Antioxidant allocation modulates sperm quality across changing social environments

摘要: In promiscuous species, male reproductive success depends on their ability to mate with fertile females and the fertilizing of sperm. such theory predicts that, owing a trade-off between pre- post-copulatory traits, males lesser access should increase resource investment into those sperm traits that enhance fertilization success-usually referred as ejaculate quality. This prediction has been validated in several taxa, yet studies physiological mechanisms modulating quality are lacking. Sperm cells highly vulnerable oxidative stress, which impairs fertility. Therefore, better protect from stress expected achieve higher Based theoretical expectations, since social dominance is major determinant mating opportunity, we predicted subordinate invest more antioxidant protection order We maintained 60 female wild-caught house sparrows Passer domesticus outdoor aviaries, where experimentally manipulated status test our predictions. measured cellular enzymatic activity blood both before after manipulating ranks. Before status, found viability correlated level sperm, dominant producing oxidized less viable ejaculates. Further, at lower end hierarchy produced ejaculates similar males, suggesting restricted resources might limit strategies. After matched new rank, while increases paralleled viability. Oxidative proposed general constraint evolution life histories. Our results highlight strategic allocation important proximate underlying