No description available.

Greenbug is one of two key insect pests of sorghum, and biotype evolution hinders the long-term usefulness of resistant sorghums. The current study sought to identify plant resistance mechanisms, plant damage characteristics, and greenbug fitness in sorghum/greenbug interactions. Choice tests were conducted to elucidate resistance mechanisms displayed by four sorghum genotypes towards several greenbug biotypes and isolates. Results indicated all three resistance modalities (antibiosis, antixenosis, tolerance) were identified in sorghums, with some genotypes displaying two or more modalities towards some biotypes. This suggests some sorghum genotypes do not select for greenbug biotypes, and the sorghum genotypes cultivated may have relatively long-term resistance. Non-choice tests were used to determine plant damage associated with greenbug feeding. Four sorghum genotype, Johnson grass, and five greenbug biotype combinations were used to elucidate plant characteristics associated with visible plant damage. Fluid loss and plant stunting were significantly associated with visible plant damage, and were also observed in some plants not incurring heavy visible damage. Additionally, some biotypes avirulent to cultivated sorghum caused significant damage to Johnson grass. These results suggest visible plant damage, routinely used in damage studies, reflects underlying causes that could lead to poor agronomic performance. Additionally, Johnson grass may harbor greenbug biotypes not commonly found in sorghum fields. Greenbug colony and individual fitness were determined by reproduction rates of five biotypes on four sorghum genotypes and Johnson grass in non-choice tests. Generally, colony and individual fitness estimates were not different within genotype/biotype combinations. Also, biotypes did best on more susceptible and worst on more resistant sorghum genotypes. Colonies and individuals of all biotypes had lowest fitness on Johnson grass. These results suggest virulent biotypes may have a fitness advantage over avirulent ones, at least in the presence of the cultivated host. The results presented herein reflect the diversity of sorghum/greenbug interactions, and underscore the need for further understanding of the nature of greenbug biotypes, and how they interact with cultivated and non-cultivated host plants.

Greenbug is one of two key insect pests of sorghum, and biotype evolution hinders the long-term usefulness of resistant sorghums. The current study sought to identify plant resistance mechanisms, plant damage characteristics, and greenbug fitness in sorghum/greenbug interactions. Choice tests were conducted to elucidate resistance mechanisms displayed by four sorghum genotypes towards several greenbug biotypes and isolates. Results indicated all three resistance modalities (antibiosis, antixenosis, tolerance) were identified in sorghums, with some genotypes displaying two or more modalities towards some biotypes. This suggests some sorghum genotypes do not select for greenbug biotypes, and the sorghum genotypes cultivated may have relatively long-term resistance. Non-choice tests were used to determine plant damage associated with greenbug feeding. Four sorghum genotype, Johnson grass, and five greenbug biotype combinations were used to elucidate plant characteristics associated with visible plant damage. Fluid loss and plant stunting were significantly associated with visible plant damage, and were also observed in some plants not incurring heavy visible damage. Additionally, some biotypes avirulent to cultivated sorghum caused significant damage to Johnson grass. These results suggest visible plant damage, routinely used in damage studies, reflects underlying causes that could lead to poor agronomic performance. Additionally, Johnson grass may harbor greenbug biotypes not commonly found in sorghum fields. Greenbug colony and individual fitness were determined by reproduction rates of five biotypes on four sorghum genotypes and Johnson grass in non-choice tests. Generally, colony and individual fitness estimates were not different within genotype/biotype combinations. Also, biotypes did best on more susceptible and worst on more resistant sorghum genotypes. Colonies and individuals of all biotypes had lowest fitness on Johnson grass. These results suggest virulent biotypes may have a fitness advantage over avirulent ones, at least in the presence of the cultivated host. The results presented herein reflect the diversity of sorghum/greenbug interactions, and underscore the need for further understanding of the nature of greenbug biotypes, and how they interact with cultivated and non-cultivated host plants.

