242 research outputs found

    Check list of ground-dwelling ant diversity (Hymenoptera: Formicidae) of the Iguazú National Park with a comparison at regional scale

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    We describe the ant fauna of Iguazú National Park (INP), a region of high biodiversity andendemism in northeastern Argentina that includes the southernmost protected area ofthe Atlantic Forest (AF). Ants were sampled over seven periods from 1998 to 2011 usinga variety of techniques. We also surveyed museum collections and the scientific literatureto obtain additional records of ants from INP. In addition to providing a species list, wecompare ant composition of INP to other sites in the Upper Paraná, Serra do Mar CoastalForest and Araucaria ecoregion of AF. A total of 172 ant species belonging to 56 genera arereported; 56 species are new records for Misiones Province and 39 species are reportedfrom Argentina for the first time. Alto Paraná and Canindeyú departments in Paraguaypresent the most similar ant fauna to INP. Serra da Bodoquena in Brazil and Pilcomayoin Argentina showed higher similarity with the Upper Paraná AF ecoregion, despite thatSerra da Bodoquena is composed of a mix of ecoregions. Ant diversity was lower in UpperParaná than in Serra do Mar Coastal Forest ecoregion. This difference may result fromhigher primary productivity and a greater altitudinal variation in the coastal region.Fil: Hanisch, Priscila Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: Calcaterra, Luis Alberto. Fundación para el Estudio de Especies Invasivas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leponce, M.. Royal Belgian Institute of Natural Sciences. Aquatic and Terrestrial Ecology unit; BélgicaFil: Achury, R.. University of Illinois at Urbana; Estados UnidosFil: Suarez, A. V.. University of Illinois at Urbana; Estados UnidosFil: Silva, R. R.. Museu Paraense Emílio Goeldi; BrasilFil: Paris, Carolina Ivon. Universidad de Buenos Aires; Argentin

    Above-belowground effects of the invasive ant Lasius neglectus in an urban holm oak forest

