Theoretical and Experimental Ecology Station
Adaptation in dynamic worlds
We have increasingly realized that selection on many traits is not always stable or consistent in contrast to longstanding assumptions in models of evolution. The same traits can be influenced by selection from a number of different origins (environmental, social) which can vary across seasons (winter vs spring), space and time, and depend on the social context where they are used. Instability in selection could help resolve a number of challenging questions that we have yet to fully understand.
For example, selection should erode genetic variation in traits, but variation in selection could preserve variation in traits, alter the trajectory of evolution, and favour plasticity which are all important to understanding how traits change in a modified landscape.
We have begun a large scale project on spatio-temporal variation in selection on life history (group size, reproductive strategies, parental care, and fitness) in both breeding and non-breeding resident birds across sharp ecological gradients (altitudinal gradient: 400m-1500m; rural to urban centre) and we survey winter social behaviour and the breeding behaviour of blue and great tits.
This work uses both observational and experimental approaches to understand how different selective pressures influence the evolution of traits and adaptation by measuring the costs and benefits of life history strategies, behaviours, and social signals under different contexts.
Through this approach, we hope to gain a better understanding of the process of adaptation in dynamic worlds.
Researchers : A. Chaine
PhD Students : L. Lejeune
Collaborators : A. Russell (U. Exeter, UK) ; C. Bonneaud (U. Exeter, UK) ; P. Heeb (U.P.S. Toulouse)
Funding : ANR-NetSelect
Evolution of Cognition Cognitive processes allow individuals to gather information from their environment, store and process that information, and use it to make appropriate responses to social and ecological variation in their environments. As such, cognition should have important impacts on fitness and should itself be subject to selection yet we still have a poor grasp of how selection acts in natural populations. Variation in cognitive abilities is rampant and we should be able to measure selection and the evolution of cognitive abilities in contrasted environments if we select cognitive abilities appropriate to the ecology of the focal species.
We study selection on specific cognitive abilities (learning, flexibility, memory, inhibition) in contrasted environments (high vs low elevation) with particular attention to the ecological drivers of variation in cognition and how it is related to specific behaviours important to fitness (sociality, foraging, parental care, social competence).
Experiments measuring inter-individual variation in cognition are conducted in the Moulis aviary facilities as well as in the wild using a custom designed automated testing device (OpenFeeder) that uses RFID technology to provide tests and record responses of free ranging birds in their natural habitat.
Taking this work one step further, we have begun to examine how individual variation in cognitive abilities translates to variation in brain structure using a small animal MRI at Moulis. Likewise, we have begun to examine the genetic basis of inter-individual variation in cognitive performance by using high-throughput genetic scans and genome-wide association methods.
As a whole, we hope to greatly advance our understanding of how selection acts on cognitive abilities in the wild and why those abilities provide benefits under specific ecological contexts.
Researchers: A. Chaine
Post-docs Researchers: M. Cauchoix; V. VanMeir
Collaborators: J. Morand-Ferron (U Ottawa, Canada); T. Serre (Brown Univ, USA); M. Verhoye (Antwerp Univ, Belgium); A. Charmantier (CEFE-CNRS, Montpellier); P. Heeb (U.P.S. Toulouse)
Funding: HFSP-WildCog; ANR-SoCo
Social interactions are often tightly linked to fitness (survival and reproduction) and therefore have an important impact on adaptation and population dynamics.
Individuals in social groups often have divergent interests despite the need for interaction and cooperation and both social information and social signals play a critical role in mediating these interactions.
Our interest in this area is focused primarily on how social signals evolve with particular attention to the role that the local environment and social context play in this process.
For example, how does variation in social structure (network structure or social context) or ecology (space, time) favours the use of some social signals over others and what are the implications of that variation for long term evolutionary dynamics.
Much of this work has focused on visual and vocal communication in birds (lark buntings, golden crowned sparrows, great tits, Reunion island grey white eyes) but also other organisms (e.g. lizards, mammals).
