28 resultados para CRAYFISH ASTACUS-LEPTODACTYLUS

em Scielo Saúde Pública - SP


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The diet of Leptodactylus ocellatus (L., 1758) was studied in specimens collected at Maldonado Department (Uruguay), where monthly surveys were made between August 1998 and March 2000. A total of 143 frogs were collected, measured, sexed, and dissected, to assess stomach contents. The anurans were grouped into three age classes and four categories (considering sex and capture date). The trophic amplitude for each age class and sex-season category was quantified using Shannon-Weaver Index, and the trophic niche overlap between ages and categories by using the Pianka Index. Comparisons among treatments were made by G-tests. The most important prey items were coleopterans (IRI = 2547), and significant correlations were found between predator and prey sizes. The major differences on diet composition were found between extreme age classes (froglets and adults). Significant differences were also detected between sexes in the cold season but not in the warm season. Any of these changes in diet may be related with the availability of prey.

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O presente trabalho registra mais uma espécie pertencente à família Leptodactylidae apresentando cuidado parental, Leptodactylus natalensis Lutz, 1930. Fêmeas foram observadas em assistência a ovos e cardumes de girinos em duas poças temporárias na mata Atlântica do Estado de Pernambuco, Brasil.

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The goal of this study was to evaluate the effects of seasonal variations on energy metabolism in different tissues of the freshwater crayfish Parastacus brasiliensis (von Martens, 1869). Crayfish were collected monthly from January 2001 to January 2003 in São Francisco de Paula, Rio Grande do Sul, Brazil, in a stream and in a culture tank. Haemolymph samples were collected from each crayfish in the field with a syringe, by puncturing the membrane at the base of the chelipeds. Hepatopancreas, gills, and abdominal muscle were removed for determination of free glucose, glycogen, total lipids, and triglycerides. The haemolymph samples were used for determination of glucose, total proteins, total lipids, and triglycerides. Statistical analysis revealed significant differences in biochemical composition in crayfish collected in the stream compared to the experimental tank during the year, principally in glucose and triglycerides in haemolymph, glycogen and total lipids in all tissues study, and triglycerides only in abdominal muscle. The regular food intake partially modified these seasonal variations of the metabolic pattern. Environmental conditions (e.g., food availability and water temperature) and reproductive period appeared to be the main factors influencing the seasonal patterns of variation in energy metabolism.

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Here we present data on the reproductive behavior of Leptodactylus mystacinus (Burmeister, 1861), including details on courtship behavior. We also describe and compared the courtship calls of L. mystacinus, L. furnarius Sazima & Bokermann, 1978 and Leptodactylus sp. (L. aff. andreae). Field works were conducted in Uberlândia (central Brazil). During courtship, a female approaches a calling male and is led to a previously excavated chamber; a female can approach a silent male that beat his hands and/or feet on the ground as well. The courtship call of L. mystacinus consists of one single arch-shaped note (duration = 0.04 s) repeated 258 times per minute; the courtship calls of L. furnarius (0.06 s, 84 times per minute) and Leptodactylus sp. (0.15 s, 5 times per minute) also are arch-shaped. The courtship behavior of L. mystacinus is similar to that of other species of the L. fuscus (Schneider, 1799) group; unique to it is that males can beat his hands and/or feet on the ground while courting. The male behavior of conducting the female to a previously excavates chamber and the arch-shaped courtship call may represent other shared derived features of members of the L. fuscus group, including the former Adenomera species.

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The aim of this study was to characterize, for the central region of the State of Rio Grande do Sul, Brazil, the reproductive biology of Leptodactylus fuscus (Schneider, 1799), based on the analysis of gonadal development of males and females, reproductive effort, size-fecundity relationships, and occurrence of sexual dimorphism in body size. Mature individuals were found from October 1996 to February 1997 and from October 1997 to December 1997. The highest input of juveniles in the population was recorded in March 1997. There was a positive and significant correlation between the number of mature individuals and the mean monthly temperature. The population did not present sexual dimorphism in size. Males presented significant correlation only between snout-vent length and testes length. All females had oocytes at four different maturation stages and there were no significant correlations regarding size-fecundity variables. The correlation between ovarian size factor and females snout-vent length was not significant either. The main difference between this population and those that inhabit tropical climate was that temperature was responsible for stimulating the reproduction activity, instead of rainfall.

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Leptodactylus(Lithodytes) lineatus (Schneider, 1799) is an Amazonian leaf litter frog considered rare or uncommon in several studies on anuran communities. Despite being a widely distributed frog in Amazonian forests, knowledge of the biology and ecology of this species is relatively scarce. This species has been reported to live in association with leaf-cutter ant nests (Atta spp.) during the breeding period. In this paper we present data on the seasonality of this species and some reproductive information gathered at a locality of Rondônia state, northwestern Brazil. Field work was carried out between April 2001 and March 2002, with the use of pitfall traps with drift fences as a survey method. Leptodactylus (L.) lineatus had a higher capture frequency in this locality compared to that of other studies carried out in other Amazonian localities, possibly because this species has secretive habits, such as calling and breeding from nests of leaf-cutting ants, and are difficult to find during visual encounter surveys. The breeding period occurs between October and March. Calling males and egg-bearing females were found between September and February and juvenile recruitment occurred mainly from the end of the rainy season to the beginning of the dry season (February to June). Males and females show sexual dimorphism in SVL, females being significantly larger than males. The number of ovarian eggs per female varies from 110 to 328 and analyses indicate that there is a significant correlation with SVL.

