Papers by Jean-Yves Rasplus
Life, Dec 27, 2023
The ber fruit fly (BFF), Carpomya vesuviana Costa, 1854 (Diptera: Tephritidae), is an important k... more The ber fruit fly (BFF), Carpomya vesuviana Costa, 1854 (Diptera: Tephritidae), is an important key pest of the jujube, Ziziphus jujuba Miller. The main control measures against this pest are to use chemical control, but the first survey for its natural enemies was performed in Iran. Here, we report eight species of parasitic wasps of the BFF from five different families. The family Eurytomidae with three species, the families Pteromalidae and Mutillidae with two species each, and the families Braconidae and Diapriidae with one species each are associated with different immature stages of the BFF, of which Eurytoma pineticola Zerova (Eurytomidae) and Cyrtoptyx lichtensteini (Masi) (Pteromalidae) were the most abundant parasitoid species. Fopius carpomyiae (Silvestri,) was not reared on BFF on the jujube during this survey, but it was reported on Ziziphus spina-christi (L.) with a high parasitism rate. Therefore, it seems to be the most important parasitoid of BFF in Iran. The parasitoid community of BFF in Khorasan, Eastern Iran, is reviewed, and an identification key to these species is proposed.
Social Science Research Network, 2021
Plant Pathology, Sep 19, 2022
The bacterium Xylella fastidiosa (Xf) is an insectborne plant pathogen native to the Americas, wh... more The bacterium Xylella fastidiosa (Xf) is an insectborne plant pathogen native to the Americas, which invaded Europe, the Middle East and Asia . The pathogen is responsible for socio-economically important plant diseases such as Pierce's disease of grapevine (PD), olive quick decline syndrome (OQDS), bacterial leaf scorch of shade trees (BLS), phony peach disease (PPD), citrus variegated chlorosis (CVC) and almond leaf scorch (ALS) . Xf develops in plant xylem, obstructing
PeerJ, Mar 24, 2020
As a vector of Xylella fastidiosa (Wells, 1987) in Europe, the meadow spittlebug Philaenus spumar... more As a vector of Xylella fastidiosa (Wells, 1987) in Europe, the meadow spittlebug Philaenus spumarius (Linnaeus, 1758) (Hemiptera, Aphrophoridae) is a species of major concern. Therefore, tools and agents to control this ubiquitous insect that develops and feeds on hundreds of plant species are wanted. We conducted a field survey of P. spumarius eggs in Corsica and provide a first report of Ooctonus vulgatus Haliday, 1833 (Hymenoptera, Mymaridae) as a potential biocontrol agent of P. spumarius in Europe. To allow species identification, we summarized the main characters distinguishing O. vulgatus from other European species of Ooctonus and generated COI DNA barcodes. Parasitism rates were variable in the four localities included in the survey but could reach 69% (for an average number of eggs that hatched per locality of 109). Based on the geographic occurrences of O. vulgatus obtained from the literature, we calibrated an ecological niche model to assess its potential distribution in the Holarctic. Obviously, several questions need to be addressed to determine whether O. vulgatus could become an effective biocontrol agent of P. spumarius in Europe. So far, O. vulgatus has been reared only from P. spumarius eggs, but its exact host-range should be evaluated to ensure efficiency and avoid non-target effect. The top-down impact of the parasitoid on vector populations should also be assessed on large data sets. Finally, the feasibility of mass rearing should be tested. We hope this report serves as a starting point to initiate research on this parasitoid wasp to assess whether it could contribute to reduce the spread and impact of X. fastidiosa in Europe.
bioRxiv (Cold Spring Harbor Laboratory), Mar 28, 2018
HAL (Le Centre pour la Communication Scientifique Directe), May 6, 2021
Biological Control, Jul 1, 2018
Parasitic hymenoptera are natural enemies of a wide range of crop pests. However, the complex tax... more Parasitic hymenoptera are natural enemies of a wide range of crop pests. However, the complex taxonomy of this group and the scarcity of taxonomic expertise make difficult the accurate identification of species, which limits their use in biological control programs. In this study, we explored the potential of a two-step PCR approach combined with Illumina sequencing to recover mitochondrial protein coding genes (COI and Cytb) from dry specimens from a reference collection, whose DNA was extracted non-destructively. We studied 18 species of afrotropical Braconidae (Microgastrinae, Opiinae and Braconinae) collected 10 to 35 years ago. Depending on the target region, sequences were obtained from 61 to 90 % of the specimens. The full barcode was reconstructed in ca 90% of the species. A customized analysis pipeline allowed us to manage the high rate of contamination and to identify co-amplified sequences of hosts of parasitoids. As a result, in a single analysis, we were able to 1) generate new barcodes for poorly known species, 2) obtain a preliminary overview of intra specific variability, 3) generate a few data on host-parasitoid associations based on remains of hosts in adult wasps. This cost-effective approach should allow to improve the quality of reference molecular databases by capitalizing on museum specimens identified by expert taxonomists, in order to set up more efficient biological control programs.
