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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

Geographic variation in behaviour and dim light adaptation in Cyrba algerina (Araneae, Salticidae)

Cerveira, Ana M. January 2007 (has links)
Cyrba algerina is a salticid (Salticidae) spider that lives on the undersides of stones. Two populations were studied, Sintra and Algarve (Portugal), and shown to have similar phenology but different dominant prey. Life cycle in the laboratory was similar for the two populations, but Sintra matured at larger size than Algarve individuals, with these differences potentially having a genetic basis. Sintra individuals used prey-specific prey-capture behaviour against allopatric (Oecobius amboseli) and sympatric (O. machadoi, Trachyzelotes bardiae) spider and insect (bristletails) species. In contrast, Algarve C. algerina only adopted specialised capture behaviour against bristletails. Sintra, but not Algarve, individuals responded to the odour of O. machadoi and T. bardiae, and showed preference for T. bardiae over O. machadoi. Interpopulation variation in the use of specific prey-capture behaviour and in sensitivity to odour cues from prey is directly related to the prey available to individuals from each population, suggesting local adaptation to local prey. Preference for oecobiids seems to be controlled by an experiencetriggered developmental switch. The optics and histology of C. algerina’s principal eye suggest that living in a microhabitat with dim ambient light has favoured sensitivity at the expense of spatial acuity. Short focal length, reduced power of the eye’s diverging lens, and wide, contiguous rhabdomeres, seem to minimise the visual constraints imposed by the low light levels in C. algerina’s microhabitat. While relying solely on vision, C. algerina can detect, identify and capture prey in dim-light conditions under which other salticids perform poorly. C. algerina’s behaviour suggest use of temporal summation to improve its visual performance in dim light.
2

Geographic variation in behaviour and dim light adaptation in Cyrba algerina (Araneae, Salticidae)

Cerveira, Ana M. January 2007 (has links)
Cyrba algerina is a salticid (Salticidae) spider that lives on the undersides of stones. Two populations were studied, Sintra and Algarve (Portugal), and shown to have similar phenology but different dominant prey. Life cycle in the laboratory was similar for the two populations, but Sintra matured at larger size than Algarve individuals, with these differences potentially having a genetic basis. Sintra individuals used prey-specific prey-capture behaviour against allopatric (Oecobius amboseli) and sympatric (O. machadoi, Trachyzelotes bardiae) spider and insect (bristletails) species. In contrast, Algarve C. algerina only adopted specialised capture behaviour against bristletails. Sintra, but not Algarve, individuals responded to the odour of O. machadoi and T. bardiae, and showed preference for T. bardiae over O. machadoi. Interpopulation variation in the use of specific prey-capture behaviour and in sensitivity to odour cues from prey is directly related to the prey available to individuals from each population, suggesting local adaptation to local prey. Preference for oecobiids seems to be controlled by an experiencetriggered developmental switch. The optics and histology of C. algerina’s principal eye suggest that living in a microhabitat with dim ambient light has favoured sensitivity at the expense of spatial acuity. Short focal length, reduced power of the eye’s diverging lens, and wide, contiguous rhabdomeres, seem to minimise the visual constraints imposed by the low light levels in C. algerina’s microhabitat. While relying solely on vision, C. algerina can detect, identify and capture prey in dim-light conditions under which other salticids perform poorly. C. algerina’s behaviour suggest use of temporal summation to improve its visual performance in dim light.
3

Ecologia alimentar da toninha Pontoporia blainvillei (Cetacea) / Feeding ecology of franciscana dolphin Pontoporia blainvillei (Cetacea)

