Data from: Metapopulation structure of a seed-predator weevil and its host plants in arms race coevolution

Although the importance of gene flow in the geographic structuring of host–parasite interactions has been well discussed, little is known about how dispersal drives the spatial dynamics of other types of coevolutionary interactions in nature. We evaluated the roles of gene flow in the geographically structured processes of a predator–prey arms race involving a seed-predatory weevil with a long mouthpart and its host camellia plant with a thick fruit coat. Molecular genetic analyses showed that both weevil and camellia populations were structured at a spatial scale of several kilometers. Importantly, the spatial pattern of the migration of weevils, but not that of camellias, imposed significant effects on the geographic configuration of the levels of coevolutionary escalation. This result suggests that even if migration is limited in one species (camellia), local coevolution with the other species that migrates between neighboring localities (weevil) can reduce the inter-population difference in the local adaptive optima of the former species. Thus, gene flow of a species potentially homogenizes local biological environments provided by the species and thereby promotes the evolutionary convergence of its coevolving counterparts. Consequently, by focusing on coevolutionary interactions in natural communities, “indirect” effects of gene flow on the adaptive divergence of organisms could be identified.

尽管基因流（gene flow）在宿主-寄生相互作用的地理结构中的重要性已得到广泛讨论，但学界对扩散如何驱动自然界中其他类型协同进化相互作用的空间动态仍知之甚少。本研究针对一场捕食者-猎物军备竞赛的地理结构化过程，评估了基因流所扮演的角色；该竞赛涉及一种具有长口器的种子捕食性象鼻虫，以及其宿主——一种拥有厚实果皮的山茶属植物。分子遗传分析显示，象鼻虫和山茶的种群均在数公里的空间尺度上呈现地理结构。值得注意的是，象鼻虫的迁移空间格局（而非山茶的迁移空间格局）对协同进化升级程度的地理分布格局产生了显著影响。该结果表明，即便某一物种（山茶）的迁移受限，其与在相邻生境间迁移的另一物种（象鼻虫）之间的本地协同进化，可降低该物种（前者）的本地适应最优值的种群间差异。据此，某一物种的基因流可能会均质化该物种所构建的本地生物环境，进而促进其协同进化伙伴的进化趋同。综上而言，通过聚焦自然群落中的协同进化相互作用，便可识别出基因流对生物适应性分化的"间接"效应。