No description available.

No description available.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-03-01T00:55:21Z No. of bitstreams: 1 DISSERTA??O augusto.pdf: 990945 bytes, checksum: 0ffa3c6ca52f5bfb881523a9ecb67d91 (MD5) / Made available in DSpace on 2016-03-01T00:55:21Z (GMT). No. of bitstreams: 1 DISSERTA??O augusto.pdf: 990945 bytes, checksum: 0ffa3c6ca52f5bfb881523a9ecb67d91 (MD5) Previous issue date: 2013-02-04 / The approach to the study of complex networks used for networks of interactions allows the identification of emergent properties such as nestdness, modularity and specialization. Consequently, we hypothesize that mutualistic networks between plants and butterflies visiting flowers in higher altitudes are characterized by few species, with low feeding selectivity. We developed the study using two organizational levels: local and global. The local level comprised mutualistic networks in two hills located in the Chapada Diamantina. The global level comprised mutualistic networks in different regions of the globe. For each network, we evaluated the relationship between altitude, modularity, nestdness and specialization. No network metric shoed a consistent change associated with altitudinal variation, not in the local and global levels. Thus, the structure of interaction networks between butterflies visiting the flowers and plants does not respond to changes in altitude, what we are left understand what factors may be determinants for this interaction. / A abordagem do estudo de redes complexas utilizada para as redes de intera??es permite a identifica??o de propriedades emergentes tais como o aninhamento, modularidade e especializa??o. Nesse sentido, propomos a hip?tese de que redes de intera??es entre borboletas visitantes florais e plantas em altas altitudes ser?o caracterizadas por poucas esp?cies, com baixa seletividade alimentar. Nossas expectativas s?o de que, ao longo de uma montanha (n?vel local), tais redes ser?o 1) menos modulares; 2) menos aninhadas e 3) compostas por esp?cies generalistas na regi?o do topo, quando comparadas com redes localizadas nas regi?es mais basais. Esperamos encontrar esse mesmo padr?o ao avaliar redes descritas em diferentes altitudes ao longo do globo (n?vel global). Realizamos o estudo utilizando dois n?veis organizacionais: local e global. O n?vel local envolveu dois morros situados na Chapada Diamantina e para cada morro, duas altitudes. O n?vel global envolveu redes de intera??es em v?rias partes do mundo com altitudes diferentes. Para cada rede avaliamos a associa??o entre altitude, modularidade, aninhamento e especializa??o. Nenhuma das tr?s m?tricas de rede revelou mudan?a consistente em rela??o ?s duas altitudes dos morros ou mesmo para a avalia??o global. Desta forma, a estrutura de redes de intera??o entre borboletas visitantes florais e plantas n?o responde a varia??es de altitude, o que nos resta entender quais os fatores que podem ser determinantes para essa intera??o.

Butterflies fulfill a unique role among insect pollinators as long-distance flyers. This makes butterflies particularly valuable as vectors of genetic diversity among spatially isolated plant populations. Like many insects, though, butterfly populations have experienced significant declines in recent years. To help inform conservation efforts, and to investigate community and species level dynamics, I studied butterflies and their floral resources as part of a three year pollinator survey across the state of North Dakota. At the community level, I analyzed butterfly-flower interaction networks across space and time. I then examined the specialization of individual species within those networks and their contributions to network structure. I also evaluated spatial and temporal distribution patterns of monarch butterflies, regal fritillaries, and their plant resources. Results revealed dynamic spatiotemporal relationships between butterflies and their plant resources that have important implications for conservation efforts and the study of ecological communities.

