Research Interests


Ecology and evolution

When mutant individuals with a changed trait are successful, they will increase in numbers and thus start affecting population dynamics, resource availability, the prevalence of parasites, the intensity of interspecific competition, community structure, and so on. Together, these effects will cause a feedback because ecological parameters will, in general, affect the traits that are favoured. More on this can be found in the introduction to my thesis (1994).

Interacting populations

Such eco-evolutionary feedback loops will be particularly intense in systems with interacting populations: adaptation and counteradaptation often have population dynamical consequences. A good example is the evolution of virulence. If avirulent parasites are common, host density increases and, with it, the force of infection. But so does the intensity of within-host competition, which favours more virulent parasites. Ecological effects will modify or sometimes even revert selection pressure on virulence.

Space

How spatial dynamics affect evolution (and vice versa) is still poorly understood. When a mutant invades a 'viscous' system it typically does so in the form of an expanding cluster of relatives. Ultimately it is therefore the characteristics of these clusters that determine whether the invasion will be successful. In other words, the unit of selection in a viscous systems is a cluster of relatives rather than the individual (which amounts to a re-discovery of Hamilton's kin selection principle). Correlation dynamics modeling provides new mathematical tools to study the effect of space on ecological interactions.

Dangerous Liaisons

Traditionally, ecology recognizes three broad kinds of interactions among organisms: competitive interactions, exploiter-victim interactions (i.e., predators and prey, host and parasites) and mutualistic interactions. Upon closer scrutiny, however, interactions between individuals often appear to be mixtures. For example, certain parasites may, under certain conditions, benefit their hosts. Under what conditions does the common interest prevail over the private interests of the partners? If we understand better under what conditions (if ever) parasites will become full-blown mutualists, we obtain much-needed insight in many evolutionary transitions, ranging from the appearance of eucaryotes to the evolution of sociality.

Communication

When an organism communicates, it does so to increase its fitness. If it can gain from misleading the recipient, it will therefore give false information. The recipient of the signal is selected to judge the signal with respect to its 'credibility'. Recipients can enforce credibility by only 'believing' signals that are costly, so costly that senders cannot afford cheating. But sometimes sender and receiver do have a sufficient common interest, however, so that both benefit from the exchange of accurate information. But what will happen if sender and receiver have only partially overlapping interests?

Kin selection, coloniality and disease

Since Darwin and Hamilton it has become obviously clear that harmony in colonies of social insects is due to the relatedness of colony members. Why, then, do we sometimes observe queens that mate with multiple males or even unrelated queens that share a nest? Either of these processes diminishes relatedness and increases the potential for conflict. One of the hypotheses that has been proposed to explain this phenomenon is that heterogeneous colonies are more resistant to parasitism. This is an interesting hypothesis, but it is not at all immediately clear whether it works if it is taken into account that such heterogeneous colonies are likely to have more parasites able to infect them.

Immune functioning and virulence

At a different level again, it has become clear that parasite evolution can be strongly affected by within-host competition among strains. What is not often realised (and certainly not in the simplest mathematical models) is that these interactions are often mediated by the immune system. Does within-host competition still lead to increased virulence or, as has been suggested recently, to reduced virulence instead?


Publications

A list of recent publications can be found here.


Brief CV

1988-1994
PhD, University of Amsterdam
1994-1995
Postdoc, University of Amsterdam
1996-1997
Postdoc, University of Warwick (UK)
1997-1999
Poste rouge, CNRS/Université Pierre et Marie Curie, Paris
1999-2001
Fellowship, Royal Dutch Academy of Arts and Sciences/University of Amsterdam
2001-2014
Chargé de Recherche, CNRS/Université Pierre et Marie Curie, Paris
2006-2011
Head of the research unit UMR 7625 « Ecologie & Evolution »
2014-present
Chargé de Recherche, CNRS/Institut Biologie de l'Ecole Normale Supérieure, Paris
2015-2017
Part-time visitor at the IHÉS in Bures-sur-Yvette.

Collaborators

Current:

Phuong Nguyen (PhD)
Evolution of the symbiotic lifestyle

Past:

Alexandre Suire (MSc, 2016)
Evolution of information use
Darja Dubravcic (with Clément Nizak, Paris. 2014)
Evolution in Dictyostelium slime moulds
Sabrina Araujo (Post-doc, 2014-2015. Researcher in Curitiba, Brasil)
Evolution in predator-prey systems
Anaïs Bompard (with Thierry Spataro, Paris. 2013)
Evolution of sex determination in Hymenopteran parasitoids
William Lee (Thesis supervisor: Vincent Jansen, Royal Holloway College, London, Viva: October 2012)
Adaptive dynamics of parasites and mutualists
Sandrine Adiba (with Frantz Depaulis, 2010)
Selection and drift in microbial ecosystems.
Sébastien Ballesteros (Thesis supervisor: Bernard Cazelles, 2009. Last I heard he was setting up a Big Data start-up in New York.)
Evolution of host-pathogen systems
Sonia Kéfi (Utrecht University, Thesis supervisor Max Rietkerk,2008. Now CNRS researcher in Montpellier.)
Bistability and desertification
Sébastien Lion (PhD, co-directed with Régis Ferrière, October 2007. Now CNRS researcher in Montpellier.)
Evolution of mutualism in spatially extended systems
Mathieu Molet (PhD, Thesis supervisor: Christian Peeters, September 2007. Now Maître de Conférences in Paris)
Evolution of reproductive strategies in queenless ants
Mathias Gauduchon (postdoc, Maître de Conférences in Marseille now.).
Dynamics and evolution of fissioning ant colonies.
Samuel Alizon (PhD: October 2006. Now CNRS researcher in Montpellier.)
Evolution of virulence and within-host processes
Carmen Bessa Gomes (Post-doc until 2004; now Maître de Conférences at University Paris XI).
Allee effects and sexual selection
Arnaud Pocheville (DEA: Sept. 2004. Went on to do a PhD, I think he is a researcher in Australia now.)
Termite thermodynamics
Sonia Kéfi (DEA: Sept. 2004.)
Bistability and desertification: bifurcation analysis and evolutionary aspects
Claire Cadet (PhD: February 2003)
Adaptation to fluctuating environments

External collaborations

A selection: Vincent Jansen (Royal Holloway College, London), Sylvain Gandon & Sébastien Lion (Montpellier), Madeleine Beekman (Sydney), Atsushi Yamauchi (Kyoto), Daniel Pinto (Porto).

My PhD supervisor, colleague and friend Maurice W. Sabelis (University of Amsterdam) sadly passed away in January 2015.




Last update April 22, 2017 by Minus