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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Estrutura genética populacional de Plasmopara viticola e progresso temporal do míldio e da ferrugem da videira / Population genetic structure of Plasmopara viticola and temporal progress of downy mildew and grapevine rust

Camargo, Meyriele Pires de 11 October 2017 (has links)
Entre as doenças de maior impacto nos vinhedos paulistas, encontram-se o míldio (Plasmopara viticola) e a ferrugem (Phakopsora euvitis). Os objetivos deste trabalho foram: i. caracterizar a estrutura genética populacional e identificar espécies crípticas de P. viticola; ii. avaliar o progresso temporal de míldio da videira, o efeito da doença na produção das plantas e verificar a contribuição da reprodução sexuada e assexuada de P. viticola na epidemia da doença e; iii. avaliar o progresso temporal de ferrugem da videira. Foram coletados 516 isolados de P. viticola em 11 municípios de São Paulo. Os isolados foram genotipados com 7 marcadores microssatélites. Para a identificação de espécies crípticas de P. viticola, uma subamostra de 130 isolados foi analisada pela técnica CAPS (Cleaved Amplified Polymorphic Sequence), e 94 isolados foram sequenciados para a região ITS1. O progresso temporal do míldio e da ferrugem da videira foram avaliados em 3 ciclos de produção (2014/15, 2015/16 e 2016/17) nos sistemas de condução em espaldeira (ESP), Y descoberto (YD) e Y sob cobertura plástica (YC). A área experimental, localizada em Piracicaba-SP, foi constituída por plantas da variedade Niágara Rosada. As variáveis analisadas foram fenologia, número de folhas por ramo, incidência e severidade das doenças. Para verificar o efeito do míldio na produção das plantas, avaliaram-se a massa média do cacho, a produção por planta, o teor de sólidos solúveis totais (SST) e a acidez titulável (AT) dos frutos. A área abaixo da curva (AAC) foi calculada para o número de folhas por ramo, a incidência e a severidade de míldio e de ferrugem. Os valores de massa do fruto, produção por planta, SST e AT, e os resultados da AAC para as variáveis analisadas, foram submetidos a análise de variância e as médias comparadas pelo teste de Tukey (P<0,05). Na safra 2015/16, 166 isolados de P. viticola foram coletados em três diferentes momentos da epidemia, os quais foram genotipados com os 7 microssatélites mencionados anteriormente. P. viticola clado aestivalis foi a única espécie críptica identificada no Estado de São Paulo. Dentre os 516 isolados analisados, 55 genótipos multilocos (MLG) foram identificados. Quatro MLGs dominantes representaram 65,7% dos genótipos observados. Para o míldio da videira, em 2 das 3 safras avaliadas observou-se desfolha precoce das plantas doentes. A severidade média máxima de míldio observada foi de 14,3% na ESP e 30,9% no YD. Para esses valores de severidade, a doença causou a redução na produção por planta (0,7 a 0,9 kg por planta) e na massa do cacho (67 a 78 g). Em nenhuma das safras houve efeito da doença no teor de SST e na AT. Maiores valores de AAC da severidade de míldio foram verificados no YD em comparação à espaldeira, sugerindo que o sistema em YD favorece o progresso da doença. No YC, a redução da incidência de míldio foi de até 93,7% em relação aos sistemas descobertos, indicando que o sistema em Y associado ao cultivo protegido foi uma ferramenta eficiente no controle da doença. O monitoramento de genótipos de P. viticola na safra 2015/16 revelou que a epidemia foi resultante, predominantemente, de infecções clonais múltiplas causadas por um único genótipo. Queda prematura de folhas em decorrência da epidemia de ferrugem foi observada para os sistemas em YC e YD com valores de severidade inferiores a 5,6%. Em função da desfolha, verificaram-se alterações na fenologia das plantas nos estádios fenológicos finais de desenvolvimento. O progresso da incidência de ferrugem foi mais rápido nos sistemas em YC e YD em relação a ESP. Diferentemente das epidemias de míldio da videira, o uso da cobertura plástica não foi suficiente para o controle satisfatório da ferrugem. / Downy mildew (Plasmopara viticola) and rust (Phakopsora euvitis) are important diseases on vineyards located in São Paulo State. The aims of this study were: i. characterize the population genetic structure and identify cryptic species of P. viticola; ii. evaluate the temporal progress of grapevine downy mildew, the disease effect on yield, and verify the contribution of sexual and asexual reproduction of P. viticola on disease epidemic and; iii. evaluate the temporal progress of grapevine rust. A total of 516 isolates of P. viticola were collected from 11 locations of São Paulo State. The isolates were genotyped with 7 microsatellite markers. To identify cryptic species of P. viticola, a subsample of 130 isolates were analized by Cleaved Amplified Polymorphic Sequence (CAPS), and 94 isolates were sequenced for ITS1 region. Temporal progress of downy mildew and rust were evaluated in 3 growing seasons (2014/15, 2015/16 and 2015/16) on vertical trellis (VT), Y-trellis without plastic cover (YWP), and Y-trellis with plastic cover (YPC). The experimental area, located in Piracicaba-SP, was composed by plants of the variety Niagara Rosada. The variables analyzed were phenology, number of leaves per shoot, disease incidence and disease severity. To verify the effect of downy mildew on yield were evaluated bunch weight, yield per plant, total soluble solids content (TSS) and titratable acidity (TA) of the fruits. Area under the curve (AUC) was calculated for number of leaves per shoot, downy mildew and rust incidence and downy mildew and rust severity. The values of bunch weight, yield per plant, TSS and TA, and AUC results for the analyzed variables, were submitted to variance analysis and the mean values were compared by Tukey test (P<0.05). In the growing season of 2015/16, 166 isolates of P. viticola were collected at three different moments of downy mildew epidemic. The isolates were genotyped with the 7 microsatellites previously mentioned. P. viticola clado aestivalis was the only cryptic species identified in São Paulo State. Among the 516 isolates analyzed, 55 multilocus genotypes (MLG) were identified. Four dominant MLGs represented 65.7% of the observed genotypes. For downy mildew, 2 of the 3 growing seasons evaluated were observed early defoliation of the diseased plants. The maximum average values of disease severity observed were 14.3% in ESP and 30.9% in YD. For these disease severity values, the disease reduced yield per plant (0.7 to 0.9 kg per plant) and bunch weight (67 to 78 g). No effect of downy mildew was verified on TSS and TA in none of the growing seasons. Higher AUC values for downy mildew severity were observed in YWP compared to the VT, suggesting that YWP favors the disease progress. On the YPC, incidence of downy mildew was reduced by up to 93.7% compared to the uncovered systems, indicating that Y-trellis associated with plastic cover was an efficient tool to control the disease. The monitoring of genotypes of P. viticola in the 2015/16 growing season revealed that disease epidemic was drived predominantly by multiple clonal infections caused by a single genotype. Early defoliation due to grape rust epidemic was observed on YWP and YPC with disease severity lower than 5.6%. Due to defoliation caused by rust modification on plant phenology were verified in the final stages of plant development. The progress of rust incidence was faster in YWP and YPC than in VT. Unlikely grape downy mildew epidemics, the use of plastic cover was not sufficient to effectivly control grape rust.
52

