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Dive into the research topics where Thomas Boivin is active.

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Featured researches published by Thomas Boivin.


Heredity | 2001

Deltamethrin resistance in the codling moth (Lepidoptera: Tortricidae): inheritance and number of genes involved.

Jean-Charles Bouvier; Robert Bues; Thomas Boivin; Liliane Boudinhon; Dominique Beslay; Benoît Sauphanor

The inheritance of deltamethrin resistance in Cydia pomonella (L.) has been investigated by crossing a resistant (Rv) and a susceptible (Sv) strain, derived from a population collected in south-eastern France in 1995. Deltamethrin resistance was suspected to be under the control of a kdr-type allele and an enhanced mixed-function oxidase (mfo). F1 and F2 progenies were therefore tested through dose–response and enzyme assays. Dose–response relationships indicated that resistance was inherited as an autosomal incompletely recessive (D=−0.199) character, involving at least two genes. Enzyme measures suggested the contribution of 1.2 genes to the expression of mfo, with incomplete dominance (D=0.460). Our results support the hypothesis of a polygenic response to deltamethrin selection in the Rv strain, including a major kdr-type allele with a minor effect of mfos. In the light of these findings, we consider the resistance in codling moth populations in south-eastern France as a product of an adaptive sequential selection process, occurring through the sequential addition of resistance genes.


Entomologia Experimentalis Et Applicata | 2001

Pleiotropy of insecticide resistance in the codling moth, Cydia pomonella

Thomas Boivin; Cécile Chabert D'Hières; Jean Charles Bouvier; Dominique Beslay; Benoît Sauphanor

The codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), has developed resistance to various insecticides. Relative fitness of one susceptible strain (Sv) and two strains selected for resistance to diflubenzuron (Rt) and deltamethrin (Rv), respectively, was measured in the absence of insecticide selection pressure. Mating rate, fecundity, fertility, developmental time, fifth instar weight, and adult longevity were compared. Both resistant strains were less fecund and fertile, developed more slowly, weighed less, and had shorter life‐spans than the susceptible strain. These results indicate that biological constraints are associated with insecticide resistance in the codling moth. We also found that fitness estimates of the Rv strain did not differ statistically from those of the Rt strain. Enhanced mixed‐function oxidase and glutathione‐S‐transferase activities have been shown to be involved in insecticide resistance in both Rt and Rv strains. This suggests that the fitness cost described in both resistant strains was mainly associated to metabolic resistance. The impact of such deleterious pleiotropy of insecticide resistance in C. pomonella in terms of resistance management in the field is discussed.


Heredity | 2003

Constraints on adaptive mutations in the codling moth Cydia pomonella (L.): measuring fitness trade-offs and natural selection

Thomas Boivin; Jean-Charles Bouvier; J Chadœuf; Dominique Beslay; Benoît Sauphanor

Adaptive changes in populations encountering a new environment are often constrained by deleterious pleiotropic interactions with ancestral physiological functions. Evolutionary responses of populations can thus be limited by natural selection under fluctuating environmental conditions, if the adaptive mutations are associated with pleiotropic fitness costs. In this context, we have followed the evolution of the frequencies of insecticide-resistant mutants of Cydia pomonella when reintroduced into an untreated environment. The novel set of selective forces after removal of insecticide pressure led to the decline of the frequencies of resistant phenotypes over time, suggesting that the insecticide-adapted genetic variants were selected against the absence of insecticide (with a selective coefficient estimated at 0.11). The selective coefficients were also estimated for both the major cytochrome P450-dependent monooxygenase (MFO) and the minor glutathione S-transferase (GST) systems (0.17 and negligible, respectively), which have been previously shown to be involved in resistance. The involvement of metabolic systems acting both through xenobiotic detoxification and biosynthetic pathways of endogenous compounds may be central to explaining the deleterious physiological consequences resulting from pleiotropy of adaptive changes. The estimation of the magnitude of the fitness cost associated with insecticide resistance in C. pomonella suggests that resistance management strategies exclusively based on insecticide alternations would be unlikely to delay such a selection process.