Em resposta aos danos ocasionados por insetos, as plantas emitem voláteis que atraem os inimigos naturais desses herbívoros. Embora essa relação tritrófica venha sendo intensamente estudada, muitos mecanismos envolvidos nesta interação ainda permanecem inexplorados. Dentre os compostos voláteis induzidos por herbivoria e emitidos pelas plantas, os terpenos são os mais expressivos e abundantes. Em resposta ao dano ocasionado por um inseto, cascatas bioquímicas são iniciadas na planta, as quais podem alterar a expressão de genes envolvidos na resposta a tal dano. Este trabalho analisou as mudanças na expressão gênica e produção de compostos voláteis em plantas de milho, Zea mays (Poaceae)promovidas por lagartas Spodoptera frugiperda (Lepidoptera: Noctuidae) ao longo do tempo. Utilizando a técnica de PCR em tempo real (qRTPCR) foram verificadas respostas no nível da expressão gênica das plantas submetidas à indução por herbivoria. Foram analisados os genes de uma lipoxigenase e de três terpeno sintases, enzimas envolvidas na produção de compostos voláteis que atraem parasitóides de S. frugiperda. As plantas submetidas à herbivoria apresentaram níveis de expressão gênica e emissão de voláteis maiores do que as plantas sadias. Os resultados fornecem bases para o entendimento dos mecanismos endógenos responsáveis pela liberação de voláteis nas plantas visando o estabelecimento de novos fundamentos para o controle biológico de pragas. / In response to insect damage, plants emit volatiles that attract natural enemies of herbivores. Although this tritrophic interaction has been intensively studied, many mechanisms involved in this interaction remain unexplored. Among the herbivore-induced volatile compounds, terpenes are the most abundant and significant ones. In response to insect damage, biochemical pathways are activated, which can alter the expression of genes involved in the response to that damage. This study examined changes in gene expression and volatile compounds production in maize plants, Zea mays (Poaceae) promoted by Spodoptera frugiperda (Lep.: Noctuidae) caterpillars through time. Using the real-time PCR technique (qRT-PCR) we verified responses on the level of gene expression of plants subjected to herbivores feeding. We analyzed genes of lipoxygenase and three terpene synthases, enzymes involved in the synthesis of volatile compounds that attract parasitoids of S. frugiperda. Plants subjected to herbivory had higher levels of gene expression and volatile emission when compared to healthy plants. Results provide basis for better understanding of plant volatile emission endogenous mechanisms in order to set new foundations for biological control of pests.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-10-03T11:27:04Z No. of bitstreams: 1 2011 - Renata Cristina de Souza Coelho.pdf: 1271616 bytes, checksum: 7e462a30d8cdde8325d226c9741f0141 (MD5) / Made available in DSpace on 2016-10-03T11:27:04Z (GMT). No. of bitstreams: 1 2011 - Renata Cristina de Souza Coelho.pdf: 1271616 bytes, checksum: 7e462a30d8cdde8325d226c9741f0141 (MD5) Previous issue date: 2011-05-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / In the Atlantic forest, deforestation and the resulting forest fragmentation have been worsening since the sixteenth century. Recent data estimate that the area covered with forest of Mata Atlantica represents between 11.6% and 16% of its original length, resulting in the extinction of species due to habitat reduction and isolation and edge effect. Among animals, insects are noted for presenting the largest number of species and participate in a large number of interactions with other organisms. Being good bioindicators in studies of environmental impact assessment, including the effects of forest fragmentation. Ant communities (Hymenoptera: Formicidae) have been used as bioindicators because of their high species richness and respond to environmental changes. The main objective was to study the effects of forest fragmentation on the richness, diversity and community composition of ants foraging on plants. Moreover, there