As ecosystems evolve, species can become extinct due to fluctuations in the environment. This leads to the evolutionary adaption known as bet-hedging, where species hedge against these fluctuations to reduce their likelihood of extinction. Environmental variation can be either within or between generations. Previous work has shown that selection for bet-hedging against within-generational variation should not occur in large populations. However, this work has been limited by assumptions of well-mixed populations, whereas real populations usually have some degree of structure. Using the framework of evolutionary graph theory, we show that through adding competition structure to the population, within-generational variation can have a significant impact on the evolutionary process for any population size. This complements research using subdivided populations, which suggests that within-generational variation is important when local population sizes are small. Together, these conclusions provide evidence to support observations by some ecologists that are contrary to the widely held view that only between-generational environmental variation has an impact on natural selection. This provides theoretical justification for further empirical study into this largely unexplored area.

随着生态系统的发展，物种可能会因环境的波动而灭绝。这导致了被称为赌注对冲的进化适应，其中物种对冲这些波动以减少它们灭绝的可能性。环境变化可以在代内或代之间。以前的工作表明，不应该在大群体中选择对冲代内变异的赌注。然而，这项工作受到了良好混合种群假设的限制，而真实种群通常具有一定程度的结构。使用进化图论的框架，我们表明，通过向种群添加竞争结构，代内变异可以对任何种群规模的进化过程产生重大影响。这补充了使用细分种群的研究，这表明当当地种群规模较小时，代内变异很重要。总之，这些结论为支持一些生态学家的观察提供了证据，这些观察与普遍持有的观点相反，即只有代际环境变化才会对自然选择产生影响。这为进一步实证研究这个很大程度上未开发的领域提供了理论依据。