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Distribui??o espacial de insetos fit?fagos e de inimigos naturais em Leucaena leucocephala utilizada como quebra-vento em regi?o de cerrado no Brasil / Spatial distribution of phytophagous insects and natural enemies in Leucaena Leucocephala utilized as windbreak in cerrado region of BrazilDamascena, Joyce Gomes 11 November 2016 (has links)
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Previous issue date: 2016 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Leucaena leucocephala (Lam.) de Wit. (Fabaceae: Mimosoideae), conhecida como leucena, ? bastante cultivada no mundo pelo valor nutricional de suas folhas e ramos finos, sendo considerado um alimento completo para ruminantes e monog?stricos, por isso utilizada em sistemas agrossilvipastoris. Esp?cie que tamb?m ? empregada para reflorestamento de ?reas degradadas podendo controlar eros?es h?dricas e e?licas, al?m de melhorar as condi??es ambientais. Al?m disso, leucena pode ser usada em quebra-vento, o que poder? influenciar na distribui??o de pragas e inimigos naturais e dificultar a localiza??o de plantas hospedeiras. A distribui??o desses insetos na planta poder? ocorrer de acordo com fatores extr?nsecos (ex.; vento, insola??o), o que varia com a regi?o que a cultura foi cultivada, e intr?nseca (ex.; componentes f?sico-qu?micos) relacionados com gen?tica da planta. O objetivo deste trabalho foi avaliar durante dois anos, a distribui??o espacial de insetos fit?fagos e de seus inimigos naturais ao longo da estratifica??o vertical do dossel (partes apical, m?dia, basal e no tronco) e horizontal (orienta??o dos galhos quanto ? exposi??o do sol nas faces norte, sul, leste e oeste) e da face foliar (adaxial e abaxial) em L. leucocephala. As avalia??es foram realizadas estando L. leucocephala em quebra-vento com 100 metros de comprimento, disposto com duas fileiras centrais de Acacia mangium Willd. (Leguminosae) (espa?amento 3 x 3 m) e duas fileiras de L. leucocephala, uma de cada lado da A. mangium, com espa?amento de 3 m entre fileiras e 2 m entre plantas. Foram avaliados os n?meros de insetos fit?fagos, polinizadores e inimigos naturais, contados quinzenalmente, em 20 ?rvores de L. leucocephala (16 meses de idade) durante o per?odo experimental. Essa contagem foi realizada por visualiza??o direta, nas faces foliares (adaxial e abaxial)/folha, na parte apical, m?dia e basal do dossel e nos galhos posicionados nas faces norte, sul, leste e oeste, entre 7 e 11 h da manh?. Al?m disso, os insetos foram contabilizados no tronco das 20 ?rvores/avalia??o. Avaliaram-se os ?ndices ecol?gicos (n?mero de indiv?duos, riqueza, diversidade e abund?ncia de esp?cies). A f?rmula de Colina foi usada para calcular a diversidade. Abund?ncia e riqueza de esp?cies (S) foram calculadas pela f?rmula de Simpson. Domin?ncia-K foi calculada tra?ando a abund?ncia percentual cumulativo contra log classifica??o de esp?cies. Os valores de domin?ncia-K indica a distribui??o de domin?ncia e uniformidade dos indiv?duos entre as esp?cies. As frequ?ncias de cada esp?cie de inseto nas amostras foram classificadas como constante, comum e rara. No geral, foi observado baixos ?ndices de insetos em L. leucocephala, sendo encontradas 18 esp?cies raras, 3 comuns e 1 constante. Os maiores n?meros de indiv?duos tanto de fit?fagos, quanto de inimigos naturais e polinizadores quanto ? estratifica??o horizontal do dossel, foram observados na posi??o norte dos ramos. Para os ?ndices de riqueza espec?fica e diversidade de fit?fagos foram observados maiores valores nos galhos voltados a oeste e, para os inimigos naturais, nos galhos voltados para norte/sul e oeste, respectivamente. Para as vari?veis, n?mero de indiv?duos, riqueza espec?fica e ?ndice de diversidade quanto ? estratifica??o vertical do dossel, os maiores valores para fit?fagos foram observados na parte apical de L. leucocephala; e de inimigos naturais nas partes apicais e medianas, respectivamente. Os maiores valores de indiv?duos, riqueza espec?fica e ?ndice de diversidade tanto para os fit?fagos como os inimigos naturais, foram observados na face abaxial de L. leucocephala. Quanto ? vari?vel abund?ncia, fit?fagos mastigadores obtiveram maior ?ndice na posi??o norte dos ramos, j? sugadores, na posi??o oeste. Maior abund?ncia de formigas foi encontrada na posi??o norte, e maior abund?ncia de abelhas da esp?cie Tetragonisca angustula Latreille (Hymenoptera: Apidae) na posi??o oeste dos ramos do dossel de L. leucocephala. Quanto ? estratifica??o vertical do dossel, maiores valores de abund?ncia de fit?fagos mastigadores e sugadores foi na regi?o apical do dossel, o que tamb?m foi para formigas, j? as abelhas T. angustula em maior abund?ncia na regi?o mediana do dossel de L. leucocephala. Quanto ? face foliar, no geral, para todos os ?ndices avaliados, os maiores valores foram encontrados na face abaxial das folhas de L. leucocephala. Com este estudo, podem-se estabelecer estrat?gias de monitoramento, sabendo-se que fit?fagos, inimigos naturais e polinizadores est?o em maior n?mero de indiv?duos na posi??o norte da regi?o apical do dossel. J? a riqueza espec?fica e diversidade, encontram-se maiores ?ndices de fit?fagos, inimigos naturais e polinizadores na posi??o oeste da regi?o apical do dossel e no geral, encontrados na face abaxial das folhas de L. leucocephala. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / Leucaena leucocephala (Lam.) of Wit.(Fabaceae: Mimosoideae), known as leucaena, is widely cultivated around the world due to the nutritional value of its leaves and thin branches, being considered a complete ruminant and monogastric feed, hence its use in agroforestry systems. This species is also used in the reforestation of degraded areas for it can control hydrous and aeolian erosion and also improve the environmental conditions. Above all, leucaena can be used in windbreaker, which may influence pests and enemies distribution and difficult the location of host plants. The distribution of those insects on the plant may occur according to extrinsic factors (e.g.: wind, insolation), which varies with the area where the culture was cultivated, and intrinsic (e.g.: physical and chemical components) related to the plant genetics. The objective of this paper was to evaluate during two years the spatial distribution of phytophagous insects and their natural enemies along the vertical canopy stratification (apical, medium and basal parts and also the trunk) and horizontal (orientation of the branches in relation to the exposition to the sun on north, south, east and west faces) and of foliar face (adaxial and abaxial) in L. leucocephala. The evaluations were performed with L. leucocephala being in windbreak with 100 meters in length, disposed in two central rows of Acacia mangium Willd. (Leguminosae) (spacing of 3 x 3 meters) and two rows of L. leucocephala, one of each side of A. mangium, with spacing of 3 meters between the rows and 2 meters between the plants. We evaluated the number of phytophagous insects, pollinator insects and natural enemies, counted every 15 days, in 20 trees of L. leucocephala (16-month old) during the experimental period. This count was performed by direct visualization on the foliar faces (adaxial and abaxial)/leaf, on the apical, medium and basal parts of the canopy and on branches placed on the north, south, east and west faces, between 7hrs and 11hrs in the morning. Above all, the insects were counted on the trunk of 20 trees/evaluation. The ecological indicators (number of individuals, affluence, diversity and abundance of species). The formula of Colina was used to calculate the diversity. Abundance and affluence of species (S) were calculated by the formula of Simpson. Dominance-K was calculated tracing cumulative percentage abundance against log classification of species. The values of dominance-K indicate the dominance and uniformity distribution of individuals between the species. The frequency of each insect species in the samples was classified as constant, common and rare. In general, it was observed low indices of insects in L. leucocephala, and 18 rare, 3 common and 1 constant species were found. The greatest number of phytophagous individuals, natural enemies and pollinators related to the horizontal canopy stratification were observed on the north side of the branches. For specific affluence and phytophagous diversity indices we observed greater values on the branches facing west, and for the bioregulators, on the branches facing north/south and west, respectively. For the variables, number of individuals, specific affluence, and diversity index in relation to the vertical canopy stratification, the greater values for phytophagous were observed on the apical part of L. leucocephala; and of bioregulators on the apical and medium parts, respectively. The greatest values of individuals, specific affluence and biodiversity index were observed on the abaxial face of L. leucocephala for both phytophagous and bioregulators. As for the abundance variable, chewing phytophagous acquired greater index on the north position of the branches, while sucking phytophagous, on west position. Greater abundance of ants was found on the north position, and greater abundance of bees of the Tetragonisca angustula Latreille (Hymenoptera: Apidae) species on the west position of the canopy branches of L. leucocephala. Regarding the vertical canopy stratification, greater abundance values of chewing and sucking phytophagous were found on the apical canopy region, the same was true for ants, whereas the T. angustula bees were more abundant on the medium canopy region of L. leucocephala. As for the foliar face, in general for all evaluated indexes the greatest values were found on the abaxial face of L. leucocephala leaves. With this paper, we can establish monitoring strategies, knowing that phytophagous, natural enemies and pollinators are in greater number of individuals on the north position of the apical canopy region. As for the specific affluence and diversity, greater phytophagous, natural enemies and pollinators were found on the west position of the apical canopy region and in general, were also found on the abaxial face of L. leucocephala leaves.
