Energetic investment associated with vitellogenesis induces an oxidative cost of reproduction

1. Oxidative stress is a potential cost of reproduction, but conclusive evidence for this relationship is lacking. The goal of this study was to serially assess across a seasonal gradient the relationship between reproduction, circulating plasma energy metabolites, and oxidative state. 2. Here we examine a study animal ideally suited to test for the oxidative costs of reproduction: The Allen Cays Rock Iguana. Female rock iguanas reproduce at varying frequencies, often skipping years, allowing for a comparison between reproductive and non-reproductive females during the same narrow, annual breeding season. This feature of iguana life-history enabled us to address not just sex and seasonal differences in physiology, but also potential oxidative costs of reproduction in females. 3. Male and female iguanas were sampled during the early (vitellogenic), late (gravid), and post-reproductive seasons. Ultrasound examinations were performed on females to quantify reproductive investment, and bl...