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 mutation load, demographic stochasticity, environmental stochasticity, and dispersal costs for the evolution of sex-biased dispersal. Most strikingly, we found 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 mutation 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）广泛存在于自然界中，其演化意义始终是进化生物学领域的核心研究议题之一。然而，现有理论迄今仍无法解释自然界中观测到的部分最普遍的扩散模式。为此，我们基于个体的模型（individual-based model）开展研究，解析突变负荷（mutation load）、种群统计随机性（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，并呈现全新的研究发现。最引人注目的是，我们发现在一雄多雌婚配制度（polygynous systems）中，雄性偏向的出生扩散会因近交回避（inbreeding avoidance）与随机性的共同作用而演化；而此前的理论仅考虑突变负荷时，预测的结果是雄性留居（male philopatry）且雌性偏向出生扩散，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类型发生变化。综上，我们的研究结果统一了此前的相关理论，使其在定性层面能够更好地匹配配偶防御型婚配制度（mate defense mating systems）中雄性偏向扩散的实证观测结果。