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Growth, metabolic rate, and energy reserves of Cherax quadricarinatus (von Martens, 1868) juveniles were evaluated in crayfish acclimated for 16 weeks to either 25ºC (temperature near optimum) or 20ºC (marginal for the species). Additionally, the modulating effect of ecdsyone on acclimation was studied. After 12 weeks of exposure, weight gain of both experimental groups acclimated to 25ºC (control: C25, and ecdysone treated: E25) was significantly higher than that of those groups acclimated to 20ºC (C20 and E20). A total compensation in metabolic rate was seen after acclimation from 25ºC to 20ºC; for both the control group and the group treated with ecdysone. A Q10value significantly higher was only observed in the group acclimated to 20ºC and treated with ecdysone. A reduction of glycogen reserves in both hepatopancreas and muscle, as well as a lower protein content in muscle, was seen in both groups acclimated to 20ºC. Correspondingly, glycemia was always higher in these groups. Increased lipid levels were seen in the hepatopancreas of animals acclimated to 20ºC, while a higher lipid level was also observed in muscle at 20ºC, but only in ecdysone-treated crayfish.

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The main object of the present paper is to furnish a brief account to the knowledgement of Protozoa parasitic in common Brazilian frog of the genus Leptodactylus for general students in Zoology and for investigators that use this frog as a laboratory animal. Hepatozoon leptodactyli (Haemogregarina leptodactyli) was found in two species of frogs - Leptodactylus ocellatus and L. pentadactylus - in which develop schizogony whereas sporogony occurs in the leech Haementeria lutzi as was obtainded in experimental conditions. Intracellular forms have been found in peripheral circulation, chiefly in erythrocytes, but we have found them in leukocytes too. Tissue stages were found in frog, liver, lungs, spleen, gut, brain and heart. The occurence of hemogregarine in the Central Nervous System was recorded by Costa & al,(13) and Ball (2). Some cytochemical methods were employed in attempt to differentiate gametocytes from trophozoites in the peripheral blood and to characterize the cystic membrane as well. The speorogonic cycle was developed in only one specie of leech. A brief description of the parasite is given.

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O gênero Toddia, criado por França 1911, para um organismo encontrado em eritrõcitos de um anfíbio anuro, tem estrutura particular e o problema de sua natureza (protozoário ou vírus) é discutido. Nosso resultados mostram reações Feulgen e Verde Metila positivas, principalmente no início da infecção. Com o decorrer da infecção as partículas são, geralmente, maiores que aquelas observadas alguns dias após as inoculações, mas as reações citoquímicas citadas anteriormente são, em geral, negativas ou fracamente positivas. Os mesmos resultados foram obtidos quando empregamos Laranja de acridina para caracterização do DNA e esta técnica foi negativa para o RNA. Estudando o desenvolvimento deste organismo e seus efeitos infecciosos foram confirmados por inoculações experimentais. As alterações no sangue do hospedeiro foram observadas e notamos que o núclo dos eritrócitos é severamente alterado durante o desenvolvimento da infecção, que é geralmente, muito intensa, terminando com a morte do hospedeiro. As inoculações experimentais demonstraram a especificidade da infecção, e diante dos conhecimentos a respeito dos organismos deste gênero, discutimos o problema da criação de espécies.

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Os autores estudaram o comportamento "in vitro" do Trypanosoma encontrado nas rãs brasileiras, visando critérios adicionais na caracterização específica deste grupo. Utilizaram diferentes meios de cultura (NNN, Novy e Mac Neal, SNB 9 de Diamond 1954, Boné & Steinert, 1956 Boné & Parent 1963 e Halevy & Gisry 1964) no isolamento do Trypanosoma rotatorium encontrado com certa freqüência na rã Leptodactylus com larga distribuição na região Neotropical. Observamso que o comportamento do T. rotatorium das rãs desta região em meios de cultura mostra características bem diferentes daquelas observadas com tripanosomas de outras regiões, quer seja pela dificuldade de manutenção em subcultura, quer pelas formas de divisão desenvolvidas. Empregamos os mesmos meios de cultura utilizados nos isolamentos dos tripanosomas de rã da Europa e como pode ser visto no Quadro I os resultados obtidos com material da região Neotropical são concordantes, surgerindo, pelo menos uma variação dentro da espécie.

