My research
PhD project: 2014 - 2018
Supervised by Denis Réale & Dany Garant
My PhD project focuses on the impacts of personality on spatial, genetic and population dynamics of rodents among a series of island.
Island environments, closed and generally simpler than oceanic and continental systems, have been studied extensively. Indeed since MacArthur & Wilson and the equilibrium theory of insular zoogeography (1963), several theories on these environments have emerged.
The island syndrome (Adler & Levins, 1994) and the island rule (Lomolino, 2005), especially, have provided a conceptual framework. These theories have put in evidence the impact of insular environments on population demography and on individual reproduction ans morphology. Many experimental studies have, subsequently, demonstrated the trustworthiness of these points.
However, in island studies, behavioural variability is not much taken into account and results of experimental studies are often in conflict with theorical studies.
Thus, my PhD includes the animal personality concept. Personality traits are defined by phenotypic behavioral tendencies of individuals (such as boldness, aggression, activity level, neophobia or sociability) which are consistent across time and contexts. Several studies have demonstrated that these phenotypic behavioral traits are often connected to morphological, metabolic, hormonal and immune traits. The relationship between this set of traits can thus be studied through an individual’s pace-of-life syndrome ("POLS", Réale et al., 2010). Many studies have demonstrated that personality traits and more broadly "POLS" could have an impact on individual fitness and characteristics of populations and ecosystems.
The main objective of my PhD project is to integrate the animal personality and pace-of-life syndrome concepts within conceptual framework on island populations. This with the quantification of personality impacts on metapopulations (i.e. collections of interactive fragmented populations) dynamics within island network. Thus, I will integrate spatial, genetic and community dynamics. This project is on two rodent species: the deer mouse (Peromyscus maniculatus) and the Southern red-backed vole (Myodes gapperi).
This PhD project is made up of three sub-objectives:
(i) To study the relationship between personality and population spatial dynamics (i.e. dispersal), while accounting for contextual factors of sample sites (island area, island-mainland distance, inter-island distance, micro-habitat, etc.).
(ii) Understand the impacts of predation, competition (inter- and intra-specific) and habitat diversity in the personality/Island syndrome relationship. In nearly every studies on island dynamic, at least one of these three factors (predation, competition or habitat diversity) has proven to be a key factor.
(iii) To assess this spatial dynamic influence on inter-population gene flows and on the population genetic structures. At the same time, I will evaluate the selection factors operating on individuals phenotypic traits (behavioral, physiological and morphological).
MSc project: 2012 - 2013
Supervised by Julien Cucherousset, Julien Cote & Simon Blanchet
The importance of intraspecific variations as a source of biological diversity affecting ecosystem functioning has been recognized only recently, but the potential role of behavioural variations is still ignored. This is despite the fact that behavioural variations, especially in animal personality, could have important effects on individuals and populations, suggesting the existence of potential impacts at higher levels of biological organization.
In this project, we tested whether changes in population personality composition (here boldness) in a predatory species could affect populations, prey communities and ecosystem functioning using an experimental approach and a freshwater predatory fish (largemouth bass, Micropterus salmoides) as a model species.
Four personality treatments (i.e. bold, intermediate, shy and mixed), each composed of three individuals, and a reference treatment (without fish) were replicated 6 times in a total of 30 mesocosms. Largemouth bass displayed positive correlation between boldness and exploration and negative correlation between boldness and stress level, demonstrating the existence of a behavioural syndrome in the model species.
In the mesocosms, behaviourally heterogeneous populations (i.e. mixed) used the habitat differently than behaviourally-homogeneous populations. Using stable isotope analyses, we found that bold and mixed populations were composed of specialist individuals while intermediate and shy populations were composed of more generalist individuals, and that growth rate significantly differed between treatments.
In the pelagic food chain, personality treatments significantly modified the community composition, but not the biomass, of primary consumers (zooplankton) and no cascading effect on pelagic primary production (phytoplankton) was observed. In the benthic food chain, we found that personality treatments had significant effects on the life history strategy and biomass of benthic primary consumers (pond snails) and on benthic primary production (periphyton) through changes in the intensity of bottom-up control.
Although understanding the direct and indirect mechanisms leading to the observed changes in ecosystem functioning requires further investigations, we demonstrated that animal personality is an additional facet of individual variations that can affect ecosystem functioning.
MSc project: 2011 - 2012
Supervised by Odile Petit & Léa Briard
In social species, group members have to coordinate their activities in order to remain cohesive and keep the benefits of this lifestyle. Collective movements are one of the most visible examples of group synchronization and are therefore the focus of various scientific studies. These mechanisms remain unknown in domestic horses and were the subject of this study. Thus, a group of nine mares with and without stallion was observed in semifree-ranging conditions to reveal the organization and the processes which generate collective movements.
44 movements were observed in presence of the stallion and 31 in its absence. The study of the number of initiations made by each group member, shows that some individuals belonging to the same social subgroups, influence other conspecifics’ decision-making, and thus demonstrated as partially distributed leadership. Furthermore, with generalized linear models we brought to light that the centrality of the initiator and emission of recruitment signals influenced the success of the movement. Eventually thanks to the social networs analysis, we showed the destructuring action of the stallion on the females’ cohesion. Thus, the decision-making of horse seems to be modulated by social, individual and behavioral factors.