Bulletin of Entomological Research, Mar 1, 2013
Scientific Reports, Feb 6, 2017
Until now, the potential of NGS for the construction of barcode libraries or integrative taxonomy... more Until now, the potential of NGS for the construction of barcode libraries or integrative taxonomy has been seldom realised. Here, we amplified (two-step PCR) and simultaneously sequenced (MiSeq) multiple markers from hundreds of fig wasp specimens. We also developed a workflow for quality control of the data. Illumina and Sanger sequences accumulated in the past years were compared. Interestingly, primers and PCR conditions used for the Sanger approach did not require optimisation to construct the MiSeq library. After quality controls, 87% of the species (76% of the specimens) had a valid MiSeq sequence for each marker. Importantly, major clusters did not always correspond to the targeted loci. Nine specimens exhibited two divergent sequences (up to 10%). In 95% of the species, MiSeq and Sanger sequences obtained from the same sampling were similar. For the remaining 5%, species were paraphyletic or the sequences clustered into divergent groups on the Sanger + MiSeq trees (>7%). These problematic cases may represent coding NUMTS or heteroplasms. Our results illustrate that Illumina approaches are not artefact-free and confirm that Sanger databases can contain non-target genes. This highlights the importance of quality controls, working with taxonomists and using multiple markers for DNA-taxonomy or species diversity assessment. While next-generation sequencing (NGS) is commonly used to analyse bulk environmental samples (metabarcoding) 1-3 , Sanger sequencing remains the standard approach in generating DNA barcode libraries 4. This is unfortunate as the cost-effective acquisition of barcode sequences from hundreds of specimens identified to species by expert taxonomists could accelerate the construction of accurate reference libraries and increase their completeness 2,5. As it generates up to 25 million paired-end reads (2 * 300 bp), the Illumina MiSeq platform makes possible the sequencing of several hundreds of individuals on a set of informative barcodes. This allows for the increase not only in the number of species but also in the number of specimens included in reference databases, which is crucial, as a better coverage of the geographical range of the species and a better characterisation of the intraspecific variability lead to more accurate identification 6,7. Two-step polymerase chain reactions (PCR) are convenient methods to generate amplicon libraries for Illumina sequencing 8-14. In the first PCR reaction the targeted DNA region is amplified using specific primers flanked by tails (Fig. 1). These tails allow for a second PCR reaction to add Illumina adaptor sequences and indexes to multiplex samples 11. Theoretically, two-step PCR approaches provide an opportunity to build on existing experience and tools (e.g. primers and PCR conditions), which make them very attractive. Combining two-step PCR approaches and high-throughput sequencing may contribute to circumvent some of the main pitfalls of barcoding revealed by many studies 15. Indeed, heteroplasms 16,17 ; NUMTS (NUclearMiTochondrial DNA segments) 18 , endosymbionts 19 , parasitoids 20 or contaminants may be sometimes preferentially amplified by the primer pair used and are frequently sequenced using Sanger methods. Using NGS, these non-target loci may be simultaneously amplified with the targeted COI, sequenced within the sequencing depth and better identified by post sequencing analyses 2. Furthermore, combining two-step PCR and MiSeq sequencing may also help to increase the number of genes sequenced for barcoding. Indeed to circumvent the main pitfalls associated with the use of a single, mitochondrial gene, it has been acknowledged that an increase in the number of genes analysed is desired, though most studies still rely on COI only 15. This increase is even more recommended when it comes to DNA-based species delimitation 21-23 or phylogeography. However, the addition
HAL (Le Centre pour la Communication Scientifique Directe), May 6, 2021
Evolutionary Ecology, 2016
Biology, Aug 31, 2022
Although global change is expected to modify the threat posed by plant pathogens, not much is kno... more Although global change is expected to modify the threat posed by plant pathogens, not much is known about how a changing climate will affect the epidemiology of generalist vectorborne diseases. In the present study, we developed a high-throughput screening method to test for the presence of a deadly plant pathogen, Xylella fastidiosa, in its insect vectors. Based on a four-year survey in climatically distinct areas of the island of Corsica (France), we found a significant positive correlation between the frequency of insect vectors positive for X. fastidiosa and temperature. We observed that a higher prevalence in insects corresponded with milder winters. We used future climate projections up to the year 2100, and found that the risk for X. fastidiosa outbreak will increase in the future. While the proportion of vectors that carry the pathogen should increase, the climate conditions will remain suitable for the bacterium and its main vector, with possible shifts towards higher elevations. Besides calling for research efforts to limit the incidence of plant diseases in temperate zones, this works reveals that recent molecular technologies could and should be used for massive screening of pathogens in vectors in order to scale-up surveillance and management efforts.
