Focusing on the life cycle and rearing of caterpillars

The life cycle

The life cycle of butterflies and moths is divided into 4 phases.

The egg stage: the caterpillar eats it's way through the shell, many eat the whole shell to provide energy. The above movie shows the caterpillar eating it's way out of the shell.

The caterpillar stage: Feeding and growth phases, with moults to permit the body to expand. It is normally between 4-6 moults for most caterpillars.

The pupa stage: The body is extensively rearranged to form the adult moth or butterfly. Moths usually construct a protective cocoon in which to pupate. Some spin leaves to form a simple cocoon, whilst other's incorporate bark and wood to make an elaborate chamber. Butterflies are mostly suspended from leaves and stems. The caterpillar spins a silk thread to hang from.

The adult stage: As the pupa skin splits open, the adult begins to emerge and swallows air to expand the body. When fully emerged, the adult rest whilst pumping blood into the wings to expand and dry them.

Rearing caterpillars.

Enjoyable and educational, rearing caterpillars can be achieved with great success.

First, a suitable 'cage' must be constructed. A simple box covered in muslin will suffice. A wooden base and top and one side, the other three sides covered in muslin. One side should have velcro sewn on, for ease of opening to feed and clean out.

If you have small caterpillars, those in the early stages, then a plastic carton with part of the top removed and covered with muslin, is an ideal start. Do not overcrowd the caterpillars as this will certainly kill them, as will direct heat/cold. A shed is ideal to keep them in.

Make sure they have plenty of food, and that it is the correct food. Twice daily remove stale food and place fresh food in. Clean away any droppings to ensure good health.

Transfer to large cages when they are a week or two old, to allow them space and movement. Don't pick them up with your fingers, use a paintbrush to transfer them, and while you are cleaning them out.

During moulting, the caterpillar will appear sluggish. Leave them alone while they moult.

When fully grown, place stems and twigs in the cage for butterflies to hang from, and bark or wood or peat for moths.

Once they have pupated, depending on the species, leave them in a shed and check occasionally for dampness and overheating.