Data from: Size matters for lice on birds: coevolutionary allometry of host and parasite body size

Body size is one of the most fundamental characteristics of all organisms. It influences physiology, morphology, behavior, and even interspecific interactions such as those between parasites and their hosts. Host body size influences the magnitude and variability of parasite size according to Harrison's Rule (HR: positive relationship between host and parasite body sizes) and Poulin’s Increasing Variance Hypothesis (PIVH: positive relationship between host body size and the variability of parasite body size). We analyzed parasite-host body size allometry for 581 species of avian lice (~15% of known diversity) and their hosts. We applied phylogenetic generalized least squares methods to account for phylogenetic non-independence controlling for host and parasite phylogenies separately and variance heterogeneity. We tested HR and PIVH for the major families of avian lice (Ricinidae, Menoponidae, Philopteridae), and for distinct ecological guilds within Philopteridae. Our data indicate that most families and guilds of avian lice follow both HR and PIVH; however, Ricinids did not follow PIVH and the "body lice" guild of Philopterid lice did not follow HR or PIVH. We discuss mathematical and ecological factors that may be responsible for these patterns, and we discuss the potential pervasiveness of these relationships among all parasites on Earth.

体型是所有生物体最核心的基本特征之一，其能够对生理学、形态学、行为学乃至种间相互作用（如寄生虫与宿主间的相互作用）产生影响。依据哈里森法则（Harrison's Rule, HR，即宿主与寄生虫体型呈正相关关系）与普林方差递增假说（Poulin’s Increasing Variance Hypothesis, PIVH，即宿主体型与寄生虫体型的变异程度呈正相关关系），宿主体型会影响寄生虫体型的大小及其变异幅度。
本研究针对581种鸟类羽虱（约占已知物种多样性的15%）及其宿主，开展了宿主-寄生虫体型异速生长（allometry）关系分析。研究采用系统发育广义最小二乘法（phylogenetic generalized least squares），以校正系统发育非独立性，同时分别对宿主与寄生虫的系统发育背景及方差异质性进行控制。本研究针对鸟类羽虱的三大科（Ricinidae、Menoponidae、Philopteridae）以及Philopteridae科内的不同生态类群，对HR与PIVH进行了验证。
研究数据显示，绝大多数鸟类羽虱科与生态类群均同时符合哈里森法则与普林方差递增假说；但Ricinidae科类群并不符合普林方差递增假说，而Philopteridae科的"体虱"生态类群则既不符合哈里森法则，也不符合普林方差递增假说。本研究探讨了可能解释上述观测模式的数学与生态学机制，并讨论了上述体型相关关系在全球所有寄生虫类群中潜在的普遍性。