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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nidificação de abelhas e vespas solitárias e biologia reprodutiva de Megachile dentipes Vachal (Hymenoptera, Megachilidae) em ninhos-armadilha

Santos, Adauto Alex dos 25 February 2011 (has links)
Made available in DSpace on 2015-04-17T14:55:16Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1302187 bytes, checksum: c5e711d7d5aae70cd68adbb071c9becf (MD5) Previous issue date: 2011-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Terrestrial ecosystems, solitary bees and wasps play important roles as pollinators, predators and parasites. Most part of the life of these Hymenoptera is designed to aspects related to nesting, including the search of the nest site, nest construction and food collection to rear the larvae. However, in natural environments the nests of these insects are difficult to find. A solution to this problem, at least for some species, is the use of artificial burrows in the field (trap nests). Using trap nests it is possible to collect standardized samples and to study the biology of some species. Thus, the community of solitary bees and wasps, nesting in trap nests was evaluated using parameters such as richness, diversity and nest abundance in two different agroecosystems of the state of Pernambuco, northeastern Brazil: sugarcane monoculture and polyculture. Moreover, the natural history and nesting biology of a bee species (Megachile dentipes) collected in the trap nests was studied. In this study, the main aspects of life history (seasonality, diameter of the nests, sex ratio, parasitism, development time) and nesting biology (nest architecture, nesting behavior, larval diet) was studied. Insects were sampled using the technique of trap nests, which consisted of 1) cardboard tubes inserted into blocks of wood of different diameters (4, 6, 8 and 10 mm), and 2) wooden planks, drilled lengthwise (5, 6, 8, 10 and 12 mm in diameter) and covered with a transparent plastic sheet (observation-nests). In each agroecosystem 3.360 cardboard tubes were available for nesting during one year (June/2009 to May/2010) and 1000 holes of observationnests during five months (October/2009 to February/2010). In the monoculture a total of 259 nests, 86 (33.2%) build by bees and 173 (66.8%) by wasps were sampled. Five species of bees were sampled, and Megachile dentipes was the most abundant bee species in the sugarcane (n = 76; 85%). In the polyculture area, 411 nests were collected, being 254 (61.8%) of bees and 157 (38.2%) of wasps. In this environment, 14 spp. nesting bee species were recorded. The leaf-cutter bee Megachile dentipes was also the most abundant (n = 117 nests, 46%). The abundance of bee nests, species richness and diversity of bees and wasps was significantly higher in the polyculture area compared to monoculture area. It is suggested that plant richness is a determining factor in the occurrence of the species. However, other factors such as distance from forest fragments and the use of herbicides and burning, might have influence in the low richness and diversity of bees and wasps in the area with sugarcane monoculture. Regarding Megachile dentipes it was shown that it is an polilectic species, collecting pollen from a wide spectrum pollen from mainly five botanical families: Asteraceae, Rubiaceae, Euphorbiaceae, Mimosaceae and Scrophulariaceae. This species showed a clear preference for nesting in the dry periods of the year in both studied areas, with peaks in October and December. Furthermore, this species had several generations throughout the year (multivoltine). It was demonstrated experimentally that recognition of the cavities by females is determined by the nest position in the blocks. Probably, chemical signals (marking the cavity) are not used, at least in the initial recognition of the nests. Nest structure of M. dentipes differs from most species because the lining of the brood cell is made from chewed leaves unlike the other species that involve the brood cells with whole leaves not chewed.. Biological and ecological characteristics of M. dentipes, as e.g. abundance and poliletia, makes this species a good candidate for management programs aimed at pollination, but further studies are necessary for that purpose. / Nos