Rubidium marking of Anopheles stephensi (Diptera : Culicidae)

Immature Anopheles stephensi Listen were reared in untreated water and wate r containing eight e-fold dilutions of rubidium (Rb) from 1,000 to 7.8 ppm to determine the concentration that allowed reliable detection and produced the least toxic effects as measured by adult emergence, weight, and surviv al. The amount of Rb detected in mosquitoes increased positively with incre asing concentrations in the rearing water. Concentrations greater than or e qual to 31.2 ppm Rb in the rearing water provided high and consistent detec tion levels of greater than or equal to 3,500 ppm Rbi mg of adult mosquito. There were no adverse effects of Rb on the weights of mosquitoes. However, increased Rb concentrations in the rearing water were associated with decr eased emergence and survival. After 8 d, percentage emergence from Rb conce ntrations of 0-31.2 ppm was greater than or equal to 50%. At day 21, Rb con centrations of 0-31.2 ppm showed less than or equal to 29% reduction of fem ale survival compared with controls. The recommended concentration for reli able Rb detection with minimal toxic effects in An. stephensi was 32 ppm.