minimizing water loss in insects

Question 1

what kind of SA:VOL ratio do insects have and why ? what does this adaptation do ?

Answer 1

• they have a large SA:VOL
  because they are small and they have a branching tracheal system
• which further increases the surface area and minimizes the distance for evaporation

Question 2

to what kind of insects is water loss a particularly huge problem

Answer 2

water loss is a problem for all insects but particularly those that live in dry conditions

Question 3

adaptations to minimize water loss

Answer 3

• the exoskeleton of an insect has a cuticle which is made out of chittin ( waterproof and airtight)so evaporation can only occur through the spiracles when they are open.
• insects show periods of inactivity so less respiration takes place and the spiracle valves can be closed
• finding shade and humid environments where the rate of evaporation will be less

Question 4

what is meant by humidity ?

Answer 4

the measure of how much water is in the air