Rapid adaptive evolution in novel environments acts as an architect of population range expansion

Colonization and expansion into novel landscapes determine the distribution and abundance of species in our rapidly changing ecosystems worldwide. Colonization events are crucibles for rapid evolution, but it is not known whether evolutionary changes arise mainly after successful colonization has occurred, or if evolution plays an immediate role, governing the growth and expansion speed of colonizing populations. There is evidence that spatial evolutionary processes can speed range expansion within a few generations because dispersal tendencies may evolve upwards at range edges. Additionally, rapid adaptation to a novel environment
can increase population growth rates, which also promotes spread. However, the role of adaptive evolution and the relative contributions of spatial evolution and adaptation to expansion are unclear. Using a model system, red flour beetles (Tribolium castaneum), we either allowed or constrained evolution of populations colonizing a novel environment, and meas...

在全球快速变化的生态系统中，物种的分布格局与种群丰度由其对新生境的定殖与扩张过程共同决定。定殖事件是快速演化的天然熔炉，但目前学界尚未明确：演化改变主要发生在成功定殖之后，还是演化会即刻发挥调控作用，决定定殖种群的增长速率与扩张速度。已有研究证据表明，空间演化过程可在数代内加速种群分布范围的扩张，这是因为种群分布边缘的扩散倾向会向增强方向演化。此外，对新生境的快速适应性演化可提升种群增长率，进而促进种群扩散。然而，适应性演化在种群扩张中的具体作用，以及空间演化与适应性演化对扩张过程的相对贡献，目前仍不明确。本研究以模式生物赤拟谷盗（Tribolium castaneum）为实验体系，对定殖新生境的种群分别设置允许演化与限制演化的两组处理，并开展了相关测量（原文后续内容未完整呈现）