Effects of Local Environmental and Landscape Variables on the Taxonomic and Trophic Composition of Aquatic Insects in a Rare Forest Formation of the Brazilian Amazon.

In the present study, we analyzed a unique phytophysiognomy in the Amazon region, which is formed by savanna-like vegetation on iron-rich soil (known locally as canga) located within an iron-ore mining region. We used the habitat template theory to test the hypothesis that changes in the physical-chemical properties of streams and the physical structure of their habitats at in-stream and micro-basin (landscape) levels affect the taxonomic and trophic composition of immature aquatic insects. For this, we used a local environmental matrix composed of nine physical-chemical and structural habitat variables, together with the Habitat Integrity Index. We also calculated landscape metrics based on the area of the micro-basin, such as relief, slope, mean current flow, and vegetation cover. We divided the aquatic insects into five functional feeding groups based on their diet and food sources. Our results indicate that changes in the trophic level of the insects of the orders Ephemeroptera, Plecoptera, and Trichoptera are more easily observed than the taxonomic structure of communities. The loss of environmental integrity and vegetation cover were responsible for 84% of the variation observed in the composition of functional feeding groups (FFGs). Our study shows that aquatic insect communities in the canga and in the Amazon regions dominated by forest require specific in-stream and landscape conditions. These findings reinforce the need for the preservation of areas of canga vegetation, which not only have a unique levels of biological diversity, but are also targeted for the exploitation of their economically valuable natural resources.

[Prurigo strophulus (concept, interpretation, therapeutic approach, prevention and clinical studies)]. / Prurigo estrófulo (estudo clínico, conceituação, interpretação, conduta terapêutica e profilaxia).

The authors in this work analyse the Prurigo Strophulus in detail, starting with its clinical study up to its therapy and prophylaxis, emphasizing two main points. It is a hypersensitivity syndrome to insects appearing in genetically predisposed individuals, partly belonging to the hyperreactive group. As to etiology, they believe it to be a sensitization to insect bites, chiefly due to diptera such as blood-sucking mosquitoes, flies and sometimes ticks and bugs.