DAYS 25-29: Larvae Hatch, Overpopulation, Work on Final Report (5-15 min, computer lab work on report- 45 minutes)
1. Larvae will begin to hatch within 3-5 days after the eggs are laid. Noting the tiny size of the eggs from which they emerge, you will realize that the caterpillars must be tiny at first. Suggest that students look on the underside of leaves, where they often tend to hang out. They will also start to spin webs, much like what was seen in the feeding containers in which the original larvae were sent.
Recently Hatched Painted Lady Larva
60x
(Photo taken with handheld QX3)
Make sure that students understand that these are different organisms than the original caterpillars. The fact that sexual reproduction took place and new individuals were formed eludes some of the students. (5 min)
2. Within a few days, the voracious larvae will have decimated the hollyhocks or mallow plants on which they are feeding. There are just too many for the size of the habitat. Unfortunately, I did not catch this problem until a Monday morning when I realized that there were no living caterpillars remaining. Discuss overpopulation with students. (10 min)
Alternatives to Death: a) You could try to maintain a few caterpillars in the habitat and get rid of most, but it is hard to collect the little guys, b) You might also try to replenish the stock of host plants, or c) Order more caterpillar meal from Carolina, and try to start the process over again. This time the students could release the adult butterflies as soon as they emerge, in hopes that they could seek out their own host plants.
3. Allot time in the computer lab for the students to work on their Natural History reports. They can find their favorite pictures taken with the camera or microscope to document the metamorphic stages visually, making a more colorful and interesting final product. It would not be necessary to take class time to work on the report, but if possible, it would be worth it. Some students may not know how to insert pictures into a Word file; including instruction on this during computer lab time could prove very beneficial to them. (45 min)