Our goal is to gain a better understanding of how selection acts on social signals, how the environment – social and ecological – influences these systems, and how this selection contributes to diversity in communication systems within and among species.
Researcher: A. Chaine
PhD Student: M. Mould
Collaborators: B. Lyon (UC Santa Cruz, USA); D. Shizuka (UN-Lincoln, USA); C. Thébaud (UPS Toulouse); B. Sinervo (UC Santa Cruz, USA); D. Miles (Ohio U., USA)
Funding: ANR-NetSelect; National Geographic; NSF-CAREER
Evolution of Cooperation
Cooperation – and especially altruism – is often tenuous since there is generally an advantage to cheaters who reap the benefits of cooperative interactions without paying the costs.
Considerable attention has focused on understanding what conditions stabilize cooperation and how co-operators protect against cheating. Our work in this area is focused on understanding not only the behaviours’ that stabilize cheater such as recognition, but also on how the local environment and neighbourhood choice can stabilize cooperation in a variety of organisms from ciliates to vertebrates.
Furthermore, altruism – an extreme versions of cooperation where the donor has decreased fitness – poses additional problems as any associated genes should be selected against.
We have begun examining the genetic basis of altruism in a variety of organisms (lizards, humans) to understand if indeed such behaviour is genetic and if so, how altruistic genotypes might be maintained in the population.
Researchers: A. Chaine; J. Clobert; S. Jacob
Technician: M. Huet
Collaborators: A. Russell (U. Exeter, UK); C. Bonneaud (U. Exeter, UK); B. Sinervo (UC Santa Cruz; USA)
Funding: TULIP-New Frontiers
Variability in phenotypic traits and their implications
for eco-evolutionary dynamics
Our interests lie in understanding the drivers of variability in phenotypic traits and their implications for eco-evolutionary dynamics. We particularly focus on traits involved in communication, cooperation, dispersal and host-microbes’ interactions. Depending on the question, we use various model species from microorganisms to vertebrates, in order to perform empirical and theoretical research both in natural and experimental systems.
Specifically, our main current project is focused on the evolution and consequences of dispersal plasticity. Individuals should benefit from settling in habitats that maximize their fitness, a form of dispersal plasticity named habitat choice. Theory predicts that habitat choice can deeply modify the consequences of dispersal for ecological and evolutionary dynamics compared to the often-assumed random dispersal.
However, our empirical knowledge of the drivers of habitat choice evolution and its ecological consequences remains rudimentary. We aim at identifying the environmental conditions favouring habitat choice evolution and at quantifying its consequences for the dynamics of populations.
To do so, we adopt an experimental approach using spatially explicit microcosms of an actively dispersing ciliate.
This experimental system offers an excellent opportunity to validate or reject theoretically-derived predictions over multiple generations and thus to provide breakthrough advances about the environmental drivers and consequences of dispersal evolution.
Researchers: S. Jacob
PhD Students: Estelle Laurent (co-supervised with Nicolas Schtickzelle, UCLouvain); Mathieu Brevet (co-supervised with Jean Clobert, SETE Moulis)
The Pyrenees are increasingly affected by climate change.
In this context, human societies across the borders must keep track of and adapt to the changes.
ECTOPYR offers a novel and ambitious strategy in this regard; that is to use a panel of 8 ectotherm organisms as bio-indicators of climate change, occurring from low-land streams to high-altitude rock-fields. ECTOPYR will generate range maps for each model organism in order to rapidly (1) assess each bio-indicator’s response to climate change, (2) describe the natural variability of the Pyrenees’ climate over vast time scales and (3) generate modelling tools in order to anticipate the effects of climate change on each model organisms.
These advances will serve decision making towards a sustainable future across the various mountainous environments, as well as thoroughly understand ecosystem functioning in the Pyrenees.
These achievements will benefit environment managers, entrepreneurs, the scientific community as well as the general public.
