Phylogenetic relationships and molecular delimitation of Culicoides Latreille (Diptera: Ceratopogonidae) species in the Afrotropical region: interest for the subgenus Avaritia

Phylogenetic relationships of Culicoides species of the Afrotropical region are problematic as different authors disagree on the placement of species into specific subgenera or groups. In this study we sequenced two mitochondrial (COI and 16S rDNA) and two nuclear (CAD and 28S rDNA) gene fragments to reconstruct phylogenetic relationships within the Avaritia, Remmia and Synhelea subgenera and the Milnei, Neavei and Similis groups of Culicoides using both Bayesian inference and maximum-likelihood approaches. Based on phylogenetic trees, we used the bGMYC (Bayesian General Mixed Yule Coalescent model) and the PTP (Bayesian Poisson Tree Processes) to investigate species boundaries. All species relationships within the studied subgenera and groups were well-supported by using morphological characters and molecular analyses. The subgenus Avaritia includes (i) all of the species of the Imicola group, as well as the putative new species, C. sp. #22, and we confirmed the monophyly of this group; (ii) the Dasyops group includes C. kanagai and C. sp. #54 Meiswinkel (new species), shown to be monophyletic; (iii) the C. sp. #20 belongs to the Orientalis group; (iv) C. grahamii, C. gulbenkiani and C. kibatiensis. Our results also show that subgenus Remmia is monophyletic. Relationships of species of the Milnei group were well-supported and demonstrate the monophyly of this group. Borkent's classification for Similis group is confirmed. In addition, C. neavei and C. ovalis (Neavei group) are placed in the subgenus Synhelea. (Résumé d'auteur

Animal trypanosomosis eliminated in a major livestock production region in Senegal following the eradication of a tsetse population

African animal trypanosomosis (AAT) was one of the main disease-related constraints to the development of intensive livestock production systems in the Niayes region of Senegal, a 30 km wide strip of land along the coast between Dakar and Saint-Louis. To overcome this constraint, the Government of Senegal initiated an area-wide integrated pest management programme combining chemical control tactics with the sterile insect technique to eradicate a population of the tsetse fly Glossina palpalis gambiensis Vanderplank, 1949 (Diptera, Glossinidae) in this area. The project was implemented following a phased conditional approach, and the target area was divided into three blocks treated sequentially. This study aims to assess the temporal dynamics of the prevalence of Trypanosoma spp. during the implementation of this programme. Between 2009 and 2022, 4,359 blood samples were collected from cattle and screened for trypanosomes using both the buffy coat and ELISA techniques, and PCR tests since 2020. The seroprevalence decreased from 18.9% (95%CI: 11.2–26.5) in 2009 to 0% in 2017–2022 in block 1, and from 92.9% (95%CI: 88.2–97) in 2010 to 0% in 2021 in block 2. The parasitological and serological data confirm the entomological monitoring results, i.e., that there is a high probability that the population of G. p. gambiensis has been eradicated from the Niayes and that the transmission of AAT has been interrupted in the treated area. These results indicate the effectiveness of the adopted approach and show that AAT can be sustainably removed through the creation of a zone free of G. p. gambiensis

Standardization of the FAO/IAEA Flight Test for Quality Control of Sterile Mosquitoes

[EN] Successful implementation of the sterile insect technique (SIT) against Aedes aegypti and Aedes albopictus relies on maintaining a consistent release of high-quality sterile males. Affordable, rapid, practical quality control tools based on the male's flight ability (ability to escape from a flight device) may contribute to meeting this requirement. Therefore, this study aims to standardize the use of the original FAO/IAEA rapid quality control flight test device (FTD) (version 1.0), while improving handling conditions and reducing the device's overall cost by assessing factors that could impact the subsequent flight ability of Aedes mosquitoes. The new FTD (version 1.1) is easier to use. The most important factors affecting escape rates were found to be tube color (or "shade"), the combined use of a lure and fan, mosquito species, and mosquito age and density (25; 50; 75; 100 males). Other factors measured but found to be less important were the duration of the test (30, 60, 90, 120 min), fan speed (normal 3000 rpm vs. high 6000 rpm), and mosquito strain origin. In addition, a cheaper version of the FTD (version 2.0) that holds eight individual tubes instead of 40 was designed and successfully validated against the new FTD (version 1.1). It was sensitive enough to distinguish between the effects of cold stress and high irradiation dose. Therefore, the eight-tube FTD may be used to assess Aedes' flight ability. This study demonstrated that the new designs (versions 1.1 and 2.0) of the FTD could be used for standard routine quality assessments of Aedes mosquitoes required for an SIT and other male release-based programs.The authors are grateful to Empresa de Transformación Agraria S.A., S.M.E, M.P. (TRAGSA), Spain, and to Wolbaki, China, for donating their strain for testing. They are grateful to the two reviewers for their useful comments/suggestions that improved our manuscript. This research was funded by the United States of America under the grant to the IAEA entitled ¿Surge expansion for the sterile insect technique to control mosquito populations that transmit the Zika virus.¿ The funders and the agency had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.Maïga, H.; Lu, D.; Mamai, W.; Somda, NSB.; Wallner, T.; Bakhoum, MT.; Masso, OB.... (2022). Standardization of the FAO/IAEA Flight Test for Quality Control of Sterile Mosquitoes. Frontiers in Bioengineering and Biotechnology. 10:1-14. https://doi.org/10.3389/fbioe.2022.8766751141

