mating plug
{{Short description|Gelatinous secretion used in the mating of some species}}
{{use dmy dates|date=September 2024}}
Image:Mating plug.jpg (Urocitellus richardsonii)]]
A mating plug, also known as a copulation plug,{{Cite book |last=Feldhamer |first=George A. |url=https://books.google.com/books?id=udCnKce9hfoC&pg=PA194 |title=Mammalogy: Adaptation, Diversity, Ecology |date=2007-09-07 |publisher=JHU Press |isbn=978-0-8018-8695-9 |language=en}} vaginal plug,{{Cite book |last=Hayssen |first=Virginia |url=https://www.google.com/books/edition/Reproduction_in_Mammals/vwE2DwAAQBAJ?hl=en&gbpv=1&pg=PA113&printsec=frontcover |title=Reproduction in Mammals: The Female Perspective |last2=Orr |first2=Teri J. |date=2017-10-27 |publisher=JHU Press |isbn=978-1-4214-2316-6 |language=en}} sperm plug, or sphragis (Latin, from {{langx|grc|σφραγίς}} {{Transliteration|grc|sphragis}}, "a seal"), is a gelatinous secretion used in the mating of some species. It is deposited by a male into a female genital tract, such as the vagina, and later hardens into a plug or glues the tract together.{{Cite book |last1=Leonard |first1=Janet |url=https://books.google.com/books?id=PgtXj5R6OfMC&pg=430 |title=The Evolution of Primary Sexual Characters in Animals |last2=Cordoba-Aguilar |first2=Alex |date=2010-07-16 |publisher=Oxford University Press |isbn=978-0-19-971703-3 |language=en}}{{cite book|author=David Quammen|title=The Flight of the Iguana: A Sidelong View of Science and Nature|url=https://books.google.com/books?id=VYIlca_fQVsC&q=%22mating+plug%22|date=16 October 2012|publisher=Simon and Schuster|isbn=978-1-4767-2873-5}} While females can expel the plugs afterwards, the male's sperm still gets a time advantage in getting to the egg, which is often the deciding factor in fertilization.
The mating plug plays an important role in sperm competition and may serve as an alternative and more advantageous strategy to active mate guarding.{{Cite book |last=Birkhead |first=Tim |url=https://books.google.com/books?id=3i4Q8SvohfEC&q=plug |title=Promiscuity: An Evolutionary History of Sperm Competition |date=2000 |publisher=Harvard University Press |isbn=978-0-674-00666-9 |language=en}} In some species, such a passive mate-guarding strategy may reduce selection on large male size.{{cite journal |last1=Dunham |first1=A. E. |last2=Rudolf |first2=V. H. W. |title=Evolution of sexual size monomorphism: the influence of passive mate guarding |journal=Journal of Evolutionary Biology |date=July 2009 |volume=22 |issue=7 |pages=1376–1386 |doi=10.1111/j.1420-9101.2009.01768.x |pmid=19486235 |citeseerx=10.1.1.714.2656 |s2cid=13617914 }} Such a strategy may be advantageous because it would allow a male to increase reproductive success by spending more time pursuing new female mates rather than active mate guarding.
Composition
Image:Parnassius apollo - sphragis 02 (HS).jpg butterfly]]
The mating plug of the Bombus terrestris was chemically analyzed and found to consist of palmitic acid, linoleic acid, oleic acid, stearic acid, and cycloprolylproline.{{cite journal |last1=Baer |first1=Boris |last2=Maile |first2=Roland |last3=Schmid-Hempel |first3=Paul |last4=Morgan |first4=E. David |last5=Jones |first5=Graeme R. |title=Chemistry of a Mating Plug in Bumblebees |journal=Journal of Chemical Ecology |date=2000 |volume=26 |issue=8 |pages=1869–1875 |doi=10.1023/A:1005596707591 |s2cid=25735506 }} It was found that the acids (without cycloprolylproline) were sufficient by themselves to create the plug. Researchers hypothesize that cycloprolylproline reduces female receptivity to further breeding.