Barbara Henning Silva 20 December 2011 (has links)
Originalmente, a teoria de nicho ecológico fundamenta-se em indivíduos de uma espécie sendo ecologicamente equivalentes por utilizarem os recursos de forma similar. Portanto, o nicho de uma espécie é definido em termos do uso médio de recursos. Porém, a qualidade e abundância de recursos consumidos, sexo, idade ou morfotipo do consumidor influenciam o comportamento alimentar individual. Estudos recentes sobre forrageamento ótimo tem foco de interesse na variação interindividual no uso de recursos. Ao longo da sua área de distribuição são reconhecidas populações da toninha Pontoporia blainvillei (Cetacea) e no litoral paulista, possivelmente hajam três subpopulações dessa espécie: norte, centro e sul. Meu primeiro objetivo foi investigar se há variação na dieta entre essas três subpopulações de toninha. Adicionalmente, investiguei quais fatores entre sazonalidade, sexo e idade dos indivíduos poderiam estruturar a dieta em uma dessas subpopulações (central). Utilizei 58 indivíduos provenientes de captura acidental no litoral paulista, com representantes das regiões norte, centro e sul. A amostra incluiu juvenis e adultos de ambos os sexos, capturados em todas as estações do ano. Identifiquei as espécies nos conteúdos estomacais usando os otólitos de peixes e os bicos de lulas. Estimei o tamanho das presas utilizando regressões com as medidas dessas estruturas e investiguei a estruturação da dieta usando um índice de variação da dieta. Houve uma clara variação na dieta ente as subpopulações paulistas, possivelmente devido à diferença espacial na disponibilidade de presas. Para a subpopulação central não houve variação na dieta decorrente da sazonalidade ou do sexo. A ausência de variação sazonal pode ser devido à pouca alteração na abundância da principal presa, P. harroweri, no ambiente ao longo do ano. A ausência de variação decorrente do sexo pode ser devido a seleção de presa estar mais relacionada a características de corpo mole e fácil digestão e não ao tamanho da presa, sendo essa seleção comum para ambos os sexos. Indivíduos de idades diferentes possuem dietas distintas, com juvenis consumindo mais espécies que os adultos. Essa mudança de nicho alimentar pode ser devida ao período de aprendizado. Finalmente, mesmo descontando os efeitos da disponibilidade temporal e espacial de presas, do sexo e da idade, houve variação interindividual da dieta na subpopulação central. Somente estudos com marcadores isotópicos poderão investigar se essa variação é devida à especialização individual em toninhas / Ecological niche theory is originally based on the assumption that individuals of a species use similar resources and therefore are ecologically equivalents. Under this framework, the niche of the species can be defined in terms of average resource use. However, factors such as quality and quantity of prey resources in the environment, consumer gender, age or morphotype may influence the individual feeding behavior. Considering that possible interindividual variation, recently studies under optimal foraging theory have variation among individuals as a focus of interest. The species P. blainvillei is partionated in populations along its range and probably, subpopulations can be found in the Sao Paulo state coast: northern, central and southern. Hence, my first goal was to investigate if there is diet variation among the three franciscana subpopulations from Sao Paulo coast. Additionally, I searched for which factors would be the diet structure defined within one of the subpopulations (the central one). I have considered the seasonality, individual gender and sex as possible factors influencing the diet structure within the central subpopulation. I had 58 franciscana specimens obtained from bycatch in the Sao Paulo coast, being them from northern, central and southern regions. They were juveniles and adults of both genders and bycaught in all the seasons. I identified the prey species from the gut contents with fish otholits and squid beaks. I estimated prey length and weight using regressions with that structures measures and I investigated the diet structure using a diet variation index. Within the central subpopulation I found no diet variation based on seasonality or individual gender, instead I found diet variation for individuals from different ages. Probably, most of the diet variation among subpopulations is due to prey availability spatial difference. The lack of diet variation based on seasonality may be due to little seasonal variation in the abundance of the main prey, P. harroweri. The lack of variation due to gender is probably related to the prey selection on soft body and easy digestion instead of prey size, being this type of selection common for both genders. Juveniles franciscana preyed on more species than the adults and that niche shift as an age effect can be consequence of forraging skills development. Enclosing, even discarding the effects of the spacial and temporal prey availability, individual gender and age, I found interindividual-level diet variation within the central subpopulation, which can points out to franciscana individual specialization, but isotopic studies are required to infer that specialization
4

Ecologia alimentar da toninha Pontoporia blainvillei (Cetacea) / Feeding ecology of franciscana dolphin Pontoporia blainvillei (Cetacea)

