Data from: 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 blood
samples were collected for physiology assays, which included reactive
oxygen metabolites (d-ROMs), antioxidants, triglycerides, free glycerol,
and glucose. 4. The early reproductive season was characterized by
significant increases in reproductive female’s triglycerides, free
glycerol, and oxidative stress compared to late and post-reproductive
periods and non-reproductive females and males during all sampling
periods. Antioxidants were significantly elevated during the early
reproductive season for reproductive females, non-reproductive females,
and males when compared to late and post-season. Follicle number in early
reproductive females was positively related to d-ROMs, triglycerides, and
free glycerol, negatively related to antioxidants, and showed no
relationship with glucose. Measures of oxidative stress, d-ROMs and
oxidative index were positively correlated with circulating levels of the
lipid metabolite free glycerol during the early reproductive period, but
this relationship weakened in the late season and disappeared in the
post-season. 5. Broadly, this study supports the hypothesis that the
relationship between reproduction and oxidative stress is driven by energy
investment, being greatest during early reproduction when vitellogenesis
is occurring.