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1
Ho, Wai-hoong. "The taxonomy and ecology of land snails in Hong Kong, with particular reference to factors affecting their distribution and population dynamics /." Hong Kong : University of Hong Kong, 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20667012.
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Al-Qattan, Nasser M. E. N. A. A. "Interpretation of Oxygen Isotopic Values (d18O) of North American Land Snails." Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1404460805.
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Ho, Wai-hoong, and 何慧紅. "The taxonomy and ecology of land snails in Hong Kong, with particular reference to factors affecting their distribution and populationdynamics." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31211458.
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Sharland, Eva Catherine. "Autecology of Vertigo angustior and Vertigo geyeri in Wales." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369889.
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Egonmwan, Rosemary Iriowen. "Reproductive biology and growth of the land snails Archachatina marginata ovum and Limicolaria flammea." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443146.
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Stephenson, Richard Javier. "Tropical land snails as precipitation proxies: Oxygen stable isotopes of shells from Trinidad Island." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563273765452653.
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Nishi, Hirotaka. "Divergence of Euhadra land snails associated with differentiation in microhabitat, shell morphology and behavior." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136804.
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Coppolino, Marla Lee. "LAND SNAIL ABUNDANCE AND DIVERSITY WITH ASSOCIATED ECOLOGICAL VARIABLES IN SIX SOUTHERN ILLINOIS COUNTIES." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/43.
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Various ecological parameters, including soil pH, calcium, and habitat complexity have been suggested in the literature as having influence on land snail abundance and diversity. I compared relationships between 15 ecological parameters and snail abundance and diversity. 5,393 snails of 72 species were collected from 60 sites in 2007. Habitat observations were recorded in the field and soil core samples taken at each site and later analyzed for soil moisture, organic matter, cation exchange capacity, pH, calcium, magnesium, zinc, potassium, phosphorus, sulfur, boron, manganese, iron and copper. Statistical analyses were run using these soil factors plus a habitat complexity index (from combined values assigned to different levels of vegetation, topography and exposed rock), for a total of 15 parameters. To reduce the number of parameters and arrive at a more biologically meaningful model, Bayesian Information Criteria analysis (BIC) was run for abundance and diversity. The resulting best-fitted BIC model for abundance contained 3 parameters (pH, S, and habitat complexity) (R2 = 0.47), all of which were positively associated with abundance in a multiple regression analysis. For diversity, the best-fitted BIC model also contained 3 parameters (Ca, Fe, and habitat complexity) (R2 = 0.54). Ca and habitat complexity showed a positive association in the multiple regression analysis, but Fe was inversely associated with diversity, suggesting Fe could potentially act as an ecological limiting factor to it. These results suggest that land snail abundance and diversity are best treated separately in analyses, as they are influenced by different variables, with the exception of habitat complexity, which is suggested to have a positive association with both abundance and diversity. The regression model equations have potential value in that they can be used to predict snail abundance and diversity in areas that have not been assessed.
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Ciparis, Serena. "Evaluation of the relationships between watershed-scale land use and contaminants in aquatic environments and the use of freshwater snails as indicators of impairment." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/37815.
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The use of manure from animal feeding operations (AFOs) as fertilizer on agricultural land may introduce contaminants to aquatic environments that can negatively affect the health of aquatic organisms. This study utilized a landscape-scale regression-based design to assess the effects of AFOs on contaminant concentrations and resident populations of a pleurocerid snail, Leptoxis carinata, in streams within the Shenandoah River watershed (Virginia, USA). Individual characteristics of L. carinata were also evaluated to provide further understanding of observed population characteristics. In streambed sediment and mollusk tissue, concentrations of the trace element arsenic, used as an additive in poultry feed, were not directly related to watershed densities of AFOs. In-stream concentrations of dissolved nutrients and estrogenic compounds, measured as estrogenic activity, were directly related to watershed densities of AFOs. Population sex ratios of L. carinata varied across study sites, from balanced to female-biased, but were not related to concentrations of estrogenic compounds. However, the spatial variation in population sex ratios, coupled with little variation in site-specific sex ratios across seasons and generations, suggest an influence of site-specific environmental conditions. Individual-level studies of L. carinata revealed that there is an eight month lag between hatching and gametogenesis which could allow disruption of sexual differentiation by environmental contaminants, but further study of the effects of specific contaminants on sexual differentiation in this species is needed. Population densities of L. carinata were related to in-stream nutrient concentrations and landscape sources of nutrients, including AFOs, but none of these factors were directly related to the infection prevalence of digenetic trematodes in L. carinata populations. Although trematode infection rates in L. carinata populations do not appear to be viable indicators of the influence of eutrophic conditions on disease incidence in aquatic organisms, the identification of five types of trematodes in L. carinata populations highlights the utility of this snail species for further investigation of transmission dynamics of trematode parasites in lotic systems.Ph. D.
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Bullard, Elizabeth. "Compositional variability of Pleistocene land snail assemblages preserved in a cinder cone volcano from Tenerife, Canary Islands." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470744125.
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Gillilland, Merritt Gale. "Dispersal ecology and control of the invasive land snail Cepaea nemoralis (L. 1758), from Ingham County, Michigan." Diss., Connect to online resource - MSU authorized users, 2006.
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Thesis (Ph. D.)--Michigan State University. Dept. of Zoology. Program in Ecology, Evolutionary Biology and Behavior, 2006.Title from PDF t.p. (viewed on Nov. 20, 2008) Includes bibliographical references (p. 161-168). Also issued in print.
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McMillan, Michele Ann. "The impact of rock climbing on vascular plants, bryophytes, lichens, and land snails of the Niagara Escarpment, Ontario, Canada." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0023/MQ51083.pdf.
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Nicolai, Annegret. "The impact of diet treatment on reproduction and thermo-physiological processes in the land snails Cornu aspersum and Helix pomatia." Rennes 1, 2010. https://tel.archives-ouvertes.fr/tel-00525296.
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Organisms often encounter environmental heterogeneity in space and time, and may adapt their life histories. In Cornu aspersum reproductive strategy depended on seasonal time constraints, and the investment in reproduction was influenced by the energy available in the environment. Nutrients deposited in eggs might enhance offspring survival. In Helix pomatia that is used recently in low input snail farms in Germany to maintain this endangered species as a regional specialty under the name Albschneck®, showed low reproductive success even with high energy food. Helix pomatia preserves ice nucleating bacteria and accumulates cryprotectants to enhance cold hardiness during hibernation. Mortality could be related to perpetual physiological adjustments to high environmental variations but also be due to limited resource allocation to survival maintaining processesLes organismes rencontrent souvent de l’hétérogénéité dans l’espace et dans le temps et devront adapter leur traits d’histoire de vie. Chez Cornu aspersum, la stratégie de reproduction dépend des contraintes saisonnières, et l’investissement dans la reproduction est influencé par l’énergie disponible dans l’environnement. Des nutriments déposés dans les oeufs pourraient augmenter la probabilité de survie des juvéniles. Chez Helix pomatia, qui est utilisé dans des élevages biologiques afin de maintenir cette espèce menacée comme spécialité régionale sous le nom Albschneck®, le succès reproducteur est faible même avec une alimentation riche en énergie. Helix pomatia préserve des bactéries nucléantes dans l’intestin et accumule des cryoprotecteurs pour améliorer la résistance au froid pendant l’hiver. La mortalité pourrait être liée à un ajustement perpétuel des processus physiologiques aux importantes variations environnementales ainsi qu’à une allocation limitée vers des processus de survie
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Sirio, Otavio José. "Verificação da potencialização do efeito cicatrizante do muco de caracóis do gênero Achatina promovida por dieta à base de Confrei (Symphytum officinale)." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/10/10135/tde-17042007-152005/.
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Os caracóis terrestres são animais capazes de produzir através de glândulas localizadas em toda superfície do seu corpo, uma secreção glicoproteica denominada muco, que dentre outras funções, apresenta poder antibacteriano, que pode auxiliar nos processos de reparação de feridas de origens diversas. Desta forma, o objetivo da presente pesquisa foi o de avaliar macroscópica e histologicamente, os efeitos reparadores do muco dos escargots Achatina fulica e Achatina achatina monochromatica, em lesões provocadas na pele de camundongos da linhagem "hairless"; verificar sua potencialização após a ingestão de uma ração contendo em sua formulação uma planta com propriedades cicatrizantes comprovadas, o Confrei (Symphytum officinale); e analisar bioquimicamente a composição do muco destes caracóis. Foram selecionados caracóis das espécies Achatina fulica (n=30) e Achatina monochromatica monochromatica (n=30), retirado seu muco através de estimulação manual da glândula podal e verificação de seu efeito reparador. Utilizaram-se camundongos da linhagem "hairless" (n=75), submetidos à intervenção cirúrgica e tratados com muco de ambas as espécies de caracóis. As características macroscópicas da lesão foram registradas em protocolo e avaliadas. Fragmentos de pele foram submetidos à biópsia aos 3, 5 e 7 dias de experimento, fixados em Paraformoldeído, processados e incluídos em parafina. Os cortes foram corados com Hematoxilina-Eosina e Tricrômio de Mason. Macroscopicamente, os animais tratados mostraram edemas menores, maior presença de crosta e maior contração das bordas das feridas ao final do experimento, quando comparados ao grupo controle. Histologicamente, os grupos tratados também revelaram melhor reparação da lesão, apresentando edemas menos intensos, grandes quantidades de tecido de granulação e infiltrados inflamatórios. O grupo tratado com muco de caracóis alimentados com ração contendo Symphytum officinale foi o que apresentou melhores resultados.Land snails are animals able to produce through glands located all over their body surface, a glycoprotein secretion called mucus. This mucus, within other roles, shows an antibacterial power that can help in the healing processes of wounds from several sources. Therefore, the aim of this study was to evaluate through macroscopic and histological techniques the repairing effects of the mucus in the snails Achatina fulica and Achatina achatina monochromatica in lesions intentionally caused to hairless linage mice skin; to investigate mucus potential effect after snails have been fed with a diet formulation containing a plant with proved scar properties, the Comfrey (Symphytum officinale); and to study the biochemical composition of mucus from these snails. Snails of Achatina fulica (n=30) and Achatina monochromatica monochromatica (n=30) species were sorted, the mucus extracted through manual stimulation of the podal gland and the repairing effect studied. Hairless linage mice (n=75) used in this study went through surgery and then treated with mucus from both species of snails. The macroscopic characteristics of the lesion were recorded and assessed. Fragments of skin were taken to biopsy at 3, 5 and 7 days of trial, fixed in paraformaldehyde, processed and embedded in wax. Sections were stained with Hematoxilin-Eosin and Tricromio of Mason. Macroscopically, treated mice showed minor swelling, higher presence of scabs and higher contraction of wound edges at the end of the trial, when compared with control. Histologically, groups that received treatment also showed better lesion repair, presenting less intense swellings, large amount of scar tissue and inflammatory infiltrates. The group treated with mucus from snails that received a diet containing Symphytum officinale presented the best results.
