If your school keeps locusts or stick insects (which have incomplete metamorphosis), compare the life cycle of these with those of moths and butterflies, where metamorphosis is complete. Get students to hypothesise on the survival advantage of complete metamorphosis, where adult and young have different habitats and different foods. Consider how different stages of the life cycle may occupy different trophic levels in a food chain.
All standard texts have the data of Kettlewell's famous experiment with the peppered moth. Comment on the methodology used and extend the work to the pleiotropic effects of the melanic or carbonaria allele.
Use a respirometer to find the metabolic rate of a caterpillar. If possible compare the metabolic rates of caterpillars at different stages of the moult cycle with that of a chrysalis.
Research the economic importance of domestic moths. There are those that attack fabrics; species which attack stored food; and the wax moth attacks brood combs in bee hives.
Compare this animal with the Death's Head Hawk moth mentioned in the article.