Lombaert E, Estoup A, Facon B, Joubard B, Grégoire J-C, Jannin A, Blin A, Guillemaud T
UMR 1355 ISA, Inra, Sophia-Antipolis, France.
UMR ISA, Université de Nice Sophia Antipolis, Sophia-Antipolis, France.
J Evol Biol. 2014 Mar;27(3):508-17. doi: 10.1111/jeb.12316. Epub 2014 Jan 21.
The evolutionary trajectories associated with demographic, genetic and spatial disequilibrium have become an issue of growing interest in population biology. Invasive species provide unique opportunities to explore the impact of recent range expansion on life-history traits, making it possible to test for a spatial arrangement of dispersal abilities along the expanding range, in particular. We carried out controlled experiments in laboratory conditions to test the hypothesis of an increase in dispersal capacity with range expansion in Harmonia axyridis, a ladybird that has been invading Europe since 2001. We found a marked increase in the flight speed of the insects from the core to the front of the invasion range in two independent sampling transects. By contrast, we found that two other traits associated with dispersal (endurance and motivation to fly off) did not follow the same spatial gradient. Our results provide a striking illustration of the way in which predictable directional genetic changes may occur rapidly for some traits associated with dispersal during biological invasions. We discuss the consequences of our results for invasion dynamics and the evolutionary outcomes of spatially expanding populations.
与种群统计学、遗传学和空间不平衡相关的进化轨迹已成为种群生物学中一个越来越受关注的问题。入侵物种为探索近期范围扩张对生活史特征的影响提供了独特的机会，尤其使得检验沿扩张范围的扩散能力的空间排列成为可能。我们在实验室条件下进行了对照实验，以检验自2001年以来一直在入侵欧洲的瓢虫异色瓢虫随范围扩张扩散能力增加这一假设。在两个独立的采样样带中，我们发现从入侵范围的核心到前沿，昆虫的飞行速度显著增加。相比之下，我们发现与扩散相关的其他两个特征（耐力和飞走的动机）并未遵循相同的空间梯度。我们的结果显著说明了在生物入侵过程中，与扩散相关的某些特征可能会迅速发生可预测的定向遗传变化。我们讨论了我们的结果对入侵动态和空间扩张种群进化结果的影响。