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Evasdotter, Liselott. "Restoration of a Rich Fen by Top Soil Removal : Temporal and Spatial Responses among Vascular Plants, Bryophytes and Land Snails during 15 years." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-152175.
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Rich fens are calcareous and nutrient poor wetlands with a rich flora of orchids, sedges and mosses. As many as one hundred plant species are rich fen specialists. Many wetlands have been drained historically, and transformed to agricultural land or production forests. Today rich fens cover only 2-3% of the total mire area in Sweden. Rich fen is a rare and valuable habitat also from a European perspective and is protected in the Natura 2000-network. To increase and maintain the biodiversity and ecosystem services rich fens can offer, it is important to increase the rich fen area by restoration and management. Rich fen restoration can be carried out in different ways. In this report the restoration method of top soil removal is investigated. The method has never been tested before in Sweden and therefore it is important to evaluate the suitability of the method for further conservation work. Before restoration, the study area had been drained, used as arable land and pasture, and finally become abandoned and overgrown by tall eutrophic herbaceous vegetation. An excavator dug away the layer of nutrient rich top soil and then the site was left for spontaneous development. Adjacent to the restored area, there is a small remnant of rich fen. Monitoring of the restored area was performed during the first five years after the restoration. I repeated the monitoring after ten years, and analyzed the long-term succession of plants and snails, in comparison with the status in the reference fen. The vegetation in the restored parts is approaching the one in the reference fen. For example, the number of rich fen specialists has increased steadily. However, the colonization of bryophytes is slow. They cover at most 20 % in the restored parts, while 80 % in the reference fen, possibly because of dispersal limitation and the fact that the restored area is drier than the reference fen. More species of herbs can be found in the restored parts than in the reference fen. Another difference is the high cover of bare soil in the restored areas, compared to none in the reference fen. Some trees and bushes are growing in the area, primarily birch (Betula pubescens) and different species of Salix. The land snails have successfully colonized the restored areas. After two years the same number of species was found in the restored area, as in the reference fen. The total number of species found in the restored areas was 26, compared to 29 in the reference fen, among them three rare rich fen indicator species. The results show how the restored site has developed from bare mineral soil to a rich fen site, approaching the species composition of the reference fen. Several species of rich fen specialists among vascular plants, bryophytes and land snails have established in the restored areas. The small rich fen close to the restored area functions as a source from where plants and animals can spread. Overall the restoration shows very positive results, going from bare soil to rich fen vegetation in only ten years.
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Ferreira, Paula Botelho. "Estudo citogenético de Leptinaria unilamellata (d´Orbigny, 1835) (Mollusca, Gastropoda, Subulinidae)." Universidade Federal de Juiz de Fora (UFJF), 2014. https://repositorio.ufjf.br/jspui/handle/ufjf/7110.
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Os moluscos pulmonados têm sido reconhecidos como modelos interessantes para o estudo de biodiversidade oculta em função de algumas características como a baixa vagilidade, capacidade de realizar auto-fecundação, além do histórico de identificações específicas baseadas somente nas conchas, caráter esse hoje sabidamente insuficiente para a distinção de espécies. A citogenética constitui uma abordagem que pode contribuir para a resolução taxonômica de grupos de moluscos terrestres, sendo, entretanto necessário o estabelecimento de protocolos experimentais. O objetivo do presente trabalho foi estabelecer protocolos para o estudo citogenético de moluscos terrestres, através da realização de bioensaios, visando testar diferentes tecidos, concentrações dos reagentes indicados e tempos de incubação. Para isso, foi realizada uma revisão prévia dos protocolos descritos para o filo Mollusca e delineados protocolos, posteriormente testados em bioensaios, utilizando-se a espécie Leptinaria unilamellata (Pulmonata, Subulinidae) como modelo experimental. O presente trabalho descreve o cariótipo da espécie L. unilamellata, com fórmula cariotípica 22m+6sm. Os resultados obtidos estão de acordo com os números cromossômicos descritos na literatura para espécies de moluscos terrestres da superfamília Achatinoidea, variando de 2n=44 a 2n=60 cromossomos. Além disso, com a técnica de coloração de nitrato de prata, observamos a presença de duas marcações no núcleolos correspondente às regiões organizadores de nucléolos, ou seja, regiões ativas do DNA. O estabelecimento de protocolos de citogenética adequados para o estudo de moluscos terrestres permitirá o aumento do número de espécies cariomorfologicamente estudadas, contribuindo para a melhor resolução da taxonomia e evolução desse grupo.
Pulmonate molluscs have been recognized as interesting models to study hidden biodiversity due to some biological characteristics as low vagility and self-fertilization capacity, besides the historic of species descriptions based solely on the shell. Cytogenetics is used to infer species relationships in several plant and animal taxa. This approach may contribute to the better resolution of the taxonomy within Pulmonata. The present study aimed to establish protocols to cytogenetic studies of terrestrial molluscs testing different target tissues, reagents concentrations and incubation times. We performed a review of the cytogenetic protocols described in the literature for phylum Mollusca and after that; we delineated protocols which were tested in bioassays, using the species Leptinaria unilamellata as experimental model. In the present study we found that L. unilamellata present diploid number of 56 chromosomes, 44 metacentrics e 12 submetacentrics. This result is in accordance with the chromosome numbers described to terrestrial snails from superfamily Achatinoidea, which varies from 2n=44 to 2n=60. Furthermore, with the technique of silver nitrate staining, we found the presence of two sites in the nucleus corresponding to nucleolus organizer regions, or active regions of DNA. The establishment of cytogenetic protocols adequate to terrestrial snails will allow increasing the number of land snail’ species karyomorphologically studied, contributing to the better resolution of the taxonomy and evolution of this group.
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Viana, Tiago Abreu. "Uso do espaço por Hypselartemon contusulus (Férussac, 1827) (Gastropoda, Streptaxidae) da Trilha da Parnaioca, Ilha Grande, Rio de Janeiro, Brasil." Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=3525.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorO comportamento espacial dos indivíduos é um componente chave para se entender a dinâmica de população dos organismos e esclarecer o potencial de migração e dispersão das espécies. Vários fatores afetam a atividade de locomoção de moluscos terrestres, como temperatura, luz, umidade, época do ano, tamanho da concha, sexo, estratégia reprodutiva, idade, densidade de coespecíficos e disponibilidade de alimento. Um dos métodos usados para estudar deslocamento de gastrópodes terrestres é o de marcação-recaptura. Gastrópodes terrestres se prestam a este tipo de estudo por causa de (1) seu reduzido tamanho, (2) fácil manejo, (3) fácil captura e (4) pequenas distâncias de deslocamento e, consequentemente, reduzidas áreas de vida. Estes organismos servem como modelo para o estudo de ecologia espacial e dispersão. Estudos de população, investigando o uso do espaço, a distribuição espacial, a densidade populacional e a área de vida são escassos para moluscos terrestres e ainda mais raros em áreas naturais tropicais. Nosso objeto de estudo é Hypselartemon contusulus (Férussac, 1827), um molusco terrestre carnívoro, da família Streptaxidae, muito abundante na serrapilheira, em trechos planos de mata secundária na Trilha da Parnaioca, Ilha Grande, Rio de Janeiro. A espécie é endêmica para o estado do Rio de Janeiro. Seu tamanho é de até 7,2 mm de altura, apresentando 6 a 7 voltas. Neste trabalho estudamos as variáveis temperatura ambiente, temperatura do solo, umidade do ar, luminosidade, profundidade do folhiço, tamanho do animal, densidade de co-específicos e densidade de presas, relacionando estes dados ecológicos ao deslocamento observado em Hypselartemon contusulus. Uma das hipóteses de trabalho é que estas variáveis afetam seu deslocamento. O trabalho foi realizado na Ilha Grande, situada ao sul do Estado do Rio de Janeiro, no município de Angra dos Reis. Os animais foram capturados e marcados com um código individual pintado na concha com corretor ortográfico líquido e caneta nanquim. As distâncias de deslocamento, em cm, foram registradas medindo-se as distâncias entre marcadores subsequentes. Os resultados encontrados indicam que o método utilizado é eficaz para marcar individualmente Hypselartemon contusulus em estudos de médio prazo (até nove meses). Sugerimos o uso deste método de marcação para estudos com gastrópodes terrestres ameaçados de extinção, como algumas espécies das famílias Bulimulidae, Megalobulimidae, Streptaxidae e Strophocheilidae. Hypselartemon contusulus não mantém uma distância mínima de seus vizinhos, é ativo ao longo de todo o ano e ao longo do dia, demonstrando atividade de locomoção e predação. Não foram encontrados animais abrigados sob pedra ou madeira morta. Não foram observados locais de atividade em oposição a lugares de repouso/abrigo. Beckianum beckianum (Pfeiffer, 1846) foi a presa preferencial. A densidade populacional variou de 0,57 a 1,2 indivíduos/m2 entre as campanhas de coleta. A espécie desloca-se, em média, 26,57 17,07 cm/24h, na Trilha da Parnaioca, Ilha Grande. A área de vida de H. contusulus é pequena, sendo de, no máximo, 0,48 m2 em três dias e 3,64 m2 em 79 dias. O deslocamento da espécie variou ao longo do ano, mas esta variação não é afetada pelas variáveis ecológicas estudadas. Este é, portanto, um comportamento plástico em H. contusulus e, provavelmente, controlado por fatores endógenos.
