ABSTRACT
Abstract: Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) has been recognized as a major owlet caterpillar associated to the herbivory of gramineaceous plants across the American continent. During outbreaks, the caterpillars are capable of completely consuming preferred hosts (grasses) and, when these hosts are destroyed, they can move to adjacent non-grass plants and cause similar damage. Meteorological variable such as temperature and humidity are described as factors that affect the development and abundance of M. latipes. This paper aimed to describe and compare the spatial and temporal distribution of M. latipes in different locations in Brazil and to evaluate the influence of meteorological variables on the temporal range. A total of 12 locations were evaluated, in each collection point light traps were installed near cultivated areas. In order to understand the influence of meteorological variables on the abundance of M. latipes, the data were analyzed using a Generalized Linear Model according to Poisson regression. A linear regression was also used to verify the relation between the abundance and the latitude. A total of 1,985 moths were collected. The highest collections were in Amazon and Cerrado biomes. Results show that abundance was inversely related to increasing latitude and Poisson regression analysis indicated that the main meteorological variables were significantly related to abundance at each site. This study shows that due to the high preference for gramineas and the high temperature requirements (30°C), M. latipes is an important species in hot regions and regions with hight humidity. Furthurmore, even in higher latitudes, in subtropical areas, during summer months, populations can Rapidly growth being able to cause economic damages.
Resumo: Mocis latipes (Guenée, 1852) (Lepidoptera: Erebidae) tem sido reconhecida como uma das principais espécies consumidoras de gramíneas em todo o continente americano. Durante os surtos, as lagartas são capazes de consumir completamente os hospedeiros preferenciais (gramíneas) e, quando os hospedeiros preferenciais são destruídos, podem mover-se para plantas adjacentes não gramíneas e causar danos semelhantes. Variáveis meteorológicas, como temperatura e umidade, são conhecidas por afetar o desenvolvimento e a abundância de suas populações. Este trabalho teve como objetivo descrever e comparar a distribuição espaço-temporal de M. latipes em diferentes localidades do Brasil e avaliar a influência de variáveis meteorológicas sobre suas variações temporais. Foram avaliados 12 locais, em cada ponto de coleta foram instaladas armadilhas luminosas próximas às áreas de cultivo. Para entender a influência das variáveis meteorológicas na abundância de M. latipes, os dados foram analisados pelo Modelo Linear Generalizado, empregando a regressão de Poisson. Uma regressão linear também foi utilizada para verificar a relação entre a abundância e a latitude. Um total de 1.985 mariposas foram coletadas. Os maiores números de indivíduos foram coletados nos biomas Amazônia e Cerrado. Os resultados mostram que a abundância de mariposas está inversamente relacionada ao aumento da latitude. A análise de regressão de Poisson indicou que as principais variáveis meteorológicas foram significativamente relacionadas à abundância em cada local. Este estudo mostra que devido à preferência por gramíneas em estado vegetativo e às altas exigências de temperatura (30°C), M. latipes é uma espécie importante em regiões quentes, especialmente nas épocas de maior umidade. Além disso, mesmo em latitudes elevadas, durante os meses de verão, as populações podem aumentar rapidamente, podendo causar danos econômicos.
ABSTRACT
A versatile preconcentration system for trace element determination by ICPMS was developed. It is composed of a commercial flow injection analysis system (FIAS) retrofitted with a home-made control unit containing three solenoid valves and working concomitantly with the FIAS, permitting selection and segmentation of sample, reagent, washing solution and elution flow. The knotted reactor used had a length of 200 cm and was made from 0.05 cm i.d. PTFE tubing. The method applies ammonium 1-pyrrolidinedithiocarbamate (APDC) as complexant, allowing the preconcentration and quantitative multi-element determination of Cu, Ni, V, Co, Nb, Mo, In, Sb and Bi. Ethanol and 4-methyl-2-pentanone were tested as eluents. Recovery tests using complex matrices and spike concentrations of 200 ng L(-1) showed typical values in the range of 90% to 110%. Relative standard deviations were < 7% for elution with ethanol and < 5% with methyl isobutyl ketone. For simulated freshwater samples using 4-methyl-2-pentanone as an eluent, a sample loading rate of 5.0 ml min(-1), and a preconcentration time of 60 s, detection limits (ng L(-1)) were in the range of 0.02 (Bi) to 30 (Cu). Under these conditions, analytical frequency was about 15 samples per hour. The feasibility of the method was demonstrated by the succesful analysis of wastewater and seawater certified reference materials.