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Assessing Subterranean Arthropod Diversity through COI Barcoding in Two Ecoregions of Southwestern Virginia, USAHarrison, Garrett Taylor 21 June 2023 (has links)
Subterranean arthropod communities are important components of North American ecosystems, contributing numerous ecosystem services and essential food-web functions. Despite this, fundamental information about species diversity in these communities remains unknown, and their taxonomic composition and ecological diversity have scarcely been assessed. Subterranean pitfall traps are a commonly used method for sampling endogean and hypogean soil habitats in Europe but have never been widely implemented in North America. Here, I employed this method to sample subterranean arthropod communities in the Ridge and Valley and Blue Ridge ecoregions of Virginia, USA in the winter and spring. In total, 2,260 arthropod specimens were collected constituting 319 distinct species. I extracted and purified DNA and amplified the mitochondrial gene: cytochrome C oxidase subunit I (COI) from each recovered morphospecies and derived a unique COI barcode for each species sequenced. Objective sequence clustering was used to establish molecular operational taxonomic units (mOTUs) for downstream diversity analyses and establishment of dynamic identification resources. Total species richness and average species richness per site were assessed and compared for both regions and seasons. The Shannon-Wiener diversity index, Hutcheson's t-test, and effective numbers of species (ENS) were employed to compare regional subterranean arthropod diversity. The richness, Shannon-Wiener, and ENS comparisons indicated that both ecoregions encompass highly diverse subterranean arthropod communities with those of the Ridge and Valley being significantly more diverse than those of the Blue Ridge. / Master of Science in Life Sciences / Arthropods are invertebrate animals with hard exoskeletons, segmented bodies, and jointed paired appendages, and include insects, arachnids, crustaceans, and myriapods. Arthropods make up the majority of animal species on the planet and are important parts of ecosystems, making it important for researchers to study them. While we know a fair amount about North American arthropods that live above-ground, relatively little is known about those that live deep within the soil and underlying rock substrate. Subterranean pitfall traps are a common method used for collecting arthropods from subterranean habitats in various regions of the world but have rarely been used in the USA. As a result, much of the life beneath our feet may be unknown. I used these traps to collect subterranean arthropods in the Ridge and Valley and Blue Ridge regions of the Appalachian Mountains. A total of 2,260 individual arthropods were collected, belonging to 319 different species. I used DNA sequencing to establish a unique fingerprint-like "barcode" for each species. These barcodes serve as helpful identification resources, and will help name new species in the future. They also allowed me to measure the number of species (diversity) of subterranean arthropods collected from each region, and compare the two to determine which region is more diverse. I used common statistical metrics of diversity including species richness (number of species) and the Shannon-Wiener diversity index to compare regional subterranean arthropod diversity. My results show that both the Ridge and Valley and Blue Ridge regions of Virginia, USA are home to highly diverse subterranean arthropod communities and those of the Ridge and Valley are significantly more diverse than those of the Blue Ridge.
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<b>WHERE THE RED QUEEN SLEEPS: HOW LABOULBENIOMYCETES CAN ELUCIDATE THE EVOLUTION OF FUNGAL PATHOGENS</b>Helen Lorraine Law (18430023) 25 April 2024 (has links)
<p dir="ltr">Spread primarily through sex, members of the microfungal class Laboulbeniomycetes are parasitic on arthropods, where they form tiny, three-dimensional thalli on the host exoskeleton. While the study of Laboulbeniomycetes has had a renaissance in the age of molecular methods, so too has the Red Queen Hypothesis, a coevolutionary theory aimed at characterizing how biotic interactions shape the evolutionary trajectory of “players” over time. While the central dogma of “laboulbeniology” is that labouls do not cause a fitness disadvantage to the host in the wild, here we report the first genome annotation data of a Laboulbeniomycete genome, indicating the possibility of past antagonistic relationships with host species. Some of the genes predicted are homologous with that of highly pathogenic entomopathogenic species, such as those within <i>Cordyceps</i>. To understand why these seemingly benign parasites possess genes associated with pathogenicity, we reviewed recent advances in molecular methods for detecting Red Queen associations, and propose a new model we call “Sleeping Red Queens”. Using Laboulbeniomycete evolutionary history, we predict that antagonists who have adapted to each other over time to a benign state can “re-awaken” or transition to a more antagonistic mode due to environmental changes. The “Sleeping Red Queen” model of Laboulbeniomycetes is supported by research on laboul ecology under artificial conditions. The purpose of this work is to review the history of Laboulbeniomycetes, examine recent advances in molecular methods through the Red Queen lens, report on our new molecular data, and discuss how our new findings can be used to apply Red Queen theory to Laboulbeniomycetes, while also hypothesizing what these future analyses could reveal. With promising advances in next-generation sequencing, we believe our Sleeping Red Queen model will be advantageous for interpretation of future genomic and bioinformatic data of Laboulbeniomycetes.</p>
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Controle hormonal da defesa à herbivoria em tomateiro / Hormonal control of herbivory defense in tomatoCampos, Marcelo Lattarulo 09 April 2009 (has links)