Spatial behavior of individuals is a key component to understanding and clarify migration and dispersion potential of species. Many factors affect locomotory activity of land mollusks, like temperature, light, humidity, period of the year, shell size, sex, reproductive strategy, age, co-specific density and food quantity. The mark-recapture method is used to study displacement of land snails. Land snails lend themselves to this kind of study because of their small size, easy handling, easy capture and small displacement distances and, consequently, small home ranges. These organisms serve as model to study spatial ecology and dispersion. Studies on population, concerning spatial behavior and distribution, population density and home range are rare for land snails and even rariest in natural tropical areas. Our study object is Hypselartemon contusulus (Férussac, 1827), a carnivorous land snail, family Streptaxidae, very common in leaf litter, in plane parts of secondary forest in the Trail of the Parnaioca, Ilha Grande, Rio de Janeiro. The species is endemic to Rio de Janeiro state. His size is 7.2 mm height, in maximum, showing six to seven whorls. In this work, we studied the environment variables temperature, soil temperature, air humidity, luminosity, leaf litter depth, shell size, co-specific density and prey density, connecting these ecologic data to the displacement observed to H. contusulus. The research hypothesis is that these variables affect its displacement. The work was carried out in Ilha Grande, south of the state of Rio de Janeiro, in the Angra dos Reis municipality. The animals were captured and marked with an individual code painted in the shell with orthographic liquid corrector and nankeen ink. The displacement distances, in cm, were recorded measuring the distances between subsequent markers. The results indicate that the used method is effective to mark individually H. contusulus in intermediate-term studies (until nine months). We suggest the use of this mark method to studies about land threatened land snailst, like some species of the families Bulimulidae, Megalobulimidae, Streptaxidae and Strophocheilidae. Hypselartemon contusulus does not maintain a minimum distance from its neighbours. The species is active during all the day and all year, showing locomotory activity and predation. Animals were not found sheltered under rock or dead wood. Sites of activity in opposition of sites of resting were not observed. Beckianum beckianum (Pfeiffer, 1846) was the preferential prey. Population density varied from 0.57 to 1.2 individuals/m2 between sampling episodes. The species move, in media, 26.57 17.07 cm/24h, in the Trail of the Parnaioca, Ilha Grande. Home range of H. contusulus is small and does not exceed 0.48 m2, in three days and 3.64 m2 in 79 days. Displacement varied during the year, but this variation is not affected by the ecological variables. This is a plastic behavior in H. contusulus and, probably, controlled by endogenous factors.
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Raheem, Dinarzarde Chirantenne. "Land-snail diversity in Sri Lankan rainforest fragments." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613834.
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Grindon, Adele. "Mitochondrial phylogeography of three European helicid land snail species." Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523072.
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Skomrock, Nicholas David. "The Biogeography of the Caribbean Land Snail Family Annulariidae." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1417706937.
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Thomas, Alex W. "A specific pulsed magnetic field and analgesia in the land snail." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0011/MQ28672.pdf.
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Ellis, David. "Evolutionary genetics of the land snail Cepaea nemoralis in the Central Pyrenees." Thesis, University College London (University of London), 2004. http://discovery.ucl.ac.uk/1446625/.
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The pattern of life is a discontinuous one: both fossils and modem taxa show a clustering of forms separated by gaps. Evolutionary theory explains these gaps by relatively rapid transitions happening long ago, leaving few identifiable intermediates. One mechanism for this 'punctuated equilibrium' process suggests that these dramatic changes take place in small isolated populations at the edges of a species' range. This notion was tested in the land snail Cepaea nemoralis in the French and Spanish Pyrenees. Geographical patterns of genetic differentiation in enzyme polymorphisms ('molecular area effects') suggest that the population was once fractured into smaller units which, after a process of genetic disruption, recolonised their original range. The interface between two of these areas was mapped by an analysis of enzyme polymorphisms. Pure populations and their hybrids were then compared for adaptational differences (shell and body colour, thermal behaviour and mortality rates), and for reproductive isolation (as calculated by estimates of selection against hybrids from the enzyme dine width using field determinations of dispersal rate). No significant adaptive differentiation or reproductive barrier could be established between the two molecular areas. Instead, the same processes of adaptation seem to have taken place within the areas, in response to altitude and insolation. Furthermore, I investigated the possibility of a hybrid advantage effect taking place within the zone of hybridisation, where mean shell size is larger, resulting in more eggs being laid. Hybrid genotypes are thus likely to disperse faster than those of the pure types, dissipating the genetic differentiation between area effects more quickly than by random mixing. Present day selection is unlikely to determine the pattem of molecular area effects, as they do not coincide with geological, climatic, and vegetational discontinuities. Rather, they are relics of history, arising from the expansion of glacial refuges. The dynamics of this process were investigated by tracking vegetation patterns from ancient pollen cores, and by an analysis of mtDNA and enzyme variant distribution. The results of this study counter the expectations of the proposed mechanism of punctuated equilibrium. They are a reminder that, for most of the time, living organisms are robust to dramatic evolutionary change.
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Gardner, Neville P. "Small-scale distribution of two modern land snail faunas : islands and boundaries of relevance to the interpretation of subfossil assemblages." Thesis, Cardiff University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315293.
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Wilson, Iain. "Factors influencing gene frequency distributions in Cepaea nemoralis." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335361.
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Patel, Simit. "Local adaptation in the land snail, Cepaea nemoralis : exploratory genetic analysis with AFLP markers." Thesis, University of Reading, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559281.
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The polymorphic land snail, Cepaea nemoralis (L.) shows a higher prevalence of yellow, banded shells in open habitats and non-yellow (Pink and brown), unbanded shells in woodland. Shell characters are genetically controlled and this pattern of local adaptation is geographically repeated, implying selection is operating. However, no molecular evidence exists to support this claim. An FSI-outlier approach revealed six AFLP loci with elevated levels of differentiation compared to neutral expectations - three in one open-woodland population pair and another three in another pair - providing evidence of positive selection operating between open and woodland habitats. The non-repeated nature of outliers suggests tlie two sites are adapting to habitats by different strategies. Pairwise F SI and a neighbour-joining tree show the two study sites to be genetically divergent from each other, probably because they are geographically isolated (~60km apart) and there are low levels of differentiation between habitats within each pair. An attempt was made at creating a preliminary AFLP linkage map for C. nemoralis using a pseudo-testcross design. A mapping population segregating for shell colour and mid-banding was established but only three, small AFLP linkage groups were identified in one of the parental maps and none in the other. This was largely due to a small proportion of loci being in testcross configuration. In addition, morph frequency data were compared to historic records to look for changes in morph/allele frequency over time. All open populations showed significant differences in colour or banding, whereas no significant differences were found in any woodland populations. This could be an adaptive response to differences in habitat stability between open and woodland, the latter being more stable. Alternatively, balancing selection could be operating in woodlands and open populations fluctuate randomly. The difference in morph frequency stability between habitats was not reflected in allele frequency changes (assuming Hardy-Weinberg equilibrium). 1.
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Coppolino, Marla L. "Land snail abundance and diversity with associated ecological variables in six southern Illinois counties /." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1885443181&sid=7&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Wall, Alexander F. "Bellwether of the Canaries: Anthropogenic Influence on the Land Snail Community of the Canary Islands." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin147947618085079.
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Aubry, Sébastien. "Factors controlling the structure of land snail communities on limestone mountains in South-Eastern France." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615608.
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Prévot, Vanya. "Exploring the taxonomy of a facultative selfing, polymorphic land snail: the genus Rumina, Gastropoda Pulmonata." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209873.