Silva, Barbara Henning 20 December 2011 (has links)
Originalmente, a teoria de nicho ecológico fundamenta-se em indivíduos de uma espécie sendo ecologicamente equivalentes por utilizarem os recursos de forma similar. Portanto, o nicho de uma espécie é definido em termos do uso médio de recursos. Porém, a qualidade e abundância de recursos consumidos, sexo, idade ou morfotipo do consumidor influenciam o comportamento alimentar individual. Estudos recentes sobre forrageamento ótimo tem foco de interesse na variação interindividual no uso de recursos. Ao longo da sua área de distribuição são reconhecidas populações da toninha Pontoporia blainvillei (Cetacea) e no litoral paulista, possivelmente hajam três subpopulações dessa espécie: norte, centro e sul. Meu primeiro objetivo foi investigar se há variação na dieta entre essas três subpopulações de toninha. Adicionalmente, investiguei quais fatores entre sazonalidade, sexo e idade dos indivíduos poderiam estruturar a dieta em uma dessas subpopulações (central). Utilizei 58 indivíduos provenientes de captura acidental no litoral paulista, com representantes das regiões norte, centro e sul. A amostra incluiu juvenis e adultos de ambos os sexos, capturados em todas as estações do ano. Identifiquei as espécies nos conteúdos estomacais usando os otólitos de peixes e os bicos de lulas. Estimei o tamanho das presas utilizando regressões com as medidas dessas estruturas e investiguei a estruturação da dieta usando um índice de variação da dieta. Houve uma clara variação na dieta ente as subpopulações paulistas, possivelmente devido à diferença espacial na disponibilidade de presas. Para a subpopulação central não houve variação na dieta decorrente da sazonalidade ou do sexo. A ausência de variação sazonal pode ser devido à pouca alteração na abundância da principal presa, P. harroweri, no ambiente ao longo do ano. A ausência de variação decorrente do sexo pode ser devido a seleção de presa estar mais relacionada a características de corpo mole e fácil digestão e não ao tamanho da presa, sendo essa seleção comum para ambos os sexos. Indivíduos de idades diferentes possuem dietas distintas, com juvenis consumindo mais espécies que os adultos. Essa mudança de nicho alimentar pode ser devida ao período de aprendizado. Finalmente, mesmo descontando os efeitos da disponibilidade temporal e espacial de presas, do sexo e da idade, houve variação interindividual da dieta na subpopulação central. Somente estudos com marcadores isotópicos poderão investigar se essa variação é devida à especialização individual em toninhas / Ecological niche theory is originally based on the assumption that individuals of a species use similar resources and therefore are ecologically equivalents. Under this framework, the niche of the species can be defined in terms of average resource use. However, factors such as quality and quantity of prey resources in the environment, consumer gender, age or morphotype may influence the individual feeding behavior. Considering that possible interindividual variation, recently studies under optimal foraging theory have variation among individuals as a focus of interest. The species P. blainvillei is partionated in populations along its range and probably, subpopulations can be found in the Sao Paulo state coast: northern, central and southern. Hence, my first goal was to investigate if there is diet variation among the three franciscana subpopulations from Sao Paulo coast. Additionally, I searched for which factors would be the diet structure defined within one of the subpopulations (the central one). I have considered the seasonality, individual gender and sex as possible factors influencing the diet structure within the central subpopulation. I had 58 franciscana specimens obtained from bycatch in the Sao Paulo coast, being them from northern, central and southern regions. They were juveniles and adults of both genders and bycaught in all the seasons. I identified the prey species from the gut contents with fish otholits and squid beaks. I estimated prey length and weight using regressions with that structures measures and I investigated the diet structure using a diet variation index. Within the central subpopulation I found no diet variation based on seasonality or individual gender, instead I found diet variation for individuals from different ages. Probably, most of the diet variation among subpopulations is due to prey availability spatial difference. The lack of diet variation based on seasonality may be due to little seasonal variation in the abundance of the main prey, P. harroweri. The lack of variation due to gender is probably related to the prey selection on soft body and easy digestion instead of prey size, being this type of selection common for both genders. Juveniles franciscana preyed on more species than the adults and that niche shift as an age effect can be consequence of forraging skills development. Enclosing, even discarding the effects of the spacial and temporal prey availability, individual gender and age, I found interindividual-level diet variation within the central subpopulation, which can points out to franciscana individual specialization, but isotopic studies are required to infer that specialization
5