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Com o objetivo de fornecer dados para o esclarecimento do controvertido problema da natureza de Cytamoeba bacterifera freqüentemente encontrada nos eritrócitos de Leptodactylus ocellatus, realizamos alguns testes citoquímicos. Demonstramos a presença do ácido ribonucleico e polissacarídeos não digeríveis pela ptialina em sua estrutura. Com o método de Feulgen, teste de referência para a caracterização do ácido desoxirribonucleico, obtivemos principlemnte resultados negativos; porém, um parasito com fraca e difusa positividade e algumas reações duvidosas também foram encontrados. Ao emrpegarmos o Verde Metila-Pironina, mesmo após o tratamento pela ribonuclease, e o Azul de Toluidina, também depois da ação desta enzima, não conseguimos confimar a presença de ADN. Como os elementos constituintes de C. bacterifera são minúsculos e, às vezes, não evidenciáveis, é possível que seu teor de ADN, porventura existente, seja muito pequeno e, conseqüentemente, de difícil demonstração por métodos cujos resultados são observados sob microscopia ótica, além de poder ficar facilmente encoberto por outras substâncias. Não estamos propensos a admitir uma provável natureza virótica para Cytamoeba baseados, principalmente, em alguns de seus aspectos estruturais (figs. 8, 15, 17 e 18) e na ausência de alteração no núcleo das células parasitadas. Apesar de não termos comprovado a presença de ADN, achamos possível que C. bacterifera seja um aglomerado intracitoplasmático de organismos modificados, cujas dimensões situam-se nas proximidades do limite de resolução do microscópio ótico, relacionados com as bactérias, assim como são, por exemplo, os Clamídios e as Riquétsias. Observamos o desenvolvimento de Cytamoeba em rã mantida em cativeiro por três meses e semanalmente examinada; constatamos decréscimo paulatino da parasitemia inicial e também que os seus tipos estruturais e medidas não estavam relacionadas com a etapa da infecção. Não conseguimos transmitir, por inoculação intra-peritoneal, Cytamoeba de L. ocellatus para Bufo crucifer.

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Durante estudos com morcegos em floresta de várzea na APA do Rio Curiaú, Amapá, Brasil, observamos três casos de predações oportunistas de morcegos frugívoros capturados em redes de neblina. Duas destas predações ocorreram por marsupiais e uma por anuro. Artibeus planirostris (Spix, 1823) (Chiroptera, Phyllostomidae) foi predado por Didelphis marsupialis Linnaeus, 1758 e Philander opossum (Linnaeus, 1758) (Didelphimorphia, Didelphidae). Carollia perspicillata (Linnaeus, 1758) (Chiroptera, Phyllostomidae) foi predado por Leptodactylus pentadactylus (Laurenti, 1768) (Anura, Leptodactylidae). A vocalização dos morcegos provavelmente atraiu os marsupiais para a rede, onde estes os predaram aproveitando que estavam presos. Este tipo de interação pode ocorrer naturalmente, no entanto, com maior dificuldade de registro.

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Some anuran amphibians use the bromeliads during the entire life cycle and others only as diurnal shelter. At the sandy coastal plain of Linhares, State of Espírito Santo, Southeastern Brazil, 676 bromeliads were examined, of which 303 of Aechmea blanchetiana (Baker) L. B. Smith., 1955, 287 of Aechmea nudicaulis (L.) Griseb., 1864, and 86 of Vrisea procera (Mart. Ex Schult. f.) Wittm, 1891. The morphometric and physical-chemical analysis of different bromeliads evidenced variations among plants. During the period sampled, six anuran species were found inside the plant axils. The hylid frog Phyllodytes luteolus (Wied, 1824) was the most abundant species (260 specimens). Its abundance was higher in the epiphyte bromeliad Vrisea procera. Phyllodytes luteolus had higher occurrences in bromeliads located at a transitional area between open and under the shrub vegetation. Specimens of Scinax alterus (Lutz, B., 1973) and Aparasphenodon brunoi Miranda-Ribeiro, 1920, were more frequent mainly in transitional areas; Bufo granulosus Spix, 1824 occurred in open and transitional areas, whereas Gastrotheca fissipis (Boulenger, 1888) and Leptodactylus fuscus (Schneider, 1799) were found only in bromeliads located in open areas.

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Although Brazil encompasses one of the most abundant anuran faunas in the world, quantitative information on anuran ecology and diet are limited, especially in the Northeastern region. We analyzed the diet of six species: Hyla albomarginata, Hyla cf. branneri, Hyla minuta, Phyllomedusa aff. hypochondrialis (Hylidae), Leptodactylus natalensis, and Physalaemus cuvieri (Leptodactylidae) in a temporary pond in a rainforest remnant in Pernambuco, between 1999-2000. We analyzed diet composition, degree of food preference, and seasonal variations in diet. Leptodactylus natalensis and P. cuvieri showed higher diet diversity, whereas H. minuta consumed fewer food items. Insecta, Arachnida, and plants were preferential items for most species. Acari were consumed by all species; Hymenoptera, Odonata, and Coleoptera were also often consumed. A slight increase in diet diversity occurred in the rainy season. The species showed a generalist feeding behaviour, although P. cuvieri consumed Formicidae as major prey item.