Water

Question 1

Outside of thermal envelope:

Answer 1

Wax melts and water is lost through the cuticle

Question 2

In high humidity

Answer 2

Less water is lost as evaporation is reduced

Question 3

Insects that develop in high temperatures:

Answer 3

More wax into cuticle and more fort into stopping water loss

Question 4

Metabolism produces _________________.

Problems:

Answer 4

Metabolic water

Increases weight if insect making flying challenging

Trade off between energy consumption and water production

Must get rid of water when flying

Question 5

Larvae of the ___________: ____________ can absorb water by __________________ so that ______________ can enter. This is deposited on the ___________ then taken up by ______________ and water is absorbed via __________________.

Answer 5

Beetle
Tenebrio
Opening their anus
Water vapour 
Rectum wall
Very very concentrated salt solution 
Countercurrent exchanger

Question 6

Discuss salinity tolerance in insects

Answer 6

Wax stops water loss but is susceptible to damage by salts

California: mono lake is drying up so is changing from fresh to high conc salt water.

Bribe flies have adapted to this using a plastron supported by hairs to form a protective coat around cuticle to prevent wax damage and consequent water loss

Bribe flies and mosquito larvae from salt water do not osmoconform when osmotic pressure increases but this from fresh water osmoconform and die

Question 7

Describe the transcellular route into the malpighian tubules

Answer 7

Ions actively pumped in via protein transporter (can’t move in without transporter).

Every comes from vATPase

Eg K+/proton antiporter: K+ pumped out of cells and H+ in, drives influx of K+ and can drive chloride in

Eg. Uric acid, alkaloids, Mg, SO4

Question 8

Describe the paracellular route into the malpighian tubules

Answer 8

Molecules move between the cells of the MTs and directly into the lumen

Typically very slow as cells joined by tight junctions

Passive