História de vida e variabilidade morfológica e molecular de Leptinaria unilamellata (d’Orbigny, 1835) (Mollusca, Pulmonata, Subulinidae)

Carvalho, Camila de Medeiros de 17 February 2009 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-10-11T11:12:29Z No. of bitstreams: 1 camillademedeirosdecarvalho.pdf: 2802334 bytes, checksum: 24c8eb756878e03e092c98273834a1a8 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-10-11T15:56:30Z (GMT) No. of bitstreams: 1 camillademedeirosdecarvalho.pdf: 2802334 bytes, checksum: 24c8eb756878e03e092c98273834a1a8 (MD5) / Made available in DSpace on 2016-10-11T15:56:30Z (GMT). No. of bitstreams: 1 camillademedeirosdecarvalho.pdf: 2802334 bytes, checksum: 24c8eb756878e03e092c98273834a1a8 (MD5) Previous issue date: 2009-02-17 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / No presente estudo, foram elucidados aspectos da história de vida e morfologia do gastrópode terrestre Leptinaria unilamellata (d’Orbigny, 1835), além disso, foi verificada a ocorrência de variabilidade nos padrões conquiliomorfológicos e conquiliomorfométricos, assim como na morfologia do sistema reprodutor de moluscos provenientes de diferentes populações. A estratégia de história de vida da espécie foi caracterizada. Foram determinados os padrões de crescimento, reprodução e longevidade e elucidada a estratégia relacionada ao desenvolvimento dos embriões. Com base nos resultados obtidos, L. unilamellata foi classificada como espécie K-estrategista, ovovivípara, cujo padrão de história de vida é determinado pela alocação diferencial de energia para diferentes funções biológicas, nas diferentes fases do ciclo de vida. O sistema reprodutor foi caracterizado anatomicamente e histologicamente. Os resultados forneceram informações até então inexistentes, a cerca da morfologia microscópica do sistema reprodutor dessa espécie, corroborando aspectos comportamentais, como o hermafroditismo simultâneo e a ovoviviparidade. Foram observados o padrão geral da morfologia da concha de L. unilamellata e sua variação entre os espécimes das localidades de Juiz de Fora, MG; Cruzília, MG; Barra Mansa, RJ, e Floriano, distrito do município de Barra Mansa, RJ. O padrão de crescimento da concha foi descrito através do estudo da alometria do crescimento de moluscos de diferentes idades. As relações entre os padrões morfométricos dos diferentes morfotipos demonstraram a presença de dois grupos similares, um composto pelos morfotipos de Barra Mansa e Floriano, e outro pelos morfotipos de Juiz de Fora e Cruzília. O estudo permitiu o conhecimento sobre o padrão de formação da concha ao longo do desenvolvimento, bem como as relações entre as diferentes medidas lineares aferidas. Foi investigada a variabilidade morfológica do sistema reprodutor de espécimes de L. unilamellata das localidades de Juiz de Fora, MG; Cruzília, MG; Belo Horizonte, MG; Barra Mansa, RJ e Floriano, distrito do município de Barra Mansa, RJ. Os moluscos provenientes das diferentes populações estudadas apresentam diferenças na morfologia do sistema reprodutor, podendo assim ser reconhecidos como morfotipos distintos. Entretanto, tais morfotipos não puderam ser distinguidos pelo perfil molecular gerado através da técnica de PCR-RFLP. Os resultados do estudo da morfologia e análises morfométricas confirmaram a maior semelhança entre os morfotipos de Barra Mansa e Floriano, e entre os morfotipos de Juiz de Fora e Cruzília. A morfologia e morfometria dos moluscos de Belo Horizonte mostraram-se mais relacionadas àquelas dos dois últimos 9   morfotipos. As variações foram verificadas principalmente nos órgãos da região proximal do sistema reprodutor, os quais, provavelmente por estarem envolvidos no sucesso do acasalamento, sofrem maiores pressões seletivas. O presente estudo representa uma contribuição para o melhor entendimento da biologia reprodutiva de L. unilamellata. O estudo da conquiliomorfometria foi uma ferramenta útil para o conhecimento do padrão de crescimento dos moluscos e para a detecção de variabilidade morfológica interpopulacional. O conhecimento da morfologia do sistema reprodutor permitiu compreender aspectos da história de vida e distinguir morfotipos provenientes de diferentes populações. A combinação das diferentes abordagens utilizadas