Department of Biology - Ethology, University of Antwerp, Wilrijk, Belgium.
PLoS One. 2013 Aug 15;8(8):e72136. doi: 10.1371/journal.pone.0072136. eCollection 2013.
Reproductive investment affects both offspring and parental fitness and influences the evolution of life histories. Females may vary their overall primary reproductive effort in relation to the phenotypic characteristics of their mate. However, the effects of male quality on differential resource allocation within clutches have been largely neglected despite the potential implications for mate choice and population dynamics, especially in species exhibiting biparental care and brood reduction. Female southern rockhopper penguins Eudyptes chrysocome paired with heavy mates reduced intra-clutch variation in egg and albumen masses. Females paired with new mates also reduced intra-clutch variation in yolk androgen levels. Since both an increased mass and increased androgen concentrations positively influence chick survival under sibling competition, the chances of fledging the whole clutch are likely to be higher for newly formed pairs with heavy males than for previously formed pairs with light males. Interestingly, total clutch provisioning did not vary with male quality. We show for the first time that females vary intra-clutch variation in resource allocation according to male quality. In species with brood reduction, it may be more adaptive for females to modulate the distribution of resources within the clutch according to breeding conditions, than to change their total clutch provisioning.
生殖投资既影响后代和父母的适合度，又影响生活史的进化。雌性可能会根据配偶的表型特征来调整其整体的主要生殖努力。然而，尽管这可能对配偶选择和种群动态有潜在影响，尤其是在具有双亲养育和减少孵育的物种中，但雄性质量对卵和蛋白质量内的资源分配差异的影响在很大程度上被忽视了。与体重较重的配偶配对的南部石企鹅 Eudyptes chrysocome 雌性减少了卵和蛋白质量内的变异。与新配偶配对的雌性也降低了蛋黄雄激素水平内的变异。由于卵的质量增加和雄激素浓度增加都有利于雏鸟在同胞竞争下的生存，因此与新形成的、雄性体重较大的配对相比，以前形成的、雄性体重较轻的配对中，整个孵育群成功出雏的几率更高。有趣的是，总卵的供给并没有随雄性质量的变化而变化。我们首次表明，雌性会根据雄性质量来调整卵内资源分配的内变异性。在具有减少孵育的物种中，根据繁殖条件来调节卵内资源的分配可能比改变总卵供给更为适应。