Anopheles oswaldoi (Diptera, Culicidae): análise do segundo espaçador interno transcrito (ITS2) do DNA ribossômico e da susceptibilidade à infecção com Plasmodium vivax. / Anopheles oswaldoi (Diptera, Culicidae): analysis of the second internal transcribed spacer (ITS2) of the ribosomal DNA and the susceptibility to infection by Plasmodium vivax.

Marrelli, Mauro Toledo 28 March 2000 (has links)
Resultados anteriores sugerem que existem diferenças biológicas entre espécimens de Anopheles oswaldoi capturados no Estado do Acre e os do Estado de Rondônia, Brasil. Esta espécie tem sido apontada como um importante vetor de malária em localidades do Peru e Acre. Entretanto, em Rondônia, somente um número pequeno de A. oswaldoi alimentados em pacientes com malária desenvolveram infecção nas glândulas salivares. Além disso, há suspeita de que espécimens identificados como A. oswaldoi, capturados em áreas abertas em Costa Marques, Rondônia, são na verdade A. konderi, e que A. oswaldoi sensu stricto estaria restrito a áreas de florestas. Estes dados, juntamente com as dificuldades encontradas na identificação de anofelinos do grupo Oswaldoi, baseadas em critérios morfológicos, sugerem que espécimens de A. oswaldoi são membros de um complexo de espécies crípticas. A distinção de espécies crípticas de insetos vetores é de grande importância, já que diferentes membros em um complexo podem exibir diferenças na ecologia, capacidade vetorial e resposta a medidas de controle. Análise de sequências de DNA, particularmente da região do ITS2 do cistron do DNA ribossômico, tem sido usada como um caracter diagnóstico em alguns grupos de espécies crípticas, tornando-se um instrumento para estudos taxonômicos e filogenéticos. A primeira parte deste estudo teve o objetivo de determinar as diferenças encontradas nas sequências de ITS2 de espécimens de A. oswaldoi capturados em várias localidades da América do Sul. As regiões dos ITS2 destes anofelinos foram amplificadas usando oligonucleotídeos iniciadores conservados das regiões 5.8S e 28S e os produtos de PCR foram clonados e sequenciados. Os ITS2 de todos os mosquitos capturados tiveram tamanho aproximado de 350 nucleotídeos, com aproximadamente 53% de conteúdo de GC. Análise do alinhamento destas sequências, mostrou similaridade variando entre 87% e 100%, e a análise de uma árvore de similaridade, neighbor-joining, produzida com p-distance usando as diferenças nas sequências de ITS2, separou estes espécimens em quatro grupos. Um deles está provavelmente relacionado ao A. oswaldoi sensu stricto, e um outro pode estar relacionado à espécie A. konderi. Os outros dois grupos podem corresponder a espécies cuja identificação morfológica permanece para ser esclarecida no complexo A. oswaldoi. Estes dados são evidências de que espécimens de A. oswaldoi estão incluídos em um complexo de espécies crípticas e que identificação por DNA pode resolver estas questões taxonômicas. A. konderi tem sido considerado uma sinonímia de A. oswaldoi. Embora estágios adultos e imaturos destas espécies de anofelinos apresentem características morfológicas idênticas, aspectos encontrados na genitália masculina podem distinguir estes taxa. A segunda parte deste estudo foi conduzida com o objetivo de comparar a susceptibilidade de A. oswaldoi s.s. e de A. konderi à infecção com Plasmodium vivax. A susceptibilidade foi baseada na proporção de mosquitos com oocistos e esporozoítos. Os anofelinos foram capturados no Acre e em Rondônia para obtenção de progênies F1. Após a emergência dos adultos, as genitálias masculinas dos mosquitos de cada progênie foram dissecadas e examinadas. Todas progênies originadas dos mosquitos capturados em Rondônia corresponderam a A. konderi, enquanto que cerca de 85,0% das progênies do Acre eram A. oswaldoi s.s.. Estas progênies F1 de A. oswaldoi s.s., A. konderi e A. darlingi foram alimentadas simultaneamente com sangue infectado com P. vivax. Estes mosquitos foram dissecados 10-12 dias após infecção e examinados para verificação da presença de oocistos e esporozoítos. Tanto A. oswaldoi s.s. como A. konderi apresentaram oocistos nos tratos digestivos, entretanto, a porcentagem de tratos digestivos positivos para oocistos foi maior em A. oswaldoi s.s. (13,8%) do que em A. konderi (3,3%). Esporozoítos foram encontrados somente nas glândulas salivares de A. oswaldoi s.s., com 6,9% de positividade. As taxas de infecção nos controles A. darlingi foram de 22,5% a 30,0%, para ambos oocistos e esporozoítos. Estes resultados indicam que A. oswaldoi s.s. pode transmitir P. vivax e sugerem que esta espécie é mais susceptível