On the relationship between body condition and parasite infection in wildlife: a review and meta‐analysis

Body condition metrics are widely used to infer animal health and to assess costs of parasite infection. Since parasites harm their hosts, ecologists might expect negative relationships between infection and condition in wildlife, but this assumption is challenged by studies showing positive or null condition–infection relationships. Here, we outline common condition metrics used by ecologists in studies of parasitism, and consider mechanisms that cause negative, positive, and null condition–infection relationships in wildlife systems. We then perform a meta‐analysis of 553 condition–infection relationships from 187 peer‐reviewed studies of animal hosts, analysing observational and experimental records separately, and noting whether authors measured binary infection status or intensity. Our analysis finds substantial heterogeneity in the strength and direction of condition–infection relationships, a small, negative average effect size that is stronger in experimental studies, and eviden...身体状况指标（body condition metrics）被广泛用于推断动物健康状况，以及评估寄生虫感染的代价。由于寄生虫会对宿主造成损害，生态学家通常会预期野生动物体内的感染程度与身体状况指标之间存在负相关关系，但这一假设受到了诸多研究的挑战——这些研究显示二者间存在正相关或零相关的关联。本文梳理了生态学家在寄生虫学研究中常用的身体状况指标，并探讨了野生动物系统中导致感染与身体状况呈现负相关、正相关及零相关关系的潜在机制。随后，我们对187项经同行评议的动物宿主研究中的553组感染与身体状况关联数据开展荟萃分析（meta-analysis），分别对观测性记录与实验性记录进行分析，并标注作者是否测量了二元感染状态或感染强度。本研究发现，感染与身体状况的关联在强度与方向上均存在显著异质性；整体平均效应量呈微弱负相关，且实验性研究中的该负相关效应更强，同时研究发现……