Food Subsidy Effects on Host Foraging Behavior Shape Host-Macroparasite Infection Dynamics

Le résumé fourni par la source

1. Anthropogenic food subsidies can have profound influences on wildlife behavior and health, including exposure to parasites. In many host-macroparasite systems, parasite exposure is tied to foraging behavior, but how different distributions of food subsidy shape macroparasite encounter and population-level impacts is poorly understood. 2. Here we modify a mathematical model of macroparasite transmission to explore how food subsidies could change parasite encounter rates and between-host variation in parasite burdens, reflecting changes in host foraging and conspecific overlap. 3. Hosts experience the highest average parasite abundance, and associated reductions in population size, when food subsidies increase and homogenize parasite encounter rates, for example when hosts center their home ranges on a point food source and overlap with many conspecifics. Conversely, hosts experience the lowest parasite abundance and impacts when subsidies result in lower and more heterogeneous parasite encounter rates, for example when multiple, patchily-distributed subsidies subdivide host populations and increase host commute times to food at the expense of time spent foraging. Even when resources affect other processes such as improving host immunity or fecundity, the overall effect of subsidies on infection is more strongly driven by changes in parasite encounter rates through altered foraging behavior. These patterns are robust to different effect sizes of resource subsidy on foraging and non-foraging parameters. 4. The finding that host foraging behavior strongly influences infection outcomes in environmentally-acquired parasites has implications for the provisioning of wildlife for recreation, conservation, and management. We advocate for distributing food subsidies in ways that reduce artificial aggregation of hosts and the time animals spend at feeding stations, or that reduce environmental parasite encounters while feeding.

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