COEVOL Multi-Scale Coevolution

Evolutionary Genetics of Interactions Group

Varaldi Julien

Maître de conférence universitaire

UCBL

Address: 69622 VILLEURBANNE cedex
69622 VILLEURBANNE cedex

Tel: 33 04 72 44 81 01

Email

My work focuses on the evolutionary genetics of insects. I am currently developing four main themes:

1. Organisms are confronted with numerous viral infections during their lifetime. Although viruses are known for their pathogenic effects, a number of them, under-studied, reveal more subtle effects, and are potentially heritable. We discovered such a virus in a parasitoid wasp, whose main effect is to manipulate the wasp's egg-laying behavior, thereby promoting horizontal transmission. This virus turned out to be the first member of a new family of viruses, the Filamentoviridae, which actually infect many parasitoid insects (Guinet et al. 2024). We are studying the distribution, diversity and phenotypic impacts of these viruses.


2.    In the course of evolution, sequences of these viruses have been able to integrate into the chromosomes of their hosts (whether or not integration is part of their natural cycle). Some of these insertions have led to major genetic innovations, as illustrated by the "invention" of the placenta in mammals. In hymenopteran parasitoids, which live as parasites on other insects, several clades have "domesticated" viruses, enabling them to address virulence factors to their hosts. These endogenized viruses are now necessary for the parasitoids' development. The first cases documented so far concerned the Ichneumonoidea superfamily. Our recent work has revealed similar, albeit completely independent, phenomena in other superfamilies, notably involving the Filamentoviridae (Di Giovanni et al. 2020, Guinet et al. 2023, 2025). One of the challenges is to define the extent and evolutionary impact of these domestications in insects.


3. Although most genetic information is transmitted from parent to offspring, through reproduction, certain regions of the genome have probably been acquired through horizontal transfer. These phenomena are well known in bacteria, but we now know that eukaryotes can also be involved. In this context, we are testing the impact of ecological connections on these transfers in closely interacting insect communities (host-parasitoids). We are also measuring the contribution of viruses domesticated by parasitoid wasps to these transfers.


4. Bedbugs, Cimex lectularius, represent a plague that is re-emerging. These hematophagous insects have experienced an extremely significant demographic boom in recent years, probably linked to the evolution of insecticide resistance. We are currently investigating the genetic determinants underlying the resistance phenotype (Haberkorn et al. 2023, 2024). In addition, this model is being studied in the context of speciation. Indeed, these bugs derive from populations that feed on bat blood, of which there are contemporary representatives. We are trying to understand the demographic history of these populations and the mechanisms that enabled the ancestral population(s) adapt to this new human host.

 

 

            Parasitoid depositing an egg (and its virus) in a Drosophila larva. (drawing credit : J. Martinez)

 

Publications

Display of 1 to 30 publications on 35 in total

Dating the origin of a viral domestication event in parasitoid wasps attacking Diptera

Benjamin Guinet, Jonathan Vogel, Nabila Kacem Haddj El Mrabet, Ralph S Peters, Jan Hrcek, Mattew L Buffington...

Proceedings of the Royal Society B: Biological Sciences . 292 ( 2039 )

DOI: 10.1098/rspb.2024.2135

Journal article

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Transcriptomic Response to Pyrethroid Treatment in Closely Related Bed Bug Strains Varying in Resistance

Chloé Haberkorn, Zaïnab Belgaïdi, Romain Lasseur, Fabrice Vavre, Julien Varaldi

Genome Biology and Evolution . 16 ( 8 ) : evae158

DOI: 10.1093/gbe/evae158

Journal article

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A novel and diverse family of filamentous DNA viruses associated with parasitic wasps

Benjamin Guinet, Matthieu Leobold, Elisabeth Herniou, Pierrick Bloin, Nelly Burlet, Justin Bredlau...

Virus Evolution . 10 ( 1 ) : veae022

DOI: 10.1093/ve/veae022

Journal article

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Community structure of heritable viruses in a Drosophila-parasitoids complex

Julien Varaldi, David Lepetit, Nelly Burlet, Camille Faber, Bérénice Baretje, Roland Allemand

Peer Community Journal . 4 : e16

DOI: 10.24072/pcjournal.371

Journal article

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A major 6 Mb superlocus is involved in pyrethroid resistance in the common bed bug Cimex lectularius

Chloé Haberkorn, Jean‐philippe David, Hélène Henri, Jean‐marie Delpuech, Romain Lasseur, Fabrice Vavre...

