Influences of different external ion-concentrations on osmolality, internal potassium and sodium levels and uric acid concentration in Musca domestica larvae

Abstract

1. l. Influences of increased salt concentrations in the rearing media on hemolymph osmolality, internal potassium, sodium and uric acid concentration were examined in third instar larvae of Musca domestica. 2. 2. The larvae are able to regulate their hemolymph osmolality which increases under osmotic stress to the characteristic osmolality of unloaded animals up to pupation. 3. 3. K +-concentration in the whole body directly follows the increased K +-content of the medium, but not in malpighian tubules, intestine, fat body and integument. 4. 4. The increased Na +-level in the whole body falls significantly behind the changed external Na +-concentration. 5. 5. Hyperosmotic conditions cause a correlative decrease of uric acid in the whole body and in the organs.