995 resultados para 1818
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1817-1818
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1818-1819
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A survey of the Streblidae batflies on the phyllostomid bats was conducted in the northeastern Rio Grande do Sul State, Brazil, during 1997. Hundred thirty three streblids were collected on 44 parasited hosts. Eleven species of batflies (Trichobius dugesii Townsend, 1891, T. tiptoni Wenzel, 1976, Trichobius sp., Paratrichobius longicrus (Miranda Ribeiro, 1907), Megistopoda aranea (Coquillett, 1899), M. proxima (Séguy, 1926), Exastinion clovisi (Pessoa & Guimarães, 1936), Paraeuctenodes longipes Pessoa & Guimarães, 1936, Anastrebla modestini Wenzel, 1966, A. caudiferae Wenzel, 1976 and Metelasmus pseudopterus Coquillett, 1907) were found on six species of phyllostomid bats (Artibeus lituratus (Olfers, 1818), A. fimbriatus Gray, 1838, Sturnira lilium (E. Geoffroy, 1810), Glossophaga soricina (Pallas, 1766), Anoura caudifera (E. Geoffroy, 1818) and A. geoffroyi Gray, 1838). All records are new for the Rio Grande do Sul and Anastrebla caudiferae is firstly recorded in Brazil. Differences in the batflies community composition in Artibeus fimbriatus and A. lituratus are discussed.
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Fourteen bird species were observed visiting one specimen of Alchornea glandulosa Poepp., 1845, at the Horto Florestal Navarro de Andrade, Rio Claro, São Paulo State, Brazil. Among them, three species seem to be the most efficient seed dispersers of A. glandulosa at the study site: Myiodinastes maculatus (Müller, 1776), Empidonomus varius (Vieillot, 1818) e Tyrannus melancholicus Vieillot, 1819. Besides to swallow fruit whole, these birds contributed with 68.5% of the total feeding visits. A. glandulosa fruit are not the mainly part of the diet of any one of the observed bird species, since they do not fit in the frugivorous specialized category. However, as almost all the observed individuals swallow fruit whole, it is suppose that they promote an efficient dispersion of their seeds.
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A survey of carnivore mammals was accomplished in Aparados da Serra National Park from February 1998 to March 2000. The park has 10,250 ha and is considered a biodiversity core area of the Atlantic Forest Biosphere Reserve in the Rio Grande do Sul State, Brazil. The landscape is characterized by relatively well preserved relicts of Araucaria angustifolia (Bertol.) Kuntze forest, grasslands and Atlantic Forest, which have contributed for the survival of endangered carnivore mammals. The National Park was divided in a grid of 16 km² cells using a 1:50,000 scale map. The animals were recorded using indirect methods, by identifying signs (scats, tracks) and direct observation in 2.5 km long and 5 m wide transects, with 10 replicates in each grid cell. Interviews with local people were also used to confirm the animal presence. A total of 13 species was recorded: Procyon cancrivorus (Cuvier, 1798), Pseudalopex gymnocercus (G. Fischer, 1814), Leopardus pardalis (Linnaeus, 1758) and Cerdocyon thous (Linnaeus, 1766) were the most frequent species registered. Nasua nasua (Linnaeus 1766), Herpailurus yaguarondi (Lacépède, 1809), Chrysocyon brachyurus (Illiger, 1815), Eira barbara (Linnaeus, 1758), Leopardus sp., Puma concolor (Linnaeus, 1771), Galictis cuja (Molina, 1782), Conepatus chinga (Molina, 1892) and Lontra longicaudis (Olfers, 1818) showed lower frequencies. The Park presented areas with significant differences (Mantel Test, P< 0.05) in species richness and composition related to habitat classes. Areas with high habitat richness presented high species richness. The Araucaria forest was the habitat that presented the higher carnivore richness. The border areas of the Park are influenced by several environmental degradation factors that could be affecting the distribution of carnivores.
