Describe osmoregulation in a terrestrial insect.

Water must be carefully conserved since most terrestrial insects are unable to drink and depend on metabolic water

• During excretion, the urine passes from the Malpighian tubules into the ileum and is mixed with feces with which it is then excreted via the rectum. In the rectum, the rectal glands absorb all the water into the body and uric acid is then excreted in solid from. The water deficit is made up by metabolic water.
• The salt fraction is regulated by the Malpighian tubules. In the proximal half, sodium and potassium ions are extracted from the blood, but carefully returned in the distal half with precipitation of uric acid. The uric acid passes in the urine to the ileum for excretion via rectum.