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    Consultable des del TDXTítol obtingut de la portada digitalitzadaLas hormigas invasoras desplazan a las especies de hormigas nativas y otros artrópodos. Como consecuencia, las interacciones biológicas del sistema invadido y los servicios ecológicos prestados por las especies nativas son modificados. El objetivo de este trabajo fue investigar los efectos de la hormiga invasora Lasius neglectus sobre algunos de los componentes superficiales y subsuperficiales de un encinar urbano y compararlos con los efectos de las hormigas nativas, en particular con Lasius grandis. Lasius neglectus visita principalmente árboles aislados donde permanece más meses atendiendo áfidos. Por el contrario, las hormigas nativas no visitaron los árboles según su ubicación (aislado, borde o centro del bosque). Excepto en el caso de la hormiga nativa Lasius grandis, que permaneció más tiempo en los árboles aislados cuando Lasius neglectus no estaba presente en el fragmento. La riqueza de especies nativas de hormigas y su visita a los árboles fue menor en fragmentos de bosque con Lasius neglectus. Crematogaster scutellaris, Temnothorax lichtensteini y Lasius grandis lograron coexistir con la hormiga invasora. La estructura de la comunidad de hormigas nativas en fragmentos con o sin Lasius neglectus mostró un patrón aleatorio. Entre Mayo y Octubre, en las encinas se encontraron dos especies de áfidos, Hoplocallis picta, ocasionalmente atendido por las hormigas, y Lachnus roborisun un mirmecófilo obligado. En encinas visitadas por la hormiga invasora, se observó que la abundancia de Lachnus roboris tendió a duplicarse, como así también su producción de melaza, porcentaje de colonias atendidas comparado con los resultados obtenidos en encinas visitadas por la hormiga nativa Lasius grandis. Consecuentemente, durante el periodo estudiado la hormiga invasora duplicó su colecta de melaza por encina respecto de la hormiga nativa. Las colonias de Lachnus roboris se ubicaron principalmente sobre las bellotas. Sin embargo, no se detectó ningún efecto en la producción o calidad de bellotas y en la emergencia o calidad de las plántulas. Ambas especies de hormigas capturaron principalmente Pscópteros y Hoplocallis picta como fuente de proteínas. El porcentaje de obreras que llevaba insectos o trozos de artrópodos entre sus mandíbulas fue superior para Lasius grandis. La comunidad de artrópodos y el nivel de herbivoría no fueron modificados por la presencia de una u otra especie de hormiga. Sin embargo, en las encinas visitadas por Lasius neglectus las arañas, los curculiónidos y los áfidos tendieron a incrementar su abundancia mientras que las larvas de coccinélidos (predadores de áfidos) disminuyeron marcadamente. La melaza que no es recogida por las hormigas puede incorporarse al suelo disuelta en el agua de trascolación de la copa como carbono orgánico disuelto (COD). La colecta de melaza de Lasius neglectus disminuyó el COD disuelto en el agua de trascolación de las encinas lo cual indicaría una interrupción del flujo de materia y energía entre la copa de las encinas y el suelo aledaño. En relación a los efectos subsuperficiales se observó que el contenido de nutrientes en el suelo aledaño a las encinas visitas por Lasius neglectus fue mayor respecto del encontrado en encinas visitadas por hormigas nativas. Asimismo, la comunidad de microorganismos se diferenció según la presencia de hormigas nativas o de la invasora; tendiendo la biomasa microbiana del suelo a ser mayor en el caso de la presencia de Lasius neglectus. Según la localidad estudiada, la calidad de la hojarasca producida fue menor en los árboles visitados por Lasius neglectus. Sin embargo, la descomposición de la hojarasca de encina no fue modificada por la presencia de la hormiga invasora. Se concluye que la presencia de Lasius neglectus modifica aquellos componentes, superficiales y subsuperficiales, del sistema de la encina que están directa o indirectamente relacionados con la colecta de melaza.Invasive ants displace native ant species and other arthropods. As a consequence, at the invaded system biological interactions and ecological services provided by native ant species are modified. The aim of this study was to investigate some of the above-belowground effects of the invasive ant Lasius neglectus in an urban holm oak forest and to compare these effects with those of native ant species, in particular related to Lasius grandis. Lasius neglectus mainly visited isolated trees where workers remained more months tending aphids and other insects. On the contrary, native ant tree visitation was not related to tree position in the fragments (isolated, edges or core trees). The only exception was the native ant Lasius grandis which remained more months at isolated trees in fragments where Lasius neglectus was not present. Native ant species richness and its tree visitation were lower at fragments where Lasius neglectus was present. Crematogaster scutellaris, Temnothorax lichtensteini y Lasius grandis were able to coexist with the invasive ant specie. Community structure of native ants did not differ from a random pattern with or without Lasius neglectus. Some effects of the ant presence were investigated in detail at the holm oak (Quercus ilex) since this tree was the most abundant at the studied forest fragments. Between May and October, two aphid species were found feeding at holm oak canopy: Hoplocallis picta, which was occasionally tended and Lachnus roboris which was the main tended species. At holm oaks visited by the invasive ant, the abundance of Lachnus roboris tended to increase twice, as well as their honeydew production related to results obtained at holm oaks visited by the native ant Lasius grandis. The percentage of tended colonies tended by Lasius neglectus was higher compared to the percentage tended by Lasius grandis. As a consequence, at the studied period, the invasive ant collected two fold of honeydew per tree related to the native ant. At holm oaks visited by Lasius neglectus or Lasius grandis colonies of Lachnus roboris fed mainly on acorn petiole or on their cap. However, there was not any difference of acorn production acorn or quality and sapling emergency or quality between these holm oaks. Both ant species mainly captured Pscoptera and Hoplocallis picta as source of proteins. The percentage of workers carrying insects or pieces of arthropods in its jaws was higher for Lasius grandis. Arthropod community and herbivory level was not modified due the presence of the invasive or the native ant. However, some particular groups showed differences of its abundance. At holm oaks visited by Lasius neglectus, spiders, weevils and aphids tended to increase its abundance while ladybird larvae (aphid predators) decreased markedly. Honeydew production that was not collected by ants may reach the soil dissolved in throughfall as dissolved organic carbon (DOC). Honeydew collection by Lasius neglectus decreased DOC content in throughfall. This result suggests that the invasive ant interrupts the flux of energy and matter between canopy and the soil surrounding holm oaks. In relation with belowground effects of Lasius neglectus soil nutrient content was higher beneath holm oaks visited by the invasive ant in relation to those trees visited by native ants. Soil microbial community was characterized by the presence of Lasius neglectus and microbial biomass tended to increase beneath holm oaks visited by this invasive ant. Depending on the study site, litter quality was lower at holm oaks visited by Lasius neglectus. Litter decomposition was not modified by the presence of the invasive ant. I conclude that Lasius neglectus presence modifies those below-aboveground components of the holm oak system that are directly or indirectly related to honeydew collection

