Meeting Abstract
The immune system is a critical component of health and fitness, whereby organisms must maintain sufficient health to survive to reproduce. Because of the key role of immunity in an organism’s fitness, the use of immunological indices is widespread. However, there is a paucity of empirical support for the best way to interpret immunological data, and the internal energetic state of the organism, as well as the external environmental pressures it faces, are often not considered concurrently. Presently, a more robust immune response is thought to be advantageous, regardless of context. In reality, a “weaker” response may ultimately lead to improved fitness if the animal incurs fewer performance costs on competing systems, especially reproduction. To determine the fitness consequences of immunity, individual immunity and reproduction must be linked to population performance. A synthesis of results will be presented using a well-studied model organism, the side-blotched lizard, from a combination of field and laboratory studies to test the hypothesis that resource availability alters energy allocation among the immune and reproductive systems. Specifically, experiments involving specific immune and reproductive metabolic and performance costs in a laboratory setting will be discussed, as well as associated demographic trade-offs between survival and reproductive success, demonstrating essential links between immunity and the population.
