Chironomus sancticaroli (Diptera, Chironomidae) as a Sensitive Tropical Test Species in Laboratory Bioassays Evaluating Metals (Copper and Cadmium) and Field Testing.

Despite that chironomids are the most widely used benthic insect test species worldwide, little research has been conducted so far with tropical chironomid representatives. This study was designed to evaluate the indigenous midge Chironomus sancticaroli as a candidate test species for use in tropical toxicity assessments. To this end, laboratory water-only toxicity tests were conducted evaluating copper and cadmium. Obtained lethal concentration values were overall comparable or lower than those reported for other chironomids, including those most commonly used in temperate regions (C. riparius and C. dilutus). In addition, C. sancticaroli was deployed in situ in the Monjolinho River (São Paulo State, Brazil), and toxicity of sediment from this river was evaluated in the laboratory. Several field water and sediment quality parameters also were measured to enable correlating these with the effects observed in these toxicity tests. Field sediment toxicity to C. sancticaroli appeared to be related with sediment endosulfan concentrations, whereas effects noted in the in situ test were likely due to low pH values measured in river water. Chironomus sancticaroli appears to be a suitable candidate for inclusion as a test species in tropical toxicity evaluations in both the laboratory and the field.

Fauna de Chironomidae (Diptera) associada à Salvinia sp. e Myriophyllum sp. num reservatório do Córrego do Espraiado, São Carlos, São Paulo, Brasil / Chironomidae (Diptera) fauna associated to Salvinia sp. and Myriophyllum sp. in a Corrego do Espraiado reservoir, São Carlos, São Paulo, Brazil

A presença de vegetação num ecossistema aquático é mais uma área disponível para a colonização. Vários estudos têm demonstrado uma relação positiva entre a presença de macrófitas e a abundância e a diversidade de Chironomidae. As variáveis ambientais e as larvas de Chironomidae associadas com as macrófitas Salvinia sp. e Myriophyllum sp. foram estudadas num reservatório com pequenas dimensões no estado de São Paulo, Brasil. Em Salvinia os grupos predominantes foram Tanytarsus, Monopelopia e Labrundinia, entretanto Cricotopus e Tanytarsus alternaram a dominância em Myriophyllum. Além disso, discutiu-se a estrutura dos grupos funcionais de alimentação associados a essas macrófitas.