Diffusion of blackfly species (Diptera, Simuliidae) in Friuli Venezia Giulia (Italy)

Blackfly occurrence was investigated on thirty plain streams of the low plain of the Friuli Venezia Giulia Region (NE Italy). Four species were found: Simulium erythrocephalum, S. angustitarse, S. ornatum, and S. paraequinum. Blackfly diffusion was larger than that reported in previous studies. Associations were found among Simuliidae species, hydrophyte species and water velocity.