938 resultados para HOST SHIFTS
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Vinte e três espécimes de Leiuris leptocephalus (Rud., 1819) Leuckard 1850 (Spirocercidae) foram recuperados do intestino delgado de uma fêmea de preguiça comum, Bradypus variegatus Shinz 1825 (Bradipodidae), em Ubatuba, estado de São Paulo. Os dados demonstram maior variabilidade morfométrica em relação aos dados da literatura, o que contribui para a caracterização morfológica desse nematódeo. Essa comunicação corresponde ao primeiro relato de B. variegatus como hospedeiro de L. leptocephalus.
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Pentastomida é um táxon de organismos parasitas obrigatórios de sistema respiratório de vertebrados, principalmente répteis. Embora esse táxon seja muito importante para a compreensão da filogenia dos Metazoa, tem recebido pouca atenção. No Brasil, existem poucas coleções que abrigam espécies de pentastomídeos, quais sejam: a Coleção Helmintológica do Instituto Oswaldo Cruz (CHIOC), a Coleção de Invertebrados do Laboratório de Zoologia da Universidade Regional do Cariri (LAZ-URCA) e a Coleção Helmintológica do Laboratório de Parasitologia de Animais Silvestres (LAPAS). O presente trabalho descreve as espécies de pentastomídeos depositados na Coleção Helmintológia do LAPAS. O trato respiratório e as cavidades do corpo dos répteis foram removidos e analisados sob Microscópio Esteroscópico; quando encontrados os pentastomídeos, foram montados slides em meio Hoyer e identificados. Foram identificadas quatro espécies e outras três ficaram identificadas no nível de gênero, tendo sido registrados quatro novos hospedeiros para as espécies de pentastomídeos.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The present report is the northernmost capture of the piscicolid leech Stibarobdella moorei in the western South Atlantic Ocean. This is also the first time S. moorei is found associated to a batoid fish in the Brazilian coast, the eyespot skate Atlantoraja cyclophora. Stibarobdella moorei was found fixed in the dorsal side of a male eyespot skate, caught by bottom trawl around of the São Paulo coast, southeastern Brazil. A brief description of the morphology of the parasite and a discussion on the taxonomic status of the S. moorei are presented.
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Aim: Studies on feeding of early life stages are very important to the understanding of the biology and trophic ecology of fish species. Therefore, the aim of this work is to describe the development of the digestive tube, and to characterize the diet of larvae and juveniles of Bryconamericus stramineus Eigenmann, 1908 of the upper Parana River floodplain; Methods: Larvae were obtained from, monthly samples during nychthemeral cycles with four-hour interval between samplings from February/91 to February/92, utilizing a conical-cylindrical plankton net; Results: At the preflexion stage, larvae at approximately 4.00 mm SL, showed a morphologically undifferentiated straight tube, with the anterior region more dilated. At the flexion stage a differentiation in the anterior region of the digestive tube occurs, with the intestine wall getting thicker (8.30 mm SL). The formation of pyloric caeca occurs at 9.00 mm SL. At the postflexion stage the first loop is formed at 9.25 mm SL and the second loop at about 10.00 mm SL. Bryconamericus stramineus consumed mainly cladocerans, also ingesting copepods, rotifers, nematodes, algae, insects and inorganic particles. Along the development, there was an increase in the number of food items and a diversification in the number of consumed taxa; Conclusions: Changes in the diet of B. stramineus larvae were not observed, being them zooplanktivores during all the initial development. However, an increase of large preys, such as insects larvae, was observed at the end of the larval period and in juveniles, suggesting a tendency towards invertivory. Larvae and juveniles preferentially fed during the night.
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Aim To evaluate whether observed geographical shifts in the distribution of the blue-winged macaw (Primolius maracana) are related to ongoing processes of global climate change. This species is vulnerable to extinction and has shown striking range retractions in recent decades, withdrawing broadly from southern portions of its historical distribution. Its range reduction has generally been attributed to the effects of habitat loss; however, as this species has also disappeared from large forested areas, consideration of other factors that may act in concert is merited.Location Historical distribution of the blue-winged macaw in Brazil, eastern Paraguay and northern Argentina.Methods We used a correlative approach to test a hypothesis of causation of observed shifts by reduction of habitable areas mediated by climate change. We developed models of the ecological niche requirements of the blue-winged macaw, based on point-occurrence data and climate scenarios for pre-1950 and post-1950 periods, and tested model predictivity for anticipating geographical distributions within time periods. Then we projected each model to the other time period and compared distributions predicted under both climate scenarios to assess shifts of habitable areas across decades and to evaluate an explanation for observed range retractions.Results Differences between predicted distributions of the blue-winged macaw over the twentieth century were, in general, minor and no change in suitability of landscapes was predicted across large areas of the species' original range in different time periods. No tendency towards range retraction in the south was predicted, rather conditions in the southern part of the species' range tended to show improvement for the species.Main conclusions Our test permitted elimination of climate change as a likely explanation for the observed shifts in the distribution of the blue-winged macaw, and points rather to other causal explanations (e.g. changing regional land use, emerging diseases).