Annals of Forest Science | 2014

Considering evolutionary processes in adaptive forestry

François Lefèvre; Thomas Boivin; Aurore Bontemps; François Courbet; Hendrik Davi; Marion Durand-Gillmann; Bruno Fady; Julie Gauzere; Cindy Gidoin; Marie-Joe Karam; Hadrien Lalagüe; Sylvie Oddou-Muratorio; Christian Pichot

ContextManaging forests under climate change requires adaptation. The adaptive capacity of forest tree populations is huge but not limitless. Integrating evolutionary considerations into adaptive forestry practice will enhance the capacity of managed forests to respond to climate-driven changes.AimsFocusing on natural regeneration systems, we propose a general framework that can be used in various and complex local situations by forest managers, in combination with their own expertise, to integrate evolutionary considerations into decision making for the emergence of an evolution-oriented forestry.MethodsWe develop a simple process-based analytical grid, using few processes and parameters, to analyse the impact of forestry practice on the evolution and evolvability of tree populations.ResultsWe review qualitative and, whenever possible, quantitative expectations on the intensity of evolutionary drivers in forest trees. Then, we review the effects of actual and potential forestry practice on the evolutionary processes. We illustrate the complexity of interactions in two study cases: the evolutionary consequences for forest trees of biotic interactions and of highly heterogeneous environment.ConclusionEvolution-oriented forestry may contribute adapting forests to climate change. It requires combining short-term and long-term objectives. We propose future lines of research and experimentation.


Agricultura Tecnica | 2004

Susceptibilidad a Insecticidas y Actividad Enzimática de Cydia pomonella L. (Lepidoptera: Tortricidae) Proveniente de Tres Huertos de la Región del Maule, Chile

Maritza Reyes; Jean Charles Bouvier; Thomas Boivin; Eduardo Fuentes-Contreras; Benoît Sauphanor

Cydia pomonella L., la principal plaga de pomaceas y nogales en Chile, ha sido controlada casi exclusivamente con aplicaciones de insecticidas organofosforados. Sin embargo, durante las ultimas temporadas se han observado crecientes niveles de frutos danados a cosecha. Dado que esta plaga ha desarrollado resistencia a insecticidas en varios paises, se evaluo la susceptibilidad a dosis diagnostico de azinfos metil y tebufenozide de larvas diapausantes provenientes de tres huertos de manzano de la Region del Maule y una cepa susceptible de referencia (S); ademas de la actividad de enzimas detoxificadoras en adultos emergidos de las mismas Tanto la actividad de oxidasas de funcion multiple (OFM) como de glutation-S-transferasas (GST) se evaluo a traves de fluorimetria, mientras la de esterasas (EST) se determino por absorbancia. La mortalidad larvaria frente a azinfos metil fue significativamente menor para Molina y Teno (30 y 85,4%, respectivamente) que para la cepa S (95,3%). Para tebufenozide la mortalidad larvaria fue significativamente menor en Molina (35,31%) que en la cepa S (88,6%). La actividad de GST fue significativamente mayor en dos de los tres huertos analizados (Teno = 13.679 unidades de fluorescencia insecto-1 y Molina =13.096 unidades de fluorescencia insecto-1). Similarmente, la actividad de OFM fue significativamente mayor en los mismos huertos, con valores 25,08 y 17,95 picogramos (pg) de 7OH insecto-1 min.-1 para Molina y Teno, respectivamente. La cepa S presento una actividad de EST significativamente mayor que la de las otras poblaciones, la cual parece no estar relacionada con la menor susceptibilidad a los insecticidas evaluados.


