The soil fauna plays an important function over the processes of organic matter decomposition, nutrient cycling, ground aeration and fertility. Thus, studies on the composition and structure of such communities are important, considering moreover the lack of information in different regions of Brazil and mainly related to the state of Piauí. This study aimed to evaluate the density and diversity of the soil arthropod fauna in a Cerrado area in preservation conditions and in a pasture area. Both are situated in the city of Teresina, capital of the state of Piauí. Pitfall traps were used for sampling. Five stations with four traps were placed in each area. The traps were constituted by a 500 mL plastic cup containing a preserving solution made with 70% alcohol and 40% formalin. The traps were weekly changed by occasion of the collections. Eight samples were performed in the period between March and April 2007. The results were evaluated using the following variables: number of orders, number of families, total of species and total number of individuals. Evaluation of the Diversity Index and Similarity Coefficient were also performed. As result, the variables and diversity indices were slightly higher in the preserved area. However, the similarity coefficient showed only 10% similarity between both areas.Keywords: soil, macrofauna, insects, savannah, conservation.Diversidade de artrópodes da fauna edáfica em área preservada e área manejada com pastagem no município de Teresina-Piauí-Brasil ResumoA fauna do solo exerce importante papel nos processos de decomposição da matéria orgânica, ciclos de nutrientes, aeração e fertilidade do solo. Assim, estudos sobre a composição e estrutura dessas comunidades são importantes, considerando, além disso, a escassez de informações nas diferentes regiões do Brasil e principalmente em relação ao estado do Piauí. Este estudo teve como objetivo avaliar a densidade e diversidade da fauna de artrópodes encontrados no solo em uma área de Cerrado em estado de preservação e uma área utilizada com pastagem. Ambas estão situadas no município de Teresina, capital do estado do Piauí. Armadilhas do tipo Pitfall foram utilizadas para amostragem. Cinco estações com quatro armadilhas foram colocadas em cada área. As armadilhas foram constituídas por um copo plástico (500 mL), contendo uma solução conservante feita de álcool 70% e formol 40%.

Este trabalho teve por objetivo determinar as doses esterilizantes e letal para ovos de T. castaneum (Herbst., 1797) (Coleoptera: Tenebrionidae), através de doses crescentes de radiação gama. Utilizou-se uma fonte de Cobalto-60, tipo Gammabeam-650, com taxa de dose de 1,28 kGy/hora. O experimento foi conduzido sob condições controladas com temperatura de 25 ± 2°C e umidade relativa de 70 ± 5%. As doses letal e esterilizante para os ovos foram respectivamente 30 e 20 Gy.

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425Resistência de genótipos de feijão-caupi ao ataque de Callosobruchus maculatus (Fabr., 1775) (Coleoptera: Chrysomelidae: Bruchinae). ABSTRACT RESISTANCE OF GENOTYPES OF COWPEA TO THE ATTACK OF CALLOSOBRUCHUS MACULATUS (FABR., 1775) (COLEOPTERA: CHRYSOMELIDAE: BRUCHINAE). The objective of this study was to evaluate the resistance of 4 genotypes of cowpea (Vigna unguiculata) to the bean weevil Callosobruchus maculatus (Fabr., 1775). The genotypes evaluated were BR 17-Gurguéia, BRS Rouxinol, TE96-290-12G and BRS Guariba. Tests were conducted with and without possibility of choice, in a completely randomized design, totaling 4 treatments each with 5 replicates, evaluating the number of eggs, number of emerged insects, egg viability (%) and instantaneous rate of population growth. In the test with possibility of choice the genotype TE96-290-12G was revealed as the most resistant. BRS Rouxinol was the most susceptible genotype.

The Thrips genus-group is a monophyletic taxon composed of 17 genera, whose representatives exhibit three main synapomorphies: absence of ocellar setae I, presence of ctenidia on tergites V-VIII, and ctenidia on tergite VIII positioned posteromesad to the spiracles. The group is native to and more diverse in the Old World, especially in Southeast Asia, but several species are widely distributed, including some pests of cultivated plants. Here, we provide an identification key to the species of the Thrips genus-group currently recorded in Brazil, including three new records of Bolacothrips striatopennatus (Schmutz), Thrips florum Schmutz, and Thrips orientalis (Bagnall), and present notes on their morphology and biology. Stenchaetothrips biformis Bagnall is excluded from the list of thrips recorded in Brazil.