Meeting Abstract
Trade-offs between competing physiological systems comprise a core pillar of life-history theory, but the mechanisms that govern these processes are still poorly understood. Moreover, quantifying the amount and type of resources invested to critical physiological systems is inherently complicated and context-dependent. In a 2×2 design, we injected female side-blotched lizards with follicle-stimulating hormone to increase their reproductive investment and subjected them to an immune challenge (cutaneous biopsy), while measuring their oxygen consumption at different time points to assess the metabolic demands of these competing challenges. In addition to this, we injected the lizards with a stable nitrogen isotope and dissected them at the end of the experiment to measure what tissues had the highest demand for protein. Lizards that invested larger quantities of protein into their eggs had larger increases in metabolic rate, but lizards that had faster wound healing had larger decreases in metabolic rate, and the relationship of this change was related to the rate of healing. Additionally, lizards with increased reproductive investment exhibited higher levels of reactive oxygen metabolites. Although neither treatment affected either performance outcome directly, both simultaneously altered metabolism and protein investment, and thus differentially altered overall resource allocation strategy, indicating that both these processes are critical for an animal’s persistence.