que A. konderi. Embora A. oswaldoi s.s. seja uma espécie exofílica e zoofílica, este anofelino pode estar envolvido na transmissão da malária humana como parece estar ocorrendo no Estado do Acre. / Previous results have suggested that biological differences could exist between specimens of Anopheles oswaldoi captured in the State of Acre and those from the State of Rondônia, Brazil. This species has been appointed as an important malaria vector in localities of Peru and Acre. However, in Rondônia, only a very low percentage of A. oswaldoi fed on malaria patients developed salivary gland infections. In addition, it was suspected that specimens identified as A. oswaldoi captured in open clearings in Costa Marques, Rondônia, were actually A. konderi, and that A. oswaldoi sensu stricto would be restricted to forested areas. These data, together with the difficulties found to identify anophelines of the Oswaldoi group based on morphologic criteria suggest that specimens of A. oswaldoi are members of a complex of cryptic species. The distinction of cryptic species of insects is of critical importance, since different members in a Complex could exhibit differences in ecology, vectorial capacity and response to control measures. DNA sequence analysis and particularly that of the ITS2 region of the rDNA cistron has provided diagnostic characters in some groups of cryptic species becoming a general tool for taxonomic and phylogenetic studies. The first part of the present study was undertaken to determine the extent of differences over the ITS2 sequence of specimens of A. oswaldoi s.l. captured in several localities of South America. The ITS2 of these anophelines were amplified using conserved primers of the 5.8S and 28S regions, cloned and sequenced. The lengths of ITS2 of all mosquitoes captured were about 350 nucleotides, with about 53% GC content. Analysis of the alignment of the sequences, which showed that the similarity varied between 87% and 100%, and analysis of a neighbor-joining tree produced with p-distance using the ITS2 sequences, separated these specimens in four groups. One of them is probably related to A. oswaldoi sensu stricto, and another one can possibly be related to A. konderi. The other two groups may correspond to species the morphologycal identification of which remains to be clarified in the A. oswaldoi complex. These data are evidences that specimens of A. oswaldoi are included in a complex of cryptic species and that the DNA identification could solve some taxonomic questions. A. konderi has been currently considered to be a synonym of A. oswaldoi. Although adults and immature stages of both these anopheline species have identical morphological characters, features of the male genitalia can distinguish these taxa. The second part of this study was conducted in order to compare the susceptibility of A. oswaldoi s.s. and of A. konderi to infection by Plasmodium vivax. The susceptibility was based on the proportion of mosquitoes with oocysts and sporozoites. Anophelines were captured in the State of Acre and Rondônia and used to obtain F1 progenies. After emergency of adults, male genitalia of mosquitoes of each family were dissected. All families originated from mosquitoes captured in Rondônia corresponded to A. konderi, while about 85.0% of the families from Acre were A. oswaldoi s.s.. F1 progeny of field-captured A. oswaldoi s.s., A. konderi and A. darlingi were fed simultaneously on P. vivax infected blood. Mosquitoes were dissected on day 10-12 after infection and examined for the presence of oocysts and sporozoites. Both A. oswaldoi s.s. and A. konderi developed oocysts in midguts, however, the percentage of oocyst-positives in A. oswaldoi s.s. (13.8%) was higher than in A. konderi (3.3%), and only A. oswaldoi s.s. developed salivary infection with sporozoites (6.9% of positivity). Infection rates in A. darlingi ranged from 22.5% to 30.0% for both oocysts and sporozoites. These results indicate that A. oswaldoi s.s. can transmit P. vivax and suggest that it is more susceptible than A. konderi. Although A. oswaldoi s.s. is an exophilic and zoophilic species, it may be involved in human malaria transmission as it seems to be occuring in the State of Acre.
53

Phylogeography in sexual and parthenogenetic European oribatida / Phylogeograhie von sexuellen und parthenogenetischen europäischen Oribatiden

Rosenberger, Martin 07 December 2010 (has links)
No description available.
54

The significance of genetic and ecological diversity in a wide-ranging insect pest, Paropsis atomaria Olivier (Coleoptera: Chrysomelidae)

