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1.
Zootaxa ; 5401(1): 1-190, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38480114

RESUMEN

Eurytomidae (Chalcidoidea) species associated with fig trees (Ficus) are still poorly documented. A phylogenetic analysis of 63 morphological characters was conducted to revise Afrotropical species of Sycophila Walker and Ficomila Bouek associated with fig trees. Based on our results, which also included Palaearctic species of Sycophila, three subgenera of Sycophila are proposed: Sycophila s. str., Tineomyza Rondani stat. rev. and a new subgenus, Ficorytoma subgen. n. Lotfalizadeh & Rasplus. Ficomila is maintained as a valid genus. Thirty-six species are also newly described by Lotfalizadeh & Rasplus, namely Ficomila artocarpoides sp. n., F. carolae sp. n., F. bouceki sp. n., F. comptoni sp. n., F. flava sp. n., F. gabonensis sp. n., F. gibba sp. n., F. guinensis sp. n., F. sinai sp. n., F. tanzanica sp. n., F. vannoorti sp. n., Sycophila (Tineomyza) beninensis sp. n., S. (T.) busseicola sp. n., S. (T.) glumosae sp. n., S. (T.) luteacola sp. n., S. (T.) maldesi sp. n., S. (T.) minuta sp. n., S. (T.) platygastra sp. n., S. (T.) risbeci sp. n., S. (T.) wiebesi sp. n., S. (T.) zebrogastra sp. n., S. (Ficorytoma) delvarei sp. n., S. (F.) persicae sp. n., S. (Sycophila) annae sp. n., S. (S.) bidentata sp. n., S. (S.) longiflagellata sp. n., S. (S.) chirindensis sp. n., S. (S.) ficophila sp. n., S. (S.) fusca sp. n., S. (S.) lasallei sp. n., S. (S.) macrospermae sp. n., S. (S.) meridionalis sp. n., S. (S.) nigra sp. n., S. (S.) nigriterga sp. n., S. (S.) suricola sp. n., S. (S.) zebra sp. n.. Seven described species of Sycophila are reclassified in the subgenus Tineomyza: Sycophila (Tineomyza) flaviclava Bouek, 1981; S. (T.) modesta Bouek, 1981; S. (T.) naso Bouek, 1981; S. (T.) punctum Bouek, 1981; S. (T.) ruandensis Risbec, 1957; S. (T.) sessilis Bouek, 1981 and S. (T.) setulosa Zerova, 2009. After this revision, Ficomila and Sycophila include 46 species associated with Afrotropical Ficus. Detailed morphological descriptions and illustrations as well as identification keys are provided for the subgenera, species-groups and species of Ficomila and Sycophila associated with Afrotropical fig trees; their host fig association and relative lack of host-specificity are also discussed.


Asunto(s)
Ficus , Gastrópodos , Himenópteros , Caracoles , Animales , Filogenia
2.
Cladistics ; 40(1): 34-63, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-37919831

RESUMEN

Chalcidoidea are mostly parasitoid wasps that include as many as 500 000 estimated species. Capturing phylogenetic signal from such a massive radiation can be daunting. Chalcidoidea is an excellent example of a hyperdiverse group that has remained recalcitrant to phylogenetic resolution. We combined 1007 exons obtained with Anchored Hybrid Enrichment with 1048 ultra-conserved elements (UCEs) for 433 taxa including all extant families, >95% of all subfamilies, and 356 genera chosen to represent the vast diversity of the superfamily. Going back and forth between the molecular results and our collective knowledge of morphology and biology, we detected bias in the analyses that was driven by the saturation of nucleotide data. Our final results are based on a concatenated analysis of the least saturated exons and UCE datasets (2054 loci, 284 106 sites). Our analyses support an expected sister relationship with Mymarommatoidea. Seven previously recognized families were not monophyletic, so support for a new classification is discussed. Natural history in some cases would appear to be more informative than morphology, as illustrated by the elucidation of a clade of plant gall associates and a clade of taxa with planidial first-instar larvae. The phylogeny suggests a transition from smaller soft-bodied wasps to larger and more heavily sclerotized wasps, with egg parasitism as potentially ancestral for the entire superfamily. Deep divergences in Chalcidoidea coincide with an increase in insect families in the fossil record, and an early shift to phytophagy corresponds with the beginning of the "Angiosperm Terrestrial Revolution". Our dating analyses suggest a middle Jurassic origin of 174 Ma (167.3-180.5 Ma) and a crown age of 162.2 Ma (153.9-169.8 Ma) for Chalcidoidea. During the Cretaceous, Chalcidoidea may have undergone a rapid radiation in southern Gondwana with subsequent dispersals to the Northern Hemisphere. This scenario is discussed with regard to knowledge about the host taxa of chalcid wasps, their fossil record and Earth's palaeogeographic history.


