Distribuição espacial de Aphis gossypii (Glover) (Hemiptera, Aphididae) e Bemisia tabaci (Gennadius) biótipo B (Hemiptera, Aleyrodidae) em algodoeiro Bt e não-Bt. O estudo da distribuição espacial de adultos de Bemisia tabaci e de Aphis gossypii nas culturas do algodoeiro Bt e não-Bt é fundamental para a otimização de técnicas de amostragens, além de revelar diferenças de comportamento de espécies não-alvo dessa tecnologia Bt entre as duas cultivares. Nesse sentido, o experimento buscou investigar o padrão da distribuição espacial dessas espécies de insetos no algodoeiro convencional não-Bt e no cultivar Bt. As avaliações ocorreram em dois campos de 5.000 m² cada, nos quais se realizou 14 avaliações com contagem de adultos da mosca-branca e colônias de pulgões. Foram calculados os índices de agregação (razão variância/média, índice de Morisita e Expoente k da Distribuição Binomial Negativa) e realizados os testes ajustes das classes numéricas de indivíduos encontradas e esperadas às distribuições teóricas de freqüência (Poisson, Binomial Negativa e Binomial Positiva). Todas as análises mostraram que, em ambas as cultivares, a distribuição espacial de B. tabaci ajustou-se a distribuição binomial negativa durante todo o período analisado, indicando que a cultivar transgênica não influenciou o padrão de distribuição agregada desse inseto. Já com relação às análises para A. gossypii, os índices de agregação apontaram distribuição agregada nas duas cultivares, mas as distribuições de freqüência permitiram concluir a ocorrência de distribuição agregada apenas no algodoeiro convencional, pois não houve nenhum ajuste para os dados na cultivar Bt. Isso indica que o algodão Bt alterou o padrão normal de dispersão dos pulgões no cultivo.

The study of spatial distribution of the adults of Bemisia tabaci and the colonies of Aphis gossypii on Bt and non-Bt cotton crop is fundamental for improving the sampling techniques and revealing differences in the behavior of non-target species between both cultivars. So, this experiment aimed to investigate the spatial distribution pattern of those species on the conventional non-Bt cotton crop, compared to the Bt cultivar. The samplings took place in two areas of 5.000 m² each, where it was done 14 evaluations counting adults of white-flies and colonies of aphids. The aggregation indexes (variance/mean rate, index of Morisita and Exponent k of the Negative Binomial Distribution) were calculated and accomplished the fitness tests of the individuals' numeric classes found and expected to the theoretical distributions of frequency (Poisson, Negative Binomial and Positive Binomial). Those analyses showed that in both cultivars, the spatial distribution of B. tabaci fitted to negative binomial distribution throughout the study period, indicating that the transgenic cultivar did not influence the pattern of aggregate distribution of this insect. With respect to the analysis for A. gossypii, the aggregation indexes showed aggregated distribution in both cultivars, but the distributions of frequency pointed to the occurrence of aggregate distribution only on conventional cotton, since there was no adjustment to the data on Bt crop. This indicates that Bt cotton has altered the aphids normal pattern of dispersion in the crop.

Entre 2000 a 2004, foi realizado levantamento da fauna de Triatominae (Hemiptera: Reduviidae) e exame de infecção natural por Trypanosomatidae, no Estado de Mato Grosso do Sul. Um total de 13.671 espécimes foram capturados. Na análise faunística das espécies capturadas, Triatoma sordida foi caracterizada como muito abundante, muito freqüente, constante e dominante. Os índices de infecção natural para Trypanosoma cruzi apresentaram os valores de 3,2% para Panstrongylus geniculatus, 0,6% para Rhodnius neglectus e 0,1% para Triatoma sordida, apesar do Estado de Mato Grosso do Sul apresentar-se livre da transmissão vetorial endêmica.

Between 2000 and 2004, a survey of Triatominae fauna (Hemiptera: Reduviidae) and examination of natural infection caused by Trypanosomatidae in the State of Mato Grosso do Sul, Brazil, was conducted. A total of 13,671 specimens were collected. Through fauna analysis on the insects that were caught, Triatoma sordida was characterized as very abundant, very frequent, constant and dominant. The rates of natural infection with Trypanosoma cruzi were 3.2% for Panstrongylus geniculatus, 0.6% for Rhodnius neglectus and 0.1% for Triatoma sordida. Nevertheless, the State of Mato Grosso do Sul is free from endemic vector transmission.

This work had as objective to compare the communities of Entomobryidae and Isotomidae (Collembola) among no-tillage in three fertility levels, conventional tillage and a natural ecosystem (native grassland). In the no-tillage in low fertility and medium fertility Entomobryidae and Isotomidae had populational picks in the winter and in the summer. In the no-tillage in area of high fertility, there was a populational pick for both families in the summer. In relation to the conventional tillage, Entomobryidae had a populational pick in the winter, and Isotomidae in the winter and in the summer. In the natural ecosystem Entomobryidae presented populational picks in the winter and in the summer and Isotomidae had regular populational fluctuation along the period of the experiment. The final mean density of Entomobryidae was larger in the natural ecosystem, proceeded by the treatments of no-tillage and finally, for the conventional tillage. In relation to Isotomidae, the no-tillage in area of low fertility was superior, coming the conventional tillage soon after, the no-tillage in médium and high fertility, and, finally, the natural ecosystem.

This work had as objective to compare the communities of Sminthuroidea and Onychiuridae (Collembola) among no-tillage in three fertility levels, conventional tillage and a natural ecosystem (native grassland). In the conventional tillage and in the no-tillage in area of medium fertility, the community of Sminthuroidea had regular fluctuation along the period of the experiment, but wtth low densities. The no-tillage in area of high fertility presented a populational pick in the autumn; the no-tillage in area of low fertility, in the spring; and, the natural ecosystem, in the summer. As the final mean density of the population of Sminthuroidea, was observed that the no-tillage in area of low fertility went numerically superior to the others, proceeded by the natural ecosystem, no-tillage in area of high fertility, conventional tillage, and, finally, no-tillage in area of medium fertility. Onychiuridae had three populational picks in the no-tillage in area of low fertility: being a larger in the winter and other two, smaller in the summer and in the autumn. In the no-tillage in area of medium fertility presented only a populational pick in the winter. In the other treatments there was not significantly populational picks. In relation to the final mean density ofthe community of Onychiuridae, the no-tillage plantation in area of low fertility was superior, proceeded by the other treatments of no-tillage, and, in third plan, the natural ecosystem and the conventional tillage.