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The thermal requirements of Palmistichus elaeisis Delvare & LaSalle, 1993 were determined by rearing this pupal parasitoid in the following lepidopteran hosts: Diatraea saccharalis (Fabricius, 1794) (Crambidae), Anticarsia gemmatalis (Hübner, 1818), Heliothis virescens (Fabricius, 1777), Spodoptera frugiperda (J.E. Smith, 1797) (Noctuidae) and Thyrinteina arnobia (Stoll, 1782) (Geometridae). The experiment was set in laboratory conditions (temperatures between 18ºC and 30ºC, RH=70 ± 10% and 14-hour photoperiod). The life cycle (egg-adult) ranged from 40.4 ± 0.63 days (18ºC, H. virescens) to 18.1 ± 0.13 days (28ºC, D. saccharalis). The thermal constant of the egg-adult period ranged from 353.1 (D. saccharalis) to 407.7 degree-days (S. frugiperda). The lowest thermal threshold ranged from 5.0ºC (A. gemmatalis) to 7.5ºC (D. saccharalis). At 30ºC, all prepupae died. These results suggest that P. elaeisis can be reared in laboratory on all the hosts tested.
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Foram obtidos extratos aquosos e alcoólicos a partir de pó de folhas secas de tomateiro (Lycopersicon esculentum, Mill.) c.v. Cereja. Por extração metanólica e precipitação alcalina, foi obtido um produto que denominamos "glicoalcalóide esteroidal bruto" (GEb), no qual foi caracterizada a presença de tomatina. Em ensaios laboratoriais, os extratos aquosos, alcoólicos e o GEb apresentaram atividade moluscicida em Biomphalaria glabrata (Say, 1818). O "glicoalcalóide esteroidal bruto" apresentou alta atividade moluscicida (CL50 = 8,01 ppm e CL90 = 13,17 ppm), comparável à atividade da tomatina. Desovas de B. glabrata mostraram-se resistentes aos extratos testados. Os níveis de atividade moluscicida apresentados pelos diversos extratos e o GEb, apontam apenas o GEb como candidato para a continuação dos estudos visando a sua possível utilização em campo.
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A importância dos frutos de Lauraceae tem sido relatada na dieta de muitas aves, principalmente das famílias Ramphastidae, Cotingidae e Trogonidae. Os objetivos deste estudo foram determinar quais espécies de aves consomem os frutos de Nectandra megapotamica (Spreng.) Mez (Lauraceae) numa área de Floresta Estacional Decidual e, com base na análise de alguns dos componentes qualitativos e quantitativos da dispersão, inferir quais aves podem atuar como dispersores de suas sementes. O estudo foi desenvolvido no Campo de Instrução de Santa Maria (CISM) (29º43'S, 53º42'W), município de Santa Maria, Rio Grande do Sul. Num total de 70 h de observação focal, foram registradas 726 visitas de 21 espécies de aves. As aves consideradas como potencialmente dispersoras de N. megapotamica foram Turdus albicollis Vieillot, 1818, T. rufiventris Vieillot, 1818, Pitangus sulphuratus (Linnaeus, 1766) e T. amaurochalinus Cabanis, 1850 entre as residentes, e Tyrannus savanna Vieillot, 1808 e Myiodynastes maculatus (Müller, 1766) entre as migratórias. As aves com dieta generalista pareceram favorecer a dispersão de N. megapotamica, pois consumiram os frutos inteiros, realizaram visitas curtas (menos de 3 minutos) e apresentaram maior freqüência de visitação que, por sua vez, está relacionada a uma maior remoção dos frutos. Nectandra megapotamica possui características que a incluem no sistema de dispersão generalista, exceto pelo alto valor nutritivo dos seus frutos.
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No período entre dezembro de 2001 a dezembro de 2003, realizaram-se coletas com rede entomológica de insetos visitantes das flores de Eryngium horridum (Apiaceae) na Região do Vale do Rio Pardo, RS, Brasil. Esta planta é perene, freqüente em campos secos e apresenta expressiva dispersão. Possui, no Rio Grande do Sul, época de floração entre novembro e janeiro. Foram capturados 1.066 insetos visitantes, destes, 569 Syrphidae. Identificaram-se 60 espécies de Syrphidae, distribuídas em 16 gêneros. O gênero Palpada Macquart, 1834 foi dominante, e Ornidia Lepeletier & Serville, 1828 e Toxomerus Macquart, 1855 abundantes. Das espécies mais freqüentes, Palpada furcata (Wiedemann, 1819) ocupou posição mais elevada. Os sirfídeos apresentaram preferência pelas temperaturas entre 28 e 32ºC, e foram mais freqüentemente coletados entre as 10 e 14 horas, com picos entre as 10 e 11 horas. As fêmeas foram as mais freqüentes. O predomínio de sirfídeos robustos e mais ágeis sobre sirfídeos de menor porte como Toxomerus e Allograpta Osten Sacken, 1875, pode ter sido resultante de competição interespecífica. Eristalinus taeniops (Wiedemann, 1818) é pela primeira vez citada para o Estado do Rio Grande do Sul. A alta diversidade e abundância dos espécimes coletados nas flores de E. horridum são indicadores da importância desta na dieta dos sirfídeos, visto que possui grande número de inflorescências e floração ocorrendo nos meses de baixa oferta de recursos alimentares na área de estudo.
