Since the insect is cold blooded, in other words it depends on the environment to increase its body temperature, it can only function at optimum levels when the conditions are suitable. During winter the insects are not active in great numbers.
The insect, like other creatures, burns food with oxygen to create energy necessary to sustain life. This process is known as metabolism. The rate at which the insect produces energy, to some extent, depends on the speed with which oxygen and food travel around the body to where they are needed and waste material removed.
A rise in temperature is accompanied by an increase in the:
- rate of chemical reactions
- solubility of solids in liquids
- speed of movement of all molecules, be they nutrient or waste molecules.
All living creatures control the rate at which they burn food to release energy. This is called the metabolic rate. Control of chemical reactions is done through special molecules(chemicals) called enzymes. Enzymes are natural catalysts that accelerate certain reactions. If an insect wants more energy it must not only provide the nutrients and oxygen but must also supply the right enzyme to make the burning proceed quickly. Enzymes are chemicals that only function well at certain temperatures and this is another reason why maintaining temperature is so important.
Flying is an exhaustive task which requires an enormous amount of energy. During egg laying the butterfly must hover over leaves for lengths of time. Only during summer is there enough heat around to allow the insect to function at maximum capacity.

How does the butterfly cope with the winter months? Compare this with other creatures.

Look at the diagram above and explain how an enzyme works.