Investigating the Evolution of Sexual Dimporphism via Artificial Selection and Field Experiments

生物体的一些最显著的特征是两性之间的差异（称为两性二态性）。性选择通常被用来解释这种差异，并可能解释由于一系列遗传效应而与获得配偶没有直接关系的性状的二态性。以往对雌雄异株植物Silene latifolia的研究表明，在开花过程中具有显著的性别二态性，产生相对较多花朵的个体代谢水平上调，并可能付出生命史代价（如较低的寿命）。在花的大小和数量上增加或减少两性二态性的人工选择系将被创造出来。这些品系将以实验阵列的形式种植，通过两种途径——交配成功（性选择）和寿命（自然选择）来评估开花对适应性的影响。通过人工选择增加性状的表型变异，并对这些品系进行随后的田间试验，这两种方法相结合，将有助于理解选择的原因和模式。这项工作将帮助我们确定两性二态性在形态、生理和生活史特征上是否通过性选择进化而来。

0075318DelphSome of the most conspicuous features of organisms are differences between the sexes (known as sexual dimorphism). Sexual selection is usually invoked to explain such differences and may explain dimorphism in characters that are not directly related to mate acquisition because of a cascade of genetic effects. Previous research with the dioecious plant Silene latifolia, which has remarkable sexual dimorphism in flower production, shows that individuals that produce a relatively high number of flowers have upregulated metabolisms and may pay life history costs (such as lower longevity). Artificial selection lines will be created that will have both increased and reduced sexual dimorphism in flower size and number. These lines will be planted out in experimental arrays to assess the consequences of flower production on fitness via two pathways - mating success (sexual selection) and longevity (natural selection).The combination of increasing the phenotypic variation in traits via artificial selection and subsequent field experimentation with these lines should yield great power in understanding the causes and patterns of selection. This work will help us determine whether sexual dimorphism in morphological, physiological, and life history traits has evolved via sexual selection.