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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.
11

Recursos pol?nicos utilizados por Melipona obscurior Moure e Apis mellifera Linnaeus na Mata Atl?ntica no sul do Brasil : subs?dios para o manejo de polinizadores e a conserva??o da biodiversidade

Hilgert-moreira, Suzane Both 21 August 2012 (has links)
Made available in DSpace on 2015-04-14T13:09:36Z (GMT). No. of bitstreams: 1 443848.pdf: 2283350 bytes, checksum: 7338583841980be045a273368e39341c (MD5) Previous issue date: 2012-08-21 / Commonly called stingless bee, species belonging to the tribe Meliponini are found in Brazil, predominantly in woods of Atlantic Forest. The growing degradation of this ecosystem results in risks to the conservation of these species. In this context is inserted Melipona obscurior Moure which is, nowadays, considered vulnerable to extinction in Rio Grande do Sul. Cohabiting in this same ecosystem one can be found Apis mellifera Linnaeus, whose rusticity allowed its spreading and fitness to different environments. Both species present perennial colonies with a big number of individuals that need food during all year. As is characteristic to social bees, they have generalist foraging behavior, making use of different flower sources to obtain pollen and nectar. Foraging activities are directly related to abiotic factors that interfere on fenology, on resources availability and on flight conditions for bees. With this, the floral resources are explored by both in a different way, in foraging strategies characteristics to each one. To identify the plants species whose pollinic resources compose the trophic niche of M. obscurior and A. mellifera, in southern Brazil, as well as the dynamic in the use of these resources, during one year of sampling, was the goal of this survey. For this study, two areas inserted into Atlantic Forest Biome, northeast Rio Grande do Sul, were used. Colonies of two species were maintained in standard hives and the pollinic resources used by them were collected, identified and analyzed. So, the number of pollinic sources used by A. mellifera was bigger in relation to M. obscurior, with representativeness in the samples that resulted in different trophic niche breadth indices, along the year. Some of these sources were explored more intensely or, yet, exclusively by one of bee species, as an indicative of temporal specialization behavior, mainly related to M. obscurior. The overlap in the use of some of these resources occurred in the most samples, but, in a diferente way. The most intense pollen sharing was related to plant species whose massive flowerings allowed concomitant use of their pollen. Here one emphasizes Eucalyptus spp. whose use in the pollinic diet was similar for both species, regardless of landscape characteristics of each area.The pollinic resources that compose the actual trophic niche of M. obscurior and A. mellifera and the dynamic of these resource partioning have, until now, allowed the coexistence of both in the two study sites. / Denominadas popularmente de abelhas sem ferr?o, as esp?cies pertencentes ? tribo Meliponini, s?o encontradas no Brasil predominantemente em florestas de Mata Atl?ntica. A crescente degrada??o deste ecossistema acarreta riscos ? conserva??o destas esp?cies. Neste contexto insere-se Melipona obscurior Moure a qual ? atualmente considerada como esp?cie vulner?vel ? extin??o no Rio Grande do Sul. Coabitando neste mesmo ecossistema, pode ser encontrada Apis mellifera Linnaeus, cuja rusticidade possibilitou sua dispers?o e adapta??o aos mais diversos ambientes. Ambas as esp?cies apresentam col?nias perenes com grande n?mero de indiv?duos, necessitando de alimento durante o ano todo. Como ? caracter?stico a abelhas sociais, possuem h?bito alimentar generalista, fazendo uso de diferentes fontes florais para obten??o de p?len e n?ctar. As atividades de forrageio est?o diretamente relacionadas aos fatores abi?ticos que interferem na fenologia, na disponibilidade dos recursos e nas condi??es de voo das abelhas. Com isso, os recursos florais s?o explorados de modo diferenciado por ambas, em estrat?gias de forrageio caracter?sticas a cada uma delas. Identificar as esp?cies vegetais cujos recursos pol?nicos comp?em o nicho tr?fico de M. obscurior e A. mellifera, no sul do Brasil, bem como a din?mica na utiliza??o destes recursos, ao longo de um ano de amostragens, foi o objetivo central deste trabalho. Para tal, utilizou-se como local de estudo duas ?reas inseridas no Bioma Mata Atl?ntica, na regi?o nordeste do estado do Rio Grande do Sul. Col?nias das duas esp?cies de abelhas foram mantidas em colmeias padronizadas e os recursos pol?nicos utilizados por elas foram coletados, identificados e analisados. Assim, o n?mero de fontes pol?nicas utilizadas por A. mellifera foi maior em rela??o ? M. obscurior, com representatividades nas amostras que resultaram em diferentes ?ndices de amplitude de nicho tr?fico ao longo do ano. Algumas destas fontes foram exploradas mais intensamente ou, ainda, exclusivamente por apenas uma das esp?cies de abelhas, indicativo de um comportamento de especializa??o temporal principalmente em rela??o ? M. obscurior. A sobreposi??o no uso de alguns destes recursos ocorreu na maioria das amostras, mas, de modo diferenciado. O compartilhamento mais intenso de p?len foi relacionado ?s esp?cies vegetais cujas flora??es maci?as permitiram o uso concomitante de seu p?len. Aqui se destaca Eucalyptus spp., cujo aproveitamento na dieta pol?nica foi semelhante para ambas as esp?cies, independente das caracter?sticas da paisagem de cada ?rea. Os recursos pol?nicos que comp?em o atual nicho tr?fico de M. obscurior e A. mellifera e a din?mica na parti??o destes recursos t?m, at? ent?o, permitido a coexist?ncia de ambas nos dois locais de estudo.

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