Hermaphrodism: What’s not to Like?
نویسندگان
چکیده
Male and female social roles are predicated on the fact that male and female reproductive functions are separated in different individuals. This paper asks why. That is, why is gonochorism, not hermaphroditism, the rule among vertebrates. We argue that (simultaneous) hermaphroditism may be unstable in the face of heterogeneity. Building on the Bateman principle – access to eggs, not sperm, limits reproductive success – and in line with Trivers-Willard, we show that low quality individuals will prefer to be all female. We also show that without secondary sexual differentiation (SSD), there is no equilibrium with males. Only females and hermaphrodites. With sufficient SSD, however, males may outcompete hermaphrodites so that hermaphrodites only mate among themselves and thus for practical purposes form their own species. We also show that, while hermaphrodites strive to mate their male function and preserve their female function, equilibrium hermaphroditic mating is reciprocal. Reciprocal mating, in turn, makes hermaphrodites susceptible to male-to-male violence, suggesting that form of SSD may have contributed to the rarity of hermaphroditism.
منابع مشابه
Hermaphrodism and sex reversal associated with the dominant hemimelia mutation in XY mice
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