Dispersal polymorphism and mutation play significant roles during biological invasions, potentially leading to evolution and complex behaviour such as accelerating or decelerating invasion fronts. However, life-history theory predicts that reproductive fitness—another key determinant of invasion dynamics—may be lower for more dispersive strains. Here, we use a mathematical model to show that unexpected invasion dynamics emerge from the combination of heritable dispersal polymorphism, dispersal-fitness trade-offs, and mutation between strains. We show that the invasion dynamics are determined by the trade-off relationship between dispersal and population growth rates of the constituent strains. We find that invasion dynamics can be ‘anomalous’ (i.e. faster than any of the strains in isolation), but that the ultimate invasion speed is determined by the traits of, at most, two strains. The model is simple but generic, so we expect the predictions to apply to a wide range of ecological, evolutionary, or epidemiological invasions.

中文翻译：

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由于分散多态性和分散 - 繁殖权衡引起的异常入侵动态

分散多态性和突变在生物入侵过程中起着重要作用，可能导致进化和复杂行为，例如加速或减速入侵前沿。然而，生活史理论预测，繁殖适应性——入侵动态的另一个关键决定因素——对于分散性更强的菌株可能较低。在这里，我们使用数学模型来表明意外的入侵动态来自可遗传的分散多态性、分散-适合度权衡和菌株之间的突变的组合。我们表明入侵动态是由组成菌株的扩散和种群增长率之间的权衡关系决定的。我们发现入侵动态可能是“异常的”（即比任何孤立的菌株都快），但最终的入侵速度是由最多两个品系的特性决定的。该模型简单但通用，因此我们希望预测适用于广泛的生态、进化或流行病学入侵。