    The fragrant orchid Vanilla chamissonis: an appraisal of the genetic structure of wild populations from Osununú Natural Reserve (Misiones, Argentina)

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    The commercial crops of vanilla face a significant risk of genetic erosion due to various factors. Vanilla chamissonis, a species with promising bioeconomic compounds, is found in limited regions in Argentina, particularly in the Osununú Natural Reserve in San Ignacio, Misiones, where it grows wildly in sectors (nuclei). This locally adapted germplasm of V. chamissonis holds considerable value and needs preservation efforts. In this study, we genetically characterized unexplored V. chamissonis germplasm and identified specimens within a phylogenetic framework using nuclear and plastid markers. The genotyping revealed that at least four gene pools contribute to the genetic diversity of these plants, with approximately 81% of total genetic variation allocated within populations. Sexual reproduction seems to predominate, and population N1 is a candidate for conservation. There is a genetic discontinuity between northeastern and southwestern nuclei,due to their different genetic constitutions and the tenuous isolation by distance. Phylogenetic results confirm the surveyed vanilla germplasm as V. chamissonis. This research provides essential insights for guiding the ongoing conservation and management efforts at the Osununú Reserve.Fil: Cascales, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Paris, Carolina Ivon. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Gottlieb, Alexandra Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

    Semantic errors in children’s narratives: The problem of reference

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    El objetivo de este trabajo es desarrollar un conjunto de categorías que nos permita describir los errores semánticos de la producción oral de narrativas en niños de 5 años. El enfoque teórico desde el cual se analizan los casos es la lingüística cognitiva funcional ya que se estudia la relación lenguaje – cognición en función de una actividad comunicativa, la lengua en un uso particular: narrar un estímulo visual dinámico. Este estudio se encuadra dentro del programa de investigación denominado ‘Gramática de interfaces’. El análisis es cualitativo y de alcance descriptivo; se les presentó a los niños dos estímulos visuales de un minuto y medio en dos ocasiones y luego se los invitó a que contaran oralmente lo que vieron en cada video. Las narrativas fueron grabadas, luego se transcribieron. En este trabajo en particular identificamos trece errores semánticos, los analizamos y los categorizamos. En un primer paso, contrastamos el significado del verbo utilizado por el niño con el segmento del estímulo potencialmente referido por esa expresión. Identificamos la información en el estímulo que no era referida por la expresión lingüística. Justificamos nuestra interpretación de la expresión como referencia fallida en la relevancia de la información omitida. El resultado son seis categorías que nos permiten empezar a clasificar problemas de la referencia en el discurso infantil.The aim of this paper is to develop a set of categories able to describe semantic slips of the tongue in oral production of narratives by five years old children. The analysis is framed within Cognitive Linguistics since it studies the relation between language and cognition in the context of a communicative situation, language in a particular context of use: the narration of a dynamic visual stimuli. In particular, this study is part of a research program called 'Interface Grammar'. We undertook a qualitative and descriptive analysis. Children were presented twice with two visual stimuli and asked to narrate them. The narratives were transcribed and analyzed. We identified thirteen semantic slips, which were described and classified. First, we contrasted the meaning of the verb used by the child with the segment of the stimuli intended to be referred to by the expression. We identified the information in the stimuli that was not covered by the verb meaning. Then, we justify our interpretation of the use of that expression as a 'failed reference' by the relevance of the omitted information. The result consists of six categories that allow us to start to classify reference problems in children's discourse.Fil: Seno, Vanesa Nancy. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentina. Universidad Nacional de Cuyo; ArgentinaFil: Gattei, Carolina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad Torcuato Di Tella; ArgentinaFil: Paris, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; Argentina. Universidad Nacional de Cuyo; Argentin

