Laurence Després

• PhD
• Professor (Full) at University Grenoble Alpes

Speciation is a key evolutionary process which has been studied in numerous organisms and at multiple scales, from lineage radiation to gene expression. However, the factors explaining the rise of new species are not yet fully understood, and the relative contribution of neutral versus selective evolutionary processes in triggering and maintaining...

We present the first chromosome-level genome assembly and annotation of the pearly heath Coenonympha arcania, generated with a PacBio HiFi sequencing approach and complemented with Hi-C data. We additionally compare synteny, gene, and repeat content between C. arcania and other Lepidopteran genomes. This reference genome will enable future populati...

1. Temperature variation is one of the best-known and studied factor constraining life history along the altitudinal gradients. 2. Ectotherms such as insects are sensitive to temperature across all life stages, resulting in a wide range of adaptations in populations and species living at different elevations. In butterflies, the egg stage is parti...

Climate is a main driver of species distributions, but all species are not equally affected by climate change, and their differential responses to similar climatic constraints might dramatically affect the local species composition. In the context of climate warming, a better knowledge of the ability of dispersal-limited and habitat-specialist spec...

This is the automatic DeepL french translation of: Ceci est la traduction automatique (avec DeepL) de l'article anglais suivant: Brühl, C. A., Després, L., Frör, O., Patil, C. D., Poulin, B., Tetreau, G., & Allgeier, S. (2020). Environmental and socioeconomic effects of mosquito control in Europe using the biocide Bacillus thuringiensis subsp. isra...

Bacillus thuringiensis subsp. israelensis (Bti) is the main larvicide used to control mosquitoes worldwide. Although there is accumulating evidence of Bti having environmental effects on non-target fauna, relatively few field studies have documented the fate of Bti spores in the environment. Spore density was quantified over a 6-yr period (2012–201...

Cry11Aa and Cry11Ba are the two most potent toxins produced by mosquitocidal Bacillus thuringiensis subsp. israelensis and jegathesan, respectively. The toxins naturally crystallize within the host; however, the crystals are too small for structure determination at synchrotron sources. Therefore, we applied serial femtosecond crystallography at X-r...

Climatic variation is a key driver of genetic differentiation and phenotypic traits evolution, and local adaptation to temperature is expected in widespread species. We investigated phenotypic and genomic changes in the native range of the Asian tiger mosquito, Aedes albopictus. We first refine the phylogeographic structure based on genome-wide reg...

Aim To determine the interplay between climate and land use changes in driving population dynamics in a butterfly species, Coenonympha hero, at the southern limit of its distribution. Location French Jura massif and Europe. Methods We analysed patterns of genetic diversity distribution at 817 loci in 136 butterflies from 31 sites using NGS to inf...

Cry11Aa and Cry11Ba are the two most potent toxins produced by mosquitocidal Bacillus thuringiensis subsp. israelensis and jegathesan, respectively. The toxins naturally crystallize within the host; however, the crystals are too small for structure determination at synchrotron sources. Therefore, we applied serial femtosecond crystallography at X-r...

Cold‐adapted species escape climate warming by latitudinal and/or altitudinal range shifts, and currently occur in Southern Europe in isolated mountain ranges within ‘sky islands’. Here we studied the genetic structure of the Apollo butterfly in five such sky islands (above 1000 m) in France, and infer its demographic history since the last intergl...

Biological invasions, the establishment and spread of non‐native species in new regions, can have extensive economic and environmental consequences. Increased global connectivity accelerates introduction rates, while climate and land‐cover changes may decrease the barriers to invasive populations spread. A detailed knowledge of the invasion history...

Environmental features impacting the spread of invasive species after introduction can be assessed using population genetic structure as a quantitative estimation of effective dispersal at the landscape scale. However, in the case of an ongoing biological invasion, deciphering whether genetic structure represents landscape connectivity or founder e...

Bacillus thuringiensis subsp. israelensis (Bti) has been used in mosquito control programs to reduce nuisance in Europe for decades and is generally considered an environmentally-safe, effective and target-specific biocide. However, the use of Bti is not uncontroversial. Target mosquitoes and affected midges represent an important food source for m...

1. Temperature acts as a major factor on the timing of activity and behaviour in butterflies, and it might represent a key driver of butterfly diversification along elevation gradients. Under this hypothesis, local adaptation should be found along the elevation gradient, with butterflies from high elevation populations able to remain active at lowe...