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Os objetivos deste estudo foram conhecer a guilda de parasitóides associados a pupas de Methona themisto (Hübner, 1818), avaliando a abundância relativa de cada espécie de parasitóide e o efeito do parasitoidismo na mortalidade do hospedeiro. Foram coletadas 160 pupas de M. themisto, 80 em outubro de 2001 e 80 em outubro de 2002. Essas foram mantidas em temperatura de 25 ± 2,0ºC e fotofase de 14 horas, sendo diariamente observadas, até a emergência de parasitóides ou borboletas. Os seguintes parasitóides foram obtidos das pupas de M. themisto: Brachymeria annulata (Fabricius, 1793), B. mnestor (Walker, 1841) (Chalcididae), Neotheronia sp. (Ichneumonidae), Palmistichus elaeisis Delvare & LaSalle, 1996 e Tetrastichus sp. (Eulophidae). Somente os gêneros Brachymeria e Neotheronia ocorreram nos dois anos de estudo, sendo que o primeiro foi mais abundante em 2001 e o último, em 2002. As outras espécies de parasitóides ocorreram somente no segundo ano de estudo. Este é o primeiro relato da associação de B. annulata, B. mnestor, Neotheronia sp. e P. elaeisis com M. themisto.
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Hemidactylus mabouia Moreau de Jonnés, 1818 is a "fixed" clutch size exotic species well established in Brazil. In this paper we investigate some reproductive strategies adopted to minimize the costs of invariant clutch size to this invader species living in an environment with marked climatic seasonality in Southeastern Brazil (22°56S; 46°55W). The study was carried out from April 2002 to March 2003. Females and males attain maturity at 47.9mm and 46.9mm SVL, respectively. Larger females tended to produce larger eggs. The reproduction occurred throughout the year, but only at the wet season the females increase the clutch frequency. There was a significant variation in mean testis volume among the months throughout the year and the largest means were recorded between August and December. Maternal investment on egg size, increase on clutch frequency and seasonal increase on testis volume can represent important reproductive strategies of this invader species living in an non-urban habitat whit climatic seasonality (dry and cold weather season).
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This manuscript presents information about the ecology of Lontra longicaudis (Olfers, 1818) in the Taquari Valley, State of Rio Grande do Sul, southern Brazil. The study was carried out in two areas located in the Forquetinha Creek and in the Forqueta River from January to December 2003. The otters are specialist feeders (Bsta = 0.24), with a diet based mostly on fish, especially those of the families Loricariidae and Cichlidae. Most shelters used by the species were excavated burrows underneath tree roots, while shelters within rocks were used less frequently. The burrows showed great variation in size, being found on average 3.5 m (sd = 3.6 m) away from the margin and 2.5 m (sd = 1.2 m) above the water level. Scent marks were made preferentially on rocks and fallen tree trunks at the edge of the water. There was a tendency to increase the reutilization of latrines in detriment of using new sites throughout the sample period.