Apesar de sua elevada importância econômica mundial, o cultivo do tomateiro é classificado como de alto risco devido à infestação da cultura por um grande número de pragas e doenças. Esse problema leva tal cultura a depender amplamente da aplicação de agroquímicos que, além de elevaram o custo de produção, são potenciais causadores de danos ambientais e do aparecimento de outras pragas e doenças. Observando o problema mais detalhadamente, pode-se perceber que uma grande parcela das perdas advém dos danos causados por artrópodes herbívoros, os quais são capazes de se alimentar de diversas partes da planta, causando, geralmente, perda de produtividade. Apesar disso, o tomateiro apresenta mecanismos de defesa naturais contra tais pragas, como tricomas e aleloquímicos, que agem intoxicando os artrópodes, dificultando sua movimentação e/ou alterando varias fases de seu desenvolvimento. A busca por genótipos de tomateiro com maior densidade de tricomas e elevado teor de aleloquímicos é hoje considerado um hot spot de pesquisa, devido ao benefício que trariam como redução do custo de produção e maior produtividade. Sabese que vários hormônios vegetais estão ligados a geração de caracteres anti-herbivoria, mas, atualmente, um grande foco vem sendo dado somente ao ácido jasmônico, devido ao seu claro papel na formação de tricomas, aleloquímicos, inibidores de proteases, dentre outros. Visando mostrar a importância de uma abordagem multi-hormonal nesse tipo de estudo, o presente trabalho teve como objetivo avaliar quais hormônios vegetais estão envolvidos com a formação de vários caracteres anti-herbivoria em tomateiro, como densidade de tricomas e teor de aleloquímicos e inibidores de protease. Para tal, fez-se uso da um grande número de mutantes hormonais introgredidos na cultivar Micro-Tom (a qual apresenta diversas facilidades de trabalho como porte reduzido e rápido ciclo de vida). Demonstrou-se que, apesar do ácido jasmônico ser extremamente importante na formação de tais caracteres, outros hormônios também atuam fortemente em tal papel. Etileno, giberelinas e auxina alteram de forma indireta a densidade de tricomas em tomateiro, através de alteração na área de células epidérmicas. O ácido jasmônico é um forte regulador positivo da formação de tricomas, do aleloquímico zingibereno e da formação de inibidores de protease. De forma antagônica, brassinosteróides parecem controlar negativamente a densidade de tricomas, a produção de zingibereno e inibidores de protease. Interessantemente, observou-se que esse controle negativo efetuado por brassinosteróides acontece através de um controle na via do ácido jasmônico, o qual foi comprovado pela produção de duplos mutantes. Resultados obtidos em testes com o herbívoro polífago Spodoptera frugiperda e com a praga de tomate Tuta absoluta (traça-do-tomateiro), bem como de análise de expressão gênica comprovaram a importância do ácido jasmônico, brassinosteróides e sua interação na defesa a herbivoria. Os resultados aqui apresentados sugerem que o foco para futuros estudos da formação de mecanismos anti-herbivoria em tomateiro deve ser voltado não só para o ácido jasmônico como para brassinosteroides e para suas ações antagônicas. / Even though the cultivation of tomato has a high economical importance, this culture is classified as being of elevated risk because of it common infestation by pests and diseases. This problem makes this culture greatly dependent of the application of several agrochemicals, which leads to increase in cost of production, environmental damages and also facilitating the appearance of new pests and diseases. Looking carefully to the problem, it is possible to conclude that a great part of tomato losses are caused by herbivory-arthropods, which are capable of feeding of several parts of the plant, causing, generally, losses in the productivity. However, tomato has natural defense mechanisms against those pests, for example trichomes and allelochemicals, which act poisoning the arthropods, hindering their movement through the plant and/or altering steps of their development. The search for tomato genotypes with great density of trichomes and elevated levels of allelochemicals is nowadays being considered as a hot spot of research, because of the benefits it would provide (for example: a decrease in the cost of production and also a higher productivity). Although it is believed that many plant hormones are involved in the generation of anti-herbivory traits, a great focus has been given only to jasmonic acid because of it clear action in the formation of those traits, such as trichomes, allelochemicals, proteinase inhibitors and many others. The present work objective was to evaluate which hormones are involved in the formation of anti-herbivory traits such as trichome density and allelochemicals and proteinase inhibitors content. For this reason, we made use of several hormonal mutants already introgressed in the Micro-Tom cultivar (which presents benefits as small size and fast life cycle). It was showed that jasmonic acid is an important hormone in the formation of these traits, but other phytohormones also play important roles. Ethylene, gibberellins and auxin alters trichome density indirectly, by altering the area of epidermal cells and thus cell number. Jasmonic acid is a positive regulator of trichome formation, the allelochemicals zingiberene content and also in the formation of proteinase inhibitors. However, brassinosteroids acts by negatively controlling all of those. Interestingly, we observed that this negative control happens through the control of jasmonic acid pathway, a hormonal interaction that was proved by double-mutant analysis. Results obtained in tests with the polyphagous insect Spodoptera frugiperda and the tomato specific pest Tuta absoluta (tomato pinworm) and also with qPCR showed the importance of jasmonic acid, brassinosteroid and their interaction in herbivory defense. Our data suggest that future studies about the formation of antiherbivory traits should be analyzed by focusing the functions not only of jasmonic acid but also brassinosteroid and their antagonist functions.