ecossistemas terrestres, abelhas e vespas solitárias desempenham essenciais papéis como polinizadores, predadores e parasitas. Grande parte da vida das fêmeas desses himenopteros é destinada à nidificação, como busca pelo local do ninho, construção do ninho e coleta do alimento larval. Contudo, os ninhos desses insetos em ambientes naturais são difíceis de serem encontrados. Uma solução para este problema, pelo menos para algumas espécies, é a utilização de cavidades artificiais no campo (ninhosarmadilha), uma vez que amostragens dos ninhos podem ser realizadas de forma padronizada em diferentes ambientes, além de fornecerem dados acerca da biologia das espécies capturadas. Diante disso, a comunidade de abelhas e vespas solitárias nidificantes em ninhos armadilha foi avaliada a partir de parâmetros como riqueza, diversidade e abundância de ninhos em dois agroecossistemas em Pernambuco: monocultura canavieira e sistema de policultura. Além disso, foi estudada a história natural e biologia de nidificação da espécie de abelha (Megachile dentipes) mais abundante nos ninhos-armadilha. Neste estudo foram avaliados os principais aspectos relacionados à história de vida (sazonalidade, razão sexual, parasitismo, tempo de desenvolvimento) e biologia de nidificação (arquitetura do ninho, comportamento de nidificação, dieta larval) de M. dentipes. Os insetos foram amostrados através da técnica de ninhos-armadilha, que consistiu de 1) tubos de cartolina inseridos em blocos de madeira de diferentes diâmetros (4, 6, 8 e 10 mm), e 2) pranchas de madeira, perfuradas longitudinalmente (5, 6, 8, 10 e 12 mm de diâmetro), cobertas com uma lâmina plástica transparente (ninhos-observação). Em cada agroecossistema estudado, foram disponibilizados para nidificação 3.360 tubos de cartolina ao longo de um ano (junho/2009 a maio/2010), e 1.000 cavidades de ninhos-observação durante cinco meses (outubro/2009 a fevereiro/2010). Um total de 259 ninhos, sendo 86 (33,2%) de abelhas e 173 (66,8%) de vespas foi coletado nas armadilhas instaladas na monocultura. Foram amostradas 5 espécies de abelhas, dentre elas, Megachile dentipes, a espécie de abelha mais abundante no canavial (n=76; 85%). Na área com policultura, foram coletados 411 ninhos, sendo 254 (61,8%) de abelhas e 157 (38,2%) de vespas. Neste ambiente, foram registradas 14 spp. de abelhas nidificantes ninhos armadilha. Mais uma vez, a espécie de abelha corta folha Megachile dentipes foi a mais abundante em número de ninhos (n=117; 46%). A abundância de ninhos de abelhas e a riqueza e diversidade de espécies de abelhas e vespas nidificantes em ninhos-armadilha foi significativamente maior em área de policultura quando comparada à monocultura canavieira. É sugerido que a riqueza florística de cada área seja um fator determinante na ocorrência das espécies. Contudo, fatores como a distância de fragmentos de mata e a utilização de herbicidas e queimadas, podem ter colaborado para uma baixa riqueza e diversidade de abelhas e vespas na área com monocultura canavieira. Quanto à espécie Megachile dentipes, observou-se que trata-se de uma espécie polilética, que coleta pólen de um amplo espectro polínico envolvendo, principalmente, cinco famílias botânicas: Asteraceae, Rubiaceae, Euphorbiaceae, Mimosaceae e Scrophulariaceae. Esta espécie mostrou uma clara preferência em fundar ninhos nos períodos mais secos do ano, em ambas as áreas estudadas, com picos de nidificação em outubro e dezembro. Além disso, apresentou várias gerações ao longo do ano (multivoltina). Foi demonstrado experimentalmente que o reconhecimento das cavidades pelas fêmeas baseia-se na posição em que o orifício se encontra no bloco de ninhos-armadilha. Provavelmente, não estão envolvidos sinais químicos (marcação da cavidade) ao menos no reconhecimento inicial dos ninhos. A estrutura do ninho de M. dentipes difere da maioria das espécies descritas até o momento, pois o revestimento da célula de cria é feito com folhas trituradas (manipuladas), diferentemente das demais espécies que envolvem as células de cria com folhas inteiras não trituradas. Características biológicas e ecológicas de M. dentipes, como e.g. abundância e polilectia, tornam esta espécie uma boa candidata a programas de manejo visando a polinização, embora sejam necessários mais estudos direcionados a essa finalidade.
2

