EFFECT OF PHYSICAL FACTORS ON THE COLONIZATION AND RELOCATION BEHAVIOR OF IMMATURE BLACK FLIES (DIPTERA, SIMULIIDAE)

Water velocity, substrate placement and the length of exposure time influenced the number of Prosimulium mixtumlfuscum Syme and Davies and Cnephia dacotensis Dyar and Shannon larvae attaching to white ceramic tiles and clear plastic tapes in the field. P. mixtumlfuscum readily attached to either substrate whereas C. dacotensis demonstrated a preference for white ceramic tiles. In an artificial stream, both species preferred specific velocity ranges although they did not increase their relocation behavior when exposed to varying depths of 2 to 30 cm and temperatures of 2° to 30°C. P. mixtumlfuscum increased relocation behavior in the absence of light. © 1979 Entomological Society of America. All rights reserved.