Life Science: Brassica & Butterfly System
Brassica & Butterfly System
The Brassica & Butterfly System (see building instructions) will allow you to observe an entire plant life cycle along with an entire animal life cycle over a relatively short time period. The plant, Brassica rapa, is a variety that belongs to the mustard family. It has been selectively bred for a rapid life cycle: from seed to seed in about 30 days. These plants have been nicknamed “Fast Plants.” The animal is Pieris rapae, an insect known as the cabbage white butterfly. Pieris also has a life cycle that occurs over about 30 days.
The connection between the two involves feeding and reproduction. Pieris larvae are particularly fond of eating Brassica leaves, while Pieris adults feed on the nectar in Brassica flowers. As the butterflies move from flower to flower, they pollinate the Brassica plants. In addition, Pieris adults are attracted to Brassica leaves for egg-laying.
There are many activities that can be done with Brassica, Pieris, or both. Life Science has suggested a few that can help you understand plant and animal life cycles better–and that can be used with great success in K-6 classrooms. The "Brassica & Butterfly Life Cycles" activity follows the progress of Brassica from seed to seed as it interconnects with the life cycle of Pieris from egg to egg. "To Bee or Not to Bee" is an activity you can do to see what happens to Brassica flowers that are pollinated and those that are not. The "Salad Bar" activity tests the feeding preferences of Pieris larvae; and in "How Sweet It Is," different sugar concentrations are used to see the effect on adult Pieris feeding. Finally, with the "Mother Knows Best" activity, you can see on what types of plants Pieris prefers to lay eggs.
For more information and acitivities for this system, visit the Fast Plants Web site at www.fastplants.org.