Made available in DSpace on 2015-03-26T13:30:55Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1693707 bytes, checksum: d0e839e141cd91095aa25a25c0f882f3 (MD5) Previous issue date: 1997-12-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Based on light-trap collections from 1981 to 1993 at Mata do Paraíso (20°46 -20°48 S; 45°50 -45°52 W), a tropical forest environment at Viçosa county, Minas Gerais State, Brazil, a total of 10,809 specimens of leafhoppers (Homoptera: Cicadellidae) were counted, belonging to 11 subfamilies: Agalliinae, Cicadellinae, Coelidiinae, Deltocephalinae, Gyponinae, Iassinae, Idiocerinae, Neocoelidiinae, Nirvaninae, Typhlocybinae and Xestocephalinae. Genera and species of Typhlocybinae were not identified. In this work are listed 62 determined genera and 156 species. Among the species 37 of them new to science and 10 are recorded for the first time to Brazil. It was also found 49 new records from Minas Gerais and 58 from Viçosa. Illustrated taxonomic keys for identification of subfamilies, tribes and genera are presented. Within and between-year fluctuations in abundance and richness of the leafhoppers were analyzed. Annual fluctuations in the population were related to local temperature and rainfall patterns. Wet season faunal structure was different from that of the dry season at Mata do Paraíso. Among the more representative species Xestocephalus desertorum (Berg, 1879), X. ancorifer Linnavuori, 1959 (Xestocephalinae), Planicephalus flavicosta (Stal, 1860), Graminella striatella Linnavuori, 1959, Balclutha sp. 1 (Deltocephalinae), Plesiommata corniculata Young, 1977 and Hortensia similis (Walker, 1951) (Cicadellinae) were significantly more abundant during the wet seasons; Curtara atomaria (Stal, 1862) (Gyponinae) and Balclutha hebe (Kirkaldy, 1906) showed no difference between wet and dry seasons. / Com base em coletas de armadilha luminosa, realizadas de 1981 a 1993, na Mata do Paraíso (20°46 -20°48 S; 45°50 -45°52 W), reserva de Mata Atlântica situada no município de Viçosa, Estado de Minas Gerais, foi obtido o total de 10.809 espécimes de cigarrinhas da família Cicadellidae (Homoptera), distribuídos em 11 subfamílias: Agalliinae, Cicadellinae, Coelidiinae, Deltocephalinae, Gyponinae, Iassinae, Idiocerinae, Neocoelidiinae, Nirvaninae, Xestocephalinae e Typhlocybinae, esta última não estudada em nível de gênero e espécie. Neste trabalho, são listados 62 gêneros determinados e 156 espécies, das quais 37 são novas para a ciência e 10 são pela primeira vez registradas para o Brasil. Também foram registradas 49 novas ocorrências para Minas Gerais e 58 para Viçosa. Chaves taxonômicas ilustradas para identificação das subfamílias, das tribos e dos gêneros são apresentadas. As variações sazonais na abundância e riqueza dos táxons foram analisadas. Flutuações anuais das populações foram relacionadas à variação da temperatura e da pluviosidade na localidade. A estrutura faunística diferiu entre as estações chuvosa e seca da Mata do Paraíso. Dentre as espécies mais representativas, Xestocephalus desertorum (Berg, 1879), X. ancorifer Linnavuori, 1959 (Xestocephalinae), Planicephalus flavicosta (Stal, 1860), Graminella striatella Linnavuori, 1959, Balclutha sp. 1 (Deltocephalinae), Plesiommata corniculata Young, 1977 e Hortensia similis (Walker, 1951) (Cicadellinae) foram significativamente mais abundantes nas estações chuvosas; Curtara atomaria (Stal, 1862) (Gyponinae) e Balclutha hebe (Kirkaldy, 1906) não sofreram diferenças significativas na abundância entre as estações.

