The polyphagous pests belonging to the genus Spodoptera are considered to be among the most important causes of damage and are widely distributed throughout the Americas'. Due to the extensive use of genetically modified plants containing Bacillus thuringiensis genes that code for insecticidal proteins, resistant insects may arise. To prevent the development of resistance, pyramided plants, which express multiple insecticidal proteins that act through distinct mode of actions, can be used. This study analyzed the mechanisms of action for the proteins Cry1Ia10 and Vip3Aa on neonatal Spodoptera frugiperda, Spodoptera albula, Spodoptera eridania and Spodoptera cosmioides larvae. The interactions of these toxins with receptors on the intestinal epithelial membrane were also analyzed by binding biotinylated toxins to brush border membrane vesicles (BBMVs) from the intestines of these insects. A putative receptor of approximately 65 kDa was found by ligand blotting in all of these species. In vitro competition assays using biotinylated proteins have indicated that Vip3Aa and Cry1Ia10 do not compete for the same receptor for S. frugiperda, S. albula and S. cosmioides and that Vip3Aa was more efficient than Cry1Ia10 when tested individually, by bioassays. A synergistic effect of the toxins in S. frugiperda, S. albula and S. cosmioides was observed when they were combined. However, in S. eridania, Cry1Ia10 and Vip3Aa might compete for the same receptor and through bioassays Cry1Ia10 was more efficient than Vip3Aa and showed an antagonistic effect when the proteins were combined. These results suggest that using these genes to develop pyramided plants may not prove effective in preventing the development of resistance in S. eridiana.

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Palavras-chave: sensoriamento remoto, SRTM, filtros de convolução, Pantanal, Nhecolândia, lagoas ácidas/alcalinas. RESUMOO trabalho apresenta o produto da aplicação de filtros de convolução proporcionais de grandes proporções sobre cartas temáticas rasterizadas de lagoas salinas, hipossalinas e lagoas totais na Nhecolândia. As imagens filtradas mostram diferentes distribuições espaciais das lagoas salinas e hipossalinas bem como as regiões de dominância relativa de um e outro tipo de lagoa. Os resultados demonstram haver relativa independência entre tais distribuições, possivelmente indicando a presença de sutis diferenças ambientais ao longo da gênese recente dos mais peculiares elementos do meio físico da Nhecolândia. Estes dados são cruzados com perfis altimétricos elaborados a partir de dados SRTM. Estes dados foram tornados operacionais após filtragem com filtro passa-baixas de média móvel ponderada, já que ruídos de alta freqüência do tipo speckle associados à monotonia topográfica tornam a relação sinal/ruído demasiado baixa, dificultando ou inviabilizando a obtenção de dados. A hipótese de estar a Nhecolândia topograficamente elevada em relação às planícies vizinhas pode ser confirmada após o processamento dos perfis altimétricos. Outra hipótese, relacionada acerca da predominância de lagoas salinas em áreas soerguidas em relação à sua vizinhança imediata, foi também verificada ao menos em parte.Keywords: remote sensing, SRTM filtering, convolution filters, Pantanal, Nhecolândia, alkaline/acid lakes. ABSTRACTThis paper presents the application of proportional convolution filters with large size kernels on rasterized thematic maps of saline and hyposaline lagoons, and all lagoons in the Pantanal of Nhecolândia. The filtered images show the spatial distribution of the saline and hyposaline lagoons as well as the relative predominance of each lagoon type. The results demonstrate a relative independence between such distributions, indicating the presence of subtle environment differences during the recent stages of formation of the most peculiar elements of Nhecolândia. These data are crossed with topographical profiles elaborated from SRTM data rendered operational for this plain region after filtering with low-pass mobile average filters. The hypothesis that Nhecolândia is topographically higher in relation to neighboring plains was confirmed after profile filtering. Another hypothesis, related to the predominance of saline lagoons in relatively uplifted areas, was also at least partially confirmed.