constitui um modelo que pode ser empregado para o melhor conhecimento da biologia de diferentes espécies de invertebrados. / In this study, were elucidated aspects of life history traits and morphology of the terrestrial gastropod Leptinaria unilamellata (d'Orbigny, 1835). In addition, was verified the occurrence of variability in patterns of shell morphology and shell morphometrics, as well as morphology of the reproductive system of snails from different populations. The life history strategy of L. unilamellata was characterized. We determined growth, reproduction, and longevity patterns of this species and the strategy related to development of embryos were determined. We might conclude from the results that L. unilamellata is a K-strategist species, ovoviviparous, whose life history patterns are determined by the differential allocation of energy for different biological functions, in different stages of life cycle. The reproductive system was characterized in terms of anatomical and histological aspects. The results provided new information about histological morphology of reproductive system of this species, corroborating behavioral aspects, such as simultaneous hermaphroditism and ovoviviparity. We were observed the general pattern of shell morphology of L. unilamellata and its variation among populations from Juiz de Fora, MG; Cruzília, MG, Barra Mansa, RJ, and Floriano, district of Barra Mansa, RJ. To describe the shell growth pattern, was accomplished the study of growth allometry with molluscs of different ages. The relationships between morphometric patterns of the morphotypes demonstrated the presence of two similar groups, one comprising the morphotypes of Barra Mansa and Floriano, and another by morphotypes of Juiz de Fora and Cruzília. The results of the present study clarified the shell growth pattern during the snails’ development, and the relationships between different shell linear variables. There was investigated the morphological variability of the reproductive system of specimens of L. unilamellata from Juiz de Fora, MG; Cruzília, MG, Belo Horizonte, MG, Barra Mansa, RJ and Floriano, RJ. As a result, were found differences in morphology of the reproductive system between molluscs from different populations, especially regarding the penial complex. So, snails from each locality could be recognized as distinct morphotypes. However, such morphotypes could not be distinguished through the molecular profile generated by PCRRFLP. The length of bursa copulatrix, width of epifalo, width of flagellum and width of oviduct were the linear measurements that differed more between snails from different localities and these, therefore, are the variables with greater strength for the distinction of morphotypes. The results of the morphological and morphometric studies, as well as the Euclidean analysis and cluster analysis, confirmed the greatest similarity between the 11   morphotypes from Barra Mansa and Floriano, and between morphotypes from Juiz de Fora and Cruzília. The morphology and morphometry of reproductive system of molluscs from Belo Horizonte were more related to those of the last two morphotypes. The patterns of similarity resulting from discriminant analysis confirmed these results. The variations were observed mainly in organs of the proximal region of reproductive system, probably because they are involved in success of mating, and consequently, more exposed to selective pressures. The present study represents a contribution to a better understanding of the reproductive biology of L. unilamellata, focusing on both biological and behavioral aspects, such as morphology of reproductive system and shell. The study of shell morphometrics has been proved to be a useful tool for understanding the pattern of growth of snails over lifetime and also for detection of morphological interpopulation variability. Similarly, knowledge of reproductive system morphology clarified aspects of life history and allowed distinguish morphotypes from different populations. The combination of the different approaches used in this study constitutes a study model that can be used for reach a better understanding about the biology of different invertebrate species.

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