The leafhopper genus Xyphon, included in the sharpshooters, is a widely distributed group of insects whose species are vectors for various plant diseases. Xyphon has historically contained up to 9 species. These species have been poorly delimited in the past and their identification has been difficult using published keys. The genus is revised here based on a new species level phylogenetic assessment that incorporates both morphological and molecular data. The genus Xyphon was erected to contain leafhoppers that possessed a reticulated forewing apex but lacked both a median sulcus on the crown and a carinate anterolateral crown-face margin both of which are present in the closely related genus Draeculacephala. Young (1977) revised most of the genera included in Xyphon's containing subfamily. He did not attempt a revision of Carneocephala (the genus that formerly contained most Xyphon species), but noted the need for a revision of its species. This revision of the genus Xyphon is based on the examination of approximately 8,000 specimens and includes a phylogenetic analysis of the genus that includes data from one gene (NDI) and 47 morphological characters. A generalized model of each preliminary taxonomic unit was used to test the monophyly of each species. These tests resulted in the synonomization of 4 former species: Xyphon gillettei to include X. balli; and X. reticulatum to include X. diductum, X. dyeri, and X. sagittiferum. Parsimony and Bayesian techniques were used to infer relationships among species. These analyses resulted in almost identical tree topologies. In all analyses Xyphon was monophyletic and Draeculacephala was its sister genus although clade support for the genus was generally low. The analyses found that X. flaviceps and X. fulgidum form a basal clade within Xyphon, above which X. gillettei and X. n. sp. 1 (new species 1) form a clade that is sister to a third clade containing X. triguttatum, X. nudum, and X. reticulatum.

Pierce's disease (PD) is a vascular disease of grapevines caused by <i>Xylella fastidiosa</i> (Wells et al.) (<i>Xf</i>) which is transmitted by xylophagous insect vectors. PD infection in Virginia vineyards was thought to be isolated to southeastern portions of the state as there have been no reports of vine loss in western Virginia and cold winter temperatures experienced there limit the effects of the bacterium from year to year. Upward trends in winter temperatures have raised PD concern in the mid-Atlantic. My risk assessment study found PD symptomatic vines beyond the modeled boundary for infection, confirmed <i>Xf</i>-positive with DAS-ELISA. Yellow sticky traps were used to survey Virginia vineyards throughout the 2006 and 2007 growing seasons to identify sharpshooter (Cicadellinae) species in six growing regions. <i>Graphocephala versuta </i>(Say) and <i>Oncometopia orbona</i> (Fabricius) (Hemiptera: Cicadellidae) were trapped in the greatest abundance and were both present in every region surveyed. This study uses geographical representation of climatological data to estimate risk for Pierce's disease. / Master of Science in Life Sciences

A Escaldadura das Folhas da Ameixeira (EFA) é uma das principais doenças que prejudicam a produção de ameixas no Brasil. Ela é causada pela bactéria Xylella fastidiosa (Wells) cujos potenciais vetores são cigarrinhas (Hemiptera: Cercopidae e Cicadellidae, Cicadellinae). Sabe-se que existem diversas espécies de cicadelídeos e cercopídeos em pomares de ameixeira, mas faltam informações sobre as plantas hospedeiras desses insetos e sua importância epidemiológica. Esta pesquisa teve por objetivo associar as cigarrinhas potenciais vetoras com as plantas de ameixeira e com plantas infestantes da vegetação de cobertura dos pomares. Para tal, realizaram-se amostragens de cigarrinhas em três pomares de ameixeira no município de Paranapanema-SP, no período de setembro/2012 a abril/2013, usando-se três métodos distintos: a) rede de varredura em plantas infestantes; b) armadilhas adesivas amarelas colocadas na copa das ameixeiras a 0,5 e 2 m acima do solo; e c) amostragens visuais em ameixeiras e certas plantas infestantes. As cigarrinhas coletadas foram triadas e identificadas em laboratório e os resultados obtidos foram submetidos à análise faunística. Para verificar se as plantas infestantes eram hospedeiras da X. fastidiosa, experimentos de inoculação mecânica foram feitos para tentar estabelecer infecção pela bactéria nas plantas de Bidens pilosa L., Parthenium hysterophorus L., Raphanus sativus L., Euphorbia heterophylla L., Sida rhombifolia L., Solanum americanum Mill. e Lantana camara L. Após meses da inoculação, as plantas foram testadas por PCR e isolamento