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International audience; Terrestrial arthropods, and mainly insects, represent nearly 60% of the described species on Earth. Their role is crucial in ecosystems due to their diversity, abundance, biomass, and ecosystem functions (decomposition of organic matter, pollination, food resources for predators, etc.). However, their populations are threatened by human activities as pesticide applications, habitat destructions, climate change, etc. Arthropods are increasingly used as bioindicators for evaluating the quality of habitats due to their diversity and/or abundance can rapidly evolve in response to their changing environment. Arthropods of Valle Exploradores (Aysén region, latitude 46 ° S) are relatively little studied. This area has a contrasting history of colonization and human activities. In the Patagonia UC research station, the human presence dates back to more than 50 years whereas in Teresa, the human activities are contemporary. This first study aims to characterize the diversity and abundance of the main groups of arthropods (Opiliones, Isopoda, Lepidoptera, Diptera, Hymenoptera, Coleoptera, Coccoidea) to identify one or more taxa valid as bioindicators. In January 2019, 2020, and 2021, arthropods were sampled using passive collecting techniques as pitfall, Malaise, light traps, and active collecting on the two contrasted sites. Beetles were one of the most represented taxa showing contrasting diversity and abundance between the two sites. This study also made it possible to update several taxa's geographical distribution and collect ecological and biological data.; Les arthropodes terrestres, et les insectes en particulier, représentent près de 60% des espèces décrites sur Terre. Ils jouent un rôle primordial dans les écosystèmes de part leur diversité, abondance, biomasse et fonctions écosystémiques (dégradation de la matière organique, pollinisation, ressources alimentaires pour les prédateurs, etc.). Toutefois, leurs populations sont menacées par les activités humaines : usage de pesticides, modification des habitats, changement climatique… Les arthropodes sont de plus en plus utilisés comme bioindicateur de la qualité des milieux car leur diversité et abondance varient rapidement en fonction des caractéristiques de leur environnement.Les arthropodes de Valle Exploradores (région de Aysén, latitude 46°S) ont été relativement peu étudié. La région présente une histoire de colonisation et une intensité des activités humaines contrastées. La présence humaine remonte à plus de 50 ans sur le secteur de la station de recherche Patagonia UC tandis que les activités humaines sont contemporaines dans le secteur de Teresa. L’objectif de cette première étude est de caractériser la diversité et l’abondance des principaux groupes d’arthropodes (Opilionida, Isopoda, Lepidoptera, Diptera, Hymenoptera, Coleoptera, Hemiptera Coccoidea) afin d’identifier un ou plusieurs taxons susceptibles d’être utilisés comme bioindicateurs.En janvier 2019, 2020 et 2021, des collectes ont été réalisées via piégeages (pitfall, Malaise, lumineux) et chasses actives sur les deux sites d’étude. Les coléoptères furent l’un des taxons les mieux représentés montrant une diversité et abondance contrastées entre les deux sites. Cette étude a aussi permis d’actualiser la distribution géographique de plusieurs taxons et de collecter des données écologiques et biologiques.

Phytophagous insects and plants are linked by complex relationships. Insect-plant interaction researches involve several biological disciplines at different levels of analysis. These insect–plant relationships are of crucial importance from an applied point of view, notably for agriculture. In this work, an interdisciplinary approach has been used to study on the mango blossom gall midge, Procontarinia mangiferae (Felt) (Diptera: Cecidomyiidae), an invasive insect pest specific to mango causing major economic damages worldwide. The objective was to improve our knowledge of the biology of this species in the subtropical Reunion Island (i) by describing its genetic diversity and investigate the ecological and biological determinants of the genetic structure of its populations, (ii) by carrying out field and controlled experiments to understand the diapause strategies involved in maintaining populations from one flowering season to the next one, (iii) by modeling the arrival and dispersion of females within an orchard in relation with their flight capacity and with the spatial and temporal distribution of the mango susceptible resources. The results showed that the single species P. mangiferae, feeding on both inflorescences and young leaves, was present all year round and in all the sampled sites on the island, regardless of the climatic and cultural conditions. Populations in Reunion Island appeared structured into two clusters in sympatry, one cluster being more frequent in the cultivated mango area. Secondly, we demonstrated the occurrence of facultative diapause all year round, with the highest rate of diapause observed in summer. The diapause allowed a developmental arrest at the 3rd larval instar in the soil, lasting between six weeks to more than one year. The decrease of temperature at the beginning of winter triggered off the emergence of diapausing individuals and synchronized adult emergence with the mango flowering period. Thirdly, non-native female gall midges were able to colonize all the trees of an orchard. Their arrival flight and trivial flight were oriented by the abundance and by the attractiveness of the mango resources, respectively. The knowledge obtained on the biological cycle of P. mangiferae and on its relationships with the mango tree should be useful to develop new agroecological pest management strategies., Les relations complexes qui unissent les insectes phytophages et les plantes peuvent être étudiées par des approches interdisciplinaires à diverses échelles. Ces études peuvent avoir un intérêt appliqué, dans l'agriculture notamment. Au cours de cette thèse, nous avons mené une étude interdisciplinaire sur la biologie de la cécidomyie des fleurs du manguier, Procontarinia mangiferae (Felt) (Diptera : Cecidomyiidae), un bio-agresseur monophage et invasif responsable de dégâts économiques majeurs dans plusieurs zones de production du monde. L'objectif était d'améliorer les connaissances sur la biologie de cette espèce à l'île de la Réunion : (1) en évaluant sa diversité génétique et les facteurs écologiques et biologiques qui peuvent expliquer la structuration génétique de ses populations ; (2) en étudiant en milieu naturel ou contrôlé les caractéristiques de sa diapause, qui lui permettent de maintenir des populations d'une saison de floraison à la suivante ; (3) en étudiant par modélisation la dispersion des femelles dans un verger lors de sa colonisation, en prenant en compte les capacités de vol et la distribution spatiale et temporelle des stades sensibles du manguier au sein du verger. Les résultats ont montré que l'espèce P. mangiferae se reproduisait à la fois sur les inflorescences et sur les jeunes feuilles, qu'elle était présente toute l'année et sur tous les sites échantillonnés sur l'île, quelles que soient les conditions culturales ou climatiques. Ses populations sont apparues structurées en deux clusters sympatriques, dont un était plus fréquent dans la zone de culture du manguier. Ensuite, nous avons prouvé l'existence d'une diapause facultative induite toute l’année, avec cependant un taux d'induction de diapause supérieur en été. Cette diapause du troisième stade larvaire se déroule dans le sol et dure entre six semaines et plus d'un an. Les températures fraiches déclenchent les émergences des individus en diapause et permettent de synchroniser l'émergence des adultes avec la période de floraison du manguier. Enfin, nous avons montré que des femelles immigrantes étaient capables de coloniser l'ensemble des arbres d'un verger. Le vol d'arrivée des femelles dans le verger et le vol actif au sein du verger se sont avérés influencés respectivement par l'abondance et par l'attractivité de la ressource. Les connaissances obtenues sur la biologie de P. mangiferae et sur ses relations avec le manguier ouvrent des pistes pour le développement de stratégies de gestion agroécologique de ce bio-agresseur.

