Meeting Abstract
Energy is limited and must be allocated among competing functions. Allocation of energy to one function can carry fitness costs through reduced energy availability to other functions. For example, individuals facing a health challenge, such as a parasite infection, might respond by shifting resources previously allocated to other life-history functions in favor of fighting said infection. Trade-offs might also exist within the same function. For instance, investing in one health parameter may implicate another. In a previous study, we found that adult male red-winged blackbirds (Agelaius phoeniceus) with higher corticosterone have greater tolerance to the Haemosporidian parasites that cause malaria. However, we do not know whether individuals with higher malarial tolerance (measured as reduced loss in hematocrits and hemoglobin) implicates health in other ways or is linked to increased costs in terms of energy expenditure, and thus if there is a trade-off between corticosterone and any of these functions. Here, we present the result of a study aimed at testing whether higher corticosterone and tolerance to malaria is associated with: 1) higher energy and metabolic expenditure, 2) higher oxidative stress, and/or 3) overall health. We test these predictions using measures of corticosterone, hematocrits, hemoglobin, glucose, oxidative stress, and intensity of malarial infection in wild red-winged blackbirds. The results of this study are part of broader research looking at the coping mechanisms employed by individuals to respond to infections.
