SINERVO, Barry; CALSBEEK, Ryan; HAZARD, Lisa; Univ. of California, Santa Cruz; Univ. of California, Los Angeles; Univ. of California, Santa Cruz: Ontogenetic Conflict Between the Sexes and Selection on Life History and Performance Traits

Intersexual ontogenetic conflict arises when an allele�s fitness optimum differs between the sexes. Conflict is increasingly recognized as an important means of maintaining genetic variation at loci under chronic selection, however, genetic evidence of conflict has not yet been described in nature. We present the first evidence of ontogenetic conflict from a wild population of the side-blotched lizard, Uta stansburiana, showing that genes for male body-size confer high or low fitness depending on sex of the progeny. We have also measured strong genetic correlations between sire body mass, performance traits, throat colour alleles, progeny body mass, egg mass, and egg laying dates. Selection on body size and male performance alleles of males was antagonized by selection on the same alleles that control life history traits of females, indicating genetic conflict between the sexes. This ontogenetic conflict resolves the paradoxical finding that additive genetic variation is maintained in traits under chronic natural and sexual selection. Furthermore, male and female performance traits experience countervailing forces of natural and sexual selection. We review other systems in which ontogenetic conflict might act on male and female performance traits. Mechanisms of hormonal regulation are conserved among vertebrates.