ln this project we intend to develop the resources necessary for high throughput QTL studies in tomato by combining the development of genomic and plant resources including: (1) a large set of SNPs in expressed sequences and flanking regions based on high throughput sequencing technology. (2) a set of 4 Illumina VeraCode chips carrying a total of 1536 SNP (3) Creation and phenotype characterisation of a multiparent advanced generation intercross (MAGIC) population to be used for QTL mapping and latter for fine mapping, as a complement to genetic resources gathered in collections. The population will be characterised for yield related traits and fruit quality (composition in sugars and acids, colour, texture). (4) Differentiai Gene Expression profiles and proteome profiles of the 8 parental lines of the MAGIC populations and the 4 Fl hybrids These resources are developed to be used in the subsequent analyses: (1) Genotyping a biallelic population in order to precisely map ail the markers present on the VeraCode chips (2) Genotypinç the MAGIC population with the Illumina VeraCode chips in order to map QTL (3) Genotyping several genetic resources (collections of cherry tomato cultivars, of old cultivars and a set of elite genotypes), in order to assess linkage disequilibrium and search for associations between SNP markers and fruit related traits (4) Expression profile analysis of the genes and proteins characterised at the 2 stages of expression; comparison among genotypes and Fl hybrids. The final expected result is a genetic map of more than 1000 SNPs which will be associated with QTL locations and expression variations of the parental lines and Fl hybrids.

Phytophagous insects that belong to the Cecidomyiidae family are among the most closely associated with their host plants. Phytophagous insects can specialize not only on a unique host plant but on particular parts of plants as well. Mango blossom gall midge, Procontarinia mangiferae, is a mango pest that causes damage to both inflorescences and leaves. The objectives of our study were to highlight the genetic diversity and ecological abilities of a monophagous gall midge and to evaluate the determinants of its genetic structure in subtropical Reunion Island. This study, carried out on an isolated island, is based on morphological and molecular data (mitochondrial DNA and microsatellites). Using mitochondrial COI gene sequences, polymorphism at 11 microsatellite loci and an extensive sampling of 27 populations at 17 sites, we tested the genetic differentiation between populations sampled on different mango organs, different mango cultivars and at different seasons. Our results showed that a single species, P. mangiferae, was present all year round at all of the sites sampled, regardless of climatic and cultural conditions, and that it fed on both inflorescences and young leaves. Moreover, our study highlighted the ecological plasticity of this species. However, unlike previous studies on other Cecidomyiidae species, the population genetic structure did not appear to be determined by the species' ability to feed on different organs of the same host plant, but rather by the geographical distribution of populations.

Scale insects (Hemiptera: Sternorrhyncha: Coccomorpha) are key pests of agricultural crops and ornamental plants worldwide. Their populations are difficult to control, even with insecticides, due to their cryptic habits. Moreover, there is growing concern over the use of synthetic pesticides for their control, due to deleterious environmental effects and the emergence of resistant populations of target pests. In this context, biological control may be an effective and sustainable approach. Hymenoptera Chalcidoidea includes natural enemies of scale insects that have been successfully used in many biological control programs. However, the correct identification of pest scale species and their natural enemies is particularly challenging because these insects are very small and highly specialized. Integrative taxonomy, coupling DNA barcoding and morphological analysis, has been successfully used to characterize pests and natural enemy species. In this study, we performed a survey of parasitoids and predators of armored and soft scales in Chile, based on 28S and COI barcodes. Fifty-three populations of Diaspididae and 79 populations of Coccidae were sampled over the entire length of the country, from Arica (18 degrees S) to Frutillar (41 degrees S), between January 2015 and February 2016. The phylogenetic relationships obtained by Bayesian inference from multilocus haplotypes revealed 41 putative species of Chalcidoidea, five Coccinellidae and three Neuroptera. Species delimitation was confirmed using ABGD, GMYC and PTP model. In Chalcidoidea, 23 species were identified morphologically, resulting in new COI barcodes for 12 species and new 28S barcodes for 14 species. Two predator species (Rhyzobius lophantae and Coccidophilus transandinus) were identified morphologically, and two parasitoid species, Chartocerus niger and Signiphora bifasciata, were recorded for the first time in Chile.