Genetics Research | 2003

Phenological segregation of insecticide resistance alleles in the codling moth Cydia pomonella (Lepidoptera : Tortricidae) : a case study of ecological divergences associated with adaptive changes in populations

Thomas Boivin; Jean-Charles Bouvier; Dominique Beslay; Benoît Sauphanor

Intrapopulation variability in the seasonal regulation of insect lifecycles has been shown to be due partly to genetic changes. Selection for insecticide resistance in the codling moth Cydia pomonella results from allelic substitution at two to three loci in south-eastern French populations of this species. However, such an adaptive process has been associated with an increased heterogeneity in the developmental responses to climatic factors such as temperature. In this paper, we investigate whether such pleiotropic effects of resistance on development induce a significant discrepancy in seasonal regulation in this species. The seasonal changes in a susceptible and two insecticide-resistant homozygous genotypes of C. pomonella, as well as their reciprocal F1 progeny, were followed under natural conditions during the reproductive season through the emergence events of adults, within-generation developmental rates and the number of generations. A significant delay in the occurrences of homozygous resistant genotypes resulted from significantly lower pre-imaginal developmental times relative to homozygous susceptible ones. Subsequent assessment of the number of generations indicated significantly higher diapause propensities in carriers of the resistance alleles (37.0-76.2%) than in susceptible homozygotes (6-7%), which mostly pupated towards a third generation of adults. In the light of these findings, pleiotropic effects of adaptive changes might be a crucial source of divergence in seasonal regulation at the population level, involving significant life-history trade-offs. In addition to man-made selective factors during the reproductive season, such an effect on the lifecycle could be a key component in the process of selection for resistance genes in south-eastern France C. pomonella populations.


Molecular Ecology | 2012

Inferences on population history of a seed chalcid wasp: invasion success despite a severe founder effect from an unexpected source population

Marie-Anne Auger-Rozenberg; Thomas Boivin; Emmanuelle Magnoux; Claudine Courtin; Alain Roques; Carole Kerdelhué

Most invasive species established in Europe originate from either Asia or North America, but little is currently known about the potential of the Anatolian Peninsula (Asia Minor) and/or the Near East to constitute invasion sources. Mediterranean forests are generally fragile ecosystems that can be threatened by invasive organisms coming from different regions of the Mediterranean Basin, but for which historical data are difficult to gather and the phylogeographic patterns are still poorly understood for most terrestrial organisms. In this study, we characterized the genetic structure of Megastigmus schimitscheki, an invasive seed‐feeding insect species originating from the Near East, and elucidated its invasion route in South‐eastern France in the mid 1990s. To disentangle the evolutionary history of this introduction, we gathered samples from the main native regions (Taurus Mountains in Turkey, Lebanon and Cyprus) and from the invaded region that we genotyped using five microsatellite markers and for which we sequenced the mitochondrial Cytochrome Oxidase I gene. We applied a set of population genetic statistics and methods, including approximate Bayesian computation. We proposed a detailed phylogeographic pattern for the Near East populations, and we unambiguously showed that the French invasive populations originated from Cyprus, although the available historical data strongly suggested that Turkey could be the most plausible source area. Interestingly, we could show that the introduced populations were founded from an extremely restricted number of individuals that realized a host switch from Cedrus brevifolia to C. atlantica. Evolutionary hypotheses are discussed to account for this unlikely scenario.


Environmental Toxicology and Chemistry | 2005

Effects of apple orchard management strategies on the great tit (Parus major) in southeastern france

Jean-Charles Bouvier; Jean-François Toubon; Thomas Boivin; Beno′t Sauphanor

The impact of conventional, organic, and integrated pest management (IPM) strategies of apple orchards on the reproduction of the great tit Parus major was investigated during a three-year period in southeastern France. The colonization process, egg-laying dates, clutch sizes, and fledging success were similar among pairs of P. major nesting in orchards conducted under the three studied management strategies. However, the mean number of young produced per ha (orchard productivity) was significantly higher in organic orchards than in both conventional and IPM orchards. Such divergences between both fledging success and orchard productivity primarily resulted from higher densities of P. major nesting pairs, but also from lower rates of nest abandonment during incubation in organic orchards. We suggest that intensive pesticide use under both IPM and conventional managements may have resulted in a substantial reduction in insect prey availability that enhanced intraspecific competition, which then led to failure in reproduction in pairs with low competitive ability. Our results highlight the relevance of P. major in assessing the environmental impact of apple orchard management strategies.


