Simon Fellous

Chargé de Recherche (CR1)
Centre de Biologie pour la Gestion des Populations
ontpellier, France

simon.fellous [arobase]

Research themes:

I am an evolutionary biologist working on the ecological and evolutionary processes that shape the interactions between organisms. I study the coevolution between symbionts and hosts - in other words, I try to understand why parasites transmit the way they transmit, and why we suffer from infection as we do.

My approach is primarily experimental. I worked with a number of systems including mosquitoes, Drosophila, spider-mites, cilliates, bacteria, virus and microsporidia.

I am particularly interested in two topics:
- What are the evolutionary and community consequences of life-cycle complexity? This question has received surprisingly little attention despite the huge number of animals (insects, parasites, amphibians, invertebrates) with discreet life-stages.

- What is the role of parasites and symbionts in evolutionary innovation? Many of them laternate between positive and  negative effects on their host (see Trends in Parasitology paper, 2009), these variations along the mutualism-parasitism continuum may permit the adaptation of the host to its environment (See Nature Reviews Genetics paper, 2011). 

What I do at INRA:

My project focuses on life-cycle complexity and its consequences for the ecology and evolution of an insect pest, the invasive fruit-fly Drosophila suzukii

Further details will come later. In the meanwhile, feel free to contact me directly for questions, internship applications and  collaborations.

...  what I did before...

Third Postdoc (2011-2012):

I joined Maria Navajas' group at CBGP-INRA (the french agronomic council) in Montpellier, France.

The aim of my work was to investigate on the specialisation of the herbivorous pests, Tetranychus urticae and T. evansi,  to their host plants. We used a combination of microcosm experiments, experimental evolution, population genetics and whole-genome sequencing to carry out this exciting and international project. 

With master 2 student Marion Orsucci (now PhD student with Rejane Streiff, CBGP-INRA), we investigated the competitive interactions between our two mite species. She tested hypotheses about intra-specific genetic variation, environmental heterogeneity and spatial dynamics.

Second Postdoc (2009-2011):

I worked with Oliver Kaltz and Michael Hochberg at the Institut des Sciences de l'Evolution de Montpellier (ISEM) in southern France. 

Teaming up with Johan Ramsayer, PhD student with Mike Hochberg, and master 2 student Elodie Parrain, we investigated, in microcosms, how evolution in response to parasites, predation and inter-specific competition may be interlinked and thus affect the community formed by paramecia and the bacteria upon which they feed and their specific viruses (Biology Letters 2012 ; papers in prep.). 

Together with Alison Duncan (postdoc) we studied how the structure of environmental variation affects the coevolution between a freshwater cilliates, Paramecium caudatum, and its bacterial parasites of the genus Holospora (Proc B 2011 ; Evolution 2011). With master student Elsa Quillery, we investigated the genetic factors that determine the movement of parasites between host patches and their successful invasion (Ecology Letters 2012 ; Biology Letters 2011). 

With postgraduate student Jonas Durand (now PhD student at University of Neufchatel, Switzerland), we studied the protection of Paramecium hosts by their Holospora parasites, its mechanism (HSPs over-expression) and long term evolution. 

First Postdoc (2008):

I worked with Brian Lazzaro (Cornell University, USA) on the ecological immunity of fruit-flies, Drosophila melanogaster

After studying how larval environment affects larval and adult immune variation (Molecular Ecology 2010), I used a quantitative genetics approach to identify the genetic correlations that link larval and adult immune investments (Molecular Ecology 2011). Molecular biology tools allowed me to phenotype the animals in an efficient and original maner.

With Miguel Rosado and Punita Juneja, from the same lab, we studied the response of D. melanogaster larvae and adults to oral exposure to bacterial pathogens.

PhD (2004-2007):

I did my PhD with Jacob C. Koella at Imperial College London, Silwood Park Campus, (UK) and at the lab of evolutionary parasitology, University Paris 6 - UPMC (France). The title of my thesis was "Variabilities in the interactions between hosts and parasites: environmental effects and their consequences for evolution"

I used for my experiments the Yellow fever mosquito, Aedes aegypti, and several of its parasites (the microsporidiums Vavraia culicis and Edhazardia aedis and the gregarine Ascogregarina culicis) . I primarily studied the competition between different parasite species coinfecting the same host (Am Nat 2009, Oecologia 2010). I investigated the role of infectious dose, host genotype and parasite genotype for the outcome of coinfections.

In parallele to these studies, I also investigated the details of the biology of the parasite Ascogregarina culicis (JEB 2009).


