Alguns aspectos da biologia de Lymnaea columella Say, 1817 (Gastropoda, Pulmonata)

Foram estudados aspectos da biologia da Lymnaea columella Say, 1817, em condições de laboratório e determinadas as variações da duração do período embrionário em relação à temperatura da água.

Ocorrência de infecção natural de Fasciola hepatica Linnaeus, 1758 em Lymnaea columella Say, 1817 no Vale do Paraíba, SP, Brasil

Foram registradas em Piquete, no vale do rio Paraíba do Sul (SP), Brasil, taxas de 1,22% e 0,14% de infecção natural em Lymnaea columella, por Fasciola hepatica. Em um único exemplar de Lymnaea columella dentre os 1.052 examinados, foram observadas rédias com xifidiocercárias, rédias com cercárias de Fasciola hepatica e metacercárias de Echinostomatidae.

Susceptibilidade de Lymnaea (pseudosuccinea) columella (Say, 1817) exposta à infecção por miracídios de Fasciola hepatica (Linnaeus, 1758)

Com o objetivo de estudar a susceptibilidade de Lymnaea (pseudosuccinea) columella de Minas Gerais, Estado onde ainda não se registraram casos autóctones de fasciolose hepática, foram utilizadas as amostras MG 1, MG 2, MG 3 e MG 4, provenientes de diferentes regiões deste Estado, para estudo comparativo com as amostras RJ e RGS procedentes dos Estados do Rio de Janeiro e Rio Grande do Sul, áreas de focos de fasciolose. A amostra de Fasciola hepatica utilizada era procedente de ovinos abatidos no município de Camapuã, no Rio Grande do Sul, e foi mantida em coelhos. Os moluscos foram infectados com 6, 8 e 10 miracídos por molusco, sendo estudadas as incidências de infecção e de mortalidade. Nas condições que se realizou o trabalho diante dos resultados obtidos, foram tiradas as seguintes conclusões: 1. A mortalidade dos caramujos parece não estar diretamente relacionada com a percentagem de infecção; 2. As amostras de Lymnaea (pseudosuccinea) columella de Minas Gerais, do Rio de Janeiro e do Rio Grande do Sul mostraram-se identicamente susceptíveis à infecção por Fasciola hepatica; 3. A população humana e os rebanhos bovino, ovino e suíno de Minas Gerais, particularmente aqueles do Vale do Rio Paraíba, podem ser considerados sujeitos à infecção por Fasciola hepatica.

Estudo morfométrico da concha de Lymnaea columella say, 1817 (Mollusca, Gastropoda, Pulmonata)

Foram estudadas variações morfométricas de conchas de L. columella, provenientes de dez criadouros localizados nos seguintes municípios do Estado de São Paulo: - Campinas, Americana, Atibaia, Pirassununga, Caçapava e Taubaté. Foram analisados os diferentes tipos de ambientes onde as limneas são encontradas com maior freqüência, estabelecendo-se a época do ano com maior abundância em espécimes, que correspondeu aos meses de julho a outubro. As medidas nas conhas dos diferentes criadouros referiram-se ao comprimento e largura da concha, comprimento e largura da abertura, comprimento da espira e número de voltas. Foram estabelecidos os coeficientes de correlação e de regressão e realizadas análises de variância entre as medidas tomadas e os índices obtidos da relação entre largura/comprimento da concha. Estas conchas foram comparadas com as de L. columella, L. viator, L. cubensis da coleção do Museu Nacional do Rio de Janeiro. Para a maioria das medidas as conchas mostraram proporções constantes, embora apresentassem diferenças em relação ao desenvolvimento. A maior variação foi observada em relação ao comprimento da espira. As variações morfométricas das conchas foram relacionadas com alguns fatores externos como pH, alcalinidade, dureza e teor da água. Aparentemente apenas a dureza total da água influiu na consistência das conchas.

Contribuição ao conhecimento da bionomia de Passalus convexus Dalman, 1817 e Passalus latifrons Percheron, 1841 (Coleoptera: Passalidae)

Coleópteros da família Passalidae, com distribuição pantropical, parecem contribuir, pelo menos em parte, para a reciclagem dos nutrientes nas florestas, facilitando a penetração de umidade e de microorganismos decompositores no interior dos troncos mortos, pela abertuda de galerias. Aspectos da bionomia de Passalus convexus Dalm. e Passalus latifrons Perch. Foram estudados durante um ciclo sazonal completo, com levantament dos tipos de troncos atacadio, fauna acompanhante e os estágios de decomposição mais propícios à colonização.

