Data from: Biogeography of avian blood parasites (Leucocytozoon spp.) in two resident hosts across Europe: phylogeographic structuring or the abundance-occupancy relationship?

Relationships between hosts and parasites represent complex co-evolving systems that can vary both temporally and spatially. This variation may contribute to different co-evolutionary outcomes, ranging from highly geographically structured parasite populations comprised of specialist lineages that are locally abundant but have restricted global occupancy, to geographically unstructured parasite populations comprised of abundant generalists with broad global occupancy. Here, we present results from a large biogeographic study of the avian blood parasites of two sedentary host species, conducted at nine sites across Europe in a single year. The aim was to determine whether the parasite lineages were geographically and genetically structured across Europe, which could imply local adaptation. Employing molecular methods, we found a large diversity of parasites, and although overall prevalence varied greatly, the parasites were not genetically structured across Europe. Several measures of local parasite abundance were associated with the number of sites that the lineage occurred in, which is consistent with the macroecological phenomenon of the abundance-occupancy relationship. Taken together, our results show that parasite dispersal is somewhat uncoupled to that of the host in this system: we suggest that broad host and/or vector preference may play an important role in determining the distribution of these parasites and in affecting host-parasite coevolution in this system.

宿主与寄生虫的相互作用构成了复杂的协同演化系统，其特征随时间与空间维度发生动态变化。这种时空变异可能催生多样的协同演化结局：从由局部丰度较高但全球分布范围受限的特化谱系构成、且具有高度地理结构的寄生虫种群，到由全球分布范围广泛的泛化谱系构成、无明显地理结构的寄生虫种群。
本研究针对欧洲9个采样点、在单一年度内开展了针对两种定居性宿主鸟类血液寄生虫的大型生物地理学研究，核心目标为解析欧洲范围内寄生虫谱系是否存在地理与遗传结构，若存在则可佐证其本地适应现象。
本研究采用分子生物学方法，共检测到丰富的寄生虫多样性；尽管整体感染率存在显著差异，但欧洲范围内的寄生虫并未呈现明显的遗传结构。多项本地寄生虫丰度指标与该谱系占据的采样点数量呈显著相关，这与宏生态学中的丰度-占据关系（abundance-occupancy relationship）现象相符。
综合来看，本研究结果表明，该系统中寄生虫的扩散与宿主的扩散存在一定程度的解耦；我们推测，广泛的宿主偏好或（及）传播媒介偏好，可能是决定此类寄生虫分布格局、并影响该系统中宿主-寄生虫协同演化过程的关键因素。