POST-ECLOSION DIURESIS IN A FLIGHTLESS INSECT, THE SILKMOTH BOMBYX-MORI

Although the silkmoth, Bombyx mori L., has lost the ability to fly, it has retained a post-eclosion diuresis, In moths removed from their co coons before eclosion, or in those which failed to spin cocoons as lar vae, the weight loss due to diuresis was 14% of the eclosion body weig ht in males. Moths which used labial fluid to escape from their cocoon s showed a correspondingly smaller diuresis (5%). Both urine and labia l fluid had high potassium and low sodium concentrations. Unlike post- eclosion diuresis in butterflies, however, the urine was isosmotic to the haemolymph. In vitro preparations of B.mori Malpighian tubules wer e stimulated by cyclic AMP, B.mori brain extracts and Manduca sexta di uretic peptide (Mas-DP I).