Écologie et taxonomie intégrative des moucherons piqueurs du genre Culicoides Latreille (Diptera Ceratopogonidae) en région Afrotropicale.

In a context of emergence or re-emergence of vector-borne diseases, certain species of Culicoides (Diptera: Ceratopogonidae) are involved in the transmission of certain viruses (Reoviridae: Orbivirus) and nematodes (Onchocercidae: Mansonella) in the Afrotropical region. However, the systematic and taxonomic schemes as well as the bio-ecology of species of veterinary interest remain to be explored. This work of integrative taxonomy aims to achieve (i) a systematic and taxonomic revision of species belonging to subgenera and groups of veterinary interest using a multi-marker molecular phylogeny and species delineation, and (ii) to develop molecular tools for studying the bioecology of species of veterinary interest and dynamics of their immature populations. Our results show (i) the presence of three monophyletic clades, the Imicola group, the Milnei group and the subgenus Remmia, (ii) a new species for science named C. sp. # 22 and affiliated into the subgenus Avaritia, Imicola group, (iii) the presence of a new undescribed species named C. sp. # 54 belonging to the Dasyops group, subgenus Avaritia, (iii) affiliating the Similis and Neavei species groups to the subgenus Synhelea, and (iv) cryptic species within C. oxystoma (subgenus Remmia). From a bioecological point of view, this work combining entomological follow-up and molecular identification with a library of barcode sequences allowed to describe the trophic behavior of C. imicola, C. kingi and C. oxystoma as well as their larval habitats in equine environments of the Niayes area in Senegal. This work completes the corpus of knowledge about the genus Culicoides in the Afrotropical region to improve our knowledge on the epidemiology of the transmitted pathogens and to propose research tracks to better control the immature and adult populations of the vector species in order to better anticipate and prevent Culicoides-borne diseases outbreaks.Dans un contexte d’émergence ou de réémergence des maladies à transmission vectorielle, certaines espèces de Culicoides (Diptera : Ceratopogonidae) sont impliquées dans la transmission de certains virus (Reoviridae : Orbivirus) et de nématodes (Onchocercidae : Mansonella) en région Afrotropicale. Cependant, le schéma systématique et taxonomique ainsi que la bio-écologie des espèces d’intérêt vétérinaire restent à explorer. Ce travail de taxonomie intégrative a pour objectifs de réaliser (i) une révision systématique et taxonomique des espèces appartenant à des sous-genres et des groupes d’intérêt à partir de phylogénie moléculaire multi-marqueur et de délimitation d’espèces, et (ii) de développer des outils moléculaires pour l’étude de la bio-écologie des espèces d’intérêt vétérinaire et de la dynamique de leurs populations d’immatures. Nos résultats mettent en évidence (i) la présence de trois clades monophylétiques le groupe d’espèces Imicola, le groupe d’espèces Milnei et le sous-genre Remmia, (ii) une nouvelle espèce pour la science nommée C. sp. #22 et affiliée au sous-genre Avaritia, groupe Imicola, (iii) la présence d’une nouvelle espèce non-décrite nommée C. sp. #54 appartenant au groupe d’espèces Dasyops, sous-genre Avaritia, (iii) d’affilier les groupes d’espèces Similis et Neavei au sous-genre Synhelea et, (iv) de poser l’hypothèse d’une présence d’espèces cryptiques au sein de C. oxystoma (sous-genre Remmia). D’un point de vue bio-écologique, le travail réalisé combinant suivi entomologique et identification moléculaire avec une librairie de séquences barcodes a permis de décrire le comportement trophique de C. imicola, C. kingi et C. oxystoma ainsi que leurs habitats larvaires dans des environnements équins de la zone des Niayes au Sénégal. L’ensemble de ce travail permet de compléter le corpus de connaissances sur le genre Culicoides en région Afrotropicale afin d’améliorer la compréhension de l’épidémiologie des pathogènes transmis et proposer des pistes de recherches pour mieux contrôler les populations immatures et adultes des espèces vectrices afin de mieux anticiper et prévenir des évènements sanitaires

Ecology and integrative taxonomy of biting midges of the genus Culicoides Latreille (Diptera Ceratopogonidae) in the Afrotropical region.

