Mating plug

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

A mating plug, also known as a copulation plug,[1] sperm plug, vaginal plug, or sphragis (Latin, from Ancient Greek: σφραγίς 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.[2][3] 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.[4] In some species, such a passive mate-guarding strategy may reduce selection on large male size.[5] 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.[5]

  1. ^ Feldhamer, George A. (7 September 2007). Mammalogy: Adaptation, Diversity, Ecology. JHU Press. ISBN 978-0-8018-8695-9.
  2. ^ Leonard, Janet; Cordoba-Aguilar, Alex (16 July 2010). The Evolution of Primary Sexual Characters in Animals. Oxford University Press. ISBN 978-0-19-971703-3.
  3. ^ 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.
  4. ^ Birkhead, Tim (2000). Promiscuity: An Evolutionary History of Sperm Competition. Harvard University Press. ISBN 978-0-674-00666-9.
  5. ^ a b 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 10.1.1.714.2656. doi:10.1111/j.1420-9101.2009.01768.x. PMID 19486235. S2CID 13617914.