Impact of infection on mate choice

Sexual selection predicts that mate choice increases individual fitness. Infection by parasites (from eukaryotes to bacteria or viruses) can reduce this individual fitness, altering the infected individualsʹ sexual traits and molecular cues. In this case, one would expect to observe mechanisms for avoiding infection during mate choice. The vast majority of host responses to infection in terms of mate choice are intended to avoid infection, but the costs of mate choice can also hinder infection avoidance. This paper highlights the main limitations in current knowledge and empirical experiments, and summarizes the key factors that should be taken into account to test the hypothesis of infection avoidance in mate choice: the time of host–parasite coevolution in the biological interaction implied, the choosy sex tested (male, female or both) and the genetic background of the individuals tested.