Asunto(s)
Parásitos , Avispas , Animales , Avispas/genética , Filogenia , Evolución Biológica
3.
Elife ; 122023 06 06.
Artículo en Inglés | MEDLINE | ID: mdl-37278068

RESUMEN

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.


Asunto(s)
Virus , Avispas , Animales , Femenino , Evolución Biológica , ADN , Domesticación , Genoma Viral , Virus/genética , Avispas/genética
4.
Nat Commun ; 14(1): 1212, 2023 03 03.
Artículo en Inglés | MEDLINE | ID: mdl-36869077

RESUMEN

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 time-calibrated 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.


Asunto(s)
Hormigas , Avispas , Abejas , Animales , Aclimatación , Carnivoría , Fenotipo
5.
Sci Rep ; 13(1): 1901, 2023 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-36732346

RESUMEN

Philaenus spumarius (Ps) is considered the main insect vector of the bacterium Xylella fastidiosa (Xf) in Europe. As such, it is a key actor of the Xf pathosystem on which surveillance and management strategies could be implemented. Although research effort has increased in the past years, the ecological factors shaping Ps abundance and distribution across landscapes are still poorly known in most regions of Europe. We selected 64 plots of 500m2 in Corsican semi-natural habitats in which we sampled nymphs and adults of Ps during three years. While local or surrounding vegetation structure (low or high scrubland) had little effect on Ps abundance, we highlighted a positive relationship between Ps abundance and the density of Cistus monspeliensis in the plots. We also found larger populations of Ps in cooler and moister plots. The pattern of host association highlighted here is unique, which calls for more studies on the ecology of Ps in Europe, to help designing surveillance and management strategy for Xf.


Asunto(s)
Hemípteros , Xylella , Animales , Enfermedades de las Plantas/microbiología , Francia , Europa (Continente) , Hemípteros/microbiología
6.
Biology (Basel) ; 11(9)2022 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-36138778

RESUMEN

Global change is expected to modify the threat posed by pathogens to plants. However, little is known regarding how a changing climate will influence the epidemiology of generalist vector-borne diseases. We developed a high-throughput screening method to test for the presence of a deadly plant pathogen, Xylella fastidiosa, in its insect vectors. Then, using data from a four-year survey in climatically distinct areas of Corsica (France), we demonstrated a positive correlation between the proportion of vectors positive to X. fastidiosa and temperature. Notably, a higher prevalence corresponded with milder winters. Our projections up to 2100 indicate an increased risk of outbreaks. 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 range shifts towards a higher elevation. Besides calling for research efforts to limit the incidence of plant diseases in the temperate zone, this work reveals that recent molecular technologies could and should be used for massive screening of pathogens in vectors to scale-up surveillance and management efforts.