Molecular Ecology | 2014

Epidemiology of asexuality induced by the endosymbiotic Wolbachia across phytophagous wasp species: host plant specialization matters

Thomas Boivin; Hélène Henri; Fabrice Vavre; Cindy Gidoin; P. Veber; J.-N. Candau; Emmanuelle Magnoux; Alain Roques; Marie-Anne Auger-Rozenberg

Among eukaryotes, sexual reproduction is by far the most predominant mode of reproduction. However, some systems maintaining sexuality appear particularly labile and raise intriguing questions on the evolutionary routes to asexuality. Thelytokous parthenogenesis is a form of spontaneous loss of sexuality leading to strong distortion of sex ratio towards females and resulting from mutation, hybridization or infection by bacterial endosymbionts. We investigated whether ecological specialization is a likely mechanism of spread of thelytoky within insect communities. Focusing on the highly specialized genus Megastigmus (Hymenoptera: Torymidae), we first performed a large literature survey to examine the distribution of thelytoky in these wasps across their respective obligate host plant families. Second, we tested for thelytoky caused by endosymbionts by screening in 15 arrhenotokous and 10 thelytokous species for Wolbachia, Cardinium, Arsenophonus and Rickettsia endosymbionts and by performing antibiotic treatments. Finally, we performed phylogenetic reconstructions using multilocus sequence typing (MLST) to examine the evolution of endosymbiont‐mediated thelytoky in Megastigmus and its possible connections to host plant specialization. We demonstrate that thelytoky evolved from ancestral arrhenotoky through the horizontal transmission and the fixation of the parthenogenesis‐inducing Wolbachia. We find that ecological specialization in Wolbachias hosts was probably a critical driving force for Wolbachia infection and spread of thelytoky, but also a constraint. Our work further reinforces the hypothesis that community structure of insects is a major driver of the epidemiology of endosymbionts and that competitive interactions among closely related species may facilitate their horizontal transmission.


Biological Invasions | 2008

Differences in life history strategies between an invasive and a competing resident seed predator

Thomas Boivin; Gaëlle Rouault; Alain Chalon; Jean-Noël Candau

Competitive interactions may arise from biological invasion if a successful invasive species requires the ecological niche of a resident one. Life-history traits that make a species a successful invader are of particular interest in elucidating both invasion success and how interspecific competition may emerge. In southeastern France, the invasion of cedar forests by the seed chalcid Megastigmus schimitscheki generated competitive relationships with the resident M. pinsapinis for the exploitation of the seed resource. Among the numerous ecological traits allowing these seed predators to exploit their niche successfully, the timing of adult emergence, initial egg load and age-specific realized fecundities of females were investigated to help understanding the issue of such interspecific relationships. Spring adult emergence of M. schimitscheki under natural conditions was significantly earlier than that of M. pinsapinis, suggesting that an advantage for the access to the seed resource for the invasive species may be associated with this trait. Initial egg load was significantly higher in M. schimitscheki than in M. pinsapinis and the analysis of age-specific realized fecundity in semi-natural conditions indicated that both M. schimitscheki and M. pinsapinis females lay a large proportion of their eggs during the early days of their lives. In the light of these findings, both earlier phenology and higher reproduction abilities of M. schimitscheki may have the potential to confer an advantage within a competitive context with M. pinsapinis through enhanced seed resource preemption. This may potentially explain the invasiveness of M. schimitscheki in southern France despite the presence of its closely related competitor M. pinsapinis.

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Benoît Sauphanor

Institut national de la recherche agronomique

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Jean-Charles Bouvier

Institut national de la recherche agronomique

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Alain Chalon

Institut national de la recherche agronomique

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Cindy Gidoin

Institut national de la recherche agronomique

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Dominique Beslay

Institut national de la recherche agronomique

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Marie-Anne Auger-Rozenberg

Institut national de la recherche agronomique

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Jean Charles Bouvier

Institut national de la recherche agronomique

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Alain Roques

Institut national de la recherche agronomique

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Emmanuelle Magnoux

Institut national de la recherche agronomique

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