primários para detectar a infecção por X. fastidiosa. Avaliou-se, também, a ocorrência de transmissão de X. fastidiosa de ameixeiras paras plantas infestantes, por cigarrinhas sabidamente vetoras, Sibovia sagata (Signoret) e Macugonalia cavifrons (Stål). Nas amostragens com rede de varredura, encontraram-se 72 espécies de cigarrinhas associadas às plantas infestantes dos pomares de ameixeiras, pertencentes às famílias Achilidae, Cercopidae, Cicadellidae, Delphacidae, Derbidae, Dictyopharidae, Flatidae e Membracidae. As cigarrinhas foram observadas em um total de oito espécies herbáceas de dicotiledôneas e sete monocotiledôneas. As plantas infestantes que abrigam maiores números de cigarrinha são Paspalum notatum Flügge, Parthenium hysterophorus L. e Raphanus sativus L. Dentre as espécies com potencial de transmitir X. fastidiosa, o cercopídeo Deois schach (Fabricius) e o cicadelíneo Plesiommata corniculata Young predominaram nas plantas infestantes dos pomares de ameixeira, podendo ter um papel chave em uma eventual disseminação primária de X. fastidiosa dessas plantas para ameixeira. Os cicadelíneos Acrogonia citrina Marucci & Cavichioli e Oncometopia facialis (Signoret) predominaram em capturas com armadilhas adesivas amarelas na copa das ameixeiras, o que sugere sua participação na disseminação secundária de X. fastidiosa entre árvores de ameixeira. O. facialis foi visualizada nos ramos de ameixeiras e de Lantana camara L. As plantas infestantes Solanum americanum Mill e L. camara permitem colonização por X. fastidiosa após inoculação mecânica. A cigarrinha Sibovia sagata (Signoret) é capaz de transmitir X. fastidiosa de ameixeira para S. americanum. / Plum Leaf Scald (PLS) is one of the major diseases that impair the production of plums in Brazil, caused by the xylem-limited bacterium Xylella fastidiosa (Wells), whose potential vectors in plums are sharpshooter leafhoppers (Hemiptera: Cicadellidae, Cicadellinae) and spittlebugs (Hemiptera: Cercopidae). A number of leafhoppers and and spittlebugs have been reported in Brazilian plum orchards, but their host plants and role in PLS epidemiology are largely unknown. The goal of this research was to investigate the association of potential hopper vectors with plum trees and weedy plants in the ground vegetation of orchards, in order to determine key vector species and weeds involved in PLS epidemiology. Therefore, a hopper survey was carried out in three plum orchards in the municipality of Paranapanema, SP, from September/2012 to April/2013, using three sampling methods: a) sweep net on weed species of the ground vegetation; b) yellow sticky cards placed on the plum canopy at 0.5 and 2 m above ground; and c) visual inspections of plum trees and some weeds. The collected hoppers were sorted and identified in the laboratory, and the data were submitted to faunistic analysis. To check if the weeds were hosts of plum strains of X. fastidiosa, bacterial suspensions were mechanically inoculated in Bidens pilosaL., Parthenium hysterophorus L., Raphanus sativus L., Euphorbia heterophylla L., Sida rhombifolia L., Solanum americanum Mill. Lantana camara L. The plants were assayed for infection of X. fastidiosa by PCR and culture at 2 months after inoculation. Transmission assays of X. fastidiosa from plum to weeds were carried out using two sharpshooter vectors, Sibovia sagata (Signoret) e Macugonalia cavifrons (Stål). The sweep net samplings revealed 72 species of seven hopper families (Achilidae, Cercopidae, Cicadellidae, Delphacidae, Derbidae, Dictyopharidae, Flatidae and Membracidae) associated with eight dicotyledoneous and seven monocotyledoneous weeds in the ground vegetation, with prevalence of Cicadellidae and Cercopidae. Among the potential hopper vectors, the spittlebug Deois schach (Fabricius) and the sharpshooter Plesiommata corniculata Young were predomimant species on the weed species, suggesting that they may play a key role in a possible primary spread of X. fastidiosa from weeds to plum. Paspalum notatum Flügge, Parthenium hysterophorus L. and Raphanus sativus L. were the weed species with the largest hopper populations. The sharpshooters Acrogonia citrina Marucci & Cavichioli e Oncometopia facialis (Signoret) were prevalent species trapped by the yellow sticky cards on the plum canopy, indicating that they may be involved in secondary spread of X. fastidiosa between plum trees in that region. O. facialis was visually detected on branches of plum trees and on the weed Lantana camara L. The weeds Solanum americanum Mill e L. camara allow colonization by X. fastidiosa after mechanical inoculation.The sharpshooter Sibovia sagata (Signoret) transmitted X. fastidiosa from plum to S. americanum.