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fêmeas de Cotesia flavipes (Cam.) foram introduzidas, individualmente, em placas de Petri contendo uma larva de seu hospedeiro Diatraea saccharalis (Fabr.). Permitiu-se que cada fêmea de C. flavipes realizasse posturas uma ou duas vezes em uma mesma larva. O período de emergência das larvas e dos adultos, a razão sexual, o número de larvas e pupas inviáveis e a longevidade dos adultos de C. flavipes registrados nas duas condições experimentais (uma ou duas posturas) foram comparados. Os resultados revelaram que duas oviposições sucessivas no hospedeiro não alteraram a razão sexual na descendência, mas aumentaram o número de parasitóides e também o número de larvas e pupas inviáveis.
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This study analyses the ontogenetic diet shifts of a Neotropical catfish, Pimelodus maculatus ( Siluriformes, Pimelodidae), from an ecomorphological standpoint. We collected 241 individuals in the Piracicaba River ( Brazil) and, in the laboratory, seven morphometric variables were recorded from each specimen: standard length (SL), body depth, head length, snout length, eye diameter, mouth height and mouth width. After standardizing these measurements ( as a proportion of SL), linear regressions were run to determine whether their growth was isometric or allometric in relation to SL. The diet analysis shows that the main food item for fish in the smaller size classes is aquatic insects, while the largest individuals feed mainly on other fish. As the great majority of the morphometric variables analyzed showed isometric growth as a function of SL - which means that these fish do not change their shape significantly during their lives - the ontogenetic diet shifts may be seen as a consequence of the absolute size increment of their mouth gape, which allows individuals to maximize their energetic gain by ingesting larger prey with a higher caloric content.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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No presente trabalho descreve-se a ocorrência de Oswaldofilaria petersi Bain & Sulahian 1974 (Nematoda, Onchocercidae) em Tropidurus hispidus Spix 1825 (Sauria, Tropiduridae). Um macho e uma fêmea de O. petersi foram coletados no músculo ileofibularis direito desse lagarto. Este é o primeiro relato deste hospedeiro para Oswaldofilaria spp. e também a descrição de um novo hospedeiro para O. petersi.
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Relata-se a ocorrência de Ophiotaenia sp. (Cestoda, Proteocephalidae) parasitando Corallus caninus (Serpentes, Boidae). A serpente foi recebida no Parque Zoológico de Goiânia, Goiás, proveniente de apreensão pelo RAN/IBAMA em tráfico de animais silvestres. O animal estava apático, com disecdise e desidratação. Após alguns dias, morreu no cativeiro. A necropsia revelou a presença de um cestódeo no intestino que foi fixado em AFA após compressão, corado em carmim e analisado em sistema de análise de imagens. Os aspectos morfológicos indicaram ser uma espécie do gênero Ophiotaenia, mas não foi possível sua identificação. Este é o primeiro relato sobre a ocorrência de um cestódeo do gênero Ophiotaenia parasitando C. caninus.
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Seeds of Mimosa bimucronata are heavily infested (pre-dispersal predation) by the bruchid beetle Acanthoscelides schrankiae in Brazil. In this study, firstly we set up experiments to assess seed germination under seven and six different light and temperature regimes, respectively, and then we evaluated the ability of seeds to germinate after predation. We tested the hypothesis that the non-predated seeds from infested fruits may respond differently when set for germination than those seeds of non-infested fruits. We also hypothesized that predation may increase the production of unviable seeds. Seeds under 18 hours of light presented the highest percentage of germination, and the alternating temperature 20-30 degrees C was considered as optimum for germination (abnormal seedlings were not considered as a successful germination). Germination of seeds from non-infested fruits was significantly higher than germination of non-predated seeds from infested fruits, and predation also caused a significant increase in the proportion of dead seeds. Our results also show a positive correlation between proportions of unviable seeds and predated seeds. These results demonstrated that seeds of M. bimucronata are strongly affected by predation because predated seeds did not germinate and non-predated seeds had their viability reduced when located in infested fruits, supporting our hypothesis.
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Although bromeliads are believed to obtain nutrients from debris deposited by animals in their rosettes, there is little evidence to support this assumption. Using stable isotope methods, we found that the Neotropical jumping spider Psecas chapoda (Salticidae), which lives strictly associated with the terrestrial bromeliad Bromelia balansae, contributed 18% of the total nitrogen of its host plant in a greenhouse experiment. In a one-year field experiment, plants with spiders produced leaves 15% longer than plants from which the spiders were excluded. This is the first study to show nutrient provisioning in a spider-plant system. Because several animal species live strictly associated with bromeliad rosettes, this type of facultative mutualism involving the Bromeliaceac may be more common than previously thought.