7.
Cladistics ; 37(1): 1-35, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-34478176

RESUMEN

Recent technical advances combined with novel computational approaches have promised the acceleration of our understanding of the tree of life. However, when it comes to hyperdiverse and poorly known groups of invertebrates, studies are still scarce. As published phylogenies will be rarely challenged by future taxonomists, careful attention must be paid to potential analytical bias. We present the first molecular phylogenetic hypothesis for the family Chalcididae, a group of parasitoid wasps, with a representative sampling (144 ingroups and seven outgroups) that covers all described subfamilies and tribes, and 82% of the known genera. Analyses of 538 Ultra-Conserved Elements (UCEs) with supermatrix (RAxML and IQTREE) and gene tree reconciliation approaches (ASTRAL, ASTRID) resulted in highly supported topologies in overall agreement with morphology but reveal conflicting topologies for some of the deepest nodes. To resolve these conflicts, we explored the phylogenetic tree space with clustering and gene genealogy interrogation methods, analyzed marker and taxon properties that could bias inferences and performed a thorough morphological analysis (130 characters encoded for 40 taxa representative of the diversity). This joint analysis reveals that UCEs enable attainment of resolution between ancestry and convergent/divergent evolution when morphology is not informative enough, but also shows that a systematic exploration of bias with different analytical methods and a careful analysis of morphological features is required to prevent publication of artifactual results. We highlight a GC content bias for maximum-likelihood approaches, an artifactual mid-point rooting of the ASTRAL tree and a deleterious effect of high percentage of missing data (>85% missing UCEs) on gene tree reconciliation methods. Based on the results we propose a new classification of the family into eight subfamilies and ten tribes that lay the foundation for future studies on the evolutionary history of Chalcididae.


Asunto(s)
Secuencia Conservada , Himenópteros/anatomía & histología , Himenópteros/clasificación , Himenópteros/genética , Filogenia , Animales , Composición de Base , Biodiversidad , Evolución Biológica , Técnicas Genéticas , Funciones de Verosimilitud
8.
Cladistics ; 37(4): 402-422, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34478193

RESUMEN

Despite many attempts in the Sanger sequencing era, the phylogeny of fig trees remains unresolved, which limits our ability to analyze the evolution of key traits that may have contributed to their evolutionary and ecological success. We used restriction-site-associated DNA sequencing (c. 420 kb) and 102 morphological characters to elucidate the relationships between 70 species of Ficus. To increase phylogenetic information for higher-level relationships, we targeted conserved regions and assembled paired reads into long loci to enable the retrieval of homologous loci in outgroup genomes. We compared morphological and molecular results to highlight discrepancies and reveal possible inference bias. For the first time, we recovered a monophyletic subgenus Urostigma (stranglers) and a clade with all gynodioecious Ficus. However, we show, with a new approach based on iterative principal component analysis, that it is not (and will probably never be) possible to homogenize evolutionary rates and GC content for all taxa before phylogenetic inference. Four competing positions for the root of the molecular tree are possible. The placement of section Pharmacosycea as sister to other fig trees is not supported by morphological data and considered a result of a long-branch attraction artefact to the outgroups. Regarding morphological features and indirect evidence from the pollinator tree of life, the topology that divides Ficus into monoecious versus gynodioecious species appears most plausible. It seems most likely that the ancestor of fig trees was a freestanding tree and active pollination is inferred as the ancestral state, contrary to previous hypotheses. However, ambiguity remains on the ancestral breeding system. Despite morphological plasticity, we advocate restoring a central role to morphology in our understanding of the evolution of Ficus, as it can help detect systematic errors that appear more pronounced with larger molecular datasets.


Asunto(s)
Evolución Biológica , ADN de Plantas/genética , Ficus/anatomía & histología , Ficus/fisiología , Filogenia , Raíces de Plantas/fisiología , Animales , ADN de Plantas/análisis , Fitomejoramiento , Polinización
9.
PLoS Negl Trop Dis ; 15(7): e0009479, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-34280193

RESUMEN

Phlebotomine sand flies are the main natural vectors of Leishmania, which cause visceral and tegumentary tropical diseases worldwide. However, their taxonomy and evolutionary history remain poorly studied. Indeed, as for many human disease vectors, their small size is a challenge for morphological and molecular works. Here, we successfully amplified unbiased copies of whole genome to sequence thousands of restriction-site associated DNA (RAD) markers from single specimens of phlebotomines. RAD markers were used to infer a fully resolved phylogeny of the subgenus Paraphlebotomus (11 species + 5 outgroups, 32 specimens). The subgenus was not recovered as monophyletic and we describe a new subgenus Artemievus subg. nov. Depaquit for Phlebotomus alexandri. We also confirm the validity of Ph. riouxi which is reinstated as valid species. Our analyses suggest that Paraphlebotomus sensu nov. originated ca 12.9-8.5 Ma and was possibly largely distributed from peri-Mediterranean to Irano-Turanian regions. Its biogeographical history can be summarized into three phases: i) a first split between Ph. riouxi + Ph. chabaudi and other species that may have resulted from the rise of the Saharan belt ca 8.5 Ma; ii) a Messinian vicariant event (7.3-5.3 Ma) during which the prolonged drought could have resulted in the divergence of main lineages; iii) a recent radiation event (3-2 Ma) that correspond to cycles of wet and dry periods in the Middle East and the East African subregions during the Pleistocene. Interestingly these cycles are also hypothetical drivers of the diversification of rodents, in the burrows of which Paraphlebotomus larvae develop. By meeting the challenge of sequencing pangenomics markers from single, minute phlebotomines, this work opens new avenues for improving our understanding of the epidemiology of leishmaniases and possibly other human diseases transmitted by arthropod vectors.


