Distribution patterns of riodinid butterflies (Lepidoptera: Riodinidae) from southern Brazil

Background: The aim of this study was to synthesize the knowledge of Riodinidae butterflies (Lepidoptera: Papilionoidea) in Rio Grande do Sul state (RS), southern Brazil, evaluating the role of climatic, topographic, and vegetational variables on the observed patterns of occurrence and distribution of these butterflies in the Pampa and Atlantic Forest biomes. The records of riodinid butterflies in RS were collected from published studies and the examination of museum collections in Brazil. Results: A total of 97 taxa of Riodinidae were recorded, distributed in 92 municipalities. The NMDS analysis and the Constrained Analysis of Principal Coordinates grouped the municipalities according to the phytogeographic regions and biomes - Pampa and Atlantic Forest domains - in which the species records were made. Distance from the ocean, precipitation and temperature were the environmental variables which most contributed to explain the distribution patterns of these butterflies. The multivariate Mantel correlogram suggests that over short distances, the composition of species shows significant levels of spatial autocorrelation, and as geographic distance increases, these levels tend to present negative values. Conclusions: The results suggest that the observed distribution pattern of Riodinidae in the different biomes and phytogeographic regions in the extreme southern Brazil could be explained by climatic, environmental variables and geographic distance

A simple and fast method for determination of phosphorus in fish diets and faeces used in animal nutritional studies

The optimization and validation of a simple and fast analytical method for the determination of phosphorus in fish diets and faeces used in animal nutrition studies are shown in this paper, starting with the validation of a preoptimized digestion procedure for biological samples, choice of the best chemical modifier and the minimal sample amounts. The digestion procedure consisted of an acid dissolution of a minimal of 100 mg of dry sample in a domestic microwave system using Parr Teflon bombs at high pressure. The P levels were determined by atomic absorption spectrometry with electrothermal atomisation, using an absorbance of 213.6 nm, a slit width of 1.0 nm, a current lamp of 20 mA and a deuterium lamp for background correction. Different furnace temperature programmes were used, and a final temperature programme was optimized. The optimization stages suggested the use of a 1,000 μg/ml La solution as chemical modifier and 1,600 and 2,700 °C as, respectively, the best pyrolysis and atomisation temperatures. The optimized analytical method was applied to different types of fish diets and faeces, and the percentages of recovery of P in spiked samples were, respectively, 94±11% (n=3) and 100±12% (n=3). The detection limit was 0.15 mg P/g of dry sample. The optimized methodology is simpler, faster and has less sample mass consumption than normally used colorimetric methods.publishe