COMPARATIVE INGESTION RATES OF CULEX-QUINQUEFASCIATUS (DIPTERA, CULICIDAE) SUSCEPTIBLE AND RESISTANT TO BACILLUS-SPHAERICUS

Larvae of laboratory and field-collected strains of Culex quinquefasci atus susceptible and resistant (37- and 31-fold, upon selection) to Ba cillus sphaericus strain 2362 were studied for their ingestion rates o f this pathogen and other particulate materials. Larvae of the resista nt strains (laboratory and field-collected) ingested B. sphaericus pre paration at significantly lower rates than did larvae of the susceptib le strains. Larvae of the resistant strains also ingested B. sphaericu s preparation at significantly lower rates than yeast (nutritious), wh ile larvae of the susceptible strains ingested B. sphaericus preparati on at the same or higher rates than yeast. The reduced ingestion rates on B. sphaericus in resistant strains could possibly serve as a behav ioristic mechanism of resistance against this microbial larvicide. (C) 1995 Academic Press, Inc.