Oxygen, telomeres and sex: experimental elucidation of oxidative stress effects in life history evolution
Oxidative stress -the imbalance between antioxidants and reactive oxygen species (ROS) generated during aerobic respiration- has often been hypothesized to play a central role in disease and life history evolution, including ageing. However, whether oxidative stress modulates patterns of growth, reproduction and survival is still an enigma, largely because the high reactivity of ROS makes oxidative stress difficult to measure.  In addition to this, the experimental manipulation of oxidative stress levels without toxic side-effects has also proven difficult. I propose to elucidate oxidative stress effects on (cellular) ageing and key fitness components using a novel non-invasive experimental approach that bypasses side effects of pharmacological approaches. To this end, I will expose birds to hyperoxic air, which is known to increase oxidative stress. This will be combined with alleviation of oxidative stress through the administration of antioxidants in a 2x2 design, to verify that the observed effects of hyperoxia can be attributed to oxidative stress. First, I will test the effect of both interventions on sexual ornamentation, sperm quality and future reproduction using captive adult zebra finches. Second, by applying the same 2x2 design to nestlings I will test how oxidative stress affects future reproduction and cellular ageing (telomere attrition). The latter aims to resolve the long-standing question whether the effect of oxidative stress in vitro is also observed in vivo, at physiological oxidative stress levels. In this way, this Action will shed light on the conundrum of the roles of oxidative stress in life history evolution and telomere dynamics. Moreover, through mutual knowledge transfer and the extension of my scientific network (both in the host institution and through dissemination events that I will organize around Europe), this Action will critically advance my career towards the establishment as independent researcher.