Date of this Version
Environmental Entomology 18:3 (June 1989), pp. 433–437.
Colonization of Simulium bivittatum Malloch and S. luggeri Nicholson and Mickel on artificial substrates exposed for two consecutive time periods of 1, 2, or 4 d was contrasted with colonization after continuous exposures of 2, 4, or 8 d. Reduced colonization of early instars of both species during the second 4-d period was attributed to an aging population, whereas reductions in total black flies after 8 d seemed to be caused by substrate changes. Numbers of pupae increased as exposure time increased.