Spatially correlated extinctions select for less emigration but larger dispersal distances in the spider mite Tetranychus urticae

Dispersal is a central process to almost all species on earth, as it connects spatially structured populations and thereby increases population persistence. Dispersal is subject to (rapid) evolution and local patch extinctions are an important selective force in this context. In contrast to the randomly distributed local extinctions considered in most theoretical studies, habitat fragmentation or other anthropogenic interventions will lead to spatially correlated extinction patterns. Under such conditions natural selection is thought to lead to more long-distance dispersal, but this theoretical prediction has not yet been verified empirically. We test this hypothesis in experimental spatially structured populations of the spider mite Tetranychus urticae and supplement these empirical results with insights from an individual-based evolutionary model. We demonstrate that the spatial correlation of local extinctions changes the entire distribution of dispersal distances (dispersal kernel) ...扩散（Dispersal）是地球上几乎所有物种的核心生命过程，其能够连接空间结构化种群（spatially structured populations），进而提升种群存续能力。扩散性状会受到（快速）演化的影响，而局域生境斑块灭绝（local patch extinctions）在此过程中是一类重要的选择压力（selective force）。与多数理论研究中所采用的随机分布局域灭绝情景不同，生境破碎化（habitat fragmentation）或其他人为干预（anthropogenic interventions）会导致灭绝模式呈现空间相关性。在此类条件下，自然选择被认为会推动个体演化出更长距离的扩散策略，但这一理论预测尚未得到实证研究的验证。本研究以二斑叶螨（Tetranychus urticae）的空间结构化实验种群为对象，对该假说开展检验，并结合基于个体的演化模型（individual-based evolutionary model）的分析结果补充实证结论。本研究证实，局域灭绝的空间相关性会彻底改变扩散距离的整体分布，即扩散核（dispersal kernel）……