Schutze, Mark Kurt January 2008 (has links)
Paropsis atomaria (Coleoptera; Chrysomelidae) is a eucalypt feeding leaf beetle endemic to southern and east coast Australia, and it is an emergent pest of the eucalypt hardwood industry. Paropsis atomaria was suspected to be a cryptic species complex based on apparent differences in life history characteristics between populations, its wide geographical distribution, and extensive host range within Eucalyptus. In this study genetic and ecological characters of P. atomaria were examined to determine the likelihood of a cryptic complex, and to identify the nature and causes of ecological variation within the taxon. Mitochondrial sequence variation of the gene COI was compared between populations from the east coast of Australia (South Australia to central Queensland) to assess genetic divergence between individuals from different localities and host plant of origin. Individuals from four collection localities used for the molecular analysis were then compared in a morphometric study to determine if observed genetic divergence was reflected by morphology, and common-garden trials using individuals from Lowmead (central Qld) and Canberra (ACT) were conducted to determine if morphological (body size) variation had a genetic component. Host plant utilisation (larval survival, development time, and pupal weight) by individuals from Lowmead and Canberra were then compared to determine whether differential host plant use had occurred between populations of P. atomaria; individuals from each population were reared on an allopatric and sympatric host eucalypt species (E. cloeziana and E. pilularis). Finally, developmental data from each population was compared and incorporated into a phenology modelling program (Dymex(tm)) using temperature as the principle factor explaining and predicting population phenology under field conditions. Molecular results demonstrated relatively low genetic divergence between populations of P. atomaria which is concomitant with the single species hypothesis, however, there is reduced gene flow between northern and southern populations, but no host plant related genetic structuring. Morphometric data revealed insufficient evidence to separate populations into different taxa; however a correlation between latitude and size of adults was discovered, with larger beetles found at lower latitudes (i.e., adhering to a converse Bergmann cline). Common garden experiments revealed body size to be driven by both genetic and environmental components. Host plant utilisation trials showed one host plant, E. cloeziana, to be superior for both northern and southern P. atomaria populations (increased larval survival and reduced larval development time). Eucalyptus pilularis had a negative effect on pupal weight for Lowmead (northern) individuals (to which it is allopatric), but not so for Canberra (southern) individuals. DYMEX(tm) modelling showed voltinism to be a highly plastic trait driven largely by temperature. Results from across all trials suggest that P. atomaria represents a single species with populations locally adapted to season length, with no evidence of differential host plant utilisation between populations. Further, voltinism is a seasonally plastic trait driven by temperature, but with secondary influential factors such as host plant quality. These data, taken combined, reveal phenotypic variability within P. atomaria as the product of multiple abiotic and biotic factors and representing a complex interplay between local adaptation, phenotypic plasticity, and seasonal plasticity. Implications for pest management include an understanding of population structure, nature of local adaptation and host use characteristics, and predictive models for development of seasonal control regimens.
55

The ecology and population genetics of a complex of cryptic bumblebee species

Scriven, Jessica J. January 2016 (has links)
Bumblebees are ecologically and economically important as pollinators, but some species are suffering severe declines and range contractions. In this thesis, three cryptic bumblebee species are studied to elucidate differences in their distribution, ecology and population genetics. As a result of their high morphological similarity, very little is known about the lucorum complex species: B. lucorum, B, cryptarum and B. magnus. In this study, their distributions across Great Britain were assessed using molecular methods, revealing that B. lucorum was the most abundant and most generalist of the three species, whereas B. magnus was the rarest and most specialised, occurring almost exclusively on heathland. Additionally, both B. magnus and B. cryptarum were more likely to be present at sites with cooler summer temperatures. Cryptic species represent interesting models to investigate the levels of niche differentiation required to avoid competitive exclusion. Characterising the niches of these species at a single site across the flight season revealed differences along three niche dimensions: temporal activity, weather sensitivity and forage-resource use. These species exhibited asymmetric niche overlap; a combination of ecological divergence and spatio-temporal heterogeneity may contribute to maintaining them in sympatry. Population genetic studies can be highly informative for understanding species ecology and for conservation management. The differences in habitat specialisation exhibited by these bumblebee species provide the opportunity to test conflicting hypotheses about links between dispersal and ecological specialisation: are habitat specialists selected to have low or high dispersal ability? Based on microsatellite analysis, the generalist B. lucorum had high levels of genetic diversity and little population structure across large spatial scales. The habitat specialist B. magnus had the lowest genetic diversity but similar levels of population differentiation to the moderate generalist, B. cryptarum. However, unlike B. cryptarum, B. magnus population differentiation was not affected by geographic distance, suggesting that this specialist species may maintain effective dispersal across large scales despite being restricted to a fragmented habitat. Bergmann’s rule is a well-known ecogeographic rule describing geographical patterns of body size variation, whereby larger endothermic species are found more commonly at higher latitudes. Ectotherms, including insects, have been suggested to follow converse Bergmann’s gradients, but the facultatively endothermic nature of bumblebees makes it unclear which pattern they should adhere to. This thesis reports caste-specific differences in body size between the three lucorum complex species in agreement with Bergmann’s rule: queens and males of B. cryptarum and B. magnus, which were found more commonly at higher latitudes and at sites with cooler temperatures, were larger than those of B. lucorum. Population genetic studies of invertebrates generally require the destruction of large numbers of individuals, which is often undesirable. Testing a variety of faecal collection and DNA extraction methods demonstrated that it is possible to obtain DNA of sufficient quality for genotyping from bumblebee faeces, without harming the individuals. This method would be valuable for studies of rare or declining bee species, for queens in reintroduction projects, and may be applicable to other arthropods. Overall this thesis contributes substantially to our knowledge of the ecology and population genetics of three important pollinator species. It provides data to inform species conservation, as well as understanding of ecosystem functioning and population dynamics. Furthermore, it successfully uses these cryptic species as a model to test several fundamental ecological theories.
56

Macro and micro-evolutionary processes within a complex of species, case study of the tropical invasive earthworm : pontoscolex corethrurus / Processus macro- et micro-évolutifs au sein d’un complexe d’espèces, cas d’étude de l’espèce tropicale et invasive de vers de terre : pontoscolex corethrurus

