Uptake and metabolism of the chemosterilants hempa and thiohempa by larvae, pupae and adults of Aedes aegypti (L.) (Diptera: Culicidae).

When larvae and pupae of yellow-fever mosquitoes, Aedes aegypti (L.), were kept in solutions of hexamethylphosphoric triamide (hempa) or hexamethylphosphorothioic triamide (thiohempa), they absorbed and metabolized the compounds rapidly to lower methylated phosphorus amides. Uptakes of the chemosterilants were determined by analyzing for residues of each compound and its metabolites in the larvae or pupae immediately after treatment. When pupae were treated with 1% hempa or 0.025% thiohempa, the adult mosquitoes contained only 0.30 or 0.45 μg/insect of the respective sterilants 12 hr after emergence.