Evolutionary Applications . 16 ( 5 ) : 1012 - 1028

DOI: 10.1111/eva.13550

Journal article

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Endoparasitoid lifestyle promotes endogenization and domestication of dsDNA viruses

Benjamin Guinet, D. Lepetit, S. Charlat, Peter N Buhl, David G Notton, Astrid Cruaud...

eLife . 12 : e85993

DOI: 10.7554/eLife.85993

Journal article

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RNA Viruses Are Prevalent and Active Tenants of the Predatory Mite Phytoseiulus persimilis (Acari: Phytoseiidae)

Tali Sarah Berman, Yehuda Izraeli, Maya Lalzar, Netta Mozes-Daube, David Lepetit, Arnon Tabic...

Microbial ecology .

DOI: 10.1007/s00248-023-02210-0

Journal article

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Genomic characterization of viruses associated with the parasitoid Anagyrus vladimiri (Hymenoptera: Encyrtidae)

Yehuda Izraeli, David Lepetit, Shir Atias, Netta Mozes-Daube, Gal Wodowski, Oded Lachman...

Journal of General Virology . 103 ( 12 )

DOI: 10.1099/jgv.0.001810

Journal article

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DROP: Molecular voucher database for identification of Drosophila parasitoids

Chia-Hua Lue, Matthew L Buffington, Sonja Scheffer, Matthew Lewis, Tyler A Elliott, Amelia R I Lindsey...

Molecular Ecology Resources .

DOI: 10.1111/1755-0998.13435

Journal article

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A behavior-manipulating virus relative as a source of adaptive genes for Drosophila parasitoids

D Di Giovanni, D. Lepetit, B Guinet, B Bennetot, M. Boulesteix, Yohann Couté...

Molecular Biology and Evolution . 37 ( 10 ) : 2791-2807

DOI: 10.1093/molbev/msaa030

Journal article

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A behavior-manipulating virus relative as a source of adaptive genes for parasitoid wasps

Deborah Di Giovanni, D. Lepetit, Matthieu Boulesteix, Marc Ravallec, Julien Varaldi

Preprint

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Deciphering the behaviour manipulation imposed by a virus on its parasitoid host: insights from a dual transcriptomic approach

Julien Varaldi, David Lepetit

Parasitology . 145 ( 14 ) : 1979-1989

DOI: 10.1017/S0031182018000835

Journal article

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Genome sequencing of the behaviour manipulating virus LbFV reveals a possible new virus family

D. Lepetit, B. Gillet, S. Hughes, K. Kraaijeveld, Julien Varaldi

Genome Biology and Evolution . 8 : 3718-3738

DOI: 10.1093/gbe/evw277

Journal article

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Additional heritable virus in the parasitic wasp Leptopilina boulardi: prevalence, transmission and phenotypic effects

Julien Martinez, David Lepetit, Marc Ravallec, Frédéric Fleury, Julien Varaldi

Journal of General Virology . 97 : 523-535

DOI: 10.1099/jgv.0.000360

Journal article

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Competitive outcome of multiple infections in a behavior-manipulating virus/wasp interaction

Julien Martinez, Frédéric Fleury, J. Varaldi

Ecology and Evolution . 5 ( 24 ) : S934-S945

DOI: 10.1002/ece3.1749

Journal article

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The influence of male wing shape on mating success in Drosophila melanogaster

Bf. Menezes, Fm. Vigoder, Aa. Peixoto, J. Varaldi, Bc. Bitner-Mathé

Animal Behaviour . 85 : 1217--1223

DOI: 10.1016/j.anbehav.2013.03.008

Journal article

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Heritable variation in an extended phenotype: the case of a parasitoid manipulated by a virus.