Taheri, Shabnam 06 March 2018 (has links)
Pontoscolex corethrurus est le ver de terre le plus répandu dans les zones tropicales et sub-tropicales ; il est par conséquent très étudié en science du sol. Il est présent dans toutes sortes d’habitats, des sols pauvres de prairie aux sols riches de forêt primaire, et ses caractéristiques écologiques sont bien connues. Ses caractéristiques biologiques ont été moins étudiées. Peu de données sur la variation génétique au sein de cette morphoespèce sont disponibles à l’exception de la découverte en 2014 de deux lignées génétiquement différentes dans l’île São Miguel des Açores. De plus, son degré de ploïdie n’est pas connu et sa stratégie de reproduction n’est pas bien décrite. L’un des objectifs de cette thèse était de comprendre les mécanismes et les caractéristiques qui font de P. corethrurus un envahisseur efficace. Notre deuxième objectif était de rechercher des lignées cryptiques dans le monde entier et de décrire leurs relations phylogénétiques. Un troisième objectif était d’identifier quelle lignée était invasive et de caractériser la structure génétique de ses populations dans les aires native et d’introduction. Le dernier objectif était de tester si les différentes espèces du complexe avaient différents degrés de ploïdie, ce qui pourrait expliquer l’isolement reproducteur entre ces espèces. Une synthèse bibliographique de 265 études couvrant tous les aspects des connaissances sur P. corethrurus a montré que la stratégie – r et la plasticité de ce ver sont les caractéristiques clefs qui lui permettent d’envahir avec succès différents habitats. Afin d’étudier la diversité cryptique au sein de P. corethrurus à une échelle mondiale, j’ai examiné 792 spécimens collectés dans 25 pays et îles différents. Ces spécimens ont été analysés à l’aide de deux marqueurs mitochondriaux (COI et ADNr 16S), deux marqueurs nucléaires (internal transcribed spacers 2 et ADNr 28S) et une matrice de données de séquence multilocus obtenue à l’aide de la méthode AHE (Anchored Hybrid Enrichment). De plus, un total de 11 caractères morphologiques, internes comme externes, ont été étudiés dans toutes les lignées caractérisées génétiquement. Quatre espèces cryptiques (L1, L2, L3 et L4) ont été observées au sein du complexe d’espèces P. corethrurus. Elles ont été trouvées en sympatrie dans plusieurs localités et des analyses basées sur des marqueurs AFLP n’ont pas montré d’hybridation entre L1 et L3. La possibilité d’isolement reproducteur lié à des degrés de ploïdie différents a été évaluée à l’aide d’expérimentations de cytogénétique pour lesquelles plusieurs obstacles ont été rencontrés, à différentes étapes. Des résultats n’ont été obtenus que pour L4 (2n = 70). L’une des espèces du complexe, L1, était géographiquement répandue. Cette espèce correspondait aux spécimens topotypiques (échantillons provenant du jardin de Fritz Müller où P. corethrurus a été décrit en premier en 1856). Nous avons ciblé cette espèce invasive dans une étude de génétique des populations et de phylogéographie. En utilisant le gène COI et des marqueurs AFLP, nous avons révélé une faible diversité génétique dans la zone tropicale, probablement due à des évènements de colonisation récents et à une reproduction asexuelle. Cependant, la diversité génétique relativement élevée dans certaines populations, associée à un déséquilibre de liaison relativement faible, suggère aussi des évènements de reproduction sexuelle. A ce jour, c’est le premier travail réalisé à l’échelle mondiale sur la diversité génétique cryptique, la génétique des populations et la phylogéographie d’une espèce de vers de terre pérégrine dans la zone tropicale. J’ai produit la première revue complète des caractéristiques de P. corethrurus. De plus, son statut taxinomique a été clarifié ainsi que sa stratégie de reproduction qui est mixte (parthénogénèse et amphimixie). Ces informations seront utiles pour les expérimentations et les recherches futures sur les espèces du complexe P. corethrurus / Pontoscolex corethrurus is the most widespread earthworm species in the tropical and sub-tropical zones, it is hence one of the most studied earthworm in soil science. Ecological aspects of P. corethrurus, which is known to be present in a wide range of habitats from poor soils of pasture to rich soils of primary forest, were intensively investigated but biological aspects are less addressed. In particular, information on the genetic variation within the morphospecies is scarce except for the finding of two genetically differentiated lineages in São Miguel Island of Azores archipelago in 2014. Moreover, the ploidy degree of the morphospecies is not yet known and its reproduction strategy is not well understood. One of the objectives of this thesis was to understand the mechanisms and characteristics which make P. corethrurus a successful invader. Our second objective was to look for cryptic lineages in the whole world and to describe the phylogenetic relationships between them. A third objective was to identify which lineage was invasive and to characterize its population genetic structure in the native and the introduced ranges. The last objective was to test if the different species of the complex have different ploidy degrees (polyploid complex). This could eventually explain the reproductive isolation among these species. A bibliographic synthesis of 265 studies covering all subjects of knowledge on P. corethrurus showed that the r strategy and plasticity of this earthworm are the key characteristics which make it a successful invader in different habitats. In order to investigate the cryptic diversity within P. corethrurus in a world-wide scale, I examined 792 specimens collected from 25 different countries and islands. These specimens were analyzed using two mitochondrial (COI and 16S rDNA) and two nuclear (internal transcribed spacers 2 and 28S rDNA) markers and a large-scale multilocus sequence data matrix obtained using the Anchored Hybrid Enrichment (AHE) method. In addition, a total of 11 morphological characters, both internal and external, were investigated in all genetically characterized lineages. Four cryptic species (L1, L2, L3 and L4) were found within the P. corethrurus species complex, and four potentially new species within the genus Pontoscolex. The cryptic species were observed in sympatry at several localities, and analyses based on AFLP markers showed no hybridization among L1 and L3. The possibility of reproductive isolation among species of the complex because of different ploidy degrees was investigated by cytogenetic experimentations. Due to different obstacles encountered at different steps of the experimentations, results were just obtained for L4 (2n=70). One of the species belonging to the complex, L1, was particularly widespread per comparison with the others. This species corresponded to topotype specimens (samples from Fritz Müller’s garden where P. corethrurus was first described in 1856). Thus, we focused on this invasive species in a population genetics and phylogeography study. Using COI gene and AFLP markers, we revealed low genetic diversity through the tropical zone, probably due to recent colonization events and asexual reproduction type. Meanwhile, due to weak linkage disequilibrium and relatively high genetic diversity in some populations, sexual reproduction was suggested for L1.To date, this is the first study investigating at a world-wide scale, cryptic species diversity, population genetics and phylogeography of a peregrine earthworm species throughout tropical zone. I produced the first comprehensive review of all ecological and biological aspects of P. corethrurus. Moreover, the taxonomic status of P. corethrurus was clarified as well as its reproduction strategy which is mixed (parthenogenetic and sexual). All these findings represent potentially useful information for future experimentations and researches on species of P. corethrurus complex
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Anopheles oswaldoi (Diptera, Culicidae): análise do segundo espaçador interno transcrito (ITS2) do DNA ribossômico e da susceptibilidade à infecção com Plasmodium vivax. / Anopheles oswaldoi (Diptera, Culicidae): analysis of the second internal transcribed spacer (ITS2) of the ribosomal DNA and the susceptibility to infection by Plasmodium vivax.

