CBC Archives

Ask students to brainstorm a definition for “life cycle.” Display an illustration of the life cycle of a butterfly to introduce (or remind) students of complete metamorphosis. Students need to understand that one stage in the life cycle is dependent upon the one before it and that a disruption at one stage will interrupt the entire cycle. You can use an illustration of the life cycle of a grasshopper to introduce students to the concept of incomplete metamorphosis. Again, students should observe the cyclic nature of the insect’s life.

Direct students to the topic What’s Eating Canada’s Trees? on the CBC Radio and Television Archives Web site and have them view Clips #1, 2, 4, 6, 7, 8, 9, and 10. As they view these clips, they should make notes about the life cycles of the insects infesting the forests. They should also note the effectiveness of natural control methods.

Divide the class into groups of three or four. Have each of the groups choose one of the insects to investigate further. They should determine whether the life cycle is complete or incomplete metamorphosis, state at which point in the insect’s life cycle the introduction of a natural method of control would be most effective, and provide reasons. Using their information, students prepare a poster of the insect’s life cycle.

Assessment Tip
Develop a rubric that outlines your expectations of student work for the poster and presentation.

Students display their posters and present their information to the class. They should state when the introduction of a natural method of controlling the insect population would be most effective and explain their reasoning.

Students can investigate the life cycle of other insects that are present in their area and whether these insects are considered pests. If they are, students can investigate what methods are used to control infestations.