Research Interests

Dispersal syndromes and metapopulation dynamic

My major goal is to understand how dispersal syndromes explain metapopulation dynamics using the common lizards as a model (Zootoca vivipara). Recent studies show that individuals leaving their natal population to settle in a novel habitat (dispersers) and individuals staying in their natal population (residents) display different suites of phenotypic traits. Those individuals might differ from residents for physiological, morphological and behavioral traits and these traits might drive their dispersal decisions from the departure to their settlement in specific habitats. Furthermore, even among dispersers, several types of individuals (with different suites of phenotypic traits) can be observed, explaining why some dispersers prefer settling in empty habitats while others settle in already occupied habitats. These different types of dispersers would depart from their population in response to different ecological factors (population density, kin competition). The dynamic and the persistence of fragmented populations (i.e. metapopulation) depend on the colonization of empty patches, the reinforcement of already occupied patches and the extinction of those already occupied patches. Colonization and reinforcement should involve different types of dispersers. The diversity of dispersal syndromes can therefore be an important factor explaining metatpopulation dynamic.

Behavioral syndromes and biological invasions

Ecological invasions are a major threat to biodiversity and an important element of global change with major economic and ecological costs. Invasions occur when a species introduced to areas beyond its native range spreads from the point of introduction and becomes abundant. At high densities, invasive species often have large negative impacts on native species. The management of invasive species is one of the major challenges in modern ecology. One classical approach is to identify characteristics that predispose a species to become a successful invader. This approach has however had only limited success in the predictability of invasion success. I have been studying on mosquitofish (Gambusia affinis) a new solution to this problem coming through the recent recognition of within-species variation in behavior. Indeed, while many previous studies have focused on species characteristics that might explain between-species differences in invasiveness, a new exciting approach looks at how individual variation in traits within species might influence invasion dynamics. In particular, an aspect of within-species variation that has garnered substantial recent interest involves individual variation in animal personalities. Animal personalities emphasize the idea that different individuals exhibit relatively stable, consistent differences in behavioral types (BT) carried over across multiple contexts. The general hypothesis is individuals’ BT may affect their colonization success, meaning that some individuals might be better invaders than others (aggressive individual, asocial individuals). With BT-dependent dispersal, individuals leading an invasion front might often display behavioral traits that facilitate the colonization of new habitats and hasten the spread of an invasive species.

Socially acquired information and dispersal decisions

Leaving its population is a fundamental question facing any candidate for dispersal, as dispersing without information on the surrounding habitats has major costs. Most studies on this topic have focused on risk-reducing strategies (e.g. exploration) developed after leaving the natal habitat. My work on common lizards showed that immigrants are a source of information about surrounding populations that might be acquired before leaving and can modulate dispersal decisions.

Ecophysiology of the stress response

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. My work shows that, 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).

Carotenoid-based coloration, oxidative stress and immune response

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).

Ongoing collaborations

Evolution and Biological Diversity (UMR 5174, Toulouse, France)

Etienne Danchin (http://www.edanchin.fr/)

Julien Cucherousset (http://sites.google.com/site/juliencucherousset/home)

Experimental ecology centre CNRS (USR 2936, Saint-Girons, France)

Jean Clobert (http://www.ecoex-moulis.cnrs.fr/Staffpages/Jeanclobert.htm)

Simon Blanchet (http://simon.blanchet1.free.fr/)

Department of Environmental Science and Policy (Davis, USA)

Andrew Sih (http://www.des.ucdavis.edu/research/sihlab/)

Sean Fogarty (spfogarty@ucdavis.edu)

Kelly Smith ( klsmithbio@gmail.com)

Jonathan Pruitt (https://sites.google.com/site/agelenopsis/home)