Asunto(s)
Evolución Molecular , Insectos Vectores/genética , Phlebotomus/genética , Distribución Animal , Animales , Marcadores Genéticos , Humanos , Insectos Vectores/anatomía & histología , Insectos Vectores/clasificación , Insectos Vectores/fisiología , Leishmaniasis/epidemiología , Leishmaniasis/transmisión , Medio Oriente/epidemiología , Phlebotomus/anatomía & histología , Phlebotomus/clasificación , Phlebotomus/fisiología , Filogenia
10.
Nat Ecol Evol ; 5(7): 974-986, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-34002050

RESUMEN

Many insects metamorphose from antagonistic larvae into mutualistic adult pollinators, with reciprocal adaptation leading to specialized insect-plant associations. It remains unknown how such interactions are established at molecular level. Here we assemble high-quality genomes of a fig species, Ficus pumila var. pumila, and its specific pollinating wasp, Wiebesia pumilae. We combine multi-omics with validation experiments to reveal molecular mechanisms underlying this specialized interaction. In the plant, we identify the specific compound attracting pollinators and validate the function of several key genes regulating its biosynthesis. In the pollinator, we find a highly reduced number of odorant-binding protein genes and an odorant-binding protein mainly binding the attractant. During antagonistic interaction, we find similar chemical profiles and turnovers throughout the development of galled ovules and seeds, and a significant contraction of detoxification-related gene families in the pollinator. Our study identifies some key genes bridging coevolved mutualists, establishing expectations for more diffuse insect-pollinator systems.


Asunto(s)
Ficus , Avispas , Adaptación Fisiológica , Animales , Humanos , Polinización , Simbiosis
11.
C R Biol ; 343(3): 311-344, 2021 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-33621458

RESUMEN

Southern France, like the rest of the world, is facing the emergence of diseases affecting plants, animals and humans, of which causative agents (viruses, parasites, bacteria) are transmitted by arthropod vectors. Global changes are accelerating the emergence and spread of these diseases. After presenting some examples related to vectors of yellow fever and dengue viruses (Aedes aegypti and Ae. albopictus), Crimean-Congo hemorrhagic fever (Hyalomma marginatum), Bluetongue (Culicoides sp.), and the phytopathogen Xylella fastidiosa (Hemiptera spp.), we will discuss what are the intrinsic and extrinsic factors that make an arthropod a vector in a given place and at a given time. We also propose some thoughts regarding these emergences, possible scenarios for their evolution and some recommendations for the future.


Le sud de la France, comme le reste du monde, est confronté à l'émergence de maladies affectant les plantes, les animaux et les populations humaines, dont les agents étiologiques (virus, parasites, bactéries) sont transmis par des arthropodes vecteurs. Les changements globaux auxquels nous faisons face accélèrent l'apparition et la diffusion de ces pathologies. Après avoir pris quelques exemples concernant les vecteurs des virus de la fièvre jaune et de la dengue (Aedes aegypti et Ae. albopictus), de la fièvre de Crimée-Congo (Hyalomma marginatum), de la fièvre catarrhale ovine (Culicoides sp.) et de la bactérie phytopathogène Xylella fastidiosa (Hemiptera spp.), nous verrons quels sont les facteurs intrinsèques et extrinsèques qui font qu'un arthropode devient un vecteur en un lieu et à un moment donné. Nous proposons des pistes de réflexion sur ces émergences et le possible devenir des maladies transmises par arthropodes. Nous concluons par quelques recommandations pour mieux anticiper les émergences.


