Distribuição espacial e variação temporal da composição de espécies de borrachudos (Diptera: Simuliidae) em uma microbacia situada no norte do Paraná / Spatial distribution and temporal variation in composition of black fly species (Diptera: Simuliidae) in a small watershed located in the Northern of Paraná State, Brazil

ABSTRACT

In this work, the survey of simuliid species and the study of their spatial distribution in four streams of a small watershed situated in Londrina, Paraná State, were carried out from January to October 2007. Changes in the species composition of the breeding sites were also checked along the sampling months. Seventeen black fly species were found, being Simulium botulibranchium Lutz, Simulium travassosi d'Andretta & d'Andretta, Simulium anamariae Vulcano, Simulium brachycladum Lutz & Pinto and Simulium metallicum s. l. Bellardi new records for Paraná State. The Canonical Correspondence Analysis showed that the environmental variables most correlated to the species distribution among sample sites were water conductivity and those linked to physical dimensions of the breeding sites, like width, depth and water velocity. The matrix of faunistic similarity among collecting dates was negatively correlated to the time interval of sampling matrix for three of the water bodies studied, showing the existence of temporal changes in the species composition. According to Multiple Regression Analysis, temporal abundance variation of Simulium perflavum Roubaud, Simulium inaequale Paterson & Shannon and Simulium lutzianum s. l. Pinto was not linked to air temperature, photoperiod and rainfall, suggesting the influence of other factors, probably those directly associated to specific breeding site conditions. The results indicate that differences in physical and chemical characteristics among water bodies may affect the taxonomic composition of simuliids in this watershed.