Sexy son hypothesis

This implies that other benefits the father can offer the mother or offspring are less relevant than they may appear, including his capacity as a parental caregiver, territory and any nuptial gifts.

Fisher's principle means that the sex ratio (except in certain eusocial insects) is always near 1:1 between males and females, yet what matters most are her "sexy sons'" future breeding successes, more likely if they have a promiscuous father, in creating large numbers of offspring carrying copies of her genes.

[5]Ronald Fisher's principle, as published in his book The Genetical Theory of Natural Selection, is one of several possible explanations for the highly diverse and often astonishing ornaments of animals.

[9] In its original context, the "narrow-sense sexy son hypothesis" of Weatherhead and Robertson refers to mating systems with care from both parents.

[12] Such can be the case for the Guianan cock-of-the-rocks, whose male members spend a majority of their time and energy maintaining their plumage and attempting to seek the most matings.

[13] Another study notes that pronghorn females engage in an obvious and energetically expensive mate sampling process to identify vigorous males.

Offspring of attractive males were more likely to survive to weaning and to age classes as late as 5 years, apparently due to faster growth rates.

[14] Because pronghorn males do not have costly ornaments, the authors conclude that female choice for good genes can exist in the absence of obvious sexual selection cues such as elaborate antlers.

Like good genes, the sexy son hypothesis assumes the existence of indirect genetic benefits that are able to compensate for any inferior direct reproductive success (i.e., fewer offspring).