"/> In the Asteraceae, dioecy may have evolved independently from hermaphroditism at least 5 or 9 times. The reverse transition, from dioecy back to hermaphroditism has also been observed, both in Asteraceae and in bryophytes, with a frequency about half of that for the forward transition.<ref name="Landry-2013">{{Cite book|last1=Landry|first1=Christian R.|url=https://books.google.com/books?id=WATFBAAAQBAJ&q=Asteraceae+dioecy&pg=PA9|title=Ecological Genomics: Ecology and the Evolution of Genes and Genomes|last2=Aubin-Horth|first2=Nadia|date=2013-11-25|publisher=Springer Science & Business Media|isbn=978-94-007-7347-9|page=9|language=en}}</ref>

In ''Silene'', since there is no monoecy, it is suggested that dioecy evolved through gynodioecy.<ref>{{Cite journal|last1=Casimiro-Soriguer|first1=Inés|last2=Buide|first2=Maria L.|last3=Narbona|first3=Eduardo|date=2015-01-01|title=Diversity of sexual systems within different lineages of the genus Silene|journal=AoB Plants|volume=7|article-number=plv037|doi=10.1093/aobpla/plv037|pmid=25862920|issn=2041-2851|pmc=4433491}}</ref>

==In mycology== {{One source section|date=June 2021}} Very few dioecious fungi have been discovered.<ref>{{Cite book|last=Gupta|first=Rajni|url=https://books.google.com/books?id=uPCATfIDZBoC&q=dioecy+in+fungi&pg=PA77|title=A Textbook of Fungi|publisher=APH Publishing|isbn=978-81-7648-737-5|page=77|language=en}}</ref>

Monoecy and dioecy in fungi refer to the donor and recipient roles in mating, where a nucleus is transferred from one haploid hypha to another, and the two nuclei then present in the same cell merge by karyogamy to form a zygote.<ref name="Esser-1971">{{cite journal |author=Esser, K. |year=1971 |title=Breeding systems in fungi and their significance for genetic recombination |journal=Molecular and General Genetics |volume=110 |issue=1 |pages=86–100 |doi=10.1007/bf00276051|pmid=5102399 |s2cid=11353336 }}</ref> The definition avoids reference to male and female reproductive structures, which are rare in fungi.<ref name="Esser-1971" /> An individual of a dioecious fungal species not only requires a partner for mating, but performs only one of the roles in nuclear transfer, as either the donor or the recipient. A monoecious fungal species can perform both roles, but may not be self-compatible.<ref name="Esser-1971" />

==Adaptive benefit== Dioecy has a disadvantage compared with monoecy: only about half of adults produce offspring. Dioecious species must therefore have fitness advantages to compensate for this cost through increased survival, growth, or reproduction. Dioecy excludes self-fertilization and promotes allogamy (outcrossing), and thus tends to reduce the expression of recessive deleterious mutations present in a population.<ref name="Charlesworth-2009">{{cite journal |vauthors=Charlesworth D, Willis JH |title=The genetics of inbreeding depression |journal=Nat. Rev. Genet. |volume=10 |issue=11 |pages=783–96 |year=2009 |pmid=19834483 |doi=10.1038/nrg2664 |s2cid=771357 }}</ref> In trees, compensation is realized mainly through increased seed production by females. This in turn is facilitated by a lower contribution of reproduction to population growth, which results in no demonstrable net costs of having males in the population compared to being hermaphroditic.<ref name="Bruijning-2017">{{cite journal |last1=Bruijning |first1=Marjolein |last2=Visser |first2=Marco D. |last3=Muller-Landau |first3=Helene C. |last4=Wright |first4=S. Joseph |last5=Comita |first5=Liza S. |last6=Hubbell |first6=Stephen P. |last7=de Kroon |first7=Hans |last8=Jongejans |first8=Eelke |title=Surviving in a Cosexual World: A Cost-Benefit Analysis of Dioecy in Tropical Trees |journal=The American Naturalist |volume=189 |issue=3 |year=2017 |pages=297–314 |issn=0003-0147 |doi=10.1086/690137|pmid=28221824 |bibcode=2017ANat..189..297B |hdl=2066/168955 |s2cid=6839285 |hdl-access=free }}</ref> Dioecy may also accelerate or retard lineage diversification in angiosperms. Dioecious lineages are more diversified in certain genera, but less in others. An analysis suggested that dioecy neither consistently places a strong brake on diversification, nor strongly drives it.<ref name="Sabath-2016">{{cite journal |last1=Sabath |first1=Niv |last2=Goldberg |first2=Emma E. |last3=Glick |first3=Lior |last4=Einhorn |first4=Moshe |last5=Ashman |first5=Tia-Lynn |last6=Ming |first6=Ray |last7=Otto |first7=Sarah P. |last8=Vamosi |first8=Jana C. |last9=Mayrose |first9=Itay |title=Dioecy does not consistently accelerate or slow lineage diversification across multiple genera of angiosperms |journal=New Phytologist |volume=209 |issue=3 |year=2016 |pages=1290–1300 |doi=10.1111/nph.13696|pmid=26467174 |bibcode=2016NewPh.209.1290S |doi-access=free }}</ref>

== References == <references> <ref name="Kliman-2016">{{cite book |last=Kliman |first=Richard |date=2016 |title=Encyclopedia of Evolutionary Biology |page=212 |publisher=Academic Press |isbn=978-0-12-800426-5 |url=https://books.google.com/books?id=_r4OCAAAQBAJ |archive-url=https://web.archive.org/web/20210506205920/https://www.google.com/books/edition/Encyclopedia_of_Evolutionary_Biology/_r4OCAAAQBAJ?hl=en&gbpv=0&kptab=overview |archive-date=6 May 2021}} [https://archive.org/details/encyclopediaofevolutionarybiology Alternative archive URL]</ref>

<ref name="Bawa-1980">{{cite journal|title=Evolution of Dioecy in Flowering Plants|author=K. S. Bawa |journal=Annual Review of Ecology and Systematics|volume=11|year=1980 |issue=1 |pages=15–39 |doi=10.1146/annurev.es.11.110180.000311|jstor = 2096901 |bibcode=1980AnRES..11...15B }}</ref> </references>

==Bibliography== *{{Cite book |last=Beentje |first=Henk |year=2010 |title=The Kew Plant Glossary |publication-place=Richmond, Surrey |publisher=Royal Botanic Gardens, Kew |isbn=978-1-84246-422-9 }} *{{Cite book |last=Mauseth |first=James D. |title=Botany: An Introduction to Plant Biology |edition=5th |year=2014 |isbn=978-1-4496-6580-7 |publisher=Jones and Bartlett Learning |location=Sudbury, MA}}

Category:Plant sexuality * Category:Sexual reproduction Category:Reproductive system Category:Sexual system