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A genetic study of the neotropical river otter Lontra longicaudis (Olfers, 1818), which has an unknown conservation status, was carried out at the Taim Ecological Station and the margins of the Vargas stream, Rio Grande do Sul, southern Brazil. Faecal samples were collected, and DNA was extracted using a silica-guanidine method. Five microsatellite loci were amplified using PCR with heterologous primers previously described for Lutra lutra (Linnaeus, 1758). Sixteen faecal samples out of 29 from Taim and 11 out of 14 from Vargas stream margins contained enough DNA for genetic analysis. A total of 49 different alleles were found at both localities, from which 18 were exclusively found in individuals from Taim and 17 were exclusives from Vargas individuals. The most common allele was the same at both locations for three loci (Lut715, Lut733, and Lut818). A high level of genetic diversity was found at both sites (NeTaim=4.1, HoTaim=0.299, HeTaim=0.681; NeVargas=4.9, HoVargas=0.355, HeVargas=0.724), being higher at the Vargas stream site. A high and significant level of heterozygote deficiency was observed at most loci according to the χ2 test. The homogeneity χ2 test (P<0.001) showed that there were significant differences in the allele frequencies between the two locations. Genotyping for more than one locus was possible in 81.5% of samples, from which only 37% were possible to genotype for more than three loci. A low degree of relatedness was found among individuals from Taim (R=0.055±0.310), but an even lower value of relatedness was found at the Vargas site (R= -0.285±0.440). The significant degree of differentiation (I=0.890; F ST=0.059) found between Taim and Vargas individuals suggests that there is more than one population of otters in the southern extreme of Brazil, which probably are associated with the water body systems found in this region, the Mirim and the Caiuvá/Flores/Mangueira Lagoons. The high genetic diversity and low relatedness found at the Vargas stream, lead us to believe that the Vargas stream may be acting as a corridor between these water bodies for otter dispersion.
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The genus Thylamys Gray, 1843 lives in the central and southern portions of South America inhabiting open and shrub-like vegetation, from prairies to dry forest habitats in contrast to the preference of other Didelphidae genera for more mesic environments. Thylamys is a speciose genus including T. elegans (Waterhouse, 1839), T. macrurus (Olfers, 1818), T. pallidior (Thomas, 1902), T. pusillus (Desmarest, 1804), T. venustus (Thomas, 1902), T. sponsorius (Thomas, 1921), T. cinderella (Thomas, 1902), T. tatei (Handley, 1957), T. karimii (Petter, 1968), and T. velutinus (Wagner, 1842) species. Previous phylogenetic analyses in this genus did not include the Brazilian species T. karimii, which is widely distributed in this country. In this study, phylogenetic analyses were performed to establish the relationships among the Brazilian T. karimii and all other previously analyzed species. We used 402-bp fragments of the mitochondrial cytochrome b gene, and the phylogeny estimates were conducted employing maximum parsimony (MP), maximum likelihood (ML), Bayesian (BY), and neighbor-joining (NJ). The topologies of the trees obtained in the different analyses were all similar and pointed out that T. karimii is the sister taxon of a group constituted of taxa from dry and arid environments named the dryland species. The dryland species consists of T. pusillus, T. pallidior, T. tatei, and T. elegans. The results of this work suggest five species groups in Thylamys. In one of them, T. velutinus and T. kariimi could constitute a sister group forming one Thylamys clade that colonized Brazil.
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Realizou-se levantamento malacológico na praia de Carne de Vaca, município de Goiana, litoral norte de Pernambuco, entre novembro de 2006 e outubro de 2007, com o objetivo de conhecer a fauna malacológica dessa localidade e verificar as condições naturais, pouco ou bastante alteradas das áreas de estudo através da aplicação de um protocolo de avaliação de diversidade de hábitats. Foram coletados 5.912 moluscos, representados por sete espécies e quatro famílias, dos quais, 5.209 exemplares de Biomphalaria glabrata (Say, 1818), 113 de Drepanotrema lucidum (Pfeiffer, 1839), 55 de Drepanotrema cimex (Moricand, 1837), 13 de Drepanotrema anatinum (Pfeiffer, 1839), 222 de Melanoides tuberculatus (Muller, 1774), 263 de Pomacea sp. e 37 de Physa marmorata Guilding, 1828. Entre os exemplares de B. glabrata coletados, 44 mostraram-se positivos para Schistosoma mansoni Sambon, 1907 e 91 mostraram-se positivos para outras larvas de trematódeos. Um exemplar de Pomacea sp. mostrou-se positivo para larva de trematódeo. Os dados obtidos, georreferenciados espacialmente, serão utilizados para a determinação das áreas de risco para a transmissão da esquistossomose na praia de Carne de Vaca, além de simulações computacionais para estudos de previsibilidade e comportamento do processo de expansão da esquistossomose no estado de Pernambuco.