Diversidade de Similiidae (Diptera, Nematocera) em córregos do estado de São Paulo, Brasil.
Resumen
With the aim to analyse the Simuliidae diversity in the State of São Paulo streams, a
program of collection was done during two weather seasons (dry/2001; wet/2002) in 33
aquatic systems, including forested and open low order streams and outflow of water
impoundments in 11 areas inside the Mata Atlântica and Cerrado forest. The immatures
were collected manually and with the Surber sampler. Overall 26 Simuliidae species were
analyzed and identified of which 8 were new occurrences to São Paulo State and 1 to Brazil.
Simulium pertinax, S. incrustatum, S. perflavum, S. noguerai and S. inaequale were the most
frequent species, collected in at least 30% of the water bodies. The numerical population
density didn t show significant difference between the weather seasons (Kruskal-Wallis non
parametric test). The relations between the taxonomic structure and the environment
variables were analyzed by cluster analyses and principal components (Spearman s rank
coefficent). Water velocity and streams dimensions were the main variables that explained
the distribution of Simuliidae species. The anthropic impact level, as impoundment or
deforestation may also influence the species distribution.