Asunto(s)
Epidemias , Mosquitos Vectores , Animales , Vectores Artrópodos , Francia , Humanos , Xylella
12.
PeerJ ; 8: e8591, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32231870

RESUMEN

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.

14.
Sci Rep ; 9(1): 8844, 2019 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-31222007

RESUMEN

The bacterium Xylella fastidiosa (Xf) is a plant endophyte native to the Americas that causes diseases in many crops of economic importance (grapevine, Citrus, Olive trees etc). Xf has been recently detected in several regions outside of its native range including Europe where little is known about its potential geographical expansion. We collected data documenting the native and invaded ranges of the Xf subspecies fastidiosa, pauca and multiplex and fitted bioclimatic species distribution models (SDMs) to assess the potential climate suitability of European continent for those pathogens. According to model predictions, the currently reported distribution of Xf in Europe is small compared to the large extent of climatically suitable areas. The regions at high risk encompass the Mediterranean coastal areas of Spain, Greece, Italy and France, the Atlantic coastal areas of France, Portugal and Spain as well as the southwestern regions of Spain and lowlands in southern Italy. The extent of predicted climatically suitable conditions for the different subspecies are contrasted. The subspecies multiplex, and to a certain extent the subspecies fastidiosa, represent a threat to most of Europe while the climatically suitable areas for the subspecies pauca are mostly limited to the Mediterranean basin. These results provide crucial information for the design of a spatially informed European-scale integrated management strategy, including early detection surveys in plants and insect vectors and quarantine measures.


Asunto(s)
Clima , Xylella/fisiología , Endófitos , Europa (Continente) , Geografía , Enfermedades de las Plantas/microbiología
15.
Mol Phylogenet Evol ; 139: 106528, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31176966

RESUMEN

The bark beetle genus Dendroctonus contains some of the most economically important pests of conifers worldwide. Despite many attempts, there is no agreement today on the phylogenetic relationships within the genus, which limits our understanding of its evolutionary history. Here, using restriction-site associated DNA (RAD) markers from 70 specimens representing 17 species (85% of the known diversity) we inferred the phylogeny of the genus, its time of origin and biogeographic history, as well as the evolution of key ecological traits (host plants, larval behavior and adults' attack strategies). For all combinations of tested parameters (from 6444 to 23,570 RAD tags analyzed), the same, fully resolved topology was inferred. Our analyses suggest that the most recent common ancestor (mrca) of all extant Dendroctonus species was widely distributed across eastern Palearctic and western Nearctic during the early Miocene, from where species dispersed to other Holarctic regions. A first main inter-continental vicariance event occurred during early Miocene isolating the ancestors of D. armandi in the Palearctic, which was followed by the radiation of the main Dendroctonus lineages in North America. During the Late Miocene, the ancestor of the 'rufipennis' species group colonized north-east Palearctic regions from western North America, which was followed by a second main inter-continental vicariance event isolating Pleistocene populations in Asia (D. micans) and western North America (D. murrayanae and D. punctatus). The present study supports previous hypotheses explaining intercontinental range disjunctions across the Northern Hemisphere by the fragmentation of a continuous distribution due to climatic cooling, host range fragmentation and geological changes during the late Cenozoic. The reconstruction of ancestral ecological traits indicates that the mrca bored individual galleries and mass attacked the boles of pines. The gregarious feeding behavior of the larvae as well as the individual attack of the base of trees have apparently independently evolved twice in North America (in the 'rufipennis' and the 'valens' species groups), which suggests a higher adaptive potential than previously thought and may be of interest for plant protection and biodiversity conservation in a rapidly changing world.


Asunto(s)
Escarabajos/clasificación , Escarabajos/genética , Marcadores Genéticos/genética , Filogenia , Animales , Asia , Biodiversidad , América del Norte , Mapeo Restrictivo , Análisis de Secuencia de ADN
16.
Mol Ecol Resour ; 19(3): 702-710, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30758892

