Studies on the mechanisms of ionic regulation in mosquito larvae : 3. Temperature dependent ionic regulation

Abstract

Variations in the concentrations of Na and Cl in haemolymph of the 4th-instar larvae of Aedes togoi (At) transferred into 150% artificial sea water (Barnes's process) at various temperatures. The At had been reared using fresh water at 23℃ over 170 generations. To measure Na and Cl radioactivation analysis was done. The concentrations of Na and Cl increased for about 10hr and the thorax of the larvae became flat and wrinkled with loss of water. In the experiments at 23℃ (Fig. 4) and 28℃ (Fig. 5) the concentrations of Na and Cl decreased and the breast swelled with water. In these cases, the larvae could live till pupation. At 4℃ (Fig. 1) and 10℃ (Fig. 2) these decreases were not observed and the larvae could not mature. The concentration of Cl increased and decreased more rapidly than that of Na, and the Na/Cl ratio was not kept constant. The variations in salt concentration are caused by transportation of both ions and water. To organize a system of ionic regulation for concentrated saline solutions, At larvae reared in fresh water need about 10hr or more and a suitable temperature, above 17℃.