Terrestrial Insects

• Insects have a fibrous exoskeleton for protection and a lipid layer to prevent water loss
• Insect Tracheal System:

  • Spiracles (valves) for air entry
  • Trachea is a network of internal tubes with rings to strengthen
  • Tracheoles are smaller tubes branching, delivering O2 to respiring cells
• Diffusion of gases down the concentration gradient in cells and tracheoles
• Mass Transport contracts and relaxes abdominal muscle to move gas on mass
• Inflight creates anaerobic respiration producing lactate, lowering water potential of cells, water moves from tracheoles to cells via osmosis, lowering volume and air being drawn in
• Insects Prevent Water Loss by...

  • Small SA:V
  • Waterproof exoskeleton
  • Spiracles can open and close