A Escaldadura das Folhas da Ameixeira (EFA) é uma das principais doenças que prejudicam a produção de ameixas no Brasil. Ela é causada pela bactéria Xylella fastidiosa (Wells) cujos potenciais vetores são cigarrinhas (Hemiptera: Cercopidae e Cicadellidae, Cicadellinae). Sabe-se que existem diversas espécies de cicadelídeos e cercopídeos em pomares de ameixeira, mas faltam informações sobre as plantas hospedeiras desses insetos e sua importância epidemiológica. Esta pesquisa teve por objetivo associar as cigarrinhas potenciais vetoras com as plantas de ameixeira e com plantas infestantes da vegetação de cobertura dos pomares. Para tal, realizaram-se amostragens de cigarrinhas em três pomares de ameixeira no município de Paranapanema-SP, no período de setembro/2012 a abril/2013, usando-se três métodos distintos: a) rede de varredura em plantas infestantes; b) armadilhas adesivas amarelas colocadas na copa das ameixeiras a 0,5 e 2 m acima do solo; e c) amostragens visuais em ameixeiras e certas plantas infestantes. As cigarrinhas coletadas foram triadas e identificadas em laboratório e os resultados obtidos foram submetidos à análise faunística. Para verificar se as plantas infestantes eram hospedeiras da X. fastidiosa, experimentos de inoculação mecânica foram feitos para tentar estabelecer infecção pela bactéria nas plantas de Bidens pilosa L., Parthenium hysterophorus L., Raphanus sativus L., Euphorbia heterophylla L., Sida rhombifolia L., Solanum americanum Mill. e Lantana camara L. Após meses da inoculação, as plantas foram testadas por PCR e isolamento primários para detectar a infecção por X. fastidiosa. Avaliou-se, também, a ocorrência de transmissão de X. fastidiosa de ameixeiras paras plantas infestantes, por cigarrinhas sabidamente vetoras, Sibovia sagata (Signoret) e Macugonalia cavifrons (Stål). Nas amostragens com rede de varredura, encontraram-se 72 espécies de cigarrinhas associadas às plantas infestantes dos pomares de ameixeiras, pertencentes às famílias Achilidae, Cercopidae, Cicadellidae, Delphacidae, Derbidae, Dictyopharidae, Flatidae e Membracidae. As cigarrinhas foram observadas em um total de oito espécies herbáceas de dicotiledôneas e sete monocotiledôneas. As plantas infestantes que abrigam maiores números de cigarrinha são Paspalum notatum Flügge, Parthenium hysterophorus L. e Raphanus sativus L. Dentre as espécies com potencial de transmitir X. fastidiosa, o cercopídeo Deois schach (Fabricius) e o cicadelíneo Plesiommata corniculata Young predominaram nas plantas infestantes dos pomares de ameixeira, podendo ter um papel chave em uma eventual disseminação primária de X. fastidiosa dessas plantas para ameixeira. Os cicadelíneos Acrogonia citrina Marucci & Cavichioli e Oncometopia facialis (Signoret) predominaram em capturas com armadilhas adesivas amarelas na copa das ameixeiras, o que sugere sua participação na disseminação secundária de X. fastidiosa entre árvores de ameixeira. O. facialis foi visualizada nos ramos de ameixeiras e de Lantana camara L. As plantas infestantes Solanum americanum Mill e L. camara permitem colonização por X. fastidiosa após inoculação mecânica. A cigarrinha Sibovia sagata (Signoret) é capaz de transmitir X. fastidiosa de ameixeira para S. americanum. / Plum Leaf Scald (PLS) is one of the major diseases that impair the production of plums in Brazil, caused by the xylem-limited bacterium Xylella fastidiosa (Wells), whose potential vectors in plums are sharpshooter leafhoppers (Hemiptera: Cicadellidae, Cicadellinae) and spittlebugs (Hemiptera: Cercopidae). A number of leafhoppers and and spittlebugs have been reported in Brazilian plum orchards, but their host plants and role in PLS epidemiology are largely unknown. The goal of this research was to investigate the association of potential hopper vectors with plum trees and weedy plants in the ground vegetation of orchards, in order to determine