Ecophysiology of the stress response
I used to work on stress response and I hope to integrate stress response in our work on climate change and predation risk. In response to stressful conditions, animals modify their behavior and physiology to avoid or balance negative effects of stress. In many cases, responses to environmental perturbations involve the production of glucocorticoids that often mediate changes in physiological pathways and behavioural expression that minimize energy expenditure. These stress responses constitute a set of adaptive changes that should promote immediate survival. In common lizards, chronic elevation of glucocorticoids as a response to a long-lasting stressor may be an adaptive mechanism inducing behavioural and physiological changes similar to those involved in the acute stress response. However, as a sustained elevation of glucocorticoid production requires more energy than a temporary one and may have negative consequences (e.g. reduced immunocompetence or neural degeneration), the behavioural and physiological modifications may not be activated in conditions in which resource availability/energetic reserves does not compensate for the energetic requirements of the stress response (e.g. low food availability context).
Past collaborators: S. Meylan, P. Fitze, J. Clobert
Project status: Research projects on pause
Coloration, oxidative stress and immune response
As for stress response, I used to work on carotenoid-based coloration and oxidative stress. Carotenoid-based coloration is a common signal of individual quality that is partly environmentally determined. Indeed, carotenoids are also used for immune function and for antioxidant activity, leading to a trade-off between ornamentation and health for limited carotenoids. I am interested in the physiological aspects of this trade-off and of the maintenance of exaggerated coloration on the common lizard and on the zebra finch (Taeniopygia guttata). I investigated physiological modulations of carotenoid-based colorations (i.e. corticosterone and immune activation) and the consequences on health and condition (i.e. oxidative stress and body condition).
Past collaborators: P. Fitze, G. Sorci, B. Faivre, E. Arnoux, Y. Voituron
Project status: Research projects on pause
Julien Cote 