PARENT SESSION
Oral Session # 57: Evolutionary Ecology II: Animal.
Presiding: S Juliano
Wednesday, August 6. 1:30 PM to 5:00 PM, SITCC Meeting Room 201.

Darwin's theory of sexual selection false and inadequate.

Roughgarden, Joan^*,1, ¹ Dept. of Biological Sciences, Stanford, CA, USA

ABSTRACT- Darwin's theory of evolution contains three propositions: species are descended from other species, natural selection causes evolution, and males and females match distinct templates. The third piece of Darwin's theory is challenged by recent discoveries. Darwin wrote that "males of almost all animals have stronger passions than females" and that "the female... with the rarest of exceptions is less eager than the male... she is coy." Darwin imagined that male characteristics evolve because females select mates who are "more attractive... vigorous and well-armed," just as "man can give beauty... to his male poultry" through selective breeding. This theory, called "sexual selection," explains the evolution of exceptional male ornaments like a peacock's tail, as the result of female choice, but now appears falsified and inadequate overall. Ten findings across vertebrate species collectively refute sexual selection theory: many body types are not solely male or female; multiple forms of males and females occur within the same species; sex roles reverse; males forego opportunities to mate; female choice is not for attractive genes, but to manage male power; family size is negotiated between males and females; sexual mimicry has been claimed but never demonstrated; same-sex sexuality is common; mating promotes relationships independent of sperm transfer; and ornaments are attractive in homosexual as well as heterosexual relations. A theory of social selection to replace sexual selection should include two new principles: transactions of reproductive opportunity, and social-inclusionary traits. A territory-controlling male blue-gill sunfish purchases marriage-broker services from a feminine male, using access to reproductive opportunity as currency. A penis in female spotted hyenas and same-sex sexuality in female bonobos are required for inclusion in the groups controlling access to food and safety from predators. A female dies or fails to reproduce without social-inclusionary traits. New approachs to gender and sexuality must replace sexual selection theory.

Key words: sexuality, homosexuality, gender, female choice