Meeting organisation:

WORKSHOP: Shared traits, extended phenotypes or G x G x E interactions: the role of the ‘environment’ in the evolutionary ecology of host-parasite interactions.

December 5th 2007 , Paris ... CLICK HERE



- The Navajas group in Montpellier

- The Ecology and Evolution of Communities lab in Montpellier

- The Lazzaro group webpage

- The Koella group webpage

- The Siva-Jothy group in Sheffield (UK)

Photos (can be freely used for scientific communication but not for publication)

Anopheles gambiae

Aedes aegypti

Aedes aegypti (GIF animation) 

Back to the first page and my photography (click me)

Publications (January 2013): 

20. Fellous, Duncan, Coulon & Kaltz, 2012, PLOS ONE.
"Quorum sensing and negative density-dependent dispersal in  an aquatic model organism"

19. Chevin, Gallet, Gomulkiewicz, Holt & Fellous. 2012, Phil Trans Royal Soc. 
"Phenotypic plasticity in evolutionary rescue experiments"

18. Fellous, Duncan, Quillery, Vale & Kaltz, 2012, Ecology Letters.
"Genetic influence on parasite spread following arrival of infected carrier"

17. Ramsayer*, Fellous*, Hochberg, Cohen, 2012, Biology Letters.
"Taylor's law holds in experimental bacterial populations but competition does not influence the slope."
*Equal authorship

16. Fellous, Duron & Rousset, 2011, Nature Reviews Genetics.
"Adaptation due to symbionts and conflicts between heritable agents of biological information."
link AmNat 2009

15. Duncan, Fellous & Kaltz, 2011, Evolution.
"Reverse evolution: Selection against costly resistance in disease-free microcosm populations."

14. A.B. Duncan, S. Fellous, E. Quillery & O. Kaltz, 2011, Research in Microbiology.
"Adaptation of Paramecium caudatum to variable conditions of temperature stress"

13. A.B. Duncan, S. Fellous & O. Kaltz, 2011, Proceedings Royal Society B.
"Temporal variation in temperature determines disease spread and maintenance in microcosm populations "
link AmNat 2009

12. S.Fellous & B. P. Lazzaro, 2011, Molecular Ecology.
"Potential of evolutionary coupling and decoupling of larval and adult immune gene expression."
link AmNat 2009

11. S. Fellous*, E. Quillery*, A.B. Duncan and O. Kaltz, 2011, Biology Letters.
"Parasitic infection reduces dispersal of cilliate host".
*Equal authorship
link AmNat 2009

10. A.B. Duncan*, S. Fellous*, S. Accot, R. Alart, M. Chantung Sobandi, K. Cosiaux & O. Kaltz, 2010. FEMS Microbiology Ecology.
"Parasite-mediated protection against osmotic stress of Paramecium caudatum infected by Holospora undulata is host genotype specific"
*Equal authorship
link AmNat 2009

9. S.Fellous & B. P. Lazzaro, 2010, Molecular Ecology.
"Larval food quality affects adult (but not larval) immune gene expression independent of effects on general condition."
link AmNat 2009

8. S. Fellous & J. C. Koella, 2010, Oecologia.
"Cost of co-infection controlled by infectious dose combinations and food availability."
link AmNat 2009

7. S. Fellous & L. Salvaudon, 2009, Trends in Parasitology.
"How can your parasites become your allies?"

6. S. Fellous & J. C. Koella, 2009, The American Naturalist.
"Infectious dose affects the outcome of the within-host competition between parasites."

link AmNat 2009

5. S. Fellous & J. C. Koella, 2009, The Journal of Evolutionary Biology.
Different transmission strategies of a parasite in male and female hosts."
link AmNat 2009

4. S. Fellous, 2009, The Journal of Parasitology.
"Positive Correlation Between Haemosporidian Parasitemia and Likelihood of PCR Detection in Co-infected Birds."

3. P. vale, L. Salvaudon, O. Kaltz & S. Fellous, 2008, Infection, Genetics and Evolution.
"The role of the environment in the evolutionary ecology of host parasite interactions."

2. C. Loiseau, S. Fellous, C. Haussy, O. Chastel & G. Sorci, 2008, Hormones and Behavior
"Condition dependent effects of corticosterone on a carotenoid-based begging signal in house sparrows"

S. Fellous, 2007, Nature
"How important is immune memory to invertebrates?" (correspondence)

1. L. Lambrechts, S. Fellous & J.C. Koella, 2006, Trends in Parasitology
"Coevolutionary interactions between host and parasites genotypes"