RESUMEN

Target enrichment is increasingly used for genotyping of plant and animal species or to better understand the evolutionary history of important lineages through the inference of statistically robust phylogenies. Limitations to routine target enrichment are both the complexity of current protocols and low input DNA quantity. Thus, working with tiny organisms such as microarthropods can be challenging. Here, we propose easy to set up optimizations for DNA extraction and library preparation prior to target enrichment. Prepared libraries were used to capture 1,432 ultraconserved elements (UCEs) from microhymenoptera (Chalcidoidea), which are among the tiniest insects on Earth and the most commercialized worldwide for biological control purposes. Results show no correlation between input DNA quantities (1.8-250 ng, 0.4 ng with an extra whole genome amplification step) and the number of sequenced UCEs on an Illumina MiSeq. Phylogenetic inferences highlight the potential of UCEs to solve relationships within the families of chalcid wasps, which has not been achieved so far. The protocol (library preparation + target enrichment) allows processing 96 specimens in five working days, by a single person, without requiring the use of expensive robotic molecular biology platforms, which could help to generalize the use of target enrichment for minute specimens.


Asunto(s)
ADN/aislamiento & purificación , Entomología/métodos , Biblioteca de Genes , Himenópteros/clasificación , Himenópteros/genética , Animales , ADN/química , ADN/genética , Genotipo , Filogenia , Análisis de Secuencia de ADN
17.
Sci Rep ; 8(1): 15628, 2018 10 23.
Artículo en Inglés | MEDLINE | ID: mdl-30353142

RESUMEN

We sampled ca 2500 specimens of Philaenus spumarius (Hemiptera: Aphrophoridae) throughout Corsica without a priori knowledge on the presence of symptoms on plants. We screened 448 specimens for the presence of Xylella fastidiosa (Xf) using qPCR and a custom nested PCR. qPCR appeared versatile and under-estimated the prevalence of Xf. Nested PCR showed that Xf was present in all populations. Molecular results were validated by prediction on the distribution of Xf made from tests conducted on plants, which shows the pertinence of using vectors in risk assessment studies. Xf was detected in tenerals and adults. Thus, P. spumarius could acquire Xf from its host plant, mostly Cistus monspeliensis in Corsica, which may act as reservoir for the next season. This contrasts with other observations and suggests that management strategies may have to be adapted on a case-by-case basis. At least two genetic entities and several variants of Xf not yet identified on plants were present in the insects, which suggests ancient introductions of Xf and a probable underestimation of the current diversity of the strains present in Corsica. Interestingly 6% of the specimens carried two subspecies of Xf. Studies are required to better characterize the strains present in Corsica and to determine how the disease was introduced, spread and why no sign of a potential epidemic was detected earlier. This study shows that, when sensitive enough methods are implemented, spittlebugs (and more specifically P. spumarius for which species distribution modelling shows it could be a good sentinel for Europe) can be used to predict and better assess the exact distribution of Xf. Furthermore, Xf multiply only in their foregut and does not become circulative, which facilitates its detection.


Asunto(s)
Hemípteros/microbiología , Xylella/fisiología , Alelos , Animales , Europa (Continente) , Francia , Geografía , Insectos Vectores/microbiología , Filogenia
18.
PeerJ ; 6: e5640, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30356952

RESUMEN

A major obstacle to high-throughput genotyping of microhymenoptera is their small size. As species are difficult to discriminate, and because complexes may exist, the sequencing of a pool of specimens is hazardous. Thus, one should be able to sequence pangenomic markers (e.g., RADtags) from a single specimen. To date, whole genome amplification (WGA) prior to library construction is still a necessity as at most 10 ng of DNA can be obtained from single specimens (sometimes less). However, this amount of DNA is not compatible with manufacturer's requirements for commercial kits. Here we test the accuracy of the GenomiPhi kit V2 on Trichogramma wasps by comparing RAD libraries obtained from the WGA of single specimens (F0 and F1 generation, about1 ng input DNA for the WGA (0.17-2.9 ng)) and a biological amplification of genomic material (the pool of the progeny of the F1 generation). Globally, we found that 99% of the examined loci (up to 48,189 for one of the crosses, 109 bp each) were compatible with the mode of reproduction of the studied model (haplodiploidy) and Mendelian inheritance of alleles. The remaining 1% (0.01% of the analysed nucleotides) could represent WGA bias or other experimental/analytical bias. This study shows that the multiple displacement amplification method on which the GenomiPhi kit relies, could also be of great help for the high-throughput genotyping of microhymenoptera used for biological control, or other organisms from which only a very small amount of DNA can be extracted, such as human disease vectors (e.g.,  sandflies, fleas, ticks etc.).