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Le genre Rumina Risso, 1926 (Subulinidae) est constitué de gastéropodes terrestres, hermaphrodites et capables de réaliser de l’autofécondation ainsi que de la fécondation croisée. Plusieurs espèces ont été décrites sur base de subtiles différences morphologiques telles que la forme et la taille de la coquille et la coloration du corps. Trois espèces sont actuellement toujours reconnue dans la littérature: Rumina decollata (Linnaeus, 1758), R. saharica Pallary, 1901 et R. paivae (Lowe 1861). Cependant, uniquement le statut spécifique de R. decollata et R. saharica a été confirmé par la morphologie de la coquille et l'anatomie génitale. L’objectif de la thèse est de clarifier la taxonomie du genre Rumina par une approche de taxonomie intégrative en associant des caractères moléculaires, morphologiques et anatomiques ainsi que les méthodes issues de la génétique des populations. Quatre gènes mitochondriaux et deux gènes nucléaires ont été séquencés pour reconstruire la phylogénie de Rumina. Les résultats confirment le statut d’espèce de R. saharica, excluent R. paivae en tant qu’espèce et proposent une nouvelle classification pour R. decollata en 6 espèces phylogénétiques. R. saharica est aussi confirmé en tant qu’espèce morphologique suite à une étude morphomètrique, cependant les nouvelles espèces de R. decollata n’ont pas pu être différenciées ni par les variables morphologiques testées, ni par des particularités dans l’anatomie génitale. Néanmoins, deux des espèces de R. decollata correspondent à deux morphotypes (clair et foncé) auparavant décrits et étudiés dans la région de Montpellier. L’étude de ces deux espèces phylogénétiques avec des microsatellites et allozymes permettent de confirmer le statut spécifique des deux morphotypes et révèlent que R. decollata pratique l’autofécondation croisée à un taux supérieur à celui rapporté dans la littérature, défiant ainsi la règle selon laquelle les hermaphrodites pratiqueraient exclusivement l’autofécondation ou exclusivement la fécondation croisée. L’espèce correspondante au morphotype foncé a été introduite en plusieurs endroits du monde et semble être l’espèce possédant la plus grande capacité invasive parmi les Rumina. Ainsi, nos résultats suggèrent que le genre Rumina, auparavant décrit comme étant composé de trois espèces, est en fait un complexe de sept espèces, qui doivent être davantage étudiées de façon à confirmer leur statut d’espèce par d’autres concepts d’espèce. / Rumina spp. Risso, 1826 (family Subulinidae) is a hermaphroditic terrestrial snail, performing both selfing and outcrossing. Several nominal species have been described based on subtle differences in the shape and size of the shell, and body coloration. Currently, three taxa are still recognized, viz. R. decollata (Linnaeus, 1758), R. saharica Pallary, 1901 and R. paivae (Lowe, 1860). Yet, species-specific differentiation has only been confirmed for R. decollata and R. saharica, based on shell and genital morphology. This work aims at resolving the taxonomy of the genus Rumina through an integrative taxonomic approach by combining molecular, morphological and anatomical characters, as well as population genetic methods. Four mitochondrial and two nuclear genes were used to infer Rumina’s phylogeny. Results suggest that R. saharica is a phylogentic species, R. paivae is not a phylogenetic species and R. decollata is composed by 6 phylogenetic species. The specific status of R. saharica was confirmed by a morphometric analysis, however the remaining phylogenetic species of R. decollata could not be differentiated neither by the shell characters analyzed nor by the genital anatomy. Nevertheless, two phylogenetic species of Rumina representing the dark and light colored strains previously described in the Montpellier region. The study of both these strains with microsatellites and allozymes confirmed their specific status and revealed that outcrossing might be more prevalent than was previously suggested in the literature, therefore defying the alleged rule that hermaphroditic species should be either strict self-fertilizers or strict outcrosser. The dark strain was introduced in several places through the world and seems to be the one with highest invasive character within the genus Rumina. Therefore, our results suggest that the genus Rumina, previously described as having three species, is in fact a complex of seven species that need to be further explored in order to confirm their species status under other species concepts.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
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New, Evan M. "Aminochronology and Time-averaging of Quaternary Land Snail Assemblages from Colluvial Soils in the Madeira Archipelago." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin153538137669338.
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Kameda, Yuichi. "Diversity and speciation mechanism of the land snail genus Satsuma (Camaenidae) endemic to the Japanese island arc." Kyoto University, 2009. http://hdl.handle.net/2433/123922.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第14707号
人博第443号
新制||人||109(附属図書館)
20||人博||443(吉田南総合図書館)
UT51-2009-D419
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 加藤 眞, 教授 松井 正文, 准教授 市岡 孝朗, 教授 曽田 貞滋
学位規則第4条第1項該当
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Padgett, Abbey E. "Early-Middle Holocene Cultural and Climate Shifts in NW Africa: Paleoenvironmental Reconstruction Using Stable Isotopes of Land Snail Shells." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522318834405742.
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Taylor, Victoria Kate. "Land snail middens in the late Pleistocene and early Holocene in North Africa : a case study from Taforalt (Grotte des Pigeons), Morocco." Thesis, University of Reading, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.657599.
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Land snail middens occur widely throughout the circum-Mediterranean with a particular concentration of sites in northwest Africa They often contain abundant terrestrial molluscs, charcoal, lithics, bone and charred plants. Previous work is limited despite the potential use for addressing questions of subsistence strategies and increasing sedentism, particularly in the context of the Broad Spectrum Revolution and the associated transition to agriculture. The work presented in this thesis forms part of the ' Cemeteries and sedentism in the Epipalaeolithic of North Africa' project which aims to investigate ritual behaviour, diet, technology and sedentism in Epipalaeolithic Morocco through a multi-proxy approach which also evaluates the role of climate and environment in any cultural developments. This thesis provides the first detailed analysis of the molluscan component from Taforalt (Grotte des Pigeons) (34°48'38"N, 2°24'30"W), a large, open cave in the Beni Snassen mountain range in northeast Morocco, 40km from the Mediterranean coast Extensive previous excavation has occurred but analysis of Mollusca has been very limited. The sequence is well dated by radiocarbon and covers the Ibermaurusian period (20,000- 12,800 Cal BP). Yellow Series deposits, with episodic evidence of human occupation, and a partly natural mollusc fauna, are overlain by Grey Series deposits which are highly anthropogenic, 99% of the molluscs having been collected and consumed by people. Four main edible species are identified: Dupotetia dupoteliana, Alabastrina soluta, Cernuella globuloidea and Olala punclata. Despite the large quantities of shells, molluscs were never a staple food and formed part of a broad based diet A modem mollusc survey identifies behavioural characteristics of mollusc clustering which facilitated collection. Results from a pilot stable isotopic study indicate wetter conditions in the Grey Series, consistent with the Greenland Interstadial 1 date shown by radiocarbon. The research is set in the wider context of a review of land mollusc middens.
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Meireles, Liliane Mara de Oliveira. "Seleção alimentar e influência de diferentes dietas sobre o crescimento, a reprodução e a sobrevivência de Bulimulus tenuissimus (d’ Orbigny, 1835) (Mollusca, Bulimulidae) em condições de laboratório." Universidade Federal de Juiz de Fora (UFJF), 2009. https://repositorio.ufjf.br/jspui/handle/ufjf/3973.
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A seleção alimentar compreende características ligadas ao alimento, como o paladar e a atratividade, e pode estar relacionado com as condições fisiológicas do molusco. Assim, a alimentação exerce grande influência no desenvolvimento dos moluscos terrestres, podendo interferir na atividade reprodutiva desses animais. Foram objetivos desse estudo verificar a seleção alimentar e a influência de diferentes dietas no crescimento, na reprodução e na sobrevivência de Bulimulus tenuissimus em condições de laboratório. Para tal, grupos de moluscos foram alimentados com seis itens alimentares diferentes, batata, chuchu, pepino, cenoura, maçã e ração, os quais foram oferecidos separadamente ou combinados por um período de 210 dias. Foi verificada a seleção pelos alimentos mais macios e com alto teor de cálcio (ração e chuchu), bem como os efeitos benéficos da combinação de dietas no crescimento, fecundidade e sobrevivência dessa espécie, provavelmente, devido ao aumento na disponibilidade de nutrientes.
Food selection includes features related to food, as taste and attractiveness, and may be related to the physiological conditions of the snail. Thus, food exerts great influence on the development of land snails, which can interfere in the reproductive activity of these animals. The objectives of this study were to verify the food selection and the influence of different diets on growth, reproduction and the survival of Bulimulus tenuissimus under laboratory conditions. Groups of snails were fed with six different food items, potato, chayote, cucumber, carrot, apple and ration, which were offered separately or combined for a period of 210 days. The food selection was observed by food softer and with higher levels of calcium (ration and chayote) and the beneficial effects of the combination of diets on growth, fecundity and survival of this species, probably due to the increase in the availability of nutrients.
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Santos, Emily Oliveira. "Aspectos da reprodução, crescimento e comportamento agregativo de Allopeas gracilis (Hutton, 1834) (Mollusca, Subulinidae)." Universidade Federal de Juiz de Fora, 2013. https://repositorio.ufjf.br/jspui/handle/ufjf/1490.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O objetivo do presente trabalho foi descrever a história de vida da espécie Allopeas gracilis, através da avaliação do crescimento e reprodução. Avaliou-se também a influência do isolamento sobre esses aspectos, o investimento reprodutivo, o comportamento de retenção de ovos no oviduto e o comportamento agregativo. Para tanto, foram realizados quatro experimentos. No primeiro experimento, que objetivou avaliar o crescimento e a reprodução de indivíduos mantidos pareados e isolados, realizou-se o acompanhamento do ciclo biológico de 60 moluscos, dos quais 30 foram mantidos aos pares e 30 foram mantidos em isolamento durante 120 dias. A. gracilis apresentou grande plasticidade na forma de alocação de energia entre crescimento e reprodução de acordo com a forma de criação, sendo a reprodução e o crescimento maior para os animais mantidos pareados. No segundo experimento, que teve como objetivo caracterizar o investimento reprodutivo da espécie acompanhou-se durante 180 dias 60 moluscos, dos quais 30 moluscos foram mantidos isolados e 30 moluscos foram mantidos pareados. Após o nascimento dos filhotes, os moluscos parentais e respectiva prole foram pesados para o cálculo do investimento reprodutivo. Na idade de 120 dias, os moluscos mantidos isolados tiveram um investimento reprodutivo maior do que os moluscos pareados, nas idades de 150 dias e 165 dias foram os moluscos mantidos pareados que apresentaram um maior investimento reprodutivo. Já na idade de 180 dias não houve diferença significativa entre os investimentos reprodutivos dos dois grupos. O terceiro experimento teve como objetivos caracterizar o comportamento de retenção de ovos no oviduto. Para tanto foram separados 60 moluscos recém-eclodidos em caixas individuais formando dois grupos experimentais de 30 moluscos cada e observados até a detecção da presença de filhotes no oviduto e constatação da maturidade sexual. Na primeira fase do experimento, um grupo foi mantido em condições favoráveis de umidade do substrato, enquanto o outro foi mantido em condições de dessecação. Foi verificada a frequência de liberação de filhotes pelos moluscos de ambos os grupos. Após um período de 40 dias, o substrato da caixa em que foi mantido o grupo submetido à dessecação foi novamente umedecido, por mais 20 dias, constituindo a segunda fase do experimento. Observou-se que o grupo mantido em condições desfavoráveis de umidade reproduziu menos do que o grupo mantido em condições favoráveis, mostrando que com a falta de umidade os moluscos retêm os ovos no oviduto. No quarto experimento, que teve como objetivo caracterizar o comportamento agregativo de A. gracilis, foram obtidos 150 moluscos, que foram distribuídos em 15 caixas plásticas. Em cada caixa foram colocados quatro discos plásticos identificados, em posição equidistante, os quais serviram de abrigos para os animais. Foram colocados 10 animais no centro de cada caixa. Após 24, 48, 72, 96, 120 e 168 horas foram observados o número de agregados formados, a posição dos agregados (sob qual disco), o número de indivíduos por agregado e o número de indivíduos isolados. Após 168 horas de experimento os indivíduos foram transferidos para outras caixas, contendo terra vegetal, três novos discos e o disco que continha o maior agregado após as 168 horas. Foi verificado, após 24 e 48 horas, o número de indivíduos sob o disco condicionado. Constatou-se que A. gracilis apresenta comportamento agregativo, assim como outras espécies de subulinídeos. Em todas as caixas utilizadas e em todos os intervalos de tempo ao longo das primeiras 168 horas e das 48 horas seguintes houve a formação de agregados.
