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Sexual mimicry
Sexual mimicry occurs when one sex mimics the opposite sex in its behavior, appearance, or chemical signalling. It is more commonly seen within invertebrate species, although sexual mimicry is also seen among vertebrates such as spotted hyenas. Sexual mimicry is commonly used as a mating strategy to gain access to a mate, a defense mechanism to avoid more dominant individuals, or a survival strategy. It can also be a physical characteristic that establishes an individual’s place in society. Sexual mimicry is employed differently across species and it is part of their strategy for survival and reproduction. Examples of sexual mimicry in animals include the spotted hyena, certain types of fish, passerine birds and some species of insect among others. These are cases of intraspecific sexual mimicry, but interspecific sexual mimicry can also occur in some plant species, especially orchids. In plants employing sexual mimicry, flowers mimic mating signals of their pollinator insects. These insects are attracted and pollinate the flowers through pseudocopulations or other sexual behaviors performed on the flower.
== Social Systems ==
Sexual mimicry can influence the species’ social system. The most common example is the spotted hyenas, ''Crocuta crocuta''. Female hyenas resemble male hyenas in their sexual anatomy: the females have peniform clitorises, resembling a penis, and false scrotal sacs. These characteristics, as well as high androgen levels in their blood, make for aggressive females, which results in their dominance over males; the female with the lowest rank is more dominant than the highest-ranking male. Within the female population in each clan, there are different ranks: the dominant females, who reproduce at an earlier age and get more access to food, and the non-dominant females. Their dominance is hierarchical and is passed from mother to daughter. By contrast, male spotted hyenas gain their social status with the length of their stay in the clan;〔East ML and Hofer H. 2001. Male spotted hyenas (Crocuta crocuta) queue for status in social groups dominated by females. Behav Ecol. 12(5): 558–568.〕 it does not involve aggressive contests. The males leave their clan between the ages of two and six and join a different clan where they gain status with age. Males also foster amicable relationships with the females to stabilize their position in the social hierarchy.〔
Because females are the dominant sex among spotted hyenas, they are the most respected. Subordinate female hyenas initiate a ‘greeting’ with dominant female hyenas as a sign of respect and are forced to do so if they refuse. This greeting used by hyenas reflects the asymmetry of their ranking; the animal being greeted (the subordinate individual) extends its hind legs and the individual doing the greeting (the dominant hyena) licks or sniffs the erect peniform clitoris. By lifting its hind legs, the hyena being greeted (the subordinate hyena) exposes its most vulnerable body part to the other individual, an act that reflects inferiority. As well, when its hind legs are lifted, a scent can be identified by the other individual. Subordinate hyenas expose their scent more often than high-ranking hyenas. This greeting, however, is not commonly seen between males and adult females; when it does occur, it is restricted to males of median or higher rank greeting dominant females.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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