Cyt1Aa is the one of four crystalline protoxins produced by mosquitocidal bacterium Bacillus thuringiensis israelensis (Bti) that has been shown to delay the evolution of insect resistance in the field. Limiting our understanding of Bti efficacy and the path to improved toxicity and spectrum has been ignorance of how Cyt1Aa crystallizes in vivo and...

Identifying the mechanisms involved in the formation and maintenance of species is a central question in evolutionary biology and distinguishing the selective drivers of populations’ divergence from demographic processes is of particular interest to better understand the speciation process. Hybrid zones are recognized to provide ideal places to inv...

Invasive species can encounter environments different from their source populations, which may trigger rapid adaptive changes after introduction (niche shift hypothesis). To test this hypothesis, we investigated whether postintroduction evolution is corre‐ lated with contrasting environmental conditions between the European invasive and source rang...

Delimiting species boundaries is central to understand ecological and evolutionary processes, and to monitor biodiversity patterns over time and space. Yet, most of our current knowledge on animal diversity and phylogeny relies on morphological and mitochondrial (mt) DNA variation, a popular molecular marker also used as a barcode to assign samples...

Adaptation to environmental conditions within the native range of exotic species can condition the invasion success of these species outside their range. The striking success of the Asian tiger mosquito, Aedes albopictus, to invade temperate regions has been attributed to the winter survival of diapause eggs in cold environments. In this study, we...

Until complete reproductive isolation is achieved, the extent of differentiation between two diverging lineages is the result of a dynamic equilibrium between genetic isolation and mixing. This is especially true for hybrid taxa, for which the degree of isolation in regard to their parental species is decisive in their capacity to rise as a new and...

Multiple introductions are key features for establishment and persistence of introduced species. However, little is known about the contribution of genetic admixture to the invasive potential of populations. To address this issue, we studied the recent invasion of the Asian tiger mosquito in Europe. Combining genome‐wide single nucleotide polymorph...

The genetic structure of a species is influenced by its history and by current gene flow. Using a population genomics approach, we infer the demographic history of the false ringlet (Coenonympha oedippus) in Europe based on 1594 genome-wide double digest restriction site associated DNA sequencing loci from 96 individuals (32 localities) sampled thr...

Understanding the interactions between pathogens sharing the same host can be complicated for holometabolous animals when larval and adult stages are exposed to distinct pathogens. In medically important insect vectors, the effect of pathogen exposure at the larval stage may influence susceptibility to human pathogens at the adult stage. We address...

The genetic structure of a species is influenced by its history and by current gene flow. Using a population genomics approach, we infer the demographic history of the false ringlet (Coenonympha oedippus) in Europe based on 1594 genome-wide double digest restriction site associated DNA sequencing loci from 96 individuals (32 localities) sampled thr...

Background: Insect microbiota is a dynamic microbial community that can actively participate in defense against pathogens. Bacillus thuringiensis (Bt) is a natural entomopathogen widely used as a bioinsecticide for pest control. Although Bt's mode of action has been extensively studied, whether the presence of microbiota is mandatory for Bt to eff...

Human-driven global environmental changes have considerably increased the risk of biological invasions, especially the spread of human parasites and their vectors. Among exotic species that have major impacts on public health, the dengue fever mosquito Aedes aegypti originating from Africa has spread worldwide during the last three centuries. Altho...

The Asian tiger mosquito Aedes albopictus, native to South-eastern Asia, is currently the most invasive mosquito in the world. The spatio-temporal dynamics of its expansion through the genetic characterization of invasive populations has been challenged so far by the limited number of genetic markers variable enough to infer the genetic structure i...

We examined how butterfly species richness is affected by human impact and elevation, and how species ranges are distributed along the elevational gradient (200–2700 m) in the Isère Department (French Alps). A total of 35,724 butterfly observations gathered in summer (May–September) between 1995 and 2015 were analyzed. The number of estimated speci...

Bacillus thuringiensis subsp. israelensis (Bti) is a natural pathogen of dipterans widely used as a biological insecticide for mosquito control. In order to characterize the response of mosquitoes to intoxication with Bti, the transcriptome profile of Bti-exposed susceptible Aedes aegypti larvae was analyzed using Illumina RNA-seq. Gene expression...

Bacillus thuringiensis israelensis (Bti) toxins are increasingly used for mosquito control, but little is known about the precise mode of action of each of these toxins, and how they interact to kill mosquito larvae. By using RNA sequencing, we investigated change in gene transcription level and polymorphism variations associated with resistance to...

