Meeting Abstract
Parasite exposure typically results in the energetically costly activation of the immune system. Despite the necessity of these responses, there is great variation in costs incurred during immune activation within and among populations. Such costs are likely driven by factors including differences in host ability to obtain resources, environmental pressures and history of exposure. This lack of consistency in costs can lead to variation in how hosts respond to and cope with an infection, ultimately affecting host-parasite dynamics (e.g., parasite virulence). While it has been well demonstrated that immune activation is costly, the relationship between costs of activation and the immune protection that results remains poorly understood. In order to better predict parasite virulence and how parasites will move through communities, we need to gain a better understanding of variation in the cost-benefit ratio associated with parasite exposure. Here, we used experimental malaria (Plasmodium sp.) infections in brown anoles (Anolis sagrei) to explore if high costs of immune activation ultimately result in better protection from parasites. Cost was determined during the acute phase of infection by measuring the amount of oxidized tracer from an oral dose of 13C-labelled glucose and correlating oxidization with parasite load 7 days later. We hypothesized that individuals that experienced higher costs of activation during the acute phase would experience greater parasite protection and consequently have lower parasite loads at 7 days post infection compared to individuals that experienced lower costs. Our results will be some of the first to demonstrate the relationship between cost of immune activation and parasite protection, paving the way for a greater understanding of how host immune responses affect host-parasite co-evolution.
