
Cabbage white butterflies are fun to keep, easy to find. They eat cabbages, nasturtiums, broccoli.

Feed caterpillars on whatever your find them living on – that will be what they eat.
Keep them in a glass container with food, replenishing frequently.
Keep them, to see what comes out. You might find something really interesting! Actually, you can never find anything really dull in the insect world.
