1. INSECT
EXCRETION

2. Principal Organs of Excretion
Malpighian tubules
nephrocytes
rectal pads

3. Excretory Organs - Malpighian tubules

4. Excretory Organs - Malpighian tubules
distal
honeycomb border
Secretory region
lumen
brush border
Absorbtive region
proximal

5. Excretory Organs - Malpighian tubules
Honey-
comb
border
Brush
border

6. Excretory Organs - Nephrocytes

7. Excretory Organs - Rectal pads

8. Nitrogenous Products
NH2 CO O C H N HN C
NH3
Ammonia CO OC C N H N H CO
Urea
Uric Acid
Toxicity

9. Removal of wastes

10. Removal of wastes Brush border Urea Honeycomb border
Precipitates as uric acid crystals or urate
excrete H20 + base
pH ≈
pH ≈ 6.5
Honeycomb border
H20 to hemocoel
H20 to hemocoel
Uric acid crystals eliminated

11. Osmotic pressures (expressed as equivalent solution of NaCl (mEq/l))
Carausius
Schistocerca
Rhodnius
Aedes
(larva)
Hemolymph
171
214
206
138
Tubule
226
228
130
Rectum
390
433
358 12
AQUATIC

12. Moved to gut as meconium
Removal of wastes
Storage Excretion
Stored as uric acid
in fat body
Moved to gut as meconium

13. Sources of water gain
fog
eating
drinking