Mauro Toledo Marrelli 28 March 2000 (has links)
Resultados anteriores sugerem que existem diferenças biológicas entre espécimens de Anopheles oswaldoi capturados no Estado do Acre e os do Estado de Rondônia, Brasil. Esta espécie tem sido apontada como um importante vetor de malária em localidades do Peru e Acre. Entretanto, em Rondônia, somente um número pequeno de A. oswaldoi alimentados em pacientes com malária desenvolveram infecção nas glândulas salivares. Além disso, há suspeita de que espécimens identificados como A. oswaldoi, capturados em áreas abertas em Costa Marques, Rondônia, são na verdade A. konderi, e que A. oswaldoi sensu stricto estaria restrito a áreas de florestas. Estes dados, juntamente com as dificuldades encontradas na identificação de anofelinos do grupo Oswaldoi, baseadas em critérios morfológicos, sugerem que espécimens de A. oswaldoi são membros de um complexo de espécies crípticas. A distinção de espécies crípticas de insetos vetores é de grande importância, já que diferentes membros em um complexo podem exibir diferenças na ecologia, capacidade vetorial e resposta a medidas de controle. Análise de sequências de DNA, particularmente da região do ITS2 do cistron do DNA ribossômico, tem sido usada como um caracter diagnóstico em alguns grupos de espécies crípticas, tornando-se um instrumento para estudos taxonômicos e filogenéticos. A primeira parte deste estudo teve o objetivo de determinar as diferenças encontradas nas sequências de ITS2 de espécimens de A. oswaldoi capturados em várias localidades da América do Sul. As regiões dos ITS2 destes anofelinos foram amplificadas usando oligonucleotídeos iniciadores conservados das regiões 5.8S e 28S e os produtos de PCR foram clonados e sequenciados. Os ITS2 de todos os mosquitos capturados tiveram tamanho aproximado de 350 nucleotídeos, com aproximadamente 53% de conteúdo de GC. Análise do alinhamento destas sequências, mostrou similaridade variando entre 87% e 100%, e a análise de uma árvore de similaridade, neighbor-joining, produzida com p-distance usando as diferenças nas sequências de ITS2, separou estes espécimens em quatro grupos. Um deles está provavelmente relacionado ao A. oswaldoi sensu stricto, e um outro pode estar relacionado à espécie A. konderi. Os outros dois grupos podem corresponder a espécies cuja identificação morfológica permanece para ser esclarecida no complexo A. oswaldoi. Estes dados são evidências de que espécimens de A. oswaldoi estão incluídos em um complexo de espécies crípticas e que identificação por DNA pode resolver estas questões taxonômicas. A. konderi tem sido considerado uma sinonímia de A. oswaldoi. Embora estágios adultos e imaturos destas espécies de anofelinos apresentem características morfológicas idênticas, aspectos encontrados na genitália masculina podem distinguir estes taxa. A segunda parte deste estudo foi conduzida com o objetivo de comparar a susceptibilidade de A. oswaldoi s.s. e de A. konderi à infecção com Plasmodium vivax. A susceptibilidade foi baseada na proporção de mosquitos com oocistos e esporozoítos. Os anofelinos foram capturados no Acre e em Rondônia para obtenção de progênies F1. Após a emergência dos adultos, as genitálias masculinas dos mosquitos de cada progênie foram dissecadas e examinadas. Todas progênies originadas dos mosquitos capturados em Rondônia corresponderam a A. konderi, enquanto que cerca de 85,0% das progênies do Acre eram A. oswaldoi s.s.. Estas progênies F1 de A. oswaldoi s.s., A. konderi e A. darlingi foram alimentadas simultaneamente com sangue infectado com P. vivax. Estes mosquitos foram dissecados 10-12 dias após infecção e examinados para verificação da presença de oocistos e esporozoítos. Tanto A. oswaldoi s.s. como A. konderi apresentaram oocistos nos tratos digestivos, entretanto, a porcentagem de tratos digestivos positivos para oocistos foi maior em A. oswaldoi s.s. (13,8%) do que em A. konderi (3,3%). Esporozoítos foram encontrados somente nas glândulas salivares de A. oswaldoi s.s., com 6,9% de positividade. As taxas de infecção nos controles A. darlingi foram de 22,5% a 30,0%, para ambos oocistos e esporozoítos. Estes resultados indicam que A. oswaldoi s.s. pode transmitir P. vivax e sugerem que esta espécie é mais