Evaluating Standard Wet Chemistry Techniques and NIR Spectroscopic Models for Determining Composition and Potential Ethanol Yields of Multi-Species Herbaceous Bioenergy Crops

Monona, Ewumbua Menyoli January 2011 (has links)
Herbaceous perennials represent a considerable portion of potential biomass feedstocks available for the growing bioenergy industry. Their chemical composition and biomass yields, which are important in determining ethanol potential on an area and mass basis, vary with plant variety and type, environment, and management practices. Therefore, a study was conducted to assess the variability of lignin and carbohydrate content, biomass yields, and theoretical ethanol yields on an area basis among different herbaceous perennial species combinations grown in Minot (2008) and Williston (2008, 2009, and 2010), North Dakota (ND). After wet chemistry compositional analysis was done, the carbohydrate contents were used to determine theoretical ethanol potential on a mass basis. Using the dry-matter yield, the theoretical ethanol yield on an area basis was also calculated for these biomass species. Total carbohydrate content for the biomass samples in Williston and Minot varied from 45 to 61% dry basis. Analysis of Variance (ANOVA) at a= 0.05 showed that carbohydrate content varied between years and environments. Also an interaction plot shows that no biomass species had consistently higher or lower carbohydrate content in the different environments. Switchgrass (Panicum vigatum L.) grown as single species or together with other perennial grasses had higher dry-matter yield and theoretical ethanol yield potential in Williston irrigated plots while mixtures containing intermediate or tall wheatgrass species (Thinopyrum spp.) produced better yields in Minot non-irrigated plots. Variability in theoretical ethanol yield on a mass basis (3.7% coefficient of variation (CV) in Williston and 9.7% CV in Minot) was much less than the variability in dry-matter yields (27.5% CV in Williston and 14.8% CV Minot). Therefore, biomass production is much more important than composition in choosing species to grow for ethanol production. Recently, many studies have focused on developing faster methods to determine biomass composition using near infrared (NIR) spectroscopy. Other NIR models have been developed on single biomass feedstocks but a broad-based model for mixed herbaceous perennials is yet to be developed. Therefore, NIR calibration models for lignin, glucan, and xylan were developed with 65 mixed herbaceous perennial species using a DA 7200 NIR spectrometer (950 - 1,650 nm) and GRAMS statistical software. The models for lignin and xylan had R(2) values of 0.844 and 0.872, respectively, upon validation and are classified as good for quality assurance purposes while glucan model had an R(2) of 0.81 which is considered sufficient for screening. The R(2) and the root mean square error of prediction (RMSEP) results showed that it is possible to develop calibration models to predict chemical composition for mixed perennial biomass when compared with results for models developed for single feedstock by Wolfrum and Sluiter (2009) and Liu et al. (2010). Studying the variability in predicting constituents using NIR spectroscopy over time (hours and days), it was observed that the average CV was between 1.4 to 1.6%. The average CV due to repacking (presentation) alone was 1.3%. The CVs for NIR predictions ranged between 1.4 to 5.7% while for wet chemistry ranged between 3.8 to 13.5%; hence, NIR predictions were more precise than wet chemistry analysis.
3

Tentativas de purificação e produção de antissoro contra  o vírus da morte súbita dos citros e isolamento do CSDaV em plantas herbáceas / Attempts to purify and produce antiserum against the citrus sudden death associated virus and CSDaV isolation in herbaceous plants

Santos, Mateus de Almeida 26 August 2011 (has links)
A morte súbita dos citros (MSC) foi identificada em 2001, no município de Comendador Gomes, Minas Gerais, e desde então foi responsável pela perda de 4 milhões de plantas na região sul do Triângulo Mineiro, e no norte e noroeste do estado de São Paulo. É uma doença de combinação copa/porta-enxerto, afetando principalmente laranjeira doce enxertada em limoeiro Cravo, e que culmina na morte das plantas. Passados dez anos do seu relato, até hoje não se tem conhecimento exato do agente causal e dos possíveis vetores. Sabe-se, todavia, que em todas as plantas com morte súbita encontram-se o vírus da tristeza dos citros (Citrus tristeza virus - CTV) e um vírus do Gênero Marafivirus, Família Tymoviridae, denominado Citrus sudden death associated virus (CSDaV). Devido esse fato, há a necessidade de separá-los para testar os postulados de Koch para o CSDaV. O principal objetivo deste trabalho foi tentar isolar o CSDaV para verificar o seu real envolvimento com a MSC. Também se procurou purificar esse vírus para a produção de antissoro policlonal para trabalhos de diagnose da doença. Para a purificação do CSDaV foi utilizado o protocolo de purificação do Potato leaf roll virus, porém os resultados não foram satisfatórios devido a constante presença do CTV. Tentativas de remoção do CTV por meio de imunoprecipitação com antissoro homólogo não foram satisfatórias. O antissoro produzido reagiu indistintamente com extratos de plantas infectadas com o CSDaV e o CTV. O CSDaV foi transmitido mecanicamente para plantas de Nicotiana sp., N. clevelandii, Chenopodium amaranticolor e C. quinoa, causando principalmente infecção localizada. A presença do vírus foi confirmada por RT-PCR e a sua identidade por meio do sequenciamento de nucleotídeos do produto da amplificação. Tentativas de transmissão do CSDaV usando inóculo de extrato de folhas de plantas do campo , por meio da Cuscuta sp., através de cortes no tronco das plantas com lâmina embebida no inóculo, com pulgões Toxoptera citricida aparentemente virulíferos somente para o tymovirus e por meio da inoculação de sementes de citros deram resultados negativos. / Citrus sudden death (CSD) disease was identified in 2001, at Comendador Comes County, State of Minas Gerais, Brazil. Since then the disease has caused the death of 4 million trees in Southwestern Minas Gerais State and Northern São Paulo State. This new and destructive disease affects sweet orange as well as other species, varieties, and hybrids when grafted on Rangpur (Citrus limonia). Then years after the first report on CSD, the causal agent and possible vector(s) have not been precisely identified. It is known, however, that all disease trees are infected with Citrus tristeza virus (CTV) and Citrus sudden death associate virus (CSDaV), which is a member of the Genus Marafivirus, Famíly Tymoviridae. Due to this, it is necessary to separate these pathogens, in order to complete Kochs postulated for the CSDaV. The main purpose of the present work was to try to isolate the CSDaV to verify its role on CSD disease. In addition, attempts were done to purify the virus and produce polyclonal antiserum for disease diagnosis. Purification was carried out as described for Potato leaf roll virus, but results were not suitable due to the constant presence of CTV. Efforts to remove CTV by immunoprecipitation with homologous antiserum did not succeed. The produced antiserum reacted indistinctly with extracts of plants infected with both viruses. SCDaV was mechanically transmitted to Nicotiana sp., N. clevelandii, Chenopodium amaranticolor, and C. quinoa, causing mainly local infection. Infection was confirmed by RT-PCR and virus identity was determined by nucleotide sequence of the amplified fragment. Efforts to transmit CSDaV, using as inoculum extract from field infected plants, by means of Cucucuta sp., by incisions on the trunk of the test-plants, with Toxoptera citricida apparently viruliferous only for the tymovirus, and by means of citrus seed inoculation gave negative results.
4

