Behavioral competence: how host behaviors can interact to influence parasite transmission risk

•Behavioral defenses decrease risk of contracting and spreading parasites.•The cumulative expression of multiple anti-parasite behaviors determines risk.•Behavioral profiles can be plastic with regard to environment or infection status.•Behavioral and immunological systems are tightly linked.

Hosts vary in their ability to transmit new parasite infections (i.e. competence). Although behavior is suggested as a source of individual-level variation, the contribution of host behavior to host-parasite dynamics at the population-level remains largely enigmatic. Here we advocate that behavioral competence be characterized as a syndrome of behaviors that interact to directly or indirectly influence transmission potential. These behaviors can be plastic in response to environmental conditions and/or infection state, and appear linked to immunological traits through shared physiological regulation. By integrating behavioral variation and covariation into a whole-organism view of host competence, disease ecologists might more realistically characterize an individual's role in host-parasite systems.