Evolutionary conflicts of interest: are female sexual decisions different?

Analyses of reproductive conflicts of interests have yielded important evolutionary insights in many areas of biology. The usefulness of conflict analyses of traits that have been traditionally interpreted as resulting from female choice is controversial, however. This article explores a possible explanation for why conflicts of interest may be ameliorated in female choice situations. In contrast to most other evolutionary contexts in which conflicts of interest are thought to have been important, sexual reproduction usually involves an extensive, irretrievable mixing of the genomes of the participants. Under certain combinations of costs and benefits to females, the genes in the female's genome can benefit, through increased reproduction of her offspring, from the very genes that produce sexually antagonistic traits in the male. In short, females can sometimes gain by "losing." Such Fisherian payoffs are also possible, though probably less important, for males. Gaining by losing is not feasible in most other contexts of evolutionary conflict, except under some conditions in parent-offspring conflict. Some apparent parent-offspring conflicts may instead be parental choice among offspring that is analogous to traditional female choice. Parent-offspring conflict may be relatively common, however, because offspring manipulation of their parents is likely to be damaging to the parents.