Ecological and Evolutionary Consequences of Parasite Avoidance

• Published in: Trends in ecology & evolution (Amsterdam) 2018-08, Vol.33 (8), p.619-632
• Main Authors: Buck, J.C., Weinstein, S.B., Young, H.S.
• Format: Article
• Language: English
• Subjects: Animals; Behavior, Animal; behavioral immunity; Biological Evolution; Communicable Diseases; Disgust; Host-Pathogen Interactions; Humans; landscape of disgust; landscape of fear; Nonconsumptive effect; Parasites
• ISSN: 0169-5347; 1872-8383
• DOI: 10.1016/j.tree.2018.05.001

Predators often cause prey to adopt defensive strategies that reduce predation risk. The ‘ecology of fear’ examines these trait changes and their consequences. Similarly, parasites can cause hosts to adopt defensive strategies that reduce infection risk. However the ecological and evolutionary consequences of these behaviors (the ‘ecology of disgust’) are seldom considered. Here we identify direct and indirect effects of parasite avoidance on hosts and parasites, and examine differences between predators and parasites in terms of cost, detectability, and aggregation. We suggest that the nonconsumptive effects of parasites might overshadow their consumptive effects, as has been shown for predators. We emphasize the value of uniting predator–prey and parasite–host theory under a general consumer–resource framework. Many predators cause prey to adopt defensive strategies that reduce predation risk. Similarly, costly, detectable, and aggregated parasites cause hosts to adopt defensive strategies that reduce infection risk. Parasite-avoidance behavior has important ecological and evolutionary consequences for hosts, parasites, and the communities in which they live. The cumulative effects of parasite avoidance might be as strong, if not stronger, than those associated with predator avoidance. Nevertheless, they have received far less attention from ecologists. Although the potential for parasites to alter host behavior is well recognized, this is usually triggered through a parasite’s consumptive effects (i.e., infection). Here we emphasize the potential for parasites to alter host behavior through their nonconsumptive effects.