Zoology in The Middle East, Jul 14, 2023
Journal of Applied Entomology, Apr 4, 2023
Studies investigating X. fastidiosa (Xf) acquisition by cicadas are scarce. We collected 169 cica... more Studies investigating X. fastidiosa (Xf) acquisition by cicadas are scarce. We collected 169 cicadas in infected areas throughout Corsica (France), belonging to the four species known from the island (Cicada orni; Cicadetta fangoana; Tibicina corsica corsica and Tibicina nigronervosa). All specimens were tested for the presence of Xf using a two‐step PCR approach followed by Illumina sequencing. All specimens tested negative. So far, there is no indication that European cicadas are playing a significant role in the spread of Xf.
eLife, Jun 6, 2023
The accidental endogenization of viral elements within eukaryotic genomes can occasionally provid... more The accidental endogenization of viral elements within eukaryotic genomes can occasionally provide significant evolutionary benefits, giving rise to their long-term retention, that is, to viral domestication. For instance, in some endoparasitoid wasps (whose immature stages develop inside their hosts), the membrane-fusion property of double-stranded DNA viruses have been repeatedly domesticated following ancestral endogenizations. The endogenized genes provide female wasps with a delivery tool to inject virulence factors that are essential to the developmental success of their offspring. Because all known cases of viral domestication involve endoparasitic wasps, we hypothesized that this lifestyle, relying on a close interaction between individuals, may have promoted the endogenization and domestication of viruses. By analyzing the composition of 124 Hymenoptera genomes, spread over the diversity of this clade and including free-living, ecto, and endoparasitoid species, we tested this hypothesis. Our analysis first revealed that double-stranded DNA viruses, in comparison with other viral genomic structures (ssDNA, dsRNA, ssRNA), are more often endogenized and domesticated (that is, retained by selection) than expected from their estimated abundance in insect viral communities. Second, our analysis indicates that the rate at which dsDNA viruses are endogenized is higher in endoparasitoids than in ectoparasitoids or free-living hymenopterans, which also translates into more frequent events of domestication. Hence, these results are consistent with the hypothesis that the endoparasitoid lifestyle has facilitated the endogenization of dsDNA viruses, in turn, increasing the opportunities of domestications that now play a central role in the biology of many endoparasitoid lineages. This important manuscript employs a rigorous and multi-pronged comparative genomics approach to unravel how lifestyle modulates the acquisition and domestication of viral genetic elements in the genomes of hymenopteran insects. Using an extensive dataset of over 120 hymenopteran genomes, the authors provide convincing evidence that endoparasitism (where parasite development occurs within hosts) facilitates the uptake and domestication of double-stranded DNA viral elements.
Nature Communications, Mar 3, 2023
The order Hymenoptera (wasps, ants, sawflies, and bees) represents one of the most diverse animal... more The order Hymenoptera (wasps, ants, sawflies, and bees) represents one of the most diverse animal lineages, but whether specific key innovations have contributed to its diversification is still unknown. We assembled the largest timecalibrated phylogeny of Hymenoptera to date and investigated the origin and possible correlation of particular morphological and behavioral innovations with diversification in the order: the wasp waist of Apocrita; the stinger of Aculeata; parasitoidism, a specialized form of carnivory; and secondary phytophagy, a reversal to plant-feeding. Here, we show that parasitoidism has been the dominant strategy since the Late Triassic in Hymenoptera, but was not an immediate driver of diversification. Instead, transitions to secondary phytophagy (from parasitoidism) had a major influence on diversification rate in Hymenoptera. Support for the stinger and the wasp waist as key innovations remains equivocal, but these traits may have laid the anatomical and behavioral foundations for adaptations more directly associated with diversification. The question of why some groups of organisms have diversified more than others has fascinated biologists since the early days of phylogenetics. The success of particular clades has often been attributed to the evolution of novel traits or key innovations conferring an evolutionary advantage 1,2 , and linking these traits to changes in diversification rates estimated from phylogenies has been a major goal in macroevolutionary research . The concept of what defines a key innovation has been fluid 1,2,7 . Originally developed to describe traits that facilitate the radiation of a clade into new adaptive zones, it has more recently been generalized in macroevolutionary studies to describe an evolutionary change in a trait leading to increased species diversification in the clade that possesses this trait . This broader definition has appeal due to its simplicity with regard to hypothesis testing; however, the idea of one trait single-handedly influencing survival and diversification has been criticized as overly simplistic 7 . More nuanced concepts and terminology have therefore been suggested for more complex evolutionary scenarios involving multiple traits . Much speculation and numerous hypotheses have attempted to account for the diversity of insects, summarized by Mayhew 12 . In particular, several morphological, physiological, and behavioral traits have been suggested as key innovations promoting the early diversification of insects and greatly influencing their success. These traits include the evolution of insect flight, complete metamorphosis, and phytophagy . The Hymenoptera, which comprise the ants, bees, wasps, and sawflies, is one of the most species-rich and abundant insect orders , possessing a remarkable diversity of life histories and
