Sexual mimicry 5334192 190192746 2008-02-09T15:54:24Z SmackBot 433328 Date the maintenance tags or general fixes {{contradict-other}} {{Cleanup|date=November 2007}} [[Image:Hyena.PNG|thumb|right|250px|Spotted Hyena]] [[Image:Mole.PNG|thumb|right|250px|European Mole]] '''Sexual mimicry''' is where one [[sex]] takes the characteristics of the other within a [[species]]. Examples of sexual [[mimicry]] in animals are the [[spotted hyena]], [[bonobo]] chimp, [[spider monkey]], [[lemur]], [[european mole]]. It also occurs in plants, where flowers of one sex may mimic those of another. Sexual mimicry can have adverse reproductive costs, for example the spotted hyena has to copulate and give birth through the long [[pseudo-penis|peniform]] [[clitoris]]. The [[umbilical cord]] is 12-18 cm long whilst the journey from [[uterus]] to the clitoris end is 60cm, resulting in death by [[anoxia]] of many young. [[Clitoromegaly]] is an example of sexual mimicry and occurs in the [[Spotted Hyena]] as first noted by [[Aristotle]]. It results from natural high levels of [[testosterone]] in the placenta causing priming of the secondary sexual characteristics of the female foetus. In this case female external genitalia resembles that of the male, having a false [[penis]] from the [[clitoris]] and false [[scrotum]] from the [[vulva]], this is a result of extreme [[Organ hypertrophy|hypertrophy]]. The females are also 10% larger, more [[aggression|aggressive]] and dominant, a trait that is normally observed in males. More specifically, the unusual features are due to an increased production of [[androstenedione]] in the maternal [[ovaries]] during [[pregnancy]]. Androstenedione is an [[androgen]] and converted to [[testosterone]] by the enzyme [[17β hydroxysteroid dehydrogenase ]] in the [[placenta]], then transported to the fetus. In most mammals, the placenta converts androstendione to [[Estrogen|oestrogen]] via the [[enzyme]] [[aromatase]]. Aromatase is deficient in the hyena placenta. The [[european mole]] is another good example of sexual mimicry. The male [[testes]] are intraabdominal and the female [[ovaries]] are bilateral meaning the bipolar gonads have both male and female features; this makes the mole very difficult to sex. The females also appear to have an enlarged peniform clitoris, these characteristics are also due to testosterone. During the breeding season, female testosterone levels decline and the pole containing interstitial ovarian tissue regresses, whilst the pole containing follicles grows. This is prevalent in Old World moles but has not been found in New World moles, suggesting it has arisen from high selective pressure. Disorders do exist in humans that cause one sex to take on characteristics of the other, for instance girls suffering from [[congenital adrenal hyperplasia]] in most extreme cases are born with external male genitalia. This is not a case of sexual mimicry though, as it is not adaptive and only survives due to [[recessive refuge]]. ==References== *Place NJ, Glickman SE. 2003 Masculinization of female mammals: lessons from nature. [http://www.vet.cornell.edu/labs/place/publications/16Place&Glickman.2004.pdf] {{Nofootnotes|date=October 2007}} {{Mimicry}} [[Category:Sex]] [[Category:Animal anatomy]] [[Category:Mimicry]]