The aim of this work was to describe the life history of the species Allopeas gracilis, through the assessment of growth and reproduction. We also evaluated the influence of isolation, the reproductive investment, the eggs retention behavior and aggregative behavior of A. gracilis. Therefore, four experiments were conducted. The first experiment aimed to evaluate the growth and reproduction of individuals kept in isolation or in pairs. A. gracilis showed great plasticity in the energy allocation between growth and reproduction, the egg production and growth rates being higher for paired animals. The second experiment aimed to evaluate the reproductive effort of A. gracilis. After the birth of the juveniles, the offspring and parental individuals were weighed to calculate the reproductive investment. At the age of 120 days, the snails kept isolated showed higher reproductive effort than paired snails. At the age of 180 days there was no significant difference between the two groups. The third experiment aimed to characterize the behavior of eggs retention. Sixty newly hatched snails were assigned to individual boxes. The molluscs were observed until the detection of embryos in the oviduct, which confirmed that the snails have attained sexual maturity. In the first phase of the experiment, one group was kept in a favorable moisture condition, while the other was maintained in a desiccation condition. At the second phase of the experiment, after a period of 40 days, the substrate of the boxes in which the snails subjected to desiccation were maintained has been moistened. It was observed that the group kept in unfavorable moisture condition produced fewer eggs than the group kept in a favorable condition, retaining these egg in the oviduct and releasing then when the terrário were moistened again. The fourth experiment aimed to characterize the aggregative behavior of A. gracilis. For this, 150 molluscs were distributed in 15 plastic boxes. In each box four labeled plastic disks were placed in equidistant positions. These disks have served as shelters for the snails. Ten snails were placed in the center of each box. After 24, 48, 72, 96, 120 and 168 hours the number of aggregates formed were observed, as well the position of the aggregates (in which disk) and the number of individuals per aggregate. After 168 hours of experiment the snails were transferred to boxes containing new substrate, three new disks and disk that contained the largest aggregate after 168 hours (conditioned disk). After 24 and 48 hours, the number of individuals in the conditioned disk was obserfved. It was found that A. gracilis exhibits aggregative behavior like other species of subulinids.
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Silva, Lidiane Cristina da. "História de vida de Bulimulus tenuissimus (d’ Orbigny, 1835) (Mollusca, Bulimulidae): variação no conteúdo dos substratos energéticos de acordo com a idade e sazonalidade." Universidade Federal de Juiz de Fora (UFJF), 2009. https://repositorio.ufjf.br/jspui/handle/ufjf/3969.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Apesar da diversidade e importância os moluscos terrestres têm sido pouco estudados, principalmente as espécies da malacofauna brasileira como é o caso de Bulimulus tenuissimus. Assim, objetivou-se com esse trabalho descrever a história de vida dessa espécie, através da avaliação do crescimento, reprodução e longevidade. Avaliou-se também a influência do isolamento sobre esses aspectos e a variação dos recursos energéticos em diferentes fases da vida, e nas diferentes estações do ano. Para tanto, foi realizado o acompanhamento do ciclo biológico de 240 moluscos, dos quais 120 foram mantidos em grupos e 120 foram mantidos em isolamento durante todo o ciclo de vida. Bulimulus tenuissimus apresentou grande plasticidade na forma de alocação de energia entre crescimento, reprodução e sobrevivência de acordo com a forma de criação, sendo a reprodução e longevidade maior para os animais mantidos em grupos, enquanto o crescimento foi mais acentuado nos isolados. Essa diferenciação no investimento energético levou a padrões de história de vida distintos nos dois grupos. Os moluscos de diferentes idades apresentam formas diferenciadas para alocação dos polissacarídeos avaliados, sendo a variação provavelmente relacionada ao estado reprodutivo dos moluscos. Além disso, constatou-se também que as reservas energéticas dos músculos são disponibilizadas e degradadas tanto na fase Adulta quanto na fase Senescente. O conteúdo de carboidratos variou de acordo com a idade, sendo a tal variação provavelmente relacionada ao estado reprodutivo dos animais. Também houve variação sazonal do conteúdo de glicogênio e galactogênio, os quais são coincidentes com o ciclo reprodutivo de B. tenuissimus, evidenciando-se que a sazonalidade reprodutiva parece ser controlada por fatores metabólicos.
There are few studies about land snails despite their importance and diversity, especially native species, such as Bulimulus tenuissimus. Thus, the objectives of this study were to describe the life history of this species evaluating the growth, reproduction and longevity. The influence of the isolation on these aspects, the change of energy resources in different ages and in different seasons were evaluated. For this purpose, there was monitoring the biological cycle of 240 snails, of which 120 were kept in groups and 120 were kept isolated during their lifetime. Bulimulus tenuissimus showed plasticity in the allocation of energy between growth, reproduction and survival. Growth of isolated snails was higher fecundity and longevity than the animals kept in isolation. However, the growth was high in isolation. Thus, the differential energetic investment has lead to distinct patterns of life history. The age influenced the allocation de glycogen and galactogen. However, there was not reduction of glycogen content in the digestive gland. It is suggest that the energy used in reproduction is acquired from food ingestion. There were seasonal changes on the contents these polysaccharides, which are coincident with the reproductive cycle of B. tenuissimus. This result showed that the reproductive seasonality of this species would be controlled by metabolic factors.
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Souza, Bruna Aparecida de. "Efeitos dos extratos aquosos de Bidens pilosa Linné e Mikania glomerata Sprengel (Asteraceae) sobre aspectos biológicos e comportamentais de Subulina octona (Bruguière,1789) (Mollusca, Subulinidae)." Universidade Federal de Juiz de Fora, 2012. https://repositorio.ufjf.br/jspui/handle/ufjf/1969.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O molusco terrestre Subulina octona (Bruguière, 1789) atua como hospedeiro intermediário de helmintos parasitos de humanos e animais domésticos. Em alta densidade populacional também pode atuar como praga agrícola, o que levanta a necessidade de medidas de controle. A busca por moluscicidas de origem vegetal tem se intensificado nos últimos anos devido às vantagens que as espécies vegetais apresentam. Os vegetais Bidens pilosa Linné e Mikania glomerata Sprengel apresentam ampla distribuição geográfica, são frequentemente utilizados na medicina popular e apresentam princípios ativos solúveis em água e com reconhecida atividade moluscicida. Objetivou-se com esse trabalho comprovar a presença desses princípios ativos, calcular as concentrações de referência (CL50 e CL90) sobre adultos de S. octona e avaliar os efeitos das CL50 obtidas sobre aspectos biológicos e comportamentais desse molusco em diferentes fases de desenvolvimento. Para a obtenção das CL50 e CL90 foram utilizadas cinco concentrações do extrato aquoso das espécies vegetais, no qual 30 moluscos (10moluscos/grupo) foram utilizados para cada concentração e para o controle. Os grupos tratados foram expostos à 5mL dos extratos por contato direto com a solução por 24 horas seguidas de 24 horas de recuperação e grupos controle foram expostos a água destilada pelo mesmo período. As concentrações de referência foram obtidas pela análise Probito utilizando o software BioStat 2008, versão 2.5 . As CL50 obtidas foram testadas sobre ovos, jovens recém-eclodidos e jovens de 30 dias e adultos que ficaram expostos aos tratamentos por 24 e 48 horas. Grupos controle ficaram expostos pelo mesmo período em água destilada. Para os adultos foram realizadas três aplicações das CL50 em intervalos de 30 dias. As observações para a análise de repelência em adultos foram realizadas nos primeiros 10 minutos após a primeira aplicação. A eclosão, sobrevivência e reprodução foram avaliadas e os dados comparados pelo teste de Kruskal-Wallis (p<0,05) utilizando o software BioEstat versão 5.0. A análise fitoquímica comprovou a presença de flavonóides, taninos e saponinas nos extratos aquosos dos dois vegetais. As CL50 e CL90 obtida para B. pilosa foi de 51,4mg/mL e 74,1mg/mL respectivamente, e para M. glomerata foi de 44,6mg/mL para CL50 e 71,9mg/mL para CL90. A atividade repelente dos extratos foi verificada logo após a aplicação. A sobrevivência dos adultos foi significativamente reduzida após a segunda aplicação dos extratos. Da mesma forma, a fecundidade diminuiu para os grupos expostos por 24 horas. Não foi verificado diferença significativa na eclosão de moluscos da prole provenientes dos adultos expostos aos tratamentos. Todavia, a eclosão dos moluscos provenientes de ovos expostos diretamente aos extratos aquosos das plantas testadas, foi, em média, significativamente reduzida. O tempo de exposição também influenciou, onde os grupos expostos pelo maior tempo tiveram sua eclosão reduzida. Os extratos também influenciaram na sobrevivência dos eclodidos proveniente dos ovos tratados e dos jovens-recém-eclodidos e dos de 30 dias. Alterações sobre o crescimento foi verificado para os tratamentos. Os resultados observados nesse estudo provavelmente foram provocados pela mistura complexa de princípios ativos que podem interagir de forma sinérgica, aditiva ou até facilitando a absorção de algum composto. A facilidade na obtenção, preparação e aplicação desses extratos tornam esses vegetais possíveis candidatos para programas de controle desse molusco.
