Mating plug

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A mating plug in a female Richardson's ground squirrel (Spermophilus richardsonii)

A mating plug, also known as a copulation plug, sperm plug, vaginal plug, or sphragis (Latin, from Greek σφραγίς sphragis, "a seal"), is 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.[1] 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. In some species, such a passive mate-guarding strategy may reduce selection on large male size.[2] 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.[2]


Sphragis on female of Parnassius apollo

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.[3] 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[edit]

Mating plugs are used by many species, including several primates,[4][2][5] kangaroos,[6][7][8] bees,[9] reptiles,[10] rats, rodents,[11] scorpions,[12] mice,[13] and spiders.[14]

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.[15] 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.[16]

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.[17] It also acts as an anaphrodisiac that prevents other males from mating with the female.[18] 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.[19] It contains sperm and important nutrients for the female,[20] and ensures that the male is the only one to fertilize the female’s eggs.[19]

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.[9]

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.[21]

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.[22]

See also[edit]


  1. ^ David Quammen (16 October 2012). The Flight of the Iguana: A Sidelong View of Science and Nature. Simon and Schuster. ISBN 978-1-4767-2873-5.
  2. ^ a b c Dunham, A. E.; Rudolf, V. H. W. (July 2009). "Evolution of sexual size monomorphism: the influence of passive mate guarding". Journal of Evolutionary Biology. 22 (7): 1376–1386. CiteSeerX doi:10.1111/j.1420-9101.2009.01768.x. PMID 19486235. S2CID 13617914.
  3. ^ Baer, Boris; Maile, Roland; Schmid-Hempel, Paul; Morgan, E. David; Jones, Graeme R. (2000). "Chemistry of a Mating Plug in Bumblebees". Journal of Chemical Ecology. 26 (8): 1869–1875. doi:10.1023/A:1005596707591. S2CID 25735506.
  4. ^ Alan F. Dixson (26 January 2012). Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes, and Humans. OUP Oxford. ISBN 978-0-19-954464-6.
  5. ^ Sauther, Michelle L. (April 1991). "Reproductive behavior of free‐ranging Lemur catta at Beza Mahafaly Special Reserve, Madagascar". American Journal of Physical Anthropology. 84 (4): 463–477. doi:10.1002/ajpa.1330840409.
  6. ^ Larry Vogelnest; Rupert Woods (18 August 2008). Medicine of Australian Mammals. Csiro Publishing. ISBN 978-0-643-09928-9.
  7. ^ Hugh Tyndale-Biscoe; Marilyn Renfree (30 January 1987). Reproductive Physiology of Marsupials. Cambridge University Press. ISBN 978-0-521-33792-2.
  8. ^ Terence Dawson (16 April 2012). Kangaroos. Csiro Publishing. ISBN 978-0-643-10627-7. Retrieved 13 July 2013.
  9. ^ a b Strassmann, J. (March 2001). "The rarity of multiple mating by females in the social Hymenoptera". Insectes Sociaux. 48 (1): 1–13. doi:10.1007/PL00001737. S2CID 20893433.
  10. ^ King, Richard B.; Jadin, Robert C.; Grue, Michael; Walley, Harlan D. (25 August 2009). "Behavioural correlates with hemipenis morphology in New World natricine snakes". Biological Journal of the Linnean Society. 98 (1): 110–120. doi:10.1111/j.1095-8312.2009.01270.x.
  11. ^ Voss, Robert (June 7, 1979). "Male accessory glands and the evolution of copulatory plugs in rodents". Occasional Papers. The Museum of Zoology University of Michigan. hdl:2027.42/57125.
  12. ^ Contreras-Garduno, Jorge; Peretti, Alfredo V.; Cordoba-Aguilar, Alex (February 2006). "Evidence that Mating Plug is Related to Null Female Mating Activity in the Scorpion Vaejovis punctatus". Ethology. 112 (2): 152–163. doi:10.1111/j.1439-0310.2006.01149.x.
  13. ^ Ittner, Lars M; Götz, Jürgen (10 May 2007). "Pronuclear injection for the production of transgenic mice". Nature Protocols. 2 (5): 1206–1215. doi:10.1038/nprot.2007.145. PMID 17546016.
  14. ^ Knoflach, Barbara; van Harten, Antonius (August 2001). "Tidarren argo sp. nov. (Araneae: Theridiidae) and its exceptional copulatory behaviour: emasculation, male palpal organ as a mating plug and sexual cannibalism". Journal of Zoology. 254 (4): 449–459. doi:10.1017/S0952836901000954.
  15. ^ The encyclopedia of land invertebrate behaviour By Rod Preston-Mafham, Ken Preston-Mafham. Pg 113.
  16. ^ Dickinson, Janis L.; Rutowski, Ronald L. (July 1989). "The function of the mating plug in the chalcedon checkerspot butterfly". Animal Behaviour. 38 (1): 154–162. doi:10.1016/s0003-3472(89)80074-0. S2CID 53175858.
  17. ^ Cardoso, Márcio Zikán; Gilbert, Lawrence E. (7 September 2006). "A male gift to its partner? Cyanogenic glycosides in the spermatophore of longwing butterflies (Heliconius)". Naturwissenschaften. 94 (1): 39–42. doi:10.1007/s00114-006-0154-6. PMID 16957921. S2CID 39830226.
  18. ^ Estrada, Catalina; Schulz, Stefan; Yildizhan, Selma; Gilbert, Lawrence E. (October 2011). "Sexual Selection Drives The Evolution Of Antiaphrodisiac Pheromones in Butterflies". Evolution. 65 (10): 2843–2854. doi:10.1111/j.1558-5646.2011.01352.x. PMID 21967426. S2CID 37752151.
  19. ^ a b Shepard, Jon; Guppy, Crispin (2011). Butterflies of British Columbia: Including Western Alberta, Southern Yukon, the Alaska Panhandle, Washington, Northern Oregon, Northern Idaho, and Northwestern Montana. UBC Press. ISBN 978-0-7748-4437-6. Retrieved 13 November 2017.
  20. ^ "parnassius smintheus". Retrieved 13 November 2017.
  21. ^ Alonso-Pimentel H, Tolbert LP, Heed WB (March 1994). "Ultrastructural examination of the insemination reaction in Drosophila". Cell and Tissue Research. 275 (3): 467–79. doi:10.1007/BF00318816. PMID 8137397. S2CID 29013736.
  22. ^ Hernández, Linda; Aisenberg, Anita; Molina, Jorge (2018). Hebets, E. (ed.). "Mating plugs and sexual cannibalism in the Colombian orb-web spider Leucauge mariana". Ethology. 124 (1): 1–13. doi:10.1111/eth.12697.