19.
Cladistics ; 34(6): 627-651, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34706481

RESUMEN

A phylogeny of the Torymidae (Chalcidoidea) is estimated using 4734 nucleotides from five genes. Twelve outgroups and 235 ingroup taxa are used, representing about 70% of the recognized genera. Our analyses do not recover Torymidae as monophyletic and we recognize instead two families: Megastigmidae (stat. rev.) and Torymidae s.s. (stat. rev.). Within Torymidae s.s., we recognize six subfamilies and six tribes, including Chalcimerinae, Glyphomerinae and Microdontomerinae (subf. nov.), and two new tribes: Boucekinini and Propalachiini (trib. nov.). Seven unclassified genera (i.e. Cryptopristus, Echthrodape, Exopristoides, Exopristus, part of Glyphomerus, Thaumatorymus, Zaglyptonotus) are assigned to tribes within our new classification. Five genera are restored from synonymy-Ameromicrus and Didactyliocerus from under Torymoides (stat. rev.), Iridophaga and Iridophagoides from under Podagrionella (stat. rev.) and Nannocerus from under Torymus (stat. rev.)-and three genera are synonymized-Allotorymus under Torymussyn. nov., Ditropinotus under Eridontomerussyn. nov. and Pseuderimerus under Erimerussyn. nov. A Palaearctic or Eurasian origin for Torymidae is proposed. The ancestral area of Megastigmidae is indicated as the Australian region. The most probable ancestral life strategy for Torymidae s.s. is ectoparasitism on gall-forming Cynipidae. The life strategy and putative hosts of the common ancestor of Megastigmidae remain uncertain.

20.
BMC Evol Biol ; 17(1): 207, 2017 08 29.
Artículo en Inglés | MEDLINE | ID: mdl-28851272

RESUMEN

BACKGROUND: Interspecific interactions have long been assumed to play an important role in diversification. Mutualistic interactions, such as nursery pollination mutualisms, have been proposed as good candidates for diversification through co-speciation because of their intricate nature. However, little is known about how speciation and diversification proceeds in emblematic nursery pollination systems such as figs and fig wasps. Here, we analyse diversification in connection with spatial structuring in the obligate mutualistic association between Ficus septica and its pollinating wasps throughout the Philippines and Taiwan. RESULTS: Ceratosolen wasps pollinating F. septica are structured into a set of three vicariant black coloured species, and a fourth yellow coloured species whose distribution overlaps with those of the black species. However, two black pollinator species were found to co-occur on Lanyu island. Microsatellite data on F. septica indicates the presence of three gene pools that broadly mirrors the distribution of the three black clades. Moreover, receptive fig odours, the specific message used by pollinating wasps to locate their host tree, varied among locations. CONCLUSIONS: F. septica and its black pollinator clades exhibited similar geographic structuring. This could be due originally to geographic barriers leading to isolation, local adaptation, and finally co-structuring. Nevertheless, the co-occurrence of two black pollinator species on Lanyu island suggests that the parapatric distribution of the black clades is now maintained by the inability of migrating individuals of black pollinators to establish populations outside their range. On the other hand, the distribution of the yellow clade strongly suggests an initial case of character displacement followed by subsequent range extension: in our study system, phenotypic or microevolutionary plasticity has allowed the yellow clade to colonise hosts presenting distinct odours. Hence, while variation in receptive fig odours allows specificity in the interaction, this variation does not necessarily lead to coevolutionary plant-insect diversification. Globally, our results evidence evolutionary plasticity in the fig-fig wasp mutualism. This is the first documentation of the presence of two distinct processes in pollinating fig wasp diversification on a host species: the formation of vicariant species and the co-occurrence of other species over large parts of their ranges probably made possible by character displacement.


Asunto(s)
Biodiversidad , Ficus/fisiología , Polinización/fisiología , Simbiosis , Avispas/fisiología , Animales , Ficus/genética , Geografía , Repeticiones de Microsatélite/genética , Odorantes , Filipinas , Filogenia , Análisis de Componente Principal , Taiwán , Avispas/genética
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