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Restabelecimento da comunidade de artrópodos edáficos e epígeos e a produção e decomposição da serapilheira em floresta estacional semidecidual restaurada: a floresta da USP como estudo de caso / Recovery of edaphic and epigeic arthropod community and litter production and decomposition in a seasonal semidecidual restored forest: the Forest of the USP as a case studyBarosela, José Ricardo 14 February 2014 (has links)
Originalmente, o estado de São Paulo tinha 87% de sua área ocupada por Floresta Atlântica e o uso de suas terras resultou numa redução de aproximadamente 90% de sua área original. Com o objetivo de manter os serviços ambientais providos pelas florestas urge restaurar parte da vegetação perdida com o plantio de árvores nativas para acelerar a sucessão secundária. Depois do plantio, porém, é necessário que vários processos ecológicos se reestabeleçam para que o novo ecossistema se perpetue. A queda da serapilheira e a sua decomposição tem um papel importante no funcionamento dos ecossistemas porque enriquecem o solo e retornam nutrientes para as próprias árvores. O objetivo deste trabalho foi estimar a queda e a decomposição da serapilheira e verificar as mudanças nas comunidades de artrópodos edáficos e epígeos que possam estar relacionadas às alterações temporais no processo de decomposição numa floresta restaurada. O estudo foi conduzido em um remanescente de floresta estacional semidecidual e em duas áreas de idades diferentes de uma floresta restaurada. A queda da serapilheira foi estimada com o uso de coletores e a sua decomposição com bolsas de malha de 2mm. Foram feitas análises químicas do solo e da serapilheira e suas faunas foram amostradas. As árvores da área restaurada mais antiga produziram tanta serapilheira quanto as do remanescente florestal, e as da restauração mais nova produziram bem menos. Apesar disso, a restauração mais antiga apresentou um solo semelhante ao da mais nova, com baixos teores de nutrientes. A decomposição foi mais rápida no remanescente florestal mostrando que este processo não foi completamente reestabelecido nas áreas plantadas. Os taninos e o nitrogênio foram as variáveis químicas da serapilheira mais relacionadas às suas taxas de decomposição. O remanescente foi o local com maior riqueza de artrópodos edáficos e epígeos, seguido pela área restaurada há mais tempo. Esta fauna foi diferente entre os três loca is e as áreas restauradas tinham comunidades mais semelhantes entre si. Dentre os fragmentadores, formigas, dípteros, proturos e isópodos foram os grupos mais relacionados ao remanescente florestal e os Hemiptera, Thysanoptera e Psocoptera foram mais relacionados à área mais jovem. Pseudoescorpiões e quilópodos se mostraram quase ausentes nas áreas restauradas. As duas restaurações são ainda jovens e somente no futuro poderemos verificar se estes locais terão condições de abrigar grupos de artrópodos mais exigentes e reestabelecer o processo de decomposição e as condições do solo. / Originally, São Paulo State had about 87% of its area occupied by the Atlantic Forest and the use of its lands resulted in the reduction of about 90% of the original area. In order to keep the environmental services we need to restore part of the lost vegetation by planting native trees to accelerate the secondary succession. After planting, it is necessary that many ecological processes take place to perpetuate the new ecosystem. The litterfall and its decomposition play an important role on the ecosystem functioning, because these processes enrich the soil and return nutrients to the trees. The goal of this work was to estimate the litter fall and decomposition besides verifying the changes in the edaphic arthropods community that may indicate the restoration progress through the decomposing process in a restored forest. We have carried out the study in a seasonal semideciduous forest remnant and in two restoration sites of different ages. We have estimated the litter fall using litter collectors and its decomposition using litterbags. We have done soil and litter chemical assays and extracted its fauna by Berlese funnels. The older restored site produced as much litter as the forest remnant while the newer one produced less. Besides that, both restored sites seemed to have similar soils, with low organic matter and mineral nutrients content. The decomposition was faster in the forest remnant showing that this process was not completely reestablished in the restored sites. Tannins and nitrogen was the litter chemicals more related to its decomposition rates. The richest site in edaphic and litter arthropod species was the forest remnant, followed by the older restored forest. The fauna was different among the three sites and the planted forests had more similar communities. Among the litter feeding animals, ants, flies, proturans and isopods were the groups more related to forest remnant. Hemiptera, Thysanoptera and Psocoptera were more abundant in the less developed restored site. Some predator arthropods as pseudoscorpions and chilopods were almost absent in the two restored sites. The restored forests are still young and only in the future we will see if these sites will have conditions to support groups of more sensitive arthropods and to reestablish the decomposition process and soil conditions.
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Restabelecimento da comunidade de artrópodos edáficos e epígeos e a produção e decomposição da serapilheira em floresta estacional semidecidual restaurada: a floresta da USP como estudo de caso / Recovery of edaphic and epigeic arthropod community and litter production and decomposition in a seasonal semidecidual restored forest: the Forest of the USP as a case studyJosé Ricardo Barosela 14 February 2014 (has links)
Originalmente, o estado de São Paulo tinha 87% de sua área ocupada por Floresta Atlântica e o uso de suas terras resultou numa redução de aproximadamente 90% de sua área original. Com o objetivo de manter os serviços ambientais providos pelas florestas urge restaurar parte da vegetação perdida com o plantio de árvores nativas para acelerar a sucessão secundária. Depois do plantio, porém, é necessário que vários processos ecológicos se reestabeleçam para que o novo ecossistema se perpetue. A queda da serapilheira e a sua decomposição tem um papel importante no funcionamento dos ecossistemas porque enriquecem o solo e retornam nutrientes para as próprias árvores. O objetivo deste trabalho foi estimar a queda e a decomposição da serapilheira e verificar as mudanças nas comunidades de artrópodos edáficos e epígeos que possam estar relacionadas às alterações temporais no processo de decomposição numa floresta restaurada. O estudo foi conduzido em um remanescente de floresta estacional semidecidual e em duas áreas de idades diferentes de uma floresta restaurada. A queda da serapilheira