Reproductive effort and oxidative stress: effects of offspring sex and number on the physiological state of a long-lived bird

• Published in: Functional Ecology
• Main Authors: Merkling, Thomas, Blanchard, Pierrick, Chastel, Olivier, Glauser, Gaétan, Vallat-Michel, Armelle, Hatch, Scott A., Danchin, Etienne, Helfenstein, Fabrice
• Other Authors: Evolution et Diversité Biologique (EDB), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Neuchâtel Platform of Analytical Chemistry (NPAC), Université de Neuchâtel (UNINE), Institute for Searbird Research and Conservation, Institute of Biology of the University of Neuchâtel
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: oxidative cost of reproduction; malondialdehydes; cost of reproduction hypothesis; sex allocation; parental care; Rissa tridactyla: superoxide dismutase; black-legged kittiwake; [SDE]Environmental Sciences; Black-legged Kittiwake; rissa tridactyla
• Online Access: https://hal.science/hal-01505317; https://doi.org/10.1111/1365-2435.12829

International audience 1. Individuals must trade-off between energetically costly activities to maximize their fitness.However, the underlying physiological mechanism remains elusive. Oxidative stress, the imbalancebetween reactive oxygen species production and antioxidant and/or repair activities, hasbeen suggested to underlie life-history trade-offs: greater investment in reproduction supposedlygenerating higher oxidative damage, thus reducing life span.2. While most studies used natural or experimental variation in offspring number to examinehow reproduction affects oxidative stress, none studied the impact of offspring sex, although itcould influence physiological costs and fitness, if the sexes differ in terms of energetic cost.3. Here, we aim at further understanding how reproduction (in terms of offspring sex, experimentallymanipulated and number, not manipulated) influences oxidative stress in a wild seabird,where sons are energetically costlier than daughters. We did so by conducting a chickfostering experiment (to disentangle foster and produced sex ratio) and using four oxidativestress markers plus baseline corticosterone.4. First, the results suggest that individual physiological state before laying modulatesupcoming reproductive effort. Individuals with higher pre-laying baseline corticosterone andlower antioxidant activity, estimated by their superoxide dismutase activity, subsequentlyinvested more in reproduction, estimated by the cumulative number of days spent rearingchicks. Hence, it seems that only individuals that could afford to invest heavily in reproductiondid so.5. Then, we examined the effects of reproductive effort on individual physiological state atthe end of the breeding season. Higher reproductive effort seemed to imply higher physiologicalcosts. Oxidative stress, estimated by the ratio of oxidized over reduced glutathione,increased with more male-biased foster sex ratio among mothers but not among fathers,whereas baseline corticosterone did so in both sexes. Similarly, lipid ...