Bacillus thuringiensis subsp. israelensis (Bti) is a natural pathogen of dipterans widely used as a biological insecticide for mosquito control. In order to characterize the response of mosquitoes to intoxication with Bti, the transcriptome profile of Bti-exposed susceptible Aedes aegypti larvae was analyzed using Illumina RNA-seq. Gene expression...

Hybridization has become a central element in theories of animal evolution during the last decade. New methods in population genomics and statistical model testing now allow the disentangling of the complexity that hybridization brings into key evolutionary processes such as local adaptation, colonization of new environments, species diversificatio...

Worldwide evolution of mosquito resistance to chemical insecticides represents a major challenge for public health, and the future of vector control largely relies on the development of biological insecticides that can be used in combination with chemicals (integrated management), with the expectation that populations already resistant to chemicals...

GO terms over-represented in genes differentially expressed as compared to the parental susceptible strain

Blast2GO analysis of all predicted peptides annotated as ‘conserved hypothetical protein’ or ‘hypothetical protein’ in Vectorbase against the protein database Swissprot (Blastp, E-value < 10-3, annotation cut-off = 55, GO weight = 5).

Results of cross resistance bioassays showing the number of dead larvae per pool of 20 larvae (18 replicates per strain and per insecticide; bars are for standard errors). Bioassays have been performed on 20 third instar larvae in 50mL tap water (WHO protocol), using a diagnotic dose for each insecticide killing half of the susceptible reference st...

Characteristics of the selected strains

RPKM correlations between cDNA library replicates. Each dot represents one transcript. Only transcripts showing more than 0.5 RPKM are shown.

List of genes with differential SNPs between LiTOX_N and LiTOX_S; non-synonymous changes are indicated.

Genes significantly differentially expressed in at least one selected strain (log2 fold ratio indicated when FDR≤0.01; ns: FDR>0.01; -Inf: no read detected in the selected strain)

List of supercontigs and genes affected by differential SNPs and their effects. The total number of SNPs affecting these genes is also shown.

GO terms enrichment analysis. Analysis was performed on transcripts significantly differentially expressed in each LiTOX phenotype as compared to the susceptible strain. GO terms associated with each transcript were extracted from Vectorbase. GO terms showing adjusted P values <0.05 were considered significantly enriched.

List of genes differently expressed between resistant and susceptible Bora-Bora strains classified according to their category.

Sequencing and mapping statistics.

Background: Despite the intensive use of Bacillus thuringiensis israelensis (Bti) toxins for mosquito control, little is known about the long term effect of exposure to this cocktail of toxins on target mosquito populations. In contrast to the many cases of resistance to Bacillus thuringiensis Cry toxins observed in other insects, there is no evid...

The bioinsecticide Bacillus thuringiensis subsp. israelensis is a larvicide used worldwide for mosquito control, which contains three Cry toxins and one Cyt toxin. We investigated for the first time in Aedes aegypti (1) the evolution of resistance and cross-resistance of strains selected with each Cry toxin, and (2) the effect of pre-selection with...

Sprays of commercial preparations of the bacterium Bacillus thuringiensis subsp. israelensis are widely used for the control of mosquito larvae. Despite an abundant literature on B. thuringiensis subsp. israelensis field efficiency on mosquito control, few studies have evaluated the fate of spores in the environment after treatments. In the present...

Bacillus thuringiensis subsp. israelensis (Bti) is increasingly used worldwide for mosquito control and is the only larvicide used in the French Rhône-Alpes region since decades. The artificial selection of mosquitoes with field-persistent Bti collected in breeding sites from this region led to a moderate level of resistance to Bti, but to relative...

Mosquito control is often the main method used to reduce mosquito-transmitted diseases. In order to investigate the genetic basis of resistance to the bio-insecticide Bacillus thuringiensis subsp. israelensis (Bti), we used information on polymorphism obtained from cDNA tag sequences from pooled larvae of laboratory Bti-resistant and susceptible Ae...

Effective vector control is currently challenged worldwide by the evolution of resistance to all classes of chemical insecticides in mosquitoes. In Martinique, populations of the dengue vector Aedes aegypti have been intensively treated with temephos and deltamethrin insecticides over the last fifty years, resulting in heterogeneous levels of resis...

Bacillus thuringiensis subsp. israelensis is a bioinsecticide used for larval mosquito control and it represents a safe alternative to chemical insecticides. Despite its environmental safety, it is less efficient and persistent than chemical insecticides. To bypass these limitations, we propose to combine the advantages of chemical and biological i...

