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）广泛分布于自然界，其演化意义始终是进化生物学的核心研究问题之一。然而，现有理论迄今仍无法准确预测野外观测到的多数常见模式。为填补这一研究空白，我们基于个体的模型（individual-based model）开展研究，揭示了近交负荷（inbreeding load）、人口统计学随机性（demographic stochasticity）、环境随机性（environmental stochasticity）与扩散成本（dispersal costs）在性别偏向扩散演化中的联合作用，并呈现了全新研究结果。尤为引人注目的是，研究发现：在多配制系统（polygynous systems）中，受近交回避（inbreeding avoidance）与随机性的共同影响，雄性偏向的出生扩散得以演化；而此前仅考虑近交负荷的理论预测结果为雄性留居（male philopatry）与雌性偏向的出生扩散，这与实际观测结果相悖。此外，扩散偏向的方向会随随机性的性质发生改变。综上，本研究结果统一了此前的理论框架，从而使其与配偶防御型交配系统（mate defense mating systems）中雄性偏向扩散的野外观测结果在定性层面实现了更优匹配。