Padrões ontogenéticos das Esterases, Leucina Aminopeptidase e X-Glicerofosfato Desidrogenase em Anopheles (Nyssorhynchus) Albitarsis lynch-arribálzaga, 1878 (Diptera: Culicidae)

Modificações na expressão gênica foram observadas nos sistemas esterase, leucina aminopeptidase e x-glicerofosfato desidrogenase, durante o desenvolvimento ontogenético de Anopheles albitarsis. A esterase revelou quatro regiões de atividade, sendo a esterase 1 detectada apenas em larvas de 4º estádio velhas e em pupas, as esterases 2 e 4 foram presentes durante todo o desenvolvimento, e a esterase 3 revelou-se praticamente apenas em larvas e raríssimas vezes em pupas. Também foram observadas quatro regiões de atividade na leucina aminopeptidase, durante a ontogenia. As LAP1 c LAP2 foram características de larvas, a LAP3 esteve presente somente em pupas e adultos e a LAP4 foi detectada nos três diferentes estágios. Uma única região foi observada para a x-glicerofosfato desidrogenase e a intensidade de sua atividade cresce à medida que se aproxima o estágio adulto.

Digamacris n. gen. (Orthoptera, Acrididae, Melanoplinae) de la region atlantica meridional de Brasil

Digamacris, a new genus of the Dichroplini (Acrididae, Melanoplinae) is described for the species Pezotettix amoenus Stal, 1878 and Dichroplus fratemus Carl, 1916, both included at present in the genus Dichroplus. These species live in edges and clearings of the Atlantic Forest (Mata Atlantica) of Brazil. D. fratemus is found in the states of Minas Gerais, Espirito Santo and Rio de Janeiro east of the Bay of Guanabara. D. amoenus in the state of Rio de Janeiro W. of the Bay of Guanabara and in the coastal area of the state of São Paulo. The species are illustrated and redescribed. Both have two neatly different chromatic forms of females, while the males are uniform in coloration and closely correspond with one of the female forms.

A morphological, isoenzymatic and behavioural study of ten populations of Anopheles(Nyssorhynchus) albitarsis Lynch-Arribalzaga, 1878 (Diptera: culicidae) including from the type-locality - Baradero, Argentina

Anopheles (Nyssorhynchus) albitarsis Lynch-Arribalzaga, 1878 shows morphological and behavioural variations which results in it being sometimes considered as a major malaria vector and at other times as playing no important role in epidemiology. With the aim of clarifying the taxonomy of the species, comparative morphological and isoenzymatic studies were made in populations from the type-locality, Baradero, Argentina and from 9 different localities inBrazil. Morphological studies consisted of the observation of eggs in scanning electron microscopy, of complete chaetotaxy of larvae and pupae and of the detailed drawing of male and female adults. Only Guajara-Mirim and Rio Branco populations, described previously as Anopheles deaneorum sp.n., showed morphological differences. Isoenzymes were studied using 4th instar larvae homogenate and agarosegel electrophoresis. Eleven enzymatic loci were analyzed. By calculation of Nei's Genetic Distance (D), the populations could be separated into 5 groups: i)Baradero, ii)Marajo, iii)Boa Vista, iv)Angra, Itaguai and Paraipaba and v)Guajara-Mirim and Rio Branco. These groups belong to 2 major clusters called I and II, separated by D = 0.345. In the I cluster are groups i, ii and iii and in II clusteriv and v. In I, D=0.246 separates i and ii from iii, while i is separated by D =0.181 from ii. In II, D = 0.223 between iv and v. Only the population of group vcould be distinguished morphologically from the others, leading to the description of an independent species An. deaneorum.

Ectoparasites Ixodida Leach, 1817 on wild mammals in the state of Paraná, Brazil

A taxonomical and ecological study was made on 264 samples of 12 species of ectoparasite ixodides collected on wild mammals from several natural regions of Paraná state, Brazil. These species of ticks as their hosts are listed by their identified evolutive forms and capture locations. A review of the early studies on the Ixodida from South Brazil is made considering the frequency of the parasite species on each host concerning the geographic distribution of such species. This paper is a contribution to the knowledge of the Ixodidae ectoparasites species of wild mammals in Brazil.