was the spatial and temporal variations of this community and the influence of vegetation structure and in the richness and diversity of arboreal ant fauna. The study was conducted during the dry season of 2009 and the rainy season of 2010. We sampled eight forest fragments in the City of Vassouras, besides Tingu? Biological Reserve, State of Rio de Janeiro. In a plot of 120 m2, 20 trees with CAP between 15 to 40 cm were marked, these being distant about 10 m apart. The same amount of sardines in edible oil, was placed in the trunk of each tree and on white paper, 10 cm x 12 cm, distributed over 20 bushes near their trees, the approximate height of 1 m. The baits were placed in the schedule between 10:30 and 11:00, one hour remaining on the vegetation. To sample the vegetation structure, we used the method of touch. All trees with CAP over 5 cm were counted and morphospecies and were also obtained the percentage of canopy cover. In order to study the influence of abiotic factors were recorded temperature and relative humidity. We collected a total of 73 morphospecies of ants distributed in 20 genera and six subfamilies, Myrmicinae (33), Dolichoderinae (15), Formicinae (12), Pseudomyrmecinae (7), Ponerinae (3), Ectatomminae (2) and Ecitoninae (1). Pheidole was the largest genus with species richness (13), followed by Linepithema (9) Solenopsis (8), Pseudomyrmex (7) and Brachymyrmex (6). Overall, the diversity index and species richness of ants were higher in the rainy season than in dry season. We found 12 unique species in the dry season and 32 in the rainy season. The variation of fragment size did not influence the species richness of ants on a local scale. The multiple regression analysis step by step to the data of vegetation structure of the fragments revealed that the richness and diversity (H') of ant species depended mainly on the density of shrubs and trees away all the vegetation structure has influenced ant community. This shows that for the arboreal ant community, the habitat quality is more important than the size of the area, stressing the importance of conservation of the Atlantic. / No bioma Mata Atl?ntica, o desmatamento e o consequente processo de fragmenta??o florestal v?m se agravando desde o s?culo XVI. Dados recentes estimam que a ?rea coberta com remanescentes florestais de Mata Atl?ntica representa entre 11,6% a 16% de sua extens?o original, tendo como consequ?ncia a extin??o de esp?cies, devido ? diminui??o e isolamento dos h?bitats e ao efeito de borda. Dentre os animais, os insetos se destacam por apresentarem o maior n?mero de esp?cies e participarem de um grande n?mero de intera??es com outros organismos. Sendo bons bioindicadores em estudos de avalia??o de impactos ambientais, incluindo os efeitos da fragmenta??o florestal. Comunidades de formigas (Hymenoptera: Formicidae) t?m sido utilizadas como bioindicadoras em fun??o de sua elevada riqueza de esp?cies e por responderem a mudan?as no ambiente. O principal objetivo deste trabalho foi estudar os efeitos da fragmenta??o florestal sobre a riqueza, a diversidade e a composi??o das comunidades de formigas que forrageiam sobre plantas. Al?m disso, verificou-se as varia??es espaciais e temporais desta comunidade e a influ?ncia da estrutura da vegeta??o e sob a riqueza e diversidade da mirmecofauna arbor?cola. O estudo foi realizado durante a esta??o seca de 2009 e a esta??o chuvosa de 2010. Foram amostrados oito fragmentos florestais do Munic?pio de Vassouras, al?m da Reserva Biol?gica do Tingu?, no Estado do Rio de Janeiro. Em uma parcela de 120 m2, 20 ?rvores com CAP entre 15 a 40 cm foram marcadas, estando estas distantes em cerca de 10 m entre si. Uma mesma quantidade de sardinha, em ?leo comest?vel, foi colocada no tronco de cada uma das ?rvores e sobre papel branco, com 10 cm x 12 cm, distribu?das sobre 20 arbustos, pr?ximos das respectivas ?rvores, a altura aproximada de 1 m. As iscas foram colocadas no hor?rio entre 10:30h e 11:00h, permanecendo 1 hora sobre a vegeta??o. Para estudar a estrutura da vegeta??o, foi utilizado o m?todo do toque. Todas as ?rvores