foi estimada com o uso de coletores e a sua decomposição com bolsas de malha de 2mm. Foram feitas análises químicas do solo e da serapilheira e suas faunas foram amostradas. As árvores da área restaurada mais antiga produziram tanta serapilheira quanto as do remanescente florestal, e as da restauração mais nova produziram bem menos. Apesar disso, a restauração mais antiga apresentou um solo semelhante ao da mais nova, com baixos teores de nutrientes. A decomposição foi mais rápida no remanescente florestal mostrando que este processo não foi completamente reestabelecido nas áreas plantadas. Os taninos e o nitrogênio foram as variáveis químicas da serapilheira mais relacionadas às suas taxas de decomposição. O remanescente foi o local com maior riqueza de artrópodos edáficos e epígeos, seguido pela área restaurada há mais tempo. Esta fauna foi diferente entre os três loca is e as áreas restauradas tinham comunidades mais semelhantes entre si. Dentre os fragmentadores, formigas, dípteros, proturos e isópodos foram os grupos mais relacionados ao remanescente florestal e os Hemiptera, Thysanoptera e Psocoptera foram mais relacionados à área mais jovem. Pseudoescorpiões e quilópodos se mostraram quase ausentes nas áreas restauradas. As duas restaurações são ainda jovens e somente no futuro poderemos verificar se estes locais terão condições de abrigar grupos de artrópodos mais exigentes e reestabelecer o processo de decomposição e as condições do solo. / Originally, São Paulo State had about 87% of its area occupied by the Atlantic Forest and the use of its lands resulted in the reduction of about 90% of the original area. In order to keep the environmental services we need to restore part of the lost vegetation by planting native trees to accelerate the secondary succession. After planting, it is necessary that many ecological processes take place to perpetuate the new ecosystem. The litterfall and its decomposition play an important role on the ecosystem functioning, because these processes enrich the soil and return nutrients to the trees. The goal of this work was to estimate the litter fall and decomposition besides verifying the changes in the edaphic arthropods community that may indicate the restoration progress through the decomposing process in a restored forest. We have carried out the study in a seasonal semideciduous forest remnant and in two restoration sites of different ages. We have estimated the litter fall using litter collectors and its decomposition using litterbags. We have done soil and litter chemical assays and extracted its fauna by Berlese funnels. The older restored site produced as much litter as the forest remnant while the newer one produced less. Besides that, both restored sites seemed to have similar soils, with low organic matter and mineral nutrients content. The decomposition was faster in the forest remnant showing that this process was not completely reestablished in the restored sites. Tannins and nitrogen was the litter chemicals more related to its decomposition rates. The richest site in edaphic and litter arthropod species was the forest remnant, followed by the older restored forest. The fauna was different among the three sites and the planted forests had more similar communities. Among the litter feeding animals, ants, flies, proturans and isopods were the groups more related to forest remnant. Hemiptera, Thysanoptera and Psocoptera were more abundant in the less developed restored site. Some predator arthropods as pseudoscorpions and chilopods were almost absent in the two restored sites. The restored forests are still young and only in the future we will see if these sites will have conditions to support groups of more sensitive arthropods and to reestablish the decomposition process and soil conditions.
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Controle hormonal da defesa à herbivoria em tomateiro / Hormonal control of herbivory defense in tomatoMarcelo Lattarulo Campos 09 April 2009 (has links)
Apesar de sua elevada importância econômica mundial, o cultivo do tomateiro é classificado como de alto risco devido à infestação da cultura por um grande número de pragas e doenças. Esse problema leva tal cultura a depender amplamente da aplicação de agroquímicos que, além de elevaram o custo de produção, são potenciais causadores de danos ambientais e do aparecimento de outras pragas e doenças. Observando o problema mais detalhadamente, pode-se perceber que uma grande parcela das perdas advém dos danos causados por artrópodes herbívoros, os quais são capazes de se alimentar de diversas partes da planta, causando, geralmente, perda de produtividade. Apesar disso, o tomateiro apresenta mecanismos de defesa naturais contra tais pragas, como tricomas e aleloquímicos, que agem intoxicando os artrópodes, dificultando sua movimentação e/ou alterando varias fases de seu desenvolvimento. A busca por genótipos de tomateiro com maior densidade de tricomas e elevado teor de aleloquímicos é hoje considerado um hot spot de pesquisa, devido ao benefício que trariam como redução do custo de produção e maior produtividade. Sabese que vários hormônios vegetais estão ligados a geração de caracteres anti-herbivoria, mas, atualmente, um grande foco vem sendo dado somente ao ácido jasmônico, devido ao seu claro papel na formação de tricomas, aleloquímicos, inibidores de proteases, dentre outros. Visando mostrar a importância de uma abordagem multi-hormonal nesse tipo de estudo, o presente trabalho teve como objetivo avaliar quais hormônios vegetais estão envolvidos com a formação de vários caracteres anti-herbivoria em tomateiro, como densidade de tricomas e teor de aleloquímicos e inibidores de protease. Para tal, fez-se uso da um grande número de mutantes hormonais introgredidos na cultivar Micro-Tom (a qual apresenta diversas facilidades de trabalho como porte reduzido e rápido ciclo de vida). Demonstrou-se que, apesar do ácido jasmônico ser extremamente importante na formação de tais caracteres, outros hormônios também atuam fortemente em tal papel. Etileno, giberelinas e auxina alteram de forma indireta a densidade de tricomas em tomateiro, através de alteração na área de células epidérmicas. O ácido jasmônico é um forte regulador positivo da formação de tricomas, do aleloquímico zingibereno e da formação de inibidores de protease. De forma antagônica, brassinosteróides parecem controlar negativamente a densidade de tricomas, a produção de zingibereno e inibidores de protease. Interessantemente, observou-se que esse controle negativo efetuado por brassinosteróides acontece através de um controle na via do ácido jasmônico, o qual foi comprovado pela produção de duplos mutantes. Resultados obtidos em testes com o herbívoro polífago Spodoptera frugiperda e com a praga de tomate Tuta absoluta (traça-do-tomateiro), bem como de análise de expressão gênica comprovaram a importância do ácido