Data from: The evolution of male-biased dispersal under the joint selective forces of inbreeding load, and demographic and environmental stochasticity

Sex-biased natal dispersal is widespread, and its significance remains a central question in evolutionary biology. However, theory so far fails to predict some of the most common patterns found in nature. To address this, we present novel results from an individual-based model investigating the joint roles of inbreeding load, demographic stochasticity, environmental stochasticity, and dispersal costs for the evolution of sex-biased dispersal. Most strikingly, we found that male-biased natal dispersal evolved in polygynous systems as a result of the interplay between inbreeding avoidance and stochasticity, whereas previous theory, in contrast to empirical observations, predicted male philopatry and female-biased natal dispersal under inbreeding load alone. Furthermore, the direction of the bias varied according to the nature of stochasticity. Our results therefore provide a unification of previous theory, yielding a much better qualitative match with empirical observations of male-biased dispersal in mate defense mating systems.性别偏向的出生扩散 (sex-biased natal dispersal) 现象广泛存在，其演化意义始终是进化生物学领域的核心议题之一。然而，现有理论迄今仍无法准确预测自然界中观测到的部分最为常见的扩散模式。为解决这一问题，我们通过一项基于个体的模型 (individual-based model) 得到了全新的研究结果，并借此探讨了近交负荷 (inbreeding load)、人口统计学随机性 (demographic stochasticity)、环境随机性 (environmental stochasticity) 以及扩散成本 (dispersal costs) 在性别偏向扩散演化中的共同作用。最引人注目的是，我们发现在一雄多雌制婚配系统 (polygynous systems) 中，受近交规避 (inbreeding avoidance) 与随机性的共同影响，演化出了雄性偏向的出生扩散模式；而此前仅基于近交负荷的理论预测结果却与实证观测 (empirical observations) 相悖——即预测雄性留居 (male philopatry) 且雌性偏向的出生扩散。此外，扩散偏向的方向会随随机性的本质特征发生变化。因此，本研究结果统一了此前的理论框架，使其在定性层面上，与配偶防御型婚配系统 (mate defense mating systems) 中雄性偏向扩散的实证观测结果实现了更高程度的契合。