Limnaea peregrina Clessin, 1882, Synonym of Lymnaea columella Say, 1817 (Gastropoda: Lymnaeidae)

A description is given of the shell, radula, renal region, reproductive system and egg capsules of topotypic specimens of limnaea peregrina Clessin, 1882. This investigation intends contributing to define the specific identity of that nominal species. A close anatomical comparison with Lymnaea columella Say, 1817 from Michigan, USA, shows that both forms are indistinguishable, giving support to previous inferences from some authors. Data on egg hatching are presented.

Rearing of Lymnaea columella (Say, 1817), intermediate host of Fasciola hepatica (Linnaeus, 1758)

The intermediate host of Fasciola hepatica, Lymnaea columella, collected in Belo Horizonte, Minas Gerais, Brazil, was reared in our laboratory. The aim of the current study was to standardize a rearing and maintenance technique. Two kinds of diet were tested: fresh lettuce (A) and rodent ration + 10% CaCO3 plus fresh lettuce (B). The age for the beginning of oviposition ranged from 27 to 57 days. Ten days after oviposition at 24.7°C, 100% eclosion occurred. The complete life cycle varied from 37 to 67 days. The average numbers of eggs per egg mass were 26.3 and 31.1 with diets (A) and (B), respectively. The lettuce and ration fed snails presented a increased growth although the difference was not statistically significant (p > 0.05). The mortality rate varied from 40 to 64% after 90 days. The maximum longevity was 183 days, 21.5 mm length and 11 mm wide. The methodology to mass breed and maintain these snails was found to be suitable in the laboratory

Thermal Constant of an Experimental Population of Muscina stabulans (Fallén 1817) (Diptera:Muscidae) in the Laboratory

A study was conducted to investigate the thermal constant in an experimental population of Muscina stabulans (Fallén 1817). A natural population was obtained from a livestock and their F1 generations were maintained at four constant temperatures (16°C, 20°C, 26°C and 31°C). The thermal constant was calculated by the hyperbole method using the base temperature, tb = 4.4°C and the thermal constant K = 35.3 GD. Ricker's geometric regression, considering tb = 7.8°C and K = 28.9 GD was also calculated.

Molluscicidal action of the latex of Euphorbia splendens var. hislopii N.E.B. ("Christ's Crown") (Euphorbiaceae) against Lymnaea columella (Say, 1817) (Pulmonata: Lymnaeidae), intermediate host of Fasciola hepatica Linnaeus, 1758 (Trematode: Fasciolidae): 1- test in laboratory

The latex action of Euphorbia splendens var. hislopii (Christ's Crown) against snails Lymnaea columella, intermediate host of Fasciola hepatica, derived from irrigation ditches of the Station of Pisciculture at Universidade Federal Rural do Rio de Janeiro, was studied in the laboratory. Lab bioassays, using aqueous solutions of the latex, varying between 0.1 and 10 mg/l, have proven molluscicidal activity of the product collected on the same day the tests were performed, during the four seasons of the year, finding the following lethal concentrations (LC90): 1.51 mg/l in the spring; 0.55 mg/l in the summer; 0.74 mg/l in the fall and 0.93 mg/l in winter, after 24 h exposure of the snails, showing significant differences among the seasons of the year (ANOVA test, F = 11.01, G.L.= 3/33, p < 0.05), as well as among the concentrations (ANOVA test, F = 27.38, G.L.= 11/33, p < 0.05). In the summer, mortality reached 100% from concentration at 0.6 mg/l, the same during fall and in winter as of 1 mg/l, while in spring it only reached 100% mortality as of 2 mg/l. Mortality in the controls was low, reaching 5% in the summer and winter and 10% in the fall and spring. None of the samples died. During the assay, with an aqueous solution of the latex at a concentration of 5 mg/l, in order to check the time of duration of the product effect, in the laboratory, it was observed that the molluscicidal activity remained stable up to the 15th day after the beginning of the test with 100% mortality of L. columella, gradually losing its effect until the 23rd day, when we no longer observed animal mortality. In the control group, there was a random daily variation in mortality rate ranging 0-50% after 48 h of observation for 30 days.