jasmônico, brassinosteróides e sua interação na defesa a herbivoria. Os resultados aqui apresentados sugerem que o foco para futuros estudos da formação de mecanismos anti-herbivoria em tomateiro deve ser voltado não só para o ácido jasmônico como para brassinosteroides e para suas ações antagônicas. / Even though the cultivation of tomato has a high economical importance, this culture is classified as being of elevated risk because of it common infestation by pests and diseases. This problem makes this culture greatly dependent of the application of several agrochemicals, which leads to increase in cost of production, environmental damages and also facilitating the appearance of new pests and diseases. Looking carefully to the problem, it is possible to conclude that a great part of tomato losses are caused by herbivory-arthropods, which are capable of feeding of several parts of the plant, causing, generally, losses in the productivity. However, tomato has natural defense mechanisms against those pests, for example trichomes and allelochemicals, which act poisoning the arthropods, hindering their movement through the plant and/or altering steps of their development. The search for tomato genotypes with great density of trichomes and elevated levels of allelochemicals is nowadays being considered as a hot spot of research, because of the benefits it would provide (for example: a decrease in the cost of production and also a higher productivity). Although it is believed that many plant hormones are involved in the generation of anti-herbivory traits, a great focus has been given only to jasmonic acid because of it clear action in the formation of those traits, such as trichomes, allelochemicals, proteinase inhibitors and many others. The present work objective was to evaluate which hormones are involved in the formation of anti-herbivory traits such as trichome density and allelochemicals and proteinase inhibitors content. For this reason, we made use of several hormonal mutants already introgressed in the Micro-Tom cultivar (which presents benefits as small size and fast life cycle). It was showed that jasmonic acid is an important hormone in the formation of these traits, but other phytohormones also play important roles. Ethylene, gibberellins and auxin alters trichome density indirectly, by altering the area of epidermal cells and thus cell number. Jasmonic acid is a positive regulator of trichome formation, the allelochemicals zingiberene content and also in the formation of proteinase inhibitors. However, brassinosteroids acts by negatively controlling all of those. Interestingly, we observed that this negative control happens through the control of jasmonic acid pathway, a hormonal interaction that was proved by double-mutant analysis. Results obtained in tests with the polyphagous insect Spodoptera frugiperda and the tomato specific pest Tuta absoluta (tomato pinworm) and also with qPCR showed the importance of jasmonic acid, brassinosteroid and their interaction in herbivory defense. Our data suggest that future studies about the formation of antiherbivory traits should be analyzed by focusing the functions not only of jasmonic acid but also brassinosteroid and their antagonist functions.
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Habitat Characteristics Affecting Site Occupation in Wintering Henslow’s Sparrows at Mississippi Sandhill Crane National Wildlife RefugeNicholson, Mary E 17 December 2011 (has links)
Henslow’s sparrow (Ammodramus henslowii) winters in recently burned sites in pine savannas of the Southeastern United States. Previous studies have suggested that factors such as seed abundance and litter depth are important to wintering Henslow’s sparrows. My study asked how habitat variables including vegetation structure, seed abundance, and arthropod abundance predict Henslow’s sparrow site occupancy at Mississippi Sandhill Crane National Wildlife Refuge. In this study, Henslow’s sparrow more often occupied sites burned one growing season earlier than sites burned two growing seasons earlier, and did not occupy sites burned three or more growing seasons earlier. Data indicated that mass of graminoid seeds borne on stalks in November and minimum total seed mass were higher in occupied sites vs. unoccupied sites while litter density was lower. This suggests that Henslow’s sparrow selects habitats that may maximize foraging efficiency and probability of survival based on information about litter density and seed availability.
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MATHEMATICAL MODELLING OF SOIL DIVERSITY INDICES UNDER DIFFERENT USES AND MANAGEMENTSSILVA, Raimunda Alves 06 March 2017 (has links)
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Previous issue date: 2017-03-06 / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão / ABSTRACT: Soil is the habitat for a number of living organisms that perform essential
functions to the ecosystem. The present work aimed to determine the edaphic diversity in
large groups under different uses and management of the soil in Cerrado Biome. The study
was developed in the city of Mata Roma (3º 70 '80.88' 'S and 43º 18' 71.27 '' W), in the eastern
region of Maranhão state, Brazil. It were installed 130 pitfall traps in five areas with different
management (millet, soybean, maize, eucalyptus, and pasture) and two reference areas with
natural vegetation with different uses (anthropized Cerrado and preserved Cerrado). The traps
remained in the field for a period of seven days, after this, the contents were maintained in
plastic bottles and taken to the laboratory, where they were sampled and identified in large
groups (orders and family). After identification, the biodiversity indexes were determined:
(Shanon index, Pielou, Average and total richness and abundance). The data were analyzed
using descriptive statistics and multivariate techniques using group dissimilarity. The
geostatistical analysis was evaluated by a semivariogram, adjusted to a geostatistical,
spherical, gaussian or exponential model. The multifractality was analyzed by the current
method, in successive segments of different sizes of 2k
, k=0 a k= 7 in the range of q = +10 to
q = -10. 20,995 arthropods were collected throughout the study. The highest abundance was
found for millet (9,974 individuals), and the lowest abundance values were reported for
soybean (222) and maize (824), respectively. The highest biodiversity index is reported for
the soybean area (2.69), although there is less abundance, in this area, the groups are evenly
distributed due to the homogeneous management in the study area. The main axis in the
analysis of the main components (PCA) explained 50.9% of the correlation of the groups with
the sampled areas. The dendrogram had demonstrated that the area of soybean and maize are
similar and had isolated the area of millet with the most dissimilar in relation to the others.
