Effects of an early‐life paraquat exposure on adult resistance to oxidative stress, plumage colour and sperm performance in a wild bird

Abstract

Early-life stressful conditions can shape individual phenotypes and ultimately influence fitness. Oxidative stress is a pervasive threat that affects many fitness-related traits and can modulate life-history trade-offs. Yet, the extent to which exposure to oxidative stress during early life can have long-lasting effects on key fitness-related traits remains to be elucidated, particularly in natural populations of vertebrates. Using a wild population of great tits Parus major, we experimentally dosed 11-day-old birds with paraquat, a pro-oxidant molecule, aiming at increasing oxidative stress. One year later, we recaptured 39 of them as adult recruiting breeders and quantified effects of the paraquat exposure on their resistance to oxidative stress, carotenoid-based plumage coloration and male sperm performance. Despite the absence of a short-term effect of paraquat on oxidative stress measured two days later, the pre-fledging exposure to paraquat induced a reduction in individual oxidative damage measured at adulthood. Paraquat-dosed individuals also had brighter plumage, but no effect was observed on male sperm performance. For the first time in a natural population of vertebrates, we experimentally show that an early-life acute exposure to a pro-oxidant has long-lasting effects on individual resistance to oxidative stress at adulthood. Our results are in line with the environmental matching and the hormesis hypotheses but may also reflect selective disappearance of individuals with lower resistance to oxidative stress.

Understanding diversity in oxidative status and oxidative stress: the opportunities and challenges ahead

“…However, results appear more conflicting when we come to the role of oxidative stress in determining lifespan or reproductive outcomes (e.g. Alonso-Alvarez et al, 2004Isaksson et al, 2011b;Noguera et al, 2012;Stier et al, 2012;Costantini, 2014;Beaulieu et al, 2015;Costantini and Dell'Omo, 2015;Blount et al, 2016;Costantini et al, 2016Costantini et al, , 2017Herborn et al, 2016;Colominas-Ciuró et al, 2017;Marasco et al, 2017;Merkling et al, 2017;Boonekamp et al, 2018;Casagrande and Hau, 2018;Losdat et al, 2018;Viblanc et al, 2018;Vágási et al, 2019). It is not trivial to assess the ecological and evolutionary relevance of oxidative stress, particularly in free-ranging animals.…”

Carry‐over effects of early thermal conditions on somatic and germline oxidative damages are mediated by compensatory growth in sticklebacks

“…Thermal stress during early life may directly influence oxidative status during adulthood if oxidative damage due to increased ROS production remains unrepaired, or if animals develop mechanisms to counteract oxidative stress under expected thermal conditions in the future (Losdat et al, 2018). Thermal stress experienced in early life may also indirectly cause delayed effects on cellular and physiological condition in adult life via compensatory growth (Metcalfe & Monaghan, 2001).…”