Dans un contexte d’émergence ou de réémergence des maladies à transmission vectorielle, certaines espèces de Culicoides (Diptera : Ceratopogonidae) sont impliquées dans la transmission de certains virus (Reoviridae : Orbivirus) et de nématodes (Onchocercidae : Mansonella) en région Afrotropicale. Cependant, le schéma systématique et taxonomique ainsi que la bio-écologie des espèces d’intérêt vétérinaire restent à explorer. Ce travail de taxonomie intégrative a pour objectifs de réaliser (i) une révision systématique et taxonomique des espèces appartenant à des sous-genres et des groupes d’intérêt à partir de phylogénie moléculaire multi-marqueur et de délimitation d’espèces, et (ii) de développer des outils moléculaires pour l’étude de la bio-écologie des espèces d’intérêt vétérinaire et de la dynamique de leurs populations d’immatures. Nos résultats mettent en évidence (i) la présence de trois clades monophylétiques le groupe d’espèces Imicola, le groupe d’espèces Milnei et le sous-genre Remmia, (ii) une nouvelle espèce pour la science nommée C. sp. #22 et affiliée au sous-genre Avaritia, groupe Imicola, (iii) la présence d’une nouvelle espèce non-décrite nommée C. sp. #54 appartenant au groupe d’espèces Dasyops, sous-genre Avaritia, (iii) d’affilier les groupes d’espèces Similis et Neavei au sous-genre Synhelea et, (iv) de poser l’hypothèse d’une présence d’espèces cryptiques au sein de C. oxystoma (sous-genre Remmia). D’un point de vue bio-écologique, le travail réalisé combinant suivi entomologique et identification moléculaire avec une librairie de séquences barcodes a permis de décrire le comportement trophique de C. imicola, C. kingi et C. oxystoma ainsi que leurs habitats larvaires dans des environnements équins de la zone des Niayes au Sénégal. L’ensemble de ce travail permet de compléter le corpus de connaissances sur le genre Culicoides en région Afrotropicale afin d’améliorer la compréhension de l’épidémiologie des pathogènes transmis et proposer des pistes de recherches pour mieux contrôler les populations immatures et adultes des espèces vectrices afin de mieux anticiper et prévenir des évènements sanitaires.In a context of emergence or re-emergence of vector-borne diseases, certain species of Culicoides (Diptera: Ceratopogonidae) are involved in the transmission of certain viruses (Reoviridae: Orbivirus) and nematodes (Onchocercidae: Mansonella) in the Afrotropical region. However, the systematic and taxonomic schemes as well as the bio-ecology of species of veterinary interest remain to be explored. This work of integrative taxonomy aims to achieve (i) a systematic and taxonomic revision of species belonging to subgenera and groups of veterinary interest using a multi-marker molecular phylogeny and species delineation, and (ii) to develop molecular tools for studying the bioecology of species of veterinary interest and dynamics of their immature populations. Our results show (i) the presence of three monophyletic clades, the Imicola group, the Milnei group and the subgenus Remmia, (ii) a new species for science named C. sp. # 22 and affiliated into the subgenus Avaritia, Imicola group, (iii) the presence of a new undescribed species named C. sp. # 54 belonging to the Dasyops group, subgenus Avaritia, (iii) affiliating the Similis and Neavei species groups to the subgenus Synhelea, and (iv) cryptic species within C. oxystoma (subgenus Remmia). From a bioecological point of view, this work combining entomological follow-up and molecular identification with a library of barcode sequences allowed to describe the trophic behavior of C. imicola, C. kingi and C. oxystoma as well as their larval habitats in equine environments of the Niayes area in Senegal. This work completes the corpus of knowledge about the genus Culicoides in the Afrotropical region to improve our knowledge on the epidemiology of the transmitted pathogens and to propose research tracks to better control the immature and adult populations of the vector species in order to better anticipate and prevent Culicoides-borne diseases outbreaks

Raw data from lab, semi-field and field trials on male mating harassment

The data include: - survival of females exposed to various sex ratios - survival of females after exposure to various sex ratios - feeding rate of females exposed to various sex ratios on artificial, human and mouse baits - field data on the impact of sterile males releases on the density of eggs (ovitrap data) and adults (BG traps and Human Landing Collection) All data sheets are corresponding to the relevant figure