The use and management of the soil in the study areas determine the occurrence of soil
arthropods in function of food availability. For the areas of millet, maize, eucalyptus,
anthropized Cerrado and pasture the Shanon diversity index obtained pure nugget effect. For
the areas of millet, maize, anthropized Cerrado and pasture, the total diversity index was
adjusted to the gaussian model. Only for the areas of soybean and pasture the staggered
semivariograms showed similarity in the spatial variability of indexes, indicating that they
behave similarly. The multifractality generated generalized dimension, D0, for all the indexes
in the millet area, with invariant values, D0 = 1.000 ± 0.000. The singularity spectra were
curves in concave parables with greater or smaller asymmetry for all areas sampled. In
general, the fauna of soil presented spatial variability and multifractal parameters. / ABSTRACT: Soil is the habitat for a number of living organisms that perform essential
functions to the ecosystem. The present work aimed to determine the edaphic diversity in
large groups under different uses and management of the soil in Cerrado Biome. The study
was developed in the city of Mata Roma (3º 70 '80.88' 'S and 43º 18' 71.27 '' W), in the eastern
region of the State of Maranhão, Brazil. Were installed 130 pitfall traps in five areas with
different management (Millet, Soybean, Maize, Eucalyptus, and Pasture) and two reference
areas with natural vegetation with different uses (anthropized Cerrado and preserved
Cerrado). The traps remained in the field for a period of seven days, after this, the contents
were maintained in plastic bottles and taken to the laboratory, where they were sampled and
identified in large groups (orders and family). After identification, the biodiversity indexes
were determined: (Shanon index, Pielou, Average and total richness and abundance). The data
were analyzed using descriptive statistics and multivariate techniques using group
dissimilarity. 20,995 arthropods were collected throughout the study. The highest abundance
was found for millet (9,974 individuals), and the lowest abundance values were reported for
soybean (222) and maize (824), respectively. The highest biodiversity index is reported for
the soybean area (2.69), although there is less abundance, in this area, the groups are evenly
distributed due to the homogeneous management in the study area. The main axis in the
analysis of the main components (PCA) explained 50.9% of the correlation of the groups with
the sampled areas. The dendrogram had demonstrated that the area of soybean and maize are
similar and had isolated the area of millet with the most dissimilar in relation to the others.
The use and management of the soil in the study areas determine the occurrence of soil
arthropods in function of food availability.
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Effects of Urbanization on Arthropod Diversity, Community Structure and Trophic DynamicsJanuary 2010 (has links)
abstract: Urban ecosystems cover less than 3% of the Earth's land surface, yet more than half of the human population lives in urban areas. The process of urbanization stresses biodiversity and other ecosystem functions within and far beyond the city. To understand the mechanisms underlying observed changes in biodiversity patterns, several observational and experimental studies were performed in the metropolitan area of Phoenix, Arizona, and the surrounding Sonoran Desert. The first study was comprised of seven years of arthropod monitoring using pitfall traps in common urban land-use types. This study revealed differences in community structure, diversity and abundance over time and between urban and wildland habitats. Urban habitats with high productivity had higher abundances of arthropods, but lower diversity compared to wildland habitats. Arthropod abundance in less-productive urban habitats was positively correlated with precipitation, but abundance in high-productivity urban habitats was completely decoupled from annual fluctuations in precipitation. This study showed the buffering capacity and the habitat heterogeneity of urban areas. To test the mechanisms controlling community diversity and structure in urban areas, a major field experiment was initiated. Productivity of the native shrub Encelia farinosa and bird predation of associated arthropods were manipulated to test whether bottom-up or top-down forces were more important in urban habitats compared to wildland habitats. Abundance, richness and similarity were monitored, revealing clear differences between urban and wildland habitats. An unusually cold and dry first season had a negative effect on plant growth and arthropod abundance. Plants in urban habitats were relatively unaffected by the low temperature. An increase in arthropod abundance with water availability indicated bottom-up forces in wildland habitats, whereas results from bird exclusions suggested that bird predation may not be as prominent in cities as previously thought. In contrast to the pitfall study, arthropod abundance was lower in urban habitats. A second field experiment testing the sheltering effect of urban structures demonstrated that reduced wind speed is an important factor facilitating plant growth in urban areas. A mathematical model incorporating wind, water and temperature demonstrated that urban habitats may be more robust than wildland habitats, supporting the empirical results. / Dissertation/Thesis / Ph.D. Biology 2010
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