Tentativas de purificação e produção de antissoro contra  o vírus da morte súbita dos citros e isolamento do CSDaV em plantas herbáceas / Attempts to purify and produce antiserum against the citrus sudden death associated virus and CSDaV isolation in herbaceous plants

Mateus de Almeida Santos 26 August 2011 (has links)
A morte súbita dos citros (MSC) foi identificada em 2001, no município de Comendador Gomes, Minas Gerais, e desde então foi responsável pela perda de 4 milhões de plantas na região sul do Triângulo Mineiro, e no norte e noroeste do estado de São Paulo. É uma doença de combinação copa/porta-enxerto, afetando principalmente laranjeira doce enxertada em limoeiro Cravo, e que culmina na morte das plantas. Passados dez anos do seu relato, até hoje não se tem conhecimento exato do agente causal e dos possíveis vetores. Sabe-se, todavia, que em todas as plantas com morte súbita encontram-se o vírus da tristeza dos citros (Citrus tristeza virus - CTV) e um vírus do Gênero Marafivirus, Família Tymoviridae, denominado Citrus sudden death associated virus (CSDaV). Devido esse fato, há a necessidade de separá-los para testar os postulados de Koch para o CSDaV. O principal objetivo deste trabalho foi tentar isolar o CSDaV para verificar o seu real envolvimento com a MSC. Também se procurou purificar esse vírus para a produção de antissoro policlonal para trabalhos de diagnose da doença. Para a purificação do CSDaV foi utilizado o protocolo de purificação do Potato leaf roll virus, porém os resultados não foram satisfatórios devido a constante presença do CTV. Tentativas de remoção do CTV por meio de imunoprecipitação com antissoro homólogo não foram satisfatórias. O antissoro produzido reagiu indistintamente com extratos de plantas infectadas com o CSDaV e o CTV. O CSDaV foi transmitido mecanicamente para plantas de Nicotiana sp., N. clevelandii, Chenopodium amaranticolor e C. quinoa, causando principalmente infecção localizada. A presença do vírus foi confirmada por RT-PCR e a sua identidade por meio do sequenciamento de nucleotídeos do produto da amplificação. Tentativas de transmissão do CSDaV usando inóculo de extrato de folhas de plantas do campo , por meio da Cuscuta sp., através de cortes no tronco das plantas com lâmina embebida no inóculo, com pulgões Toxoptera citricida aparentemente virulíferos somente para o tymovirus e por meio da inoculação de sementes de citros deram resultados negativos. / Citrus sudden death (CSD) disease was identified in 2001, at Comendador Comes County, State of Minas Gerais, Brazil. Since then the disease has caused the death of 4 million trees in Southwestern Minas Gerais State and Northern São Paulo State. This new and destructive disease affects sweet orange as well as other species, varieties, and hybrids when grafted on Rangpur (Citrus limonia). Then years after the first report on CSD, the causal agent and possible vector(s) have not been precisely identified. It is known, however, that all disease trees are infected with Citrus tristeza virus (CTV) and Citrus sudden death associate virus (CSDaV), which is a member of the Genus Marafivirus, Famíly Tymoviridae. Due to this, it is necessary to separate these pathogens, in order to complete Kochs postulated for the CSDaV. The main purpose of the present work was to try to isolate the CSDaV to verify its role on CSD disease. In addition, attempts were done to purify the virus and produce polyclonal antiserum for disease diagnosis. Purification was carried out as described for Potato leaf roll virus, but results were not suitable due to the constant presence of CTV. Efforts to remove CTV by immunoprecipitation with homologous antiserum did not succeed. The produced antiserum reacted indistinctly with extracts of plants infected with both viruses. SCDaV was mechanically transmitted to Nicotiana sp., N. clevelandii, Chenopodium amaranticolor, and C. quinoa, causing mainly local infection. Infection was confirmed by RT-PCR and virus identity was determined by nucleotide sequence of the amplified fragment. Efforts to transmit CSDaV, using as inoculum extract from field infected plants, by means of Cucucuta sp., by incisions on the trunk of the test-plants, with Toxoptera citricida apparently viruliferous only for the tymovirus, and by means of citrus seed inoculation gave negative results.
5