Julien Martinez, Frédéric Fleury, Julien Varaldi

Journal of Evolutionary Biology . 25 ( 1 ) : 54-65

DOI: 10.1111/j.1420-9101.2011.02405.x

Journal article

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An inherited Virus manipulating the behavior of its parasitoid host : epidemiology and evolutionary consequences

Julien Varaldi, Julien Martinez, Sabine Patot, David Lepetit, Frédéric Fleury, Sylvain Gandon

Parasitoid Viruses. Symbionts and Pathogens . 978-0-12-384858-1 : 203-214

DOI: 10.1016/B978-0-12-384858-1.00017-5

Book chapter

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An inherited virus influences the coexistence of parasitoid species through behaviour manipulation.

Sabine Patot, Roland Allemand, Frédéric Fleury, Julien Varaldi

Ecology Letters . 15 ( 6 ) : 603-10

DOI: 10.1111/j.1461-0248.2012.01774.x

Journal article

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Influence of the virus LbFV and of Wolbachia in a host-parasitoid interaction.

Julien Martinez, Anne Duplouy, Megan Woolfit, Fabrice Vavre, Scott L O'Neill, Julien Varaldi

PLoS ONE . 7 ( 4 ) : 1-10

DOI: 10.1371/journal.pone.0035081

Journal article

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Prevalence of a virus inducing behavioural manipulation near species range border

Sabine Patot, Julien Martinez, Roland Allemand, Sylvain Gandon, Julien Varaldi, Frédéric Fleury

Molecular Ecology . 19 ( 14 ) : 2995-3007

DOI: 10.1111/j.1365-294X.2010.04686.x

Journal article

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Evolution and manipulation of parasitoid eggload

Sylvain Gandon, Julien Varaldi, Frédéric Fleury, Ana R Rivero

Evolution - International Journal of Organic Evolution . 63 ( 11 ) : 2974-2984

DOI: 10.1111/j.1558-5646.2009.00776.x

Journal article

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A Virus-Shaping Reproductive Strategy in a Drosophila Parasitoid

Julien Varaldi, Sabine Patot, Maxime Nardin, Sylvain Gandon

Advances in Parasitology . 70 : 334-359

DOI: 10.1016/S0065-308X(09)70013-2

Journal article

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Molecular Detection Penetrance and Transmission of an Inherited Virus Responsible for Behavioral Manipulation of an Insect Parasitoid

S. Patot, D. Lepetit, D. Charif, Julien Varaldi, Frédéric Fleury

Applied and Environmental Microbiology . 75 ( 3 ) : 703-710

DOI: 10.1128/AEM.01778-08

Journal article

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Behavioural manipulation of insect parasitoids by a maternally inherited virus: ecological consequences and potential applications for biological control

Julien Varaldi, S. Patot, M. Maache, D. Lepetit, Frédéric Fleury

Entomological Research . 37 : A11-A73

Journal article

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Artifical transfer and morphological description of virus particles associated with superparasitism behaviour in a parasitoid wasp.

Julien Varaldi, M. Ravallec, C. Labrosse, M. Lopez-Ferber, M. Boulétreau, Frédéric Fleury

Journal of Insect Physiology . 52 ( 11-12 ) : 1202-1212

DOI: 10.1016/j.jinsphys.2006.09.002

Journal article

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Superparasitism evolution: adaptation or manipulation?

Sylvain Gandon, Ana R Rivero, Julien Varaldi

The American Naturalist . 167 ( 1 ) : E1-E22

DOI: 10.1086/498398

Journal article

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The virus infecting the parasitoid Leptopilina boulardi exerts a specific action on superparasitism behaviour

Julien Varaldi, S. Petit, M. Boulétreau, Frédéric Fleury

Parasitology . 132 : 747-756

Journal article

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A Newly Discovered Virus Manipulates Superparasitism Behavior in a Parasitoid Wasp

Julien Varaldi, Sylvain Gandon, Ana R Rivero, Sabine Patot, Frédéric Fleury

Insect Symbiosis . 2 : 119-139

DOI: 10.1201/9781420005936

Book chapter

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Cost induced by viral particles manipulating superparasitism behaviour in the parasitoid Leptopilina boulardi

Julien Varaldi, M. Boulétreau, Frédéric Fleury

Parasitology . 131 : 161-168

Journal article

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