key vector species and weeds involved in PLS epidemiology. Therefore, a hopper survey was carried out in three plum orchards in the municipality of Paranapanema, SP, from September/2012 to April/2013, using three sampling methods: a) sweep net on weed species of the ground vegetation; b) yellow sticky cards placed on the plum canopy at 0.5 and 2 m above ground; and c) visual inspections of plum trees and some weeds. The collected hoppers were sorted and identified in the laboratory, and the data were submitted to faunistic analysis. To check if the weeds were hosts of plum strains of X. fastidiosa, bacterial suspensions were mechanically inoculated in Bidens pilosaL., Parthenium hysterophorus L., Raphanus sativus L., Euphorbia heterophylla L., Sida rhombifolia L., Solanum americanum Mill. Lantana camara L. The plants were assayed for infection of X. fastidiosa by PCR and culture at 2 months after inoculation. Transmission assays of X. fastidiosa from plum to weeds were carried out using two sharpshooter vectors, Sibovia sagata (Signoret) e Macugonalia cavifrons (Stål). The sweep net samplings revealed 72 species of seven hopper families (Achilidae, Cercopidae, Cicadellidae, Delphacidae, Derbidae, Dictyopharidae, Flatidae and Membracidae) associated with eight dicotyledoneous and seven monocotyledoneous weeds in the ground vegetation, with prevalence of Cicadellidae and Cercopidae. Among the potential hopper vectors, the spittlebug Deois schach (Fabricius) and the sharpshooter Plesiommata corniculata Young were predomimant species on the weed species, suggesting that they may play a key role in a possible primary spread of X. fastidiosa from weeds to plum. Paspalum notatum Flügge, Parthenium hysterophorus L. and Raphanus sativus L. were the weed species with the largest hopper populations. The sharpshooters Acrogonia citrina Marucci & Cavichioli e Oncometopia facialis (Signoret) were prevalent species trapped by the yellow sticky cards on the plum canopy, indicating that they may be involved in secondary spread of X. fastidiosa between plum trees in that region. O. facialis was visually detected on branches of plum trees and on the weed Lantana camara L. The weeds Solanum americanum Mill e L. camara allow colonization by X. fastidiosa after mechanical inoculation.The sharpshooter Sibovia sagata (Signoret) transmitted X. fastidiosa from plum to S. americanum.

A doença conhecida como enfezamento vermelho, associada a um fitoplasma do grupo 16SrI, subgrupo B, foi relatada em áreas brasileiras cultivadas com milho ainda no início da década de setenta. A importância econômica da doença se expressou a partir da década seguinte, com a introdução dos plantios de safrinha. O patossistema tem sido muito explorado em termos de pesquisa, porém falhas no conhecimento ainda são significativas. No presente trabalho foi investigada a sobrevivência do fitoplasma e da sua cigarrinha vetora Dalbulus maidis em algumas espécies forrageiras de alto interesse agronômico. Para isto, foram utilizadas cinco variedades de capim Panicum maximum cv. Mombaça, P. maximum x P. infestum cv. Massai, Brachiaria bizantha cv Marandu, B. brizantha cv. Piatã e B. decumbens cv. Basilisk (popularmente conhecida por Decumbens), os quais foram inoculados com o fitoplasma por meio de insetos infectivos alimentados em plantas de milho comprovadamente portadoras do patógeno. As avaliações foram realizadas tomando-se como critérios a detecção do fitoplasma nos tecidos dos capins, usando a técnica molecular de PCR, e a contagem diária do número de cigarrinhas mortas encontradas nas plantas forrageiras inoculadas. Amostragens de tecidos para a detecção do patógeno foram feitas aos 28, 56, 84, 112 e 140 dias após a inoculação, sendo as plantas cortadas para posterior rebrota, após cada amostragem. Também foi conduzido um ensaio em que cigarrinhas foram alimentadas em todas as variedades de