Betydelsen av urbana bostadsgårdars ålder för dess artrikedom av inhemska örtartade växter och förekomst av fåglar / The importance of age of urban residential yards for the species richness of native herbs and of birds

Grimlycke, Anna January 2023 (has links)
Life on Earth is currently experiencing a sixth species extinction, where urbanization, as one of the main driving forces, fragments and causes losses of near-urban habitats. At the same time, a rich variety of habitats can be found in urban landscapes that may harbour biodiversity. Knowledge of how urban ecosystems develops over time is fundamental for application of relevant nature conservation measures that promote species richness. This study aims to shed light on the importance of age in urban residential yards for the species richness of native herbaceous plants and of birds. The study was carried out in Linköping during the summer of 2023, and it included surveys of native herbaceous plants and birds in three area types (natural area, old and young residential yards). In total, 114 species of native herbs and 34 species of birds were found. Sites in the natural area had (mean ± SE) 25,8 (± 1,8) and 6,6 (± 0,7) species of plants and birds respectively, whereas the corresponding values for old residential yards were 23,2 (± 1,2) and 5,7 (± 0,5) and for young residential yards 19,9 (± 1,3) and 3,3 (± 0,7). Jaccard's coefficient showed that the largest proportion of shared species occurred between ‘old’ and 'young' residential yards. Overall, the results of my study showed some support for my prediction that age of residential yards is important for species richness of native herbaceous plants and birds. The results indicate that urban environments (old and young residential yards) harbour a selection of species that can withstand anthropogenic disturbance. / Livet på jorden upplever ett sjätte artutdöende där urbaniseringen, som en av de främsta drivkrafterna, fragmenterar och orsakar förluster av stadsnära habitat. Samtidigt finns en rik variation av livsmiljöer i stadslandskap som hyser en biologisk mångfald. Kunskap om hur urbana ekosystem utvecklas över tid är grundläggande för tillämpning av relevanta naturvårdsåtgärder i staden som främjar artrikedom. Denna studie syftar till att belysa betydelsen av urbana bostadsgårdars ålder för artrikedomen hos inhemska örtartade växter och fåglar. Studien genomfördes i Linköping under sommaren 2023 och omfattade inventeringar av inhemska örtartade växter och fåglar i tre områdestyper (naturområde, äldre och unga bostadsgårdar). Totalt hittades 114 arter av inhemska örter och 34 arter av fåglar. Naturområdet hade (medelvärde ± SE) 25,8 (± 1,8) respektive 6,6 (± 0,7) arter av växter och fåglar, medan motsvarande värden för äldre bostadsgårdar var 23,2 (± 1,2) och 5,7 (± 0,5) och för unga bostadsgårdar 19,9 (± 1,3) och 3,3 (± 0,7). Jaccards koefficient visade att den största andelen överlappande arter förekom mellan ’äldre’ och ’unga’ bostadsgårdar. Sammantaget visade resultaten av min studie ett visst stöd för min förutsägelse att bostadsgårdarnas ålder är av betydelse för artrikedomen hos inhemska örtartade växter och fåglar. Resultaten tyder på att stadsmiljöer (äldre och unga bostadsgårdar) hyser ett urval av arter som tål antropogena, av människan orsakade, störningar.
6

Vegetation dynamics and the efficacy of prescribed fires in restoring oak-dominated ecosystems in southern Ohio

Petersen, Sheryl M. 31 January 2012 (has links)
No description available.

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