    Vine mealybugs disrupt biomass allocation in grapevine

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    Vine mealybug Planococcus ficus Signoret (Hemiptera: Pseudococcidae) is an important phloem-feeding pest species in many grapevine producing areas worldwide. The economic damage of P. ficus is thought to be mainly caused by sooty mould on infested grape clusters and transmission of plant viruses. Direct damage caused by mealybug feeding to grapevine plants (Vitis vinifera, L.) has only been vaguely described or otherwise completely discarded. The present study is the first to give an insight into the direct impacts of P. ficus on vegetative growth and biomass dynamics of grapevine plants. In a screenhouse, three-year-old, potted grapevine plants were infested with mealybugs at two different densities, imitating high and low field infestation levels. Mealybug numbers, plant biomass, leaf area, leaf size and leaf number were monitored over six months and compared to a control treatment without mealybugs. High infestation levels reduced leaf and stem biomass by one third, while low levels of P. ficus impacted only stem biomass, indicating a higher sensibility of the perennial parts of the plant or a reallocation of biomass. Leaf area, size and number were not affected by mealybug feeding. In conclusion, grapevine response to P. ficus is gradual and involves different plant parts depending on the severity of the attack. Contrary to previous assumptions, this study demonstrates considerable direct impacts of mealybug feeding on temporal and perennial parts of grapevine plants.Fil: Schulze sylvester, Maria. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Corronca, Jose Antonio. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Paris, Carolina Ivon. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentin

    Recent range expansion and population genetics of the Argentine ant

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    Dissertação de Mestrado Integrado em Arquitectura, apresentada ao Departamento de Arquitectura da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.A habitação remonta às origens do homem, tendo evoluído do abrigo, que proporcionava proteção, até às casas dos nossos dias, representativas dos indivíduos que as habitam. Na atualidade, no mundo ocidental, a habitação tem que permitir aos seus moradores satisfazer as necessidades básicas de conforto, privacidade, higiene e alimentação, possibilitando um espaço de dormir, de lazer e de trabalho, adaptado às famílias contemporâneas. Numa altura em que é reconhecida a qualidade dos arquitetos portugueses a nível internacional, torna-se pertinente observar/perceber, de que forma estes desenvolvem a habitação unifamiliar, representativa do maior encargo financeiro na vida quotidiana das famílias portuguesas, que conta com o maior número de amadores. De forma a aprofundar a habitação unifamiliar contemporânea, em Portugal, a presente dissertação recorre à análise de dois empreendimentos que lhe servem de casos de estudo, o Bom Sucesso, Architecture Resort, Leisure & Golf, em Óbidos e o Vila Utopia, em Oeiras. Destinados um a primeira habitação e outro a segunda, abrangem um grupo de arquitetos de renome. Para facilitar a sua análise, ambos são estudados quer enquanto conjunto, quer através de algumas moradias representativas dos mesmos.The housing goês back to the origins of man, having evolved from the shelter, which provided protection to the homes of today, representative of the individuals who inhabit them. Today, in the western world, housing is required to allow its residents meet the basic needs of comfort, privacy, hygiene and nutrition, providing a space to sleep, leisure and work, adapted to contemporary families. At a time of recognition of the quality of Portuguese architects internationally, it is pertinent to note/notice, how they develop the single-family housing, representing the largest financial burden on thedaily lives of Portuguese families, which hás the largest number amateur. In order to deepen the contemporary family house in Portugal, this thesis refers to the analysis of two projects which serve as a case study, the Bom Sucesso Architecture Resort, Leisure & Golf in Obidos and the Vila Utopia, in Oeiras. The first one for as the primary housing and the second as a secondary house, cover a group of renowned architects. To facilitate the analysis, both are studied either as a body or through some representative of themselves

    The relationship between teaching experience and effective administrative behavior

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    The purpose of this study was to examine the possible relationship between two variables, years of teaching experience and administrative behavior. The common practice of boards of education requiring teaching experience as one of the criteria necessary for employment as principal provided the impetus needed to examine quantitatively this possible correlation. The implications of such a requirement prompted the development of a second phase of the study which qualitatively examined the world of the principalship as perceived by' practicing administrators. As a result of this two-phase study, it was determined that, mainly due to the bureaucratic structure of our public school system, very little leadership behavior is exhibited by the school principal. On the other hand, due to the school structure, the main type of behavior exhibited by principals is administrative. The participating principals indicated that administrative behavior is advocated and promoted by the central administration and local boards of education. Furthermore, it was determined that instructional leadership is considered by the central administration a secondary role of the principal
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