Data from: Biological and statistical processes jointly drive population aggregation: using host–parasite interactions to understand Taylor's power law

The macroecological pattern known as Taylor's power law (TPL) represents the pervasive tendency of the variance in population density to increase as a power function of the mean. Despite empirical illustrations in systems ranging from viruses to vertebrates, the biological significance of this relationship continues to be debated. Here we combined collection of a unique dataset involving 11 987 amphibian hosts and 332 684 trematode parasites with experimental measurements of core epidemiological outcomes to explicitly test the contributions of hypothesized biological processes in driving aggregation. After using feasible set theory to account for mechanisms acting indirectly on aggregation and statistical constraints inherent to the data, we detected strongly consistent influences of host and parasite species identity over 7 years of sampling. Incorporation of field-based measurements of host body size, its variance and spatial heterogeneity in host density accounted for host identity effects, while experimental quantification of infection competence (and especially virulence from the 20 most common host–parasite combinations) revealed the role of species-by-environment interactions. By uniting constraint-based theory, controlled experiments and community-based field surveys, we illustrate the joint influences of biological and statistical processes on parasite aggregation and emphasize their importance for understanding population regulation and ecological stability across a range of systems, both infectious and free-living.

被称为泰勒幂定律（Taylor's power law, TPL）的宏观生态学模式，指种群密度的方差随均值的幂函数形式增长的普遍趋势。尽管该规律在从病毒到脊椎动物的各类系统中均有实证例证，但这一关系的生物学意义至今仍存在争议。本研究整合了一份涵盖11987个两栖动物宿主与332684个吸虫类寄生虫的独特数据集，以及针对核心流行病学结局的实验测量数据，以此明确检验各类假说性生物学过程对寄生虫聚集现象的驱动作用。本研究运用可行集理论（feasible set theory），对间接作用于聚集现象的机制以及数据本身固有的统计约束进行校正后，在长达7年的采样过程中，检测到宿主与寄生虫的物种属性对聚集现象具有高度一致的影响。通过纳入野外实测的宿主体型、体型方差以及宿主密度的空间异质性数据，我们解释了宿主属性效应的来源；而针对20种最常见宿主-寄生虫组合的感染能力（尤其是毒力）的实验定量分析，则揭示了物种-环境互作的作用。本研究通过结合约束性理论、受控实验与基于群落的野外调查，阐明了生物学过程与统计过程对寄生虫聚集现象的共同影响，并强调二者对于理解各类（包括寄生与自由生活的）系统中的种群调控与生态稳定性均具有重要意义。