com CAP acima de 5 cm foram contadas e morfoespeciadas e tamb?m foram obtidas a porcentagem de cobertura do dossel. A fim de estudar a influ?ncia dos fatores abi?ticos, foram registradas, com termohigr?metro, a temperatura e a umidade relativa do ar. Foi coletado um total de 73 morfoesp?cies de formigas distribu?das em 20 g?neros e seis subfam?lias: Myrmicinae (33), Dolichoderinae (15), Formicinae (12), Pseudomyrmecinae (7), Ponerinae (3), Ectatomminae (2) e Ecitoninae (1). Pheidole foi o g?nero com maior riqueza de esp?cies (13), seguido de Linepithema (9) Solenopsis (8), Pseudomyrmex (7) e Brachymyrmex (6). No geral, o ?ndice de diversidade e a riqueza de esp?cies de formigas foram maiores na esta??o chuvosa que na esta??o seca. Foram encontradas 12 esp?cies exclusivas na esta??o seca e 32 na esta??o chuvosa. A varia??o de tamanho dos fragmentos n?o influenciou a riqueza de esp?cies de formigas numa escala local. As an?lises de regress?o m?ltipla passo a passo para os dados da estrutura da vegeta??o dos fragmentos revelaram que a riqueza e a diversidade (H?) de esp?cies de formigas dependeram, principalmente, da densidade de arbustos e ?rvores. Isto mostra que para a comunidade de formigas arbor?colas, a qualidade do h?bitat ? mais importante do que o tamanho da ?rea, ressaltando a import?ncia do estado de conserva??o dos fragmentos para a prote??o da biodiversidade da Mata Atl?ntica

Em resposta aos danos ocasionados por insetos, as plantas emitem voláteis que atraem os inimigos naturais desses herbívoros. Embora essa relação tritrófica venha sendo intensamente estudada, muitos mecanismos envolvidos nesta interação ainda permanecem inexplorados. Dentre os compostos voláteis induzidos por herbivoria e emitidos pelas plantas, os terpenos são os mais expressivos e abundantes. Em resposta ao dano ocasionado por um inseto, cascatas bioquímicas são iniciadas na planta, as quais podem alterar a expressão de genes envolvidos na resposta a tal dano. Este trabalho analisou as mudanças na expressão gênica e produção de compostos voláteis em plantas de milho, Zea mays (Poaceae)promovidas por lagartas Spodoptera frugiperda (Lepidoptera: Noctuidae) ao longo do tempo. Utilizando a técnica de PCR em tempo real (qRTPCR) foram verificadas respostas no nível da expressão gênica das plantas submetidas à indução por herbivoria. Foram analisados os genes de uma lipoxigenase e de três terpeno sintases, enzimas envolvidas na produção de compostos voláteis que atraem parasitóides de S. frugiperda. As plantas submetidas à herbivoria apresentaram níveis de expressão gênica e emissão de voláteis maiores do que as plantas sadias. Os resultados fornecem bases para o entendimento dos mecanismos endógenos responsáveis pela liberação de voláteis nas plantas visando o estabelecimento de novos fundamentos para o controle biológico de pragas. / In response to insect damage, plants emit volatiles that attract natural enemies of herbivores. Although this tritrophic interaction has been intensively studied, many mechanisms involved in this interaction remain unexplored. Among the herbivore-induced volatile compounds, terpenes are the most abundant and significant ones. In response to insect damage, biochemical pathways are activated, which can alter the expression of genes involved in the response to that damage. This study examined changes in gene expression and volatile compounds production in maize plants, Zea mays (Poaceae) promoted by Spodoptera frugiperda (Lep.: Noctuidae) caterpillars through time. Using the real-time PCR technique (qRT-PCR) we verified responses on the level of gene expression of plants subjected to herbivores feeding. We analyzed genes of lipoxygenase and three terpene synthases, enzymes involved in the synthesis of volatile compounds that attract parasitoids of S. frugiperda. Plants subjected to herbivory had higher levels of gene expression and volatile emission when compared to healthy plants. Results provide basis for better understanding of plant volatile emission endogenous mechanisms in order to set new foundations for biological control of pests.