Evolutionary time-series analysis reveals the signature of frequency-dependent selection on a female mating polymorphism

A major challenge in evolutionary biology is understanding how stochastic and deterministic factors interact and influence macroevolutionary dynamics in natural populations. One classical approach is to record frequency changes of heritable and visible genetic polymorphisms over multiple generations. Here, we combined this approach with a maximum likelihood–based population-genetic model with the aim of understanding and quantifying the evolutionary processes operating on a female mating polymorphism in the blue-tailed damselfly Ischnura elegans. Previous studies on this color-polymorphic species have suggested that males form a search image for females, which leads to excessive mating harassment of common female morphs. We analyzed a large temporally and spatially replicated data set of between-generation morph frequency changes in I. elegans. Morph frequencies were more stable than expected from genetic drift alone, suggesting the presence of selection toward a stable equilibrium that...进化生物学领域的核心挑战之一，在于阐明随机因子与确定性因子如何相互作用，并影响自然种群的宏观进化动态。经典研究方法之一，是记录多世代间可遗传且可观测的遗传多态性（genetic polymorphism）的频率变化。本研究将该方法与基于最大似然法（maximum likelihood）的种群遗传模型（population-genetic model）相结合，旨在解析并量化作用于蓝尾豆娘（Ischnura elegans）雌性交配多态性的进化过程。针对该颜色多态物种的前期研究表明，雄性会对雌性形成搜索图像，进而导致常见雌性形态个体遭受过度的交配骚扰。我们对蓝尾豆娘（Ischnura elegans）世代间形态频率变化的大型时空重复数据集展开了分析。形态频率的稳定性远超仅由遗传漂变（genetic drift）所能预期的水平，这表明存在指向稳定平衡的选择作用，且……