susceptível que A. konderi. Embora A. oswaldoi s.s. seja uma espécie exofílica e zoofílica, este anofelino pode estar envolvido na transmissão da malária humana como parece estar ocorrendo no Estado do Acre. / Previous results have suggested that biological differences could exist between specimens of Anopheles oswaldoi captured in the State of Acre and those from the State of Rondônia, Brazil. This species has been appointed as an important malaria vector in localities of Peru and Acre. However, in Rondônia, only a very low percentage of A. oswaldoi fed on malaria patients developed salivary gland infections. In addition, it was suspected that specimens identified as A. oswaldoi captured in open clearings in Costa Marques, Rondônia, were actually A. konderi, and that A. oswaldoi sensu stricto would be restricted to forested areas. These data, together with the difficulties found to identify anophelines of the Oswaldoi group based on morphologic criteria suggest that specimens of A. oswaldoi are members of a complex of cryptic species. The distinction of cryptic species of insects is of critical importance, since different members in a Complex could exhibit differences in ecology, vectorial capacity and response to control measures. DNA sequence analysis and particularly that of the ITS2 region of the rDNA cistron has provided diagnostic characters in some groups of cryptic species becoming a general tool for taxonomic and phylogenetic studies. The first part of the present study was undertaken to determine the extent of differences over the ITS2 sequence of specimens of A. oswaldoi s.l. captured in several localities of South America. The ITS2 of these anophelines were amplified using conserved primers of the 5.8S and 28S regions, cloned and sequenced. The lengths of ITS2 of all mosquitoes captured were about 350 nucleotides, with about 53% GC content. Analysis of the alignment of the sequences, which showed that the similarity varied between 87% and 100%, and analysis of a neighbor-joining tree produced with p-distance using the ITS2 sequences, separated these specimens in four groups. One of them is probably related to A. oswaldoi sensu stricto, and another one can possibly be related to A. konderi. The other two groups may correspond to species the morphologycal identification of which remains to be clarified in the A. oswaldoi complex. These data are evidences that specimens of A. oswaldoi are included in a complex of cryptic species and that the DNA identification could solve some taxonomic questions. A. konderi has been currently considered to be a synonym of A. oswaldoi. Although adults and immature stages of both these anopheline species have identical morphological characters, features of the male genitalia can distinguish these taxa. The second part of this study was conducted in order to compare the susceptibility of A. oswaldoi s.s. and of A. konderi to infection by Plasmodium vivax. The susceptibility was based on the proportion of mosquitoes with oocysts and sporozoites. Anophelines were captured in the State of Acre and Rondônia and used to obtain F1 progenies. After emergency of adults, male genitalia of mosquitoes of each family were dissected. All families originated from mosquitoes captured in Rondônia corresponded to A. konderi, while about 85.0% of the families from Acre were A. oswaldoi s.s.. F1 progeny of field-captured A. oswaldoi s.s., A. konderi and A. darlingi were fed simultaneously on P. vivax infected blood. Mosquitoes were dissected on day 10-12 after infection and examined for the presence of oocysts and sporozoites. Both A. oswaldoi s.s. and A. konderi developed oocysts in midguts, however, the percentage of oocyst-positives in A. oswaldoi s.s. (13.8%) was higher than in A. konderi (3.3%), and only A. oswaldoi s.s. developed salivary infection with sporozoites (6.9% of positivity). Infection rates in A. darlingi ranged from 22.5% to 30.0% for both oocysts and sporozoites. These results indicate that A. oswaldoi s.s. can transmit P. vivax and suggest that it is more susceptible than A. konderi. Although A. oswaldoi s.s. is an exophilic and zoophilic species, it may be involved in human malaria transmission as it seems to be occuring in the State of Acre.
58

