Temporal and spatial covariation of gender and oxidative stress in the Galápagos land iguana Conolophus subcristatus.
Abstract Physiological responses to organismal stress can have direct impacts on individual fitness. While responses to stressors mediated by glucocorticoid hormones are well studied, the regulation of the redox system via pro-oxidant and antioxidant balance as well as the natural causes of oxidative stress in nature remain poorly known, especially for reptiles. In this study, we investigate the interpopulation and intersex variation in oxidative damage and plasma antioxidant capacity in the Galápagos land iguana, Conolophus subcristatus, over a 3-yr study to evaluate what factors (e.g., season, food availability, reproductive activity) can explain levels and patterns of oxidative damage and of plasma antioxidant capacity. Our results indicate that (1) males showed lower levels of oxidative damage, higher levels of plasma antioxidant capacity, and better body condition than females and (2) significant interactions exist among patterns of oxidative damage across sexes, sampling localities, body condition, and season. These results suggest that reproductive activity and food abundance might act as determinants shaping levels and patterns of oxidative stress of land iguanas.
Costantini
David
D
Ornis italica, Piazza Crati 15, I-00199 Roma, Italy. david.costantini@uniroma1.it
Dell'Omo
Giacomo
G
De Filippis
Stefania Paola
SP
Marquez
Cruz
C
Snell
Howard L
HL
Snell
Heidi M
HM
Tapia
Washington
W
Brambilla
Gianfranco
G
Gentile
Gabriele
G
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D004484:Ecuador; D005260:Female; D007076:Iguanas / Q000378:metabolism* / Q000502:physiology; D008297:Male; D018384:Oxidative Stress; D011157:Population Dynamics; D012098:Reproduction; D012621:Seasons; D012727:Sex Characteristics; D013997:Time Factors
D000975:Antioxidants