Occurrence in nature
Mating plugs are used by many species, including several primates,{{cite book|author=Alan F. Dixson|title=Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes, and Humans|url=https://books.google.com/books?id=Z9N_BokMAMkC&q=plug|date=26 January 2012|publisher=OUP Oxford|isbn=978-0-19-954464-6}}{{cite journal |last1=Sauther |first1=Michelle L. |title=Reproductive behavior of free-ranging Lemur catta at Beza Mahafaly Special Reserve, Madagascar |journal=American Journal of Physical Anthropology |date=April 1991 |volume=84 |issue=4 |pages=463–477 |doi=10.1002/ajpa.1330840409 }} kangaroos,{{cite book|author1=Larry Vogelnest|author2=Rupert Woods|title=Medicine of Australian Mammals|url=https://books.google.com/books?id=lWbgqMsyq8UC&q=%22copulatory+plug%22|date=18 August 2008|publisher=Csiro Publishing|isbn=978-0-643-09928-9}}{{cite book|author1=Hugh Tyndale-Biscoe|author2=Marilyn Renfree|title=Reproductive Physiology of Marsupials|url=https://books.google.com/books?id=HpjovN0vXW4C&q=%22copulatory+plug%22|date=30 January 1987|publisher=Cambridge University Press|isbn=978-0-521-33792-2}}{{cite book |author=Terence Dawson |title=Kangaroos |url= https://books.google.com/books?id=qaFUU7XnctAC&q=%22copulatory+plug%22 |access-date= 13 July 2013 |date=16 April 2012 |publisher= Csiro Publishing |isbn=978-0-643-10627-7}} bees,{{cite journal |last1=Strassmann |first1=J. |title=The rarity of multiple mating by females in the social Hymenoptera |journal=Insectes Sociaux |date=March 2001 |volume=48 |issue=1 |pages=1–13 |doi=10.1007/PL00001737 |s2cid=20893433 }} reptiles,{{cite journal |last1=King |first1=Richard B. |last2=Jadin |first2=Robert C. |last3=Grue |first3=Michael |last4=Walley |first4=Harlan D. |title=Behavioural correlates with hemipenis morphology in New World natricine snakes |journal=Biological Journal of the Linnean Society |date=25 August 2009 |volume=98 |issue=1 |pages=110–120 |doi=10.1111/j.1095-8312.2009.01270.x |doi-access=free }} rodents,{{Cite journal |last=Harcourt |first=A. H. |date=March 1991 |title=Sperm Competition and the Evolution of Nonfertilizing Sperm in Mammals |url=https://academic.oup.com/evolut/article/45/2/314/6869932 |journal=Evolution |language=en |volume=45 |issue=2 |pages=314–328 |doi=10.1111/j.1558-5646.1991.tb04406.x|pmid=28567878 |url-access=subscription }}{{Cite book |last=Knobil |first=Ernst |url=https://books.google.com/books?id=6j-mOAcNnPUC&q=plug |title=Knobil and Neill's Physiology of Reproduction |date=2006 |publisher=Gulf Professional Publishing |isbn=978-0-12-515401-7 |language=en}}{{cite journal |last1=Voss |first1=Robert |title=Male accessory glands and the evolution of copulatory plugs in rodents |journal=Occasional Papers |publisher=The Museum of Zoology University of Michigan |date=June 7, 1979 |hdl=2027.42/57125 }}{{cite journal |last1=Ittner |first1=Lars M |last2=Götz |first2=Jürgen |date=10 May 2007 |title=Pronuclear injection for the production of transgenic mice |journal=Nature Protocols |volume=2 |issue=5 |pages=1206–1215 |doi=10.1038/nprot.2007.145 |pmid=17546016 |doi-access=free}} scorpions,{{cite journal |last1=Contreras-Garduno |first1=Jorge |last2=Peretti |first2=Alfredo V. |last3=Cordoba-Aguilar |first3=Alex |title=Evidence that Mating Plug is Related to Null Female Mating Activity in the Scorpion Vaejovis punctatus |journal=Ethology |date=February 2006 |volume=112 |issue=2 |pages=152–163 |doi=10.1111/j.1439-0310.2006.01149.x |bibcode=2006Ethol.112..152C }} bats,{{cite book|author1=Elizabeth G. Crichton|author2=Philip H. Krutzsch|title=Reproductive Biology of Bats|url=https://books.google.com/books?id=f1aNgZwGsYoC|date=12 June 2000|publisher=Academic Press|isbn=978-0-08-054053-5}}{{Cite book |last=Smith |first=Robert L. |url=https://books.google.com/books?id=OIh4DX7tk_0C&pg=PA575 |title=Sperm Competition and the Evolution of Animal Mating systems |date=2012-12-02 |publisher=Elsevier |isbn=978-0-323-14313-4 |language=en}} and spiders.{{cite journal |last1=Knoflach |first1=Barbara |last2=van Harten |first2=Antonius |title=Tidarren argo sp. nov. (Araneae: Theridiidae) and its exceptional copulatory behaviour: emasculation, male palpal organ as a mating plug and sexual cannibalism |journal=Journal of Zoology |date=August 2001 |volume=254 |issue=4 |pages=449–459 |doi=10.1017/S0952836901000954 }}
Use of a mating plug as a strategy for reproductive success can also be seen in a few taxa of Lepidoptera and other insects and is often associated with pupal mating.The encyclopedia of land invertebrate behaviour By Rod Preston-Mafham, Ken Preston-Mafham. Pg 113. For example, to protect their paternity, male variable checkerspot butterflies pass a mating plug into the genital opening of females to prevent them from remating.{{cite journal |last1=Dickinson |first1=Janis L. |last2=Rutowski |first2=Ronald L. |title=The function of the mating plug in the chalcedon checkerspot butterfly |journal=Animal Behaviour |date=July 1989 |volume=38 |issue=1 |pages=154–162 |doi=10.1016/s0003-3472(89)80074-0 |s2cid=53175858 }}