The land snail Subulina octona (Bruguière, 1789) is an intermediate host of helmints that parasitizes humans and domestic animals. In high densities it can also be a crop pest making necessary the application of control measures. The search for plant molluscicide increased in last years due to its advantages. The plants Bidens pilosa Linné and Mikania glomerata Sprengel are widely distributed and are frequently used in folk medicine. They have active principles that are water soluble and with proven action against snails. The aim of this study was to confirm the presence of these active principles, to calculate the reference concentrations (LC50 e LC90) in adult S. octona and to evaluate the effects of the LC50 obtained on biological and behavioral aspects of this snail in different development phases. To obtain the LC50 e LC90 five concentrations were utilized for each plant aqueous extract, and 30 snails (10snails/group) were utilized for each concentration and for control group. The groups were exposed to 5mL of the extracts by direct contact with the solution for 24 hours followed by 24 hours of recovery period and the control groups were exposed to distilled water for the same time period. The reference concentrations were obtained using the Probit analysis through (BioStat 2008 software, version 2.5). The LC50 obtained were tested on eggs, newly hatched, 30 day old individuals and adults that were exposed to the treatments for 24 and 48 hours period. Control groups were exposed to distilled water. For the adults, were utilized three applications of the LC50 every 30 days. The observations to analyse the repellency in adults were made at the realized at the 10 first minutes after the first application. The hatchability, survival and reproduction were evaluated and the data were compared by using the Kruskal-Wallis (p<0,05) (BioEstat software, version 5.0). The phytochemical analysis confirmed the presence of flavonoids, tannins and saponins in the aqueous extracts of both plants. The LC50 and LC90 obtained for B. pilosa was 51.4mg/mL and 74.1mg/mL respectively, and for M. glomerata was 44.6mg/mL for LC50 and 71.9mg/mL for LC90. The repellency of the extracts was verified after the application. The survival of adult snails was signficantly diminished after the second application of the extracts. In the same way, the fecundity was reduced in groups exposed for 24 hours. It was not verified significantly difference in offspring hatchability from adult snails exposed to the treatment. However, the eggs exposed directly to the treatments had significantly reduction in hatchability means. The mean hatchability of the snail from eggs directly exposed to the treatments were significantly reduced. The extracts also influenced the survival of snails hatched from treated eggs, in newly hatched and 30 day old individuals. Alterations on growth were verified in all treatments. The results obtained in this study were probably due to the complex combination of the active principles that can interact synergistically, aditive or antagonist or even facilitating absorption of some compounds. The facility in the plant collection, extract preparation and application of these extracts turn these plants candidates in the control of this species.
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Souza, Fabíola Almeida Matos de. "Ciclo de vida e biologia comportamental de Rumina decollata Linnaeus, 1758 (Mollusca, Subulinidae) em laboratório." Universidade Federal de Juiz de Fora, 2013. https://repositorio.ufjf.br/jspui/handle/ufjf/1058.
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O filo Mollusca é composto por diversas espécies que são amplamente utilizadas pelo ser humano na economia em setores diversos como alimentação e saúde pública. Devido a isto, houve intensa disseminação de espécies exóticas entre diversas regiões do globo, tornando necessário o conhecimento sobre a biologia e o comportamento desses moluscos nas áreas onde foram introduzidos para se prever os possíveis danos à malacofauna e flora nativas. Tais estudos também são relevantes para o desenvolvimento de estratégias de manejo quando o aumento excessivo da população de uma determinada espécie torna-se prejudicial ao ambiente, além de uma possível utilização de moluscos como ferramentas de controle biológico. Rumina decollata (Linnaeus, 1758) é uma espécie oriunda da região Mediterrânea que foi introduzida na América do Norte para o controle biológico de Helix aspersa Müller, 1774 em plantações de frutas cítricas, porém, houve intenso aumento das populações que levou a uma proibição da entrada e criação de R decollata em algumas regiões dos EUA e atualmente, a espécie é encontrada em países da América do Sul como Argentina e Brasil. Não há estudos que descrevam os atos comportamentais nem a biologia da espécie no Brasil, apesar da sua ocorrência em algumas regiões do país. Este estudo foi realizado para esclarecer aspectos biológicos tais como crescimento, reprodução, mortalidade e comportamento de R. decollata em condições de laboratório. Para a realização dos experimentos sobre a biologia da espécie, foram utilizados moluscos criados agrupados (10 moluscos/ grupo) e isolados (30 moluscos/grupo). Para observar o padrão de crescimento os moluscos foram pesados e medidos mensalmente para posterior comparação. Os moluscos foram criados isolados para verificar a ocorrência de autofecundação, e comparar tempo para alcance de maturidade, fecundidade e eclodibilidade dos ovos. Os resultados demonstraram que moluscos agrupados e isolados diferiram quanto ao crescimento entre 0 a 60 dias, com uma maior taxa para os moluscos criados isolados, seguido de uma estabilização, caracterizando um crescimento determinado, padrão que difere do encontrado para outros subulinídeos. O peso diferiu significativamente entre isolados e agrupados, com maiores valores para moluscos agrupados. Não houve mortalidade para os moluscos isolados durante o período de observação. O alcance da maturidade sexual ocorreu a partir de 90 dias para os agrupados e 120 dias para os isolados. Verificou-se a ocorrência de autofecundação, porém, os moluscos realizaram preferencialmente a fecundação cruzada, a qual também foi responsável por um maior número de ovos viáveis. Ficou evidenciado que R. decollata apresentou diferenças em sua biologia quando comparada com os estudos de outros autores em diferentes localidades. Para a descrição do comportamento e interações entre adultos e jovens, foram utilizados 30 moluscos jovens e o mesmo número de adultos observados durante 24 horas através do método scan sample a intervalos de 20 minutos. Os moluscos adultos e jovens apresentaram-se mais ativos durante o período noturno, com somente um ato comportamental (“Interagir”) diferindo significativamente durante as 24 horas de observação, com maior interação entre os adultos. Adultos e jovens diferiram quanto ao ato “Alimentar” e “Deslocar” somente em dois horários e três distintos do período noturno respectivamente. Não houve influência da umidade relativa do ar no comportamento dos moluscos, porém, houve correlação entre a temperatura média e a atividade de adultos e jovens. Tais resultados comprovam que o horário de atividade de R. decollata é semelhante ao descrito para diversos moluscos gastrópodes, inclusive subulinídeos. A diferença entre os atos comportamentais de jovens e adultos demonstra uma possível diferenciação de nichos.
The phylum Mollusca is composed by several species that are largely used in many economic sectors such as food and public health. Because of it, there was a dissemination of alien species among several parts of the world, what make necessary the knowledge of life cycle and behavior in the regions of introduction of these species, in order to predict possible damages to native fauna and flora. These studies are also important to the development of control strategies in case of populations increase, turning a species into a pest, besides, its is useful tin case of using a species as biological control. Rumina decollata (Linnaeus, 1758) is a land snail from Mediterranean area that was introduced in the North of USA to control populations of Helix aspersa Müller, 1774 in citrus sp plantations, however, occurred an overpopulation that lead to a prohibition of R. decollata entrance and rearing in this country and nowadays, the species is found in South America in Argentina and Brazil. There is a lack of studies that describe the behavioral biology and the lifecycle of this species in Brazil, despite its occurrence in some districts of the country. This study was realized in order to clarify biological traits such growth, reproduction and behavior of this species in laboratory conditions. For life cycle assay, snails were created grouped (10 snails/ group) and isolated (30 snails 1/goup). To analyze growth patterns, snails were weighted and measured every month. The isolation was to verify the occurrence of self-fertilization and to compare the time to onset sexual maturity, fecundity and egg hatchability. Results showed that snails grouped and isolated differed in growth between 0 and 60 days, with high rate to isolated snails. There was stabilization that characterize determinate growth pattern that differ from other subulinids. Weight was significantly different, with higher rates to grouped snails. It was not observed mortality in isolated snails during the observation period. The reaching of maturity occurred from 90 days for grouped snails and from 120 days to isolate. It was verified selffertilization, although the cross fertilization seems to be the pattern what can be confirmed by the higher number of viable eggs. It was evidenced that R. decollata showed differences in its biology when compared to studies realized in other regions. To describe behavior of juvenile and adult individuals, it was used 30 snails of each age, observed for 24 hours by the scan samplé method. Adult and juvenile were more active during nocturnal period, with only one act (“Interact”) significantly different during the 24 hours, with more interaction between adults. Adult and juvenile showed difference in the acts “Feed” and “Dislocate” in two and three different hours in nocturnal period respectively. It was not observed influence of relative air humidity, but there was a correlation between mean temperature and the activity of adult and juvenile snails. Such results demonstrate that the activity period of R. decollata is alike to other terrestrial snails, including subulinids. The difference between behavioral displays of juvenile and adults indicate the occurrence of niche differentiation.
