Host Performance as a Target of Manipulation by Parasites: A Meta-Analysis

TLDR: It is argued that performance capacity is an important target of parasitic manipulation, and the study of performance with that of parasitic manipulations of host behavior and fitness is integrated.

Abstract: The mechanisms underlying parasite-altered host behavior and fitness remain largely unanswered. The purpose of this review is to provide a perspective that has not been fully incorporated into the debate on how parasites manipulate their hosts. We argue that performance capacity is an important target of parasitic manipulation, and we aim to integrate the study of performance with that of parasitic manipulations of host behavior and fitness. We performed a meta-analysis from the published literature of 101 measures of the effect of parasites on host performance capacity to address the following questions. (1) Do parasites exert an important effect on host performance capacity? (2) Is that effect routinely to decrease or enhance performance capacity? And, (3) what factors explain variation in the effect sizes that have been quantified? Although negligible–small effect sizes were detected in 40/101 measures, host performance capacity was overall affected by parasitic infection, with a negative dir...