Do high females produce high quality sons? Maternal effects on fitness and fitness-related traits of male offspring in a social mammal

自然选择作用于可遗传的性状，并影响个体的适应性。因此，对健康相关特征、影响这些特征的因素及其可遗传性的研究是我们理解进化过程的基础。个体的表型性状是由个体的基因型、发育过程中所经历的环境影响或两者的结合形成的。因为在哺乳动物中，发育期间的环境主要由母亲提供，雌性哺乳动物可能对其后代的身体和社会发展产生强烈的影响。然而，在自然环境中生活在自然选择压力下的哺乳动物中，母体对雄性后代的适应性和适应性相关性状的影响从未被研究过。本文拟研究自由放养斑点鬣狗雌性表型质量与其雄性后代的适合度及其相关性状之间的关系。该研究将揭示社会地位和经验——斑点鬣狗和许多其他社会性哺乳动物雌性品质的两个最重要的决定因素——是否影响分散性后代的适合度，雌性品质如何转移到后代适合度，以及受母体效应影响的适合度相关性状是否具有遗传性。通过比较雄性鬣狗、雌性鬣狗和其他物种雌性鬣狗的适合度和适合度相关性状的遗传力，可以进一步揭示母性影响是否取决于诸如分散模式和两性间优势关系等特征。

Natural selection operates on traits that are heritable and influence the fitness of individuals. The study of fitness-related traits, of factors that influence these traits and of their heritability is thus fundamental to our understanding of evolutionary processes. Individual phenotypic traits are shaped by the individual’s genotype, environmental effects it experiences during development, or a combination of both. Because in mammals, the environment during development is provided mainly by the mother, female mammals are likely to have a strong impact on the physical and social development of their offspring. Maternal effects on fitness and fitness-related traits of male offspring however have never been investigated in mammals living under natural selection pressures in their natural environment. Here I propose to investigate the relationship between the phenotypic quality of females and the fitness and fitness-related traits of their male offspring in free-ranging spotted hyenas. The study will reveal whether social status and experience, the two most important determinants of female quality in spotted hyenas and many other social mammals, influence the fitness of offspring of the dispersing sex, how female quality transfers into offspring fitness and whether fitness-related traits influenced by maternal effects are heritable. A comparison of maternal effects on fitness and heritability of fitness-related traits of male hyenas, female hyenas and females of other species may further reveal whether maternal effects depend on characteristics such as the dispersal pattern and dominance relationships within and between the sexes.