ECTOPYR will be a stepping stone towards a sustainable future in the Pyrenees, and will make people, managers and communities feel and work closer together.
Researchers: Fabien Aubret (CI), Jean Clobert, Simon Blanchet, Hervé Philippe, Christine Perrin (MNHN)
Engineers: Elodie Darnet, Hugo Le Chevalier, Olivier Calvez, Olivier Guillaume
Post-Docs Researchers: Audrey Trochet, Romain Bertrand, Andreaz Dupoué, Rebeca Martin Garcia
PhD Students: Jérémie Souchet, Marine Deluen
Collaborations : CRARC (Espagne), BOMOSA (Andorre), Nature Occitanie.
Climate change is driving many species to migrate along the altitudinal gradient of mountainous landscapes. While the impacts of temperature shifts on range expansion are well established, the effects of altitude-related hypoxia on the ability of organisms to colonize and adapt to higher altitudes during warming have, to our knowledge, not received scientific interest.
Specifically, the short, medium and long term effects of acute and chronic hypoxia on the growth, survival, reproductive biology and colonization dynamics of animals reaching higher altitude refuges remain unknown. PODARCIS will generate such knowledge, via a detailed study of physiological responses to hypoxia across an altitudinal gradient in a species that undergoes upward range expansion, the wall lizard Podarcis muralis.
1. Assess multivariate acclimation responses in embryos and adult lizards from low to high altitude using common garden and reciprocal transplant experiments (i.e. to assess the effectiveness for plastic responses to enable colonization and detect changes in the degree of plasticity across the altitudinal gradient) and
2. Predict the dynamics of colonization by integrating data on physiological plasticity, reproductive output and dispersal. Taken together, this project will combine hard-to-obtain empirical data with theoretical modelling approaches to provide valuable insights into the ecological and evolutionary processes that determine a species' response to climate change.
PODARCIS requires a multidisciplinary approach, drawing from the fields of physiology, quantitative genetics, evolutionary theory, and computer modelling.
Researcher: Fabien Aubret (CI), Eric Gangloff
Post Doc researcher: Eric Gangloff
Collaborators : Tobias Uller (Suede), Antonio Cordero (Allemagne), Daniel Noble (Australie), Brooke Bodensteiner (USA)
A substantial proportion of adaptive responses in animals can occur through the epigenetic regulation of genes
1. Epigenetic modifications allow a rapid, but potentially enduring response to a new environment by means of phenotypic plasticity. Recent work has shown that inherited epigenetic plasticity directly increases a species ability to evolve, and although the link between epigenetics and body size has seldom been demonstrated in natural populations of vertebrates, there are also several other examples in which the interaction between environment and epigenetics affects morphology. Concurrently, morphological evolution can occur over very short time scales
2. And adaptive plasticity plays a significant role in facilitating evolution, notably in radiation and colonization events
3. In this context, we will assess the interplays of epigenetics and levels of adaptive plasticity in rapidly evolving snake populations in a natural context, using a timeframe for isolation events.
Researchers : Fabien Aubret (CI)
Collaborators : Christoph Grunau, Benoit Pujol, Vicki Thomson (Australie)
Urban Wetlands Conservation
Impact of urbanisation on Tiger Snakes in Wetlands of Perth and its surrounds. The research will measure if and how environmental degradation through urbanisation and pollution renders wetland vertebrates more susceptible to disease and parasites, by identifying the difference in tiger snake population health and ecology across geographic and historical gradients.
This project will assess the degradation of wetland health (habitat structure and water quality) across an urban matrix; determine the effects of contaminant bioaccumulation in tiger snakes; determine the effects of wetland degradation on parasitism in tiger snakes; and integrate all information to determine whether tiger snakes can be used as an ecological indicator for of wetland health.
Researchers : Fabien Aubret (Co-I)
PhD Student : Damian Lettoof (Australie)
Collaborators : Bill Bateman (Australie), Monique Gagnon (Australie), Ruchira Somaweera (Australie)