The Heliconius charithonia butterfly uses a mating plug in the form of a spermatophore that provides predatory defense chemicals and protein sources for developing eggs.{{cite journal |last1=Cardoso |first1=Márcio Zikán |last2=Gilbert |first2=Lawrence E. |title=A male gift to its partner? Cyanogenic glycosides in the spermatophore of longwing butterflies (Heliconius) |journal=Naturwissenschaften |date=7 September 2006 |volume=94 |issue=1 |pages=39–42 |doi=10.1007/s00114-006-0154-6 |pmid=16957921 |s2cid=39830226 }} It also acts as an anaphrodisiac that prevents other males from mating with the female.{{cite journal |last1=Estrada |first1=Catalina |last2=Schulz |first2=Stefan |last3=Yildizhan |first3=Selma |last4=Gilbert |first4=Lawrence E. |title=Sexual Selection Drives The Evolution Of Antiaphrodisiac Pheromones in Butterflies |journal=Evolution |date=October 2011 |volume=65 |issue=10 |pages=2843–2854 |doi=10.1111/j.1558-5646.2011.01352.x |pmid=21967426 |s2cid=37752151 |doi-access=free }} Similarly in Parnassius smintheus butterflies, the male deposits a waxy genital plug on the tip of the female's abdomen to prevent the female from mating again.{{cite book |last1= Shepard |first1=Jon |last2=Guppy |first2= Crispin |title=Butterflies of British Columbia: Including Western Alberta, Southern Yukon, the Alaska Panhandle, Washington, Northern Oregon, Northern Idaho, and Northwestern Montana |date=2011 |publisher= UBC Press |isbn=978-0-7748-4437-6 |url= https://books.google.com/books?id=il6rJ7glHNQC&q=parnassius+smintheus&pg=PA53 |access-date=13 November 2017 |ref= butterflybook |language=en}} It contains sperm and important nutrients for the female,{{cite web |title= parnassius smintheus |url= http://imnh.isu.edu/digitalatlas/bio/insects/butrfly/fampap/pasm.htm |website= imnh.isu.edu |access-date= 13 November 2017}} and ensures that the male is the only one to fertilize the female's eggs.
Most species of stingless bees, like Plebeia remota, are only mated once, and thus make use of mating plugs to store all the sperm they collect for future use.
Another species of insect that uses a copulatory plug is Drosophila mettleri, a Sonoran Desert Fly species from the Diptera family. These plugs serve as a means of male-female control during mating interactions.{{cite journal|vauthors=Alonso-Pimentel H, Tolbert LP, Heed WB|date=March 1994|title=Ultrastructural examination of the insemination reaction in Drosophila|journal=Cell and Tissue Research|volume=275|issue=3|pages=467–79|doi=10.1007/BF00318816|pmid=8137397|s2cid=29013736|url=https://zenodo.org/record/805734}}
A peculiar example of mate plugging occurs in Leucauge mariana spiders. Both male and female participation is required to create a mate plug. The male alone cannot create a functional plug. Female participation in creating a mating plugs, and her presumed benefit from them, have led to multiple studies of sexual selection on the sexual behavior of L. mariana.{{Cite journal|last1=Hernández|first1=Linda|last2=Aisenberg|first2=Anita|last3=Molina|first3=Jorge|date=2018|editor-last=Hebets|editor-first=E.|title=Mating plugs and sexual cannibalism in the Colombian orb-web spider Leucauge mariana|url=http://doi.wiley.com/10.1111/eth.12697|journal=Ethology|language=en|volume=124|issue=1|pages=1–13|doi=10.1111/eth.12697|bibcode=2018Ethol.124....1H |url-access=subscription}}
In Thamnophis sirtalis parietalis, commonly known as red-sided garter snakes, males deposit a gelatinous copulatory plug to seal female snake's cloacal opening to prevent re-mating, leakage of the deposited sperm, and alters female pheromonal cues that attract mates.{{cite journal |last1=Crews |first1=David |first2=William R. |last2=Garstka |title=The Ecological Physiology of a Garter Snake |journal=Scientific American |date=1982 |volume=247 |issue=5 |pages=158–71 |publisher=JSTOR|doi=10.1038/scientificamerican1182-158 |bibcode=1982SciAm.247e.158C }}
Some cetaceans have folds in the vagina that do not occur in other mammals. The function of these folds is unknown, but it is possible that they form vaginal plugs or retain sperm after copulation.{{Cite book |last1=Perrin |first1=William F. |url=https://books.google.com/books?id=2rkHQpToi9sC&q=vagina&pg=PA427 |title=Encyclopedia of Marine Mammals |last2=Würsig |first2=Bernd |last3=Thewissen |first3=J. G. M. |date=2009-02-26 |publisher=Academic Press |isbn=978-0-08-091993-5 |language=en}}
See also
References
{{reflist}}
{{Animal sexual behavior}}