Studies on the Exchange and Regulation of Sodium in the Larva of Aedes Aegypti (L.)

Abstract

1. The steady-state exchange of sodium in the 4th instar larva of Aëdes aegypti (L.) has been studied by means of flame photometry and ²²Na. 2. The steady-state exchange of sodium between the larva and medium is more rapid in fed larvae (T_½ about 10 hr.) than in starved larvae (T_½ about 60 hr.). There is no difference between the sodium levels of fed and starved larvae. 3. In both fed and starved larvae about 90% of the exchange occurs through the anal papillae so these organs must be responsible for about 90% of the difference between fed and starved larvae in the rate of exchange. 4. Cytological changes in the anal papillae following upon feeding and starvation are described. 5. The results are discussed in terms of possible carrier mechanisms in the anal papillae.