The bioinsecticide Bacillus thuringiensis var. israelensis (Bti) is increasingly used worldwide for mosquito control. Although no established resistance to Bti has been described in the field so far, a resistant Aedes aegypti strain (LiTOX strain) was selected in the laboratory using field-collected leaf litter containing Bti toxins. This selected...

Bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. Despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of B. thuringiensis subsp. israelensis can occur under specific, u...

Fate of Bti in the field: from the unknown to the unexpected

Bacillus thuringiensis var. israelensis (Bti) is a natural larval mosquito pathogen producing pore-forming toxins targeting the midgut of Diptera larvae. It is used worldwide for mosquito control. Resistance mechanisms of an Aedes aegypti laboratory strain selected for 30 generations with field-collected leaf litter containing Bti toxins were inves...

All the 3512 transcripts detected by microarrays experiments in at least 5 hybridizations out of 6. For each transcript, accession number, corrected p-value, expression level changes, Vectorbase annotation and functional category are indicated.

Validation of microarray data by RT-qPCR on fifteen selected genes. Both experiments were performed on the same mRNA extracted from dissected larval midguts. ALP2, Alkaline phosphatase AAEL003298; ALP3, AAEL003313; ALP5, AAEL015070; ALP6, AAEL011175; APN1, N-Aminopeptidase AAEL012774; APN2, AAEL012776; APN3, AAEL012778; Cad2, Cadherin AAEL007488; H...

2D-DIGE gels from the two biological replicates and dye-swapping. BBMV prepared from first (A and B) and second (C and D) biological replicate are separated in function of their size (kDa) and their isoelectric point (pI). BBMV from Bti resistant strain are labeled with Cy3 and susceptible strain with Cy5 (A and C) or resistant strain with Cy5 and...

Cadherin detection by immunoblotting. BBMV proteins from the susceptible Bora-Bora strain (lane 1), LiTOX strain (lane 2) and the UGAL Aedes strain (lane 3) were separated in SDS-PAGE and stained with coomassie blue (panel A) or probed with α-AgCad1 antibodies (panel B), α-AgCad2 antibodies (panel C) or with pre-immune serum from α-AgCad2 rabbit (p...

70 transcripts significantly (corrected P-val<0.01) more than 3-fold differentially transcribed in the LiTOX strain. Transcripts are classified according to their putative function using the 13 functional categories. For each transcript, accession number, corrected P-value, expression level changes, Vectorbase annotation and supercontig are indicat...

Primer pairs used for RT-qPCR analyses. For each primer pair, sequence, corresponding gene name and accession number, product length, Tm and optimal annealing temperature used in PCR program are indicated. PCR efficiency and different parameters of the calibration curves (R2, slope and y-intercept) are also indicated. Specificity of each primer pai...

Protein identification of the 56 spots picked on deep purple stained 2D-gel. When different spots pointed to the same protein, they were differentiated using arbitrary letters after the access number. For each identification, the predicted pI, the predicted mass in kilodaltons, the percentage of sequence coverage, their functional category, and the...

Glycosylphosphatidylinositol (GPI)-anchor domains detection by four predictive computational programs. For each gene and protein, their accession number, the transcript and protein sizes are indicated. Results from the big-GPI and GPI-SOM softwares are indicated as ‘YES’ when they found a potential GPI-domain and ‘NO’ when no GPI-domain was determi...

The Amplified fragment Length Polymorphism (AFLP) is one of the cost-effective and useful fingerprinting techniques to study non-model species. One crucial AFLP step in the AFLP procedure is the choice of restriction enzymes and selective bases providing good-quality AFLP profiles. Here, we present a user-friendly program (ISIF) that allows carryin...

Genome scans based on anonymous Amplified Fragment Length Polymorphism (AFLP) markers scattered throughout the genome are becoming an increasingly popular approach to study the genetic basis of adaptation and speciation in natural populations. A shortcoming of this approach is that despite its efficiency to detect signatures of selection, it can ha...

Bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing Cry and Cyt proteins, which are toxic for mosquito larvae. Nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. In the presen...

Plant secondary metabolites play a key role in plant-insect interactions, whether constitutive or induced, C- or N-based. Anti-herbivore defences against insects can act as repellents, deterrents, growth inhibitors or cause direct mortality. In turn, insects have evolved a variety of strategies to act against plant toxins, e.g., avoidance, excretio...

AFLP-based genome scans are widely used to study the genetics of adaptation and to identify genomic regions potentially under selection. However, this approach usually fails to detect the actual genes or mutations targeted by selection owing to the difficulties of obtaining DNA sequences from AFLP fragments. Here, we combine classical AFLP outlier...

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