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Santos, Tércia Vargas dos. "Variabilidade conquiliológica, anatômica e molecular em Subulina octona (Brugüière, 1789) (Mollusca, Gastropoda, Subulinidae)." Universidade Federal de Juiz de Fora, 2012. https://repositorio.ufjf.br/jspui/handle/ufjf/1549.
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FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais
O conhecimento atual da diversidade de moluscos terrestres não leva em consideração a variabilidade intra e interespecífica, principalmente no que diz respeito a espécies de clima tropical, como é o caso de Subulina octona. A associação entre análises morfométricas e moleculares, ambas inéditas para estudos em S. octona, tem permitido a identificação de táxons e a compreensão de suas relações. No presente estudo, foi observada variabilidade na concha, no sistema reprodutor, na coloração corporal e na estrutura molecular com base na COI do DNA mitocondrial de populações de S. octona. A análise morfométrica ao longo do desenvolvimento demonstrou que a variabilidade intrapopulacional diminuiu ao longo do desenvolvimento dos moluscos e foi maior nas populações com dois fenótipos de coloração corporal. O componente que melhor explicou a variabilidade na maior parte da vida foi o comprimento da concha, seguido pela largura da abertura. Como a distância geográfica não explicou a variação na forma da concha, acredita-se que possa estar havendo um considerável fluxo gênico por ação antrópica e que a seleção esteja atuando modelando os padrões morfométricos na espécie. O fato de os padrões de crescimento e a forma final da concha na idade adulta terem variado entre populações mesmo em condições idênticas de criação, demonstra o importante papel da determinação genética. A anatomia do sistema reprodutor foi semelhante entre populações, mas a morfometria foi variável entre indivíduos e entre populações. Dentro das populações a porção masculina do sistema reprodutor foi mais variável que a feminina, conforme esperado para estruturas que sofrem seleção sexual. Já entre populações, a maior diferença foi observada na porção feminina. O sistema reprodutor foi mais variável que a concha, porém apresentando compatibilidade entre as populações quanto à forma das estruturas. A diferenciação morfométrica e fenotípica para coloração corporal não foram corroboradas pela variação molecular uma vez que indivíduos com mesmo haplótipo COI foram variáveis para concha e cor da massa cefalopodal. O modelo de evolução neutra das sequências foi aceito para as amostras analisadas apesar de nem todas as mutações serem silenciosas, destacando o papel da deriva na evolução da espécie. A baixa variabilidade de algumas populações pode ser reflexo da forte endogamia, devido à baixa capacidade de dispersão e capacidade de autofecundação da espécie, a despeito do fluxo gênico via dispersão passiva por ação antrópica. Foi observada estruturação genética para uma das populações, por apresentar um haplótipo exclusivo e formação de uma linhagem diferenciada no dendrograma de Máxima Verossimilhança. As diferentes linhagens apresentaram diferenças morfométricas para estruturas reprodutivas que evidenciam a evolução independente das linhagens. Tais observações devem ser investigadas com mais detalhes a fim de confirmar a existência de espécies crípticas. A análise da diversidade encontrada no presente estudo forneceu ainda subsídios para pesquisas posteriores que visem esclarecer sobre a origem de S. octona.
Current knowledge of the diversity of terrestrial molluscs does not take into account the intraand interspecific variability, particularly with regard to species from tropical climates, as is the case of Subulina octona. The association between morphometric and molecular analysis, which remain unpublished for studies in S. octona, has allowed the identification of taxa and understanding of their relationships. In the present study, we observed variability in the shell, reproductive system, body color and molecular structure based on COI of mitochondrial DNA between populations of S. octona. Morphometric analysis along development showed that within-population variability decreased during the development of molluscs and was higher in populations with two body color phenotypes. The best component to explain the variability in most of lifetime was the shell length, followed by the opening width. Because the geographic distance does not explain the variation in shell shape, we believe that there may be considerable gene flow favored by human activities and that the selection may be shaping the morphometric patterns in this species. The interpopulation variation in growth patterns and shell shape in adulthood, even under identical rearing conditions, shows the important role of genetic determination. The anatomy of reproductive system was similar between populations, but the morphology was variable between individuals and populations. Within populations, the male portion of the reproductive system was more variable than the female portion, as expected for structures that are under sexual selection. Among populations, the largest difference was observed in the female portion. The reproductive system was more variable than the shell, but showed interpopulation compatibility for the shape of structures. Morphometric and body color phenotypic differentiation were not corroborated by molecular variation since individuals with the same COI haplotype were variable to shell shape and color head-foot mass. The neutral evolution model of sequences has been accepted for the samples analyzed even though not all mutations are silent, highlighting the role of drift in the species evolution. The low variability of some populations may reflect the strong inbreeding due to low dispersal ability and capacity of selfing species, in spite of gene flow via passive dispersal by human activities. We observed a genetic structure of populations, because it presents a unique haplotype and form a distinct lineage in the maximum likelihood dendrograma. Different lineages showed morphometric differences in reproductive structures, which show their independent evolution. These observations must be investigated in more detail to confirm the existence of cryptic species. The analysis of the diversity found in this study also provided grants for further research aimed at shedding light on the origin of S. octona.
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Saafi, Ismail. "Contribution de la malacofaune continentale dans l'économie de subsistance des populations capsiennes et néolithiques en Tunisie durant l'holocène." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0134.
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La malacofaune continentale constitue l’une des caractéristiques d’une rammadiya. Si les quantités de coquilles découvertes sont remarquables, les travaux sur ce sujet sont rares et sommaires. L’étude de la malacofaune terrestre provenant de huit sites en Tunisie vise à comprendre son rôle dans l’économie de subsistance durant le Capsien et le Néolithique.L’alimentation représente la principale utilisation des mollusques. A l’aide de plusieurs méthodes, la reconstitution de la chaîne opératoire liée à la consommation des gastéropodes a été établie. Cette faune a un rôle secondaire dans le régime alimentaire des groupes humains. La variation des quantités des coquilles découvertes dans chaque site est en relation avec l’abondance des espèces lors de la période de collecte. La dominance des espèces albinos du Capsien Typique au Néolithique montre la stabilité de stratégie de ramassage : Une collecte principale vers la fin du printemps et le début de l’été suivie par un ramassage secondaire durant plusieurs périodes de l’année.Les modifications identifiées sur la paroi des tests sont représentés surtout par les perforations régulières qui servent principalement à l’extraction de l’animal de sa coquille et à la production des colliers. Au Capsien, les perforations concernent principalement les espèces prédominantes. Au Néolithique, les espèces exploitées sont plus nombreux. Ce geste est limité aux sites continentaux. La présence des perforations systématiques dans certains sites représente des traditions culinaires et culturelles uniques de certains groupes humainsContinental malacofauna is one of the characteristics of a rammadiya. While the amount of shells discovered is remarkable, work on this topic is rare and summary. The study of terrestrial malacofauna from eight sites in Tunisia aims to understand its role in the subsistence economy during the Capsian and Neolithic periods.Food is the main use of molluscs. Using a number of methods, the reconstruction of the chain of operation related to the consumption of gastropods was established. This fauna has a secondary role in the diet of human groups. The variation in the quantities of shells found at each site was related to the abundance of species during the collection period. The dominance of the Albino species of Capsian Typical to Neolithic shows the stability of collection strategy: A primary collection in late spring and early summer followed by a secondary collection for several periods of the year.The changes identified on the test wall are mainly represented by regular perforations, which are used mainly to extract the animal from its shell and produce the necklaces. In Capsien, perforations mainly concern predominant species. In Neolithic times, there are more exploited species. This gesture is limited to continental sites. The presence of systematic perforations in some sites represents unique culinary and cultural traditions of certain human groups
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Nunes, Gleisse Kelly Meneses. "Diversidade, variação altitudinal e fatores ambientais que influenciam a distribuição da malacofauna terrestre em cinco localidades da Ilha Grande, Angra dos Reis, Rio de Janeiro, Brasil." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=5570.
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Hylander, Kristoffer. "Living on the edge : effectiveness of buffer strips in protecting biodiversity in boreal riparian forests /." Doctoral thesis, Umeå : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-233.
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ffitch, Madeline S. "Stay and Fight, a Novel." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1542290577052013.
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Liang, Shih-yu, and 梁師瑀. "Trail-Following Behavior of Land Snails." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/94587822451297950124.
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碩士國立中山大學
生物科學系研究所
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Pheromone is produced by animals and secreted in variously ways to form trails which can be used by conspecifics or between species. The functions for trail-following in terrestrial gastropod are aggregating, mating, predating, homing and energy saving. In this study, I used two species of terrestrial gastropod, Satsuma succincta and Cyclophorus friesianus, which are abundance in Mt. Shoushan, Kaohsiung, Taiwan to test three questions: (1) Do these land snails follow the chemical trail laid by conspecifics? (2) If followed, what kind of chemical trail would they follow? (3) Whether trail-following is a mating strategy for dioecious species? Every following behavior test I used two snails, marker for leaving trail and tracker for following trail. Both of the two species showed trail-following behavior, and there were no difference between two studying areas. S. succincta had trail-following behavior both by mucus and odor, but odor was the main chemical cue for C. friesianus. In test for sexual difference on trail-following behavior, although there were no significant difference between the different and same sex groups, the frequency was higher in different sex group and female followed by male was higher than other sexual combining pairs. This test supported that mucus trail-following might be a purpose for energy saving due to the trail overlapped about half of the marker’s trail.
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Hsiung, Ta-Wei, and 熊大維. "The Spatial Distribution Models of Land Snails in I_Lan." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/13121254323651875126.
