Uptake of radioactive phosphorus by larvae and adults of mosquitoes.

Abstract

EIGHT batches of twenty-five second instar larvae of Aedes aegypti were immersed in separate beakers filled with a radioactive bath composed of 30 ml. tap water and progressively increasing amounts of a solution of radioactive disodium hydrogen phosphate (Na2H32PO4). The concentrations of the radio-isotope ranged from 17 to 4,480 mµc./ml. Rolled oats (0.25 gm.) was added to each beaker to serve as larval food. Larvae in baths with a concentration of 17–68 mµc. of phosphorus-32 showed the earliest (seven days from the day of immersion) and highest frequency of emergence as adults (approximately 60 per cent). Larvae in baths with progressively higher concentrations of the radioisotope showed a delayed pupation, though at the end of two weeks most of the larvae in all baths pupated except for the bath with the concentration of phosphorus-32 amounting to 4,480 mµc./ml. In concentration up to 140 mµc./ml., the emergence from pupae took place on the average within 48 hr. after pupation, and there was a considerable mortality of emerged or half-emerged adults. This mortality was roughly proportional to the concentration of the radioactive isotope in the larval bath.