Spécialisation parasitaire chez les Aphidiinae : existe-t-il des parasitoïdes de pucerons généralistes ? / Parasitic specialization in Aphidiinae : there are generalist aphid parasitoids ?

Navasse, Yoann 07 December 2016 (has links)
Les parasitoïdes de pucerons Aphidiinae (Hymenoptera : Braconidae) comprennent des espèces qui présentent un gradient de spécialisation allant d’espèces monophages à des espèces capables de parasiter plusieurs dizaines d’espèces hôtes. Le caractère généraliste ou spécialiste d’un ennemi naturel va conditionner son efficacité à réguler les populations d’un ravageur, mais également sa capacité à pouvoir exploiter d’autres ressources dans les habitats semi-naturels, et assurer ainsi son maintien dans l’environnement en l'absence du ravageur. L’objectif premier de ce travail est de définir s’il existe des espèces généralistes au sein des Aphidiinae, dans un contexte agronomique spatialement et temporellement délimité. Dans un deuxième temps, il s'agit d’étudier les facteurs qui peuvent influencer la spécialisation parasitaire à l’échelle inter et intraspécifique. Les facteurs ciblés sont l’hôte, la plante, de par leurs caractéristiques écologiques comme l’abondance et la fréquence, et le type d'habitat, cultivé ou non cultivé. Nous avons étudié au sein d’un agrosystème et au cours d’une saison de végétation les réseaux trophiques plantes-pucerons-parasitoïdes dans le milieu cultivé et dans les habitats semi-naturels. Nous avons cherché à identifier des situations d’exploitation d’hôtes multiples dans les deux compartiments de l’agrosystème et à définir les facteurs pouvant influencer la répartition des espèces généralistes et spécialistes dans le temps et l’espace. Puis nous avons étudié le parasitisme en conditions naturelles et contrôlées d’une espèce en particulier, Diaeretiella rapae pour déterminer son degré de spécialisation parasitaire et la dynamique d’exploitation des hôtes sur les plantes cultivées et sauvages. Enfin, l’existence de structuration génétique des populations, voire d’espèces cryptiques, a été recherchée chez les espèces les plus généralistes, grâce à une approche moléculaire de type barcoding. Nos résultats révèlent qu’il n’y a pas à proprement parlé de vrai généraliste parmi les Aphidiinae présents dans l'agroécosystème étudié. Les espèces supposées généralistes ayant un possible intérêt agronomique ont en réalité des spectres d’hôtes limités, elles ne parasitent que rarement et très ponctuellement des ressources dans les habitats semi-naturels. La plupart présentent des structurations génétiques de leurs populations (hormis A. ervi) en fonction de l’hôte, de la plante ou de l’interaction des deux. Des espèces cryptiques ont été détectées chez D rapae. La conséquence de cette spécialisation parasitaire et des structurations génétiques intraspécifiques est un rôle probablement très faible des habitats semi-naturels comme réservoirs d'Aphidiinae, leur gestion n'étant alors pas un levier pour la mise en place d'une lutte biologique par conservation. / Aphid parasitoids of the sub-family Aphidiinae (Hymenoptera: Braconidae) include species with a gradient of specialization from monophagous to polyphagous species, able to parasitize several dozen of host species. Generalist or specialist trait for a natural enemy will determine its effectiveness in regulating pest populations, but also its ability to exploit other resources in semi-natural habitats and then to ensure its maintenance in the environment in the absence of pests. The first objective of this work is to determine if there are real generalists species within Aphidiinae in a peculiar agroecosystem over the time and in different habitats. Secondly, we studied the factors that may influence the parasitic specialization at inter- and intraspecific level. Targeted factors are the host, the plant, regarding their ecological characteristics, such as abundance and frequency, and the type of habitat, cultivated or uncultivated. We studied the trophic network between plant-aphid-parasitoid in cultivated areas and in semi-natural habitats in an agroecosystem and during a growing season. We sought to identify situations of multiple exploitation of different host in the two compartments of agroecosystem and to identify factors influencing the distribution of generalists and specialists species in time and space. Then, we studied the parasitism of a particular species Diaeretiella rapae in natural and controlled conditions to determine its degree of parasitic specialization and its temporal dynamic of host exploitation on cultivated and wild plants. Finally, the existence of genetic structure of populations, even cryptic species, was investigated in the most generalist species, with a molecular barcoding method. Our results reveal that there is no true generalist species among Aphidiinae present in the studied agroecosystem. The supposed generalist species actually have limited host ranges, they parasite rarely and very timely resources of semi-natural habitats. Most of them show a genetic structuration of their populations (except A. ervi) depending on the host, the plant or the interaction of both. Cryptic species were detected in D rapae. The consequence of this parasitic specialization and intraspecific genetic structuring is probably a very low role of host reservoir played by the semi-natural habitats for Aphidiinae species, their management then not being a lever for the implementation of conservation biological control.
59

Prévalence et mécanismes de résistance aux triazolés des espèces d’Aspergillus section Fumigati

Parent-Michaud, Maxime 03 1900 (has links)
No description available.
60

Testing for Cryptic Diversity and Inference of Population Structure in the Cosmopolitan Hoplonemertean Emplectonema gracile (Nemertea)

Delaney, Paul L, IV 01 January 2019 (has links)
Emplectonema gracile (Johnston 1837) is a hoplonemertean of marine intertidal hard-bottom communities and is distributed throughout the Northern Hemisphere. Although possessing a planktonic larval stage in its life history, the range of such cosmopolitan marine invertebrate species is often explained by cryptic speciation and anthropogenic transport. The purpose of this study is to test for possible cryptic species using mtDNA markers (COI and 16S rDNA) and to investigate population structure in E. gracile over a portion of its geographic range using mtDNA markers and ddRADseq nuclear SNP data. The results of both phylogenetic- and tree-based species delimitation revealed that E. gracileis a morphotype containing cryptic species. Three North Atlantic and one Pacific coast population are inferred as one species (E. gracile sensu stricto) and two Pacific coast populations (Akkeshi, Japan and Charleston, Oregon) are inferred as another species (Emplectonemasp 1), strongly confirming an earlier study and extending the range of the latter species to the Pacific coast of Japan. Anthropogenic transport is suggested as the likely mode of transport for E. gracile.Both Fst, PCA and haplotype network analyses suggest a lack of differentiation between E. gracile populations separated by large geographic distances.In contrast corresponding analyses forEmplectonemasp. 1 indicate differentiation between the two populations sampled. Further research will be necessary to reveal if rare anthropogenic transport or natural dispersal (larval transport, rafting) between geographically adjacent yet to be delimitedE. gracile morphotype populations is responsible for its seemingly disjunct distribution.

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