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碩士國立臺灣大學
森林環境暨資源學研究所
97
Studying the spatial distribution of organisms is one essential topic for ecological research. By using data of field investigations, spatial distribution database of species and prediction models that depict environmental relationships of species distribution can be constructed and will provide tremendous helps for relevant issues such as identifying biodiversity hotspot, habitat conservation, and species management. The spatial distribution of Camaenidae in Taiwan has been reported, however no study has constructed spatial distribution models and predicted potential habitats of land snails in Taiwan. This study was aimed to (1) investigate the spatial distribution of land snails in I-Lan County ; (2) link the species presence records with environmental factors by Geographic Information System; and (3) construct spatial distribution models that predict occurrence probabilities and potential habitats of species. During the four-year field investigations, 226 sites were sampled, and 3,252 individuals (1,515 living snails and 1,737 emptied shells) were recorded, including 24 families and 89 species. Logistic regression and Ecological-Niche Factor Analysis (ENFA) were employed to link the records of land snails with environmental factors and predict the occurrence probability of land snail species in I-Lan County. Results showed that distribution hotspots of most species were located in the borders of I-Lan Plain with surrounding foothills. Non-native species and common species were mainly distributed in the plains. The occurrence probabilities were low in mountain areas for most species. Nevertheless, many tiny land snail species were tended to distribute in mid-elevation areas in I-Lan County, instead of lower-elevation foothills and plains. Differences in predicted distribution, model predictor variables, and model accuracy were found between logistic regression and ENFA. Although the overall accuracy of logistic regression was satisfying, its sensitivity was low, and the accuracy of ENFA was generally low. For species with more presence records, logistic regression and ENFA provided better match in predicted distribution and hotspots and had higher model accuracy, indicating the predicted results and model accuracy might be affected by the number of presence records. The discrepancy in the predictions of logistic regression and ENFA might result from (1) uneven distribution of sampling sites, (2) insufficient presence records of species, (3) not match the model presumptions and prerequisites, and (4) inadequate environmental factors.
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Hwang, Chung-Chi, and 黃重期. "Mitochondrial DNA Analysis of the Phylogenetic Relationship of the Land Snails Genus Camaena." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/98157161750118387658.
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碩士國立中山大學
生命科學研究所
83
Using mitochondrial DNA RFLP, multivariate analysis of shell morphology and comparison of genitalia system , I studied the phylogeny and taxonomy of 3 species of Camaena in Taiwan and neighboring islands. The estimated evolution rate of mtDNA of Camaena is faster than other organisms. The total length of mtDNA is from 17 kb to 26 kb due to several tandem repeat sequence, each with a length about 200 bp. The results suggest that the two populations of dextral C. bacca were the result of homoplasy from adjacent sinistral C. batanica. The characters of mtDNA and morphology of these two species are very similar, but they can still be classified as different paraphyletic species . The shell size variation of C. batanica can not be explained by the mtDNA phylogeny, but might be influenced by nutrients or climate factor. The morphological differences of C. batanica are not great, so all the C. batanica in Taiwan, Lanyu and Lutao should belong to the same subspecies. On the other hand, the mtDNA phylogeny of two populations of C. succincta is highly divergent , and this high divergence may result from historical divergence by geographical isolation. Nevertheless, the morphological characters of the two are very similar, so the phylogeny and taxonomy of this species need further study. According to this study, the ecological factors would greatly modify the shell morphology, so it is suggested that the taxonomy of Camaena in Taiwan need further study.
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Huang, Chih-Wei, and 黃致維. "Speciation history of land snails Aegista subchinensis (Möllendorff, 1884) and its related species." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/7sh64r.
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博士國立臺灣師範大學
生命科學系
103
Species is the fundamental unit for evolutionary biology. The big question of how species evolved should be based on the correct assignment of species. Integrating multiple independent evidences improve the inferences of systematics and speciation scenario. The Ryukyu Islands is an island chain located on the margin of Asia Continent in East Asia. Many phylogenetic or phylogeographic research conducted in this region were limited to vertebrates and arthropods with relatively high dispersal ability. The speciation history of terrestrial restricted animals with low dispersal ability has not yet been explored. In this dissertation, I focused on the speciation history of land snail Aegista spp. distributes in Taiwan, Ishigaki Island and Miyako Island. A cryptic species was identified from A. subchinensis in eastern Taiwan and described as a new species named A. diversifamilia based on molecular and morphological evidences (Chapter 2). Novel nuclear markers were developed from transcriptome since limited nuclear marker available for Mollusca (Chapter 3). In order to calculate a reasonable molecular clock that could be applied in Aegista spp., divergence time of Aegista was estimated based on calibrated mitogenomic phylogeny with three additional newly sequenced mitogenome, A. mackensii, A. diversifamilia and Dolicheulota formosensis (Chapter 4). Based on these results, species tree, demographic history and historical gene flow were estimated using multiple loci dataset (Chapter 5). The species tree inferred from the combination of two mitochondrial and ten nuclear DNA suggested A. subchinensis was diverged about 2.05 Mya, A. vermis separated from the common ancestor of A. diversifamilia and A. oculus at 1.55 Mya, and the latter ancestor speciated subsequently around 1.40 Mya. Vicariance speciation with asymmetric gene flow from A. diversifamilia and A. oculus was inferred based on IMa2 analysis. Statistical tests of highly polymorphic genes suggested no signature of population expansion for each species, while population fluctuation was inferred using extended Bayesian skyline plot.
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Lan, Jui-Chien, and 藍瑞倩. "Investigation of Terrestrial Molluscs (Land Snails) Species in Yisheng Village,Fuxing District, Taoyuan." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/q9nh6d.
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碩士國立臺北教育大學
自然科學教育學系
105
The main purpose of this study was to comprehend the relationship between land snail species diversity and their micro-habitat environment in Yisheng Village. Six smapling lines and one smapling point were selected for research from Feb, 2016 to May,2017. 29 species with 262 living land snails and 8 species land snail shells were recorded during this investigation. There were 65.6% arboreal land snails, 19.1% sheltered ground land snails and 15.3% exposed round land snails in total living land snails. The environmental factors were measured at the location of land snails were found, with 68% confidence interval, the temperatures of land snail micro-habitats were between 21.5 ℃ ~ 29.0 ℃, the humidities were between 76.5% ~ 87.2% and the light levels were between 108.5 Lux ~ 517.5 Lux. Xiaowulai scenic hiking trails and Shueiyuandi trails had the narrow land for Alocasia odora and Elatostema platyphylloides growing which provided habitats for arboreal land snail species, the leaf litter of bamboo forest in these area provided habitats for epigeal land snail species. The snail habitats were broken by steep slope of three mountain trails which had plenty of land snail species with few population. The steep slope of mountains and rivers prevented the migratioin of exotic species, therefore land snail species in Yisheng elementary school and in the entrance of Shueiyuandi trails were significantly different from land snail species in Xiaowulai scenic hiking trails and in the three mountain trails. According to historical record of biogeography, some districts of northern Taiwan had more than 10 as same land snail species as in Yisheng Village, most of these districts also belong to Xue Mountain Range, this phenomenon might indicate land snail species in Yisheng Village expanded their population through Xue Mountain Range.
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Guo, Din-Wun, and 郭丁溫. "The Relationship of Species Diversity and Environmental Factors of Land Snails in Northern Chaishan, Kaohsiung City." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/95039628915489765916.
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碩士高雄師範大學
生物科技系
98
ABSTRACT This study is to investigate species diversity and environmental factor of land snails in northern Chaishan. Five study regions were selected based on different vegetation structures. Major plant species in 5 regions respectively included Ehretia resinosa, Arenga tremula, Ficus microcarpa, Alocasia odora and mixed forest. Six species and 2221 specimens of land snails were recorded from May 2008 to June 2009. Six snails species could be separated into three functional niches of semi-arboreal, exposed ground and sheltered ground groups. Sheltered ground groups have the highest abundance of small snails (about 90 %). Human disturbance did not cause significant different on species richness and diversity of land snails except in Arenga tremula region. The result showed that the low human disturbance zone in Arenga tremula region has low species diversity may due to severe water erosion in the rainy season. The species diversity index (H，) of land snails were significant different among five study regions. Studies on feeding habits of snails found that no preference for vegetation among species. Soil hardness, moisture, pH, Ca and carbon content are significant different among five study regions. Soil Ca content may be the primary factors causes the species diversity varied, and while soil pH, and soil moisture also contributed. In this study, mixed forest and the Arenga tremula region located in Creek Shell Mound near Chaishan Lungcheng Shrine, exhibited diverse species of snails. Thus, Lungcheng Shrine Creek Shell Mound is not only a cultural assets but also rich in ecological resources, should be properly preserved.
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Gouveia, Cátia Sofia Alves. "Predicting the impacts of climate change on the distribution and conservation of endemic forest land snails of Madeira Island." Master's thesis, 2014. http://hdl.handle.net/10362/13783.
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Climate change is emerging as one of the major threats to natural communities of the world’s ecosystems; and biodiversity hotspots, such as Madeira Island, might face a challenging future in the conservation of endangered land snails’ species. With this thesis, progresses have been made in order to properly understand the impact of climate on these vulnerable taxa; and species distribution models coupled with GIS and climate change scenarios have become crucial to understand the relations between species distribution and environmental conditions, identifying threats and determining biodiversity vulnerability.
With the use of MaxEnt, important changes in the species suitable areas were obtained. Laurel forest species, highly dependent on precipitation and relative humidity, may face major losses on their future suitable areas, leading to the possible extinction of several endangered species, such as Leiostyla heterodon.
Despite the complexity of the biological systems, the intrinsic uncertainty of species distribution models and the lack of information about land snails’ functional traits, this analysis contributed to a pioneer study on the impacts of climate change on endemic species of Madeira Island. The future inclusion of predictions of the effect of climate change on species distribution as part of IUCN assessments could contribute to species prioritizing, promoting specific management actions and maximizing conservation investment.