Effects of mosquito larval feeding behavior on Bacillus sphaericus efficacy

Three species of mosquito larvae, representing three genera, were exposed from 10 min to 2 hr to the pathogen Bacillus sphaericus. Culex quinquefasciatus rapidly ingested the bacterium with resulting high mortality. Anopheles albimanus ingested it at a much lower rate initially with correspondingly low mortality. At the longest time interval they had accumulated approximately the same number of bacterial cells as C. quinquefasciatus but achieved a lower mortality. Aedes aegypti ingested and accumulated bacterium at the same rate as C. quinquefasciatus but was resistant to all time intervals. Utilizing ¹⁴C-labeled bacteria, we demonstrated that these differences were attributable to larval behavior in the case of A. albimanus but not in the case of A. aegypti.