Phylogenetic signal in module composition and species connectivity in compartmentalized host-parasite networks

Across different taxa, networks of mutualistic or antagonistic interactions show consistent architecture. Most networks are modular, with modules being distinct species subsets connected mainly with each other and having few connections to other modules. We investigate the phylogenetic relatedness of species within modules and whether a phylogenetic signal is detectable in the within- and among module connectivity of species using 27 mammal-flea networks from the Palaearctic. In the 24 networks that were modular, closely-related hosts co-occurred in the same module more often than expected by chance; in contrast, this was rarely the case for parasites. The within- and among-module connectivity of the same host or parasite species varied geographically. However, among-module but not within-module connectivity of host and parasites was somewhat phylogenetically constrained. These findings suggest that the establishment of host-parasite networks results from the interplay between phylogene...不同生物分类群中，互利或拮抗互作网络均呈现出一致的架构特征。绝大多数网络具有模块化结构，模块即主要内部连通、与其他模块间连接极少的物种子集。本研究以古北界（Palaearctic）的27组哺乳动物-跳蚤互作网络为研究对象，探究模块内物种的系统发育亲缘关系，以及物种在模块内部与模块间的连通性中是否存在可检测的系统发育信号。在24个呈现模块化结构的网络中，亲缘关系相近的宿主物种共现于同一模块的概率显著高于随机预期；与之相反，寄生物种则鲜有此规律。同一宿主或寄生物种的模块内、模块间连通性存在地理变异。不过，宿主与寄生物的模块间连通性（而非模块内连通性）存在一定程度的系统发育约束。本研究结果表明，宿主-寄生物网络的形成源于系统发育与