124 resultados para Biological Species Concept


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The objective of this work was to evaluate the development, survival, reproductive capacity, and longevity of the Asian ladybug Harmonia axyridis in comparison with Cycloneda sanguinea and Hippodamia convergens. Coccinellid larvae and adults were fed daily with Schizaphis graminum. Ten couples of each species were isolated for evaluation of the adult phase. The duration of the larval stage of H. axyridis is the longest (10.2 days) and its adults are the heaviest (29.7 mg) compared with C. sanguinea and H. convergens. The three species showed similar percentages of survival during the developmental stages. An average of 82% of C. sanguinea, H. axyridis, and H. convergens larvae reached adulthood, which indicates that temperature (25°C) and the offered prey are favorable to coccinellid development. Harmonia axyridis produces a higher total number of eggs per female (1,029.2) than the other evaluated species. However, H. axyridis, which lives for an average of 147.2 days, does not show a significantly greater longevity than C. sanguinea (87.2 days) and H. convergens (134.3 days).

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This study evaluated the decomposition process of leaf litter from the main Brazilian mangrove species Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. Senescent leaves were collected, dried and placed in nylon bags with different mesh sizes (fine: 2x2mm and coarse: 8x8mm). The bags were distributed over the sediment, and replicates of each species and mesh size were collected periodically over 4months. In the laboratory, the dry weight of the samples was measured, and the decomposition coefficient (k) for each species and mesh size was obtained over time. All species showed a rapid decomposition rate at the beginning of the experiment, followed by a slower but steady rate of decomposition over time. The rate of leaf litter decomposition was highest in A. schaueriana, intermediate in L. racemosa and lowest in R. mangle. The difference was mainly linked to the activity and abundance of detritivores, together with the different litter quality of the species, which determined their palatability and probably influenced the decomposition process.

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The invasive thistle Carduus nutans has been reported to be allelopathic, yet no allelochemicals have been identified from the species. In a search for allelochemicals from C. nutans and the closely related invasive species C. acanthoides, bioassay-guided fractionation of roots and leaves of each species were conducted. Only dichloromethane extracts of the roots of both species contained a phytotoxin (aplotaxene, (Z,Z,Z)-heptadeca-1,8,11,14-tetraene) with sufficient total activity to potentially act as an allelochemical. Aplotaxene made up 0.44 % of the weight of greenhouse-grown C. acanthoides roots (ca. 20 mM in the plant) and was not found in leaves of either species. It inhibited growth of lettuce 50%(I-50) in soil at a concentration of ca. 0.5 mg g(-1) of dry soil (ca. 6.5 mM in soil moisture). These values gave a total activity in soil value (molar concentration in the plant divided by the molarity required for 50 % growth inhibition in soil = 3.08) similar to those of some established allelochemicals. The aplotaxene I-50 for duckweed (Lemna paucicostata) in nutrient solution was less than 0.333 mM, and the compound caused cellular leakage of cucumber cotyledon discs in darkness and light at similar concentrations. Soil in which C. acanthoides had grown contained aplotaxene at a lower concentration than necessary for biological activity in our short-term soil bioassays, but these levels might have activity over longer periods of time and might be an underestimate of concentrations in undisturbed and/or rhizosphere soil.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Neoparaphytoseius charapa n. sp. is described, based on the morphology of adult females and males collected on Inga edulis ( Mart.) ( Fabaceae) in northeastern Peru. Neoparaphytoseius Chant & McMurtry is redefined on the basis of the new species and re-examination of its type species N. sooretamus Chant & McMurtry.

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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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Tributyltin exposure is the primary cause of imposex development in gastropods, making them excellent bioindicators. The present research represents the first examination of butyltin (BT) contamination in surface sediments associated with imposex in Leucozonia nassa and L. ocellata in a harbour complex area in Espirito Santo, southeastern Brazil. The objectives of this study were to evaluate the organotin pollution in the area and to assess the sensitivity of both species to BT pollution through imposex development. Specimens were collected between 2007 and 2010 and the sediments were sampled in 2007. Imposex intensity was evaluated based on the percentage of imposexed females, the relative penis length index (RPLI) and the average value of the vas deferens sequence index (VDSI). BTs were analysed using gas chromatography equipped with a pulsed flame photometric detector (PFPD). The results demonstrated the occurrence of elevated concentrations of BTs in the sediment ranging from 383.7 to 7172.9 ng Sn g(-1), indicating a severe contamination of the area, which was confirmed by the biological monitoring results. Our findings also indicated that L. ocellata is a less sensitive species than L. nassa and that this differential sensitivity plays a key role in the distributions of the populations of both species in the studied area.

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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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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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Paracoccidioides lutzii, formerly known as 'Pb01-like' strains in the P. brasiliensis complex, is proposed as a new species based on phylogenetic and comparative genomics data, recombination analysis, and morphological characteristics. Conidia of P. lutzii are elongated, different from those of P. brasiliensis. P. lutzii occurs in the central and northern regions of Brazil. Studies comparing P. brasiliensis and P. lutzii may have significant clinical consequences for the diagnosis and treatment of paracoccidioidomycosis.