Acta Oecologica-international Journal of Ecology, Jul 1, 2018
The high adaptive success of parasitic Hymenoptera might be related to the use of different ovipo... more The high adaptive success of parasitic Hymenoptera might be related to the use of different oviposition sites, allowing niche partitioning among co-occurring species resulting in life history specialization and diversification. In this scenario, evolutionary changes in life history and resources for oviposition can be associated with changes in ovipositor structure, allowing exploitation of different substrates for oviposition. We used a formal phylogenetic framework to investigate the evolution of ovipositor morphology and life history in agaonid wasps. We sampled 24 species with different life histories belonging to all main clades of Agaonidae including representatives of all described genera of non-pollinating fig wasps (NPFW). Our results show an overall correlation between ovipositor morphology and life history in agaonid fig wasps. Ovipositor morphologies seem to be related to constraints imposed by features of the oviposition sites since ovipositor morphology has experienced convergent evolution at least four times in Sycophaginae (Agaonidae) according to the resource used. Nongalling species have more distantly spaced teeth with uneven spacing, as opposed to the observed morphology of galling species. Our results suggest that the ancestral condition for ovipositor morphology was most likely the presence of one or two apical teeth. Regarding life history, ovary galling species that oviposit in receptive figs possibly represent the ancestral condition. Different ovipositor characteristics allow exploitation of new niches and may be related to resource partitioning and species co-existence in the fig-fig wasp system.
Evolutionary Ecology, May 24, 2016
Ficus and their mutualistic pollinating wasps provide a unique model to investigate joint diversi... more Ficus and their mutualistic pollinating wasps provide a unique model to investigate joint diversification in a high dispersal system. We investigate genetic structuring in an extremely wide-ranging Ficus species, Ficus racemosa, and its pollinating wasp throughout their range, which extends from India to Australia. Our samples were structured into four large, vicariant populations of figs and wasps which may correspond to distinct (sub)species, located in India, China-Thailand, Borneo, and Australia. However, the genetically most divergent group was the Indian population for the figs and the China-Thailand population for the wasps, suggesting different evolutionary histories of populations. Molecular dating for the wasps shows that diversification of the pollinator clade is surprisingly old, beginning about 13.6 Ma. Data on both the host fig species and its pollinating wasps suggest that strong genetic flow within biogeographic groups over several hundreds of kilometers has limited genetic and morphological differentiation and, potentially, local adaptation. This is probably due to long-distance dispersal of pollinating wasps. The genetic clustering into large geographic units observed in F. racemosa and its pollinators is reminiscent of what can be observed in some other high-dispersal organisms characterized by morphology that varies little over huge distances. The implications of strong gene flow for diversification processes and adaptation to different ecological conditions in Ficus and their pollinating wasps are just beginning to emerge.
Zenodo (CERN European Organization for Nuclear Research), 2020
The recent outbreaks of the xylem-limited bacterium <em>Xylella fastidiosa</em> in Eu... more The recent outbreaks of the xylem-limited bacterium <em>Xylella fastidiosa</em> in Europe require the improvement of prevention measures and of integrated management strategies for the diseases caused by this destructive pathogen. These needs are adressed by the XF-ACTORS consortium. Within the workpackage 5 of this project, faunistic surveys have been carried out in various habitats of southern and central Europe and in olive groves in Brazil to monitor the presence of xylem-sap feeding Auchenorrhyncha as confirmed or potential vectors of <em>X. fastidiosa</em>. The metadata of the collection are reported in this database. It provides general information about the occurrence and abundance of xylem-sap feeder species in Europe. This work has received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 727987 - XF-ACTORS "Xylella Fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy"
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Papers by Jean-Yves Rasplus