forrageiras, portadoras do fitoplasma e, em seguida, confinadas em plantas sadias de milho. Os resultados revelaram que o fitoplasma estava presente em todas as plantas das diferentes variedades de capim, aos 28 dias após a inoculação. Aos 56 dias após a inoculação, o fitoplasma foi detectado em 66% das plantas de Marandu, 50% das plantas de Massai e 16% das plantas de Decumbens, Mombaça e Piatã. Aos 84, 112 e 140 dias após a inoculação, o patógeno não foi mais detectado nos tecidos rebrotados das plantas amostradas. Quanto à sobrevivência da cigarrinha, os capins se comportaram similarmente, dentro de cada um dos períodos de avaliação correspondentes a 24, 48, 72, 96 e 120 horas após o confinamento dos insetos nas plantas; no período de 120 horas, praticamente todos os insetos estavam mortos. Em relação à infecção de plantas de milho por insetos alimentados em plantas forrageiras portadoras do patógeno, os dados evidenciaram ausência do fitoplasma em todas as plantas de milho inoculadas. Estes resultados evidenciaram que, em condições naturais, provavelmente, as forrageiras podem servir como reservatórios; no entanto, sugerem que estas forrageiras podem não atuar como fonte de inóculo do patógeno para plantas de milho. Ainda, os dados apontaram que nenhuma das variedades testadas se destacou como sendo mais favorável à sobrevivência do vetor. / Maize bushy stunt, associated with a phytoplasma of the group 16SrI, subgroup B, has been reported in Brazilian areas cultivated with corn since 1970s.The economic importance of the disease was expressed from 1980s, with the introduction of a cultivation system named \"safrinha\" maize. The pathosystem has long been explored, but failures of knowledge are yet significant. In the present work it was investigated the survival of the fitoplasma and its vector, the leafhopper Dalbulus maidis, in various forage species of high agronomic interest. So, five varieties of forage (Panicum maximum cv. Mombaça, P. maximum x P. infestum cv. Massai, Brachiaria bizantha cv Marandu, B. brizantha cv. Piatã e B. decumbens cv. Basilisk (popularly known by Decumbens) were used, which were inoculated with the phytoplasma via infective insects fed in corn plants infected by the pathogen. Assessment was conducted based on the detection of phytoplasma using PCR tecnique and daily counting of dead leafhoppers found in the inoculated forage plants. Tissues were collected for detection 28, 56, 84, 112 and 140 days after inoculation and plants were cut immediately after each sampling. In addition, an assay was conducted, in which insects were fed in infected plants belonging to all forage varieties and, subsequently, confined in healthy corn plants. The results allowed to detect the phytoplasma in all distinct forage varieties, 28 days after inoculation. Assesment made to the 56 days allowed to detect the pathogen in 66% of the plants of Marandu, in 50% of Massai, and 16% of plants of the varieties Decumbens, Mombaça and Piatã. In evaluations conducted to the 84, 112, and 140 days after inoculation, the phytoplasma was not more detected in the new tissues from forage plants. Concerning survival of leafhoppers, the different forage showed the same behavior, within each period corresponding to 24, 48, 72, 96 e 120 hours after confining of the insects in the plants; in the period of 120 hours, almost all insects were dead. In relation to the infection of corn plants by insects fed in forage plants infected with the pathogen, the analysis showed absence of the phytoplasma in all inoculated corn plants. These results pointed that, in natural conditions, probably the forages to serve as reservoir; however, they also suggested that these forages probably do not act as inoculum sources of the pathogen for corn plants. In addition, the results also demonstrated that none variety stood out as more favorable to survival of the leafhopper.

Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2018-02-07T23:24:09Z No. of bitstreams: 1 492644.pdf: 9684351 bytes, checksum: f9908407ebf5918b6010cce76c8fb41f (MD5) / Made available in DSpace on 2018-02-07T23:24:10Z (GMT). No. of bitstreams: 1 492644.pdf: 9684351 bytes, checksum: f9908407ebf5918b6010cce76c8fb41f (MD5) Previous issue date: 1999-12-02 / FAPERJ / CAPES / O gênero neotropical Lissoscarta Stâl é composto por sete espécies conhecidas: L. beckeri Mejdalani & Felix, L. catutara Young, L. nipata Young, L. pebasensis Young, L. pereneensis Young, L. schlingeri Young e L. vespiformis (Fabricius). Essas espécies são muito semelhantes em termos de coloração e morfologia externa, podendo ser identificadas somente através do estudo da genitália masculina. Os integrantes desse gênero são, aparentemente, mímicos batesianos de vespas da tribo Epiponini (Vespidae: Polistinae). Esse caso de mimetismo envolve não só características morfológicas, mas também aspectos comportamentais. Uma análise filogenética de... / The Neotropical genus Lissoscarta Stâl is composed of seven known species: L. beckeri Mejdalani & Felix, L. catutara Young, L. nipata Young, L. pebasensis Young, L. pereneensis Young, L. schlingeri Young, and L. vespiformis (Fabricius). These species are very similar in terms of color and external morphology and can be identified only through the study of the male genitalia. The members of this genus are apparently Batesian mimics of wasps of the tribe Epiponini (Vespidae: Polistinae). This case of mimicry involves morphological and behavioral features. A phylogenetic analysis of...

La Flavescence dorée est une maladie à phytoplasme incurable qui affecte la vigne. Cette pathologie est uniquement transmise de plante à plante par la cicadelle vectrice Scaphoideus titanus. Malgré l'importance de cette maladie, peu d'études ont été menées sur le vecteur. Ce travail de thèse vise à apporter des connaissances sur la biologie et l'écologie de S. titanus mais aussi de manière plus générale sur l'écologie des insectes phytophages. Trois grands thèmes ont été abordés dans ce mémoire : i) les relations entre l'insecte et son environnement à travers l'influence des températures hivernales sur les œufs en diapause, ii) les relations de l'insecte avec sa plante hôte en examinant l'attractivité de cette dernière et le comportement alimentaire du vecteur, iii) les interactions entre congénères par l'étude du comportement d'agrégation des larves. Les résultats obtenus indiquent que 1) des températures froides ne sont pas indispensables à la levée de diapause mais affectent la protandrie en régulant le sex-ratio opérationnel, 2) l'attractivité de la plante hôte est en grande partie liée à sa couleur et il existe des différences de comportement en fonction du stade de développement, 3) les mâles et les femelles n'ont pas le même comportement alimentaire, ce qui pourrait expliquer leur différentes capacités de vection, 4) l'agrégation des larves ne semble pas due à un recrutement actif de leur part et pourrait contribuer à un transfert horizontal de phytoplasme d'insecte à insecte via la plante. A terme, ces connaissances pourront contribuer à l'élaboration de pistes alternatives à la lutte chimique actuelle contre cette cicadelle dans le cadre d'une réduction des intrants. / The Flavescence dorée is an incurable phytoplasma disease of grapevine. This pathology is exclusively transmitted from plant to plant by the leafhopper vector Scaphoideus titanus. Despite the importance of this disease, few studies have been conducted on the vector. This thesis aims to provide knowledge on the biology and ecology of S. titanus but also more broadly on the ecology of phytophagous insects. Three major themes were addressed in this thesis: i) the relationships between the insect and its environment through the influence of winter temperatures on diapausing eggs, ii) the relationships of the insect with its host plant by examining the attractiveness of the plant and the feeding behaviour of the vector, iii) interactions between congeners in the study of the aggregative behaviour of larvae. Our results indicate that 1) cold temperatures are not essential to break the diapause but contribute to protandry through operational sex ratio regulation, 2) the attractiveness of the host plant is largely due to its colour and different instars exhibit differences in behavioural choices, 3) males and females have different feeding behaviour which may explain their different efficiencies at vection, 4) the aggregation of larvae did not seem to result from active recruitment and could contribute to horizontal insect to insect transfer of phytoplasma through the plant. Such knowledge can contribute to the development of alternative S. titanus pest management techniques.