Context-dependent expression of sexual dimorphism in island populations of the common wall lizard (Podarcis muralis)

The condition-dependent sexual dimorphism model explains the evolution and maintenance of sexual dimorphism in traits targeted by sexual selection, and predicts that the magnitude of sexual dimorphism depends on the variability of individual condition, male traits being more variable than female corresponding traits. Most convincing examples concern insects, while studies among vertebrates are scanty because manipulating condition often is not possible, and the time to reach sexual maturity may be too long. Islands offer a unique opportunity to compare how the environment affects the expression of sexual dimorphism, since they represent ‘natural experimental sets’ in which different populations of the same species may experience alternative environmental constraints. We investigated the occurrence of context-dependent expression in sexual dimorphism of head shape in insular populations of the common wall lizards (Podarcis muralis) inhabiting the Tuscan Archipelago (Tyrrhenian Sea). Alte...条件依赖型性二态模型（condition-dependent sexual dimorphism model）阐释了性选择（sexual selection）所靶向的性状中，性二态（sexual dimorphism）的演化与维持机制，并预测性二态的强弱程度取决于个体条件（individual condition）的变异水平，且雄性相关性状的变异程度高于雌性对应性状。目前最具说服力的相关研究案例多集中于昆虫类群，而脊椎动物类群的相关研究较为匮乏，原因往往在于难以对个体条件进行人工操控，且脊椎动物达到性成熟所需的时长通常过长。岛屿为探究环境如何影响性二态的表达提供了独特契机，因为岛屿可视为"天然实验平台"，同一物种的不同种群在此可能面临截然不同的环境限制因子。本研究针对栖息于第勒尼安海托斯卡纳群岛的普通壁蜥（Podarcis muralis）的岛屿种群，探究了其头部形状性二态的语境依赖性表达现象。Alte...