If you want to demonstrate how beautiful creatures can also be destructive, the cabbage butterfly caterpillar is a great species. These butterflies, commonly sold as eggs, are readily available through biological suppliers like Carolina Biological Supply or Connecticut Valley Biological Supply.
Before you order them, though, one thing you should remember is that you should have some decent-sized cabbage plants for them to feed on. Depending on how many eggs you purchase, about a dozen plants roughly 4-6″ tall (minimum) should be sufficient to get you going. They grow quickly, though, so you may need to have another 12 plants at the ready to feed the mature caterpillars…again, depending on how many eggs and caterpillars you’re rearing.
Just a few mature caterpillars can nearly completely defoliate a medium sized cabbage plant within a few days.
The chrysalises are wonderful to watch and can tolerate some very light, sensitive handling. The adult butterflies can be fed a sugar water solution, and once mated, the females will lay eggs on cabbages readily in a cage.
Beyond Insect Life Cycles
As with all living colonies, cabbage caterpillars can demonstrate more than just the obvious aspects of the butterfly’s life cycle. Even a small cabbage butterfly rearing project can also show the tension between food production and food consumption. These “tensions” become even more pronounced during times of economic downturn and/or extreme fuel prices. When there is food shortages, the caterpillars must make do with less; by using live colonies to show these relationships, even young learners can be “primed” to receive (and understand) concepts like supply and demand.