Overview & Lesson Sequence

Focus on Standards & Assessment

Materials Needed, Preparation & Planning, Management Strategies

Background Info

Intro Activity
Why Study Predator - Prey interactions?

Activity 1
Observation of a predator-prey interaction

Activity 2
What makes a predator successful?

Research Project
Designing a predator - prey experiment

Optional Activity
Biological Control vs. Pesticides

Case Study
Rabbits in Australia

References

Glossary

Suppliers

Resource Sheets

Enforcers Home

CISEO Home

Materials, Prepare/Plan, & Management Strategies

Materials Needed
Follow the Resouce Sheets link on the left navigation bar for the specific materials. See the Plant Propagation and Aphid Rearing sheets for a list of supplies needed to grow the plants and aphid colonies.  See the Rearing sheets for the different predators for a list of supplies needed to raise those insects.  For additional materials needed, see the list within each activity.

Insect Note
Pea aphids are considered plant pests and should not be released into the wild.  In addition, many of the predators that you purchase have been raised in artificial environments and should also not be released into the wild.  At the end of the lesson, all pea plants and insects need to be destroyed.  An easy method is to wrap the plants and insects in plastic or a plastic bag and place in the freezer for at least 48 hours.

Preparation & Planning
Initial preparation for this unit must be done 4-12 weeks before the Introductory activities to ensure that there are large enough aphid colonies, plenty of robust pea plants, and adequate numbers of predacious insects on hand. Insects don’t like to travel. Don’t be surprised by a shipment containing some dead individuals.  Order well in advance.

8-12 weeks in advance
If you choose to use Praying mantids as one of your predators, order 3-4 praying mantid egg cases (each egg case can potentially produce 50-100 hatchling mantids, but many may eat each other or die before your students begin their experiments.  3-4 egg cases should provide more than enough mantids).

Mantids eat Drosophila (fruit lies) or 1-2 day-old crickets.  Order a culture of wingless or flightless Drosophila to serve as mantid food until lesson time.  See the Mantid Rearing sheet for instructions on raising fruit flies.

6-8 weeks in advance
Plant several (one container for each student group) pint-sized containers with 3-4 bush pea seeds approximately 6-8 weeks before the start of the lesson.

4-6 weeks in advance
Order or collect aphids two weeks after the initial planting date. Infest two-week old plants with aphids.

Plant additional pots of bush peas every two weeks after the initial planting date and infect each with aphids so that you will have a continuous supply of aphids for the Research Project and other activities.
Order ladybird beetle larvae
Order adult lady bird beetles
Order lacewing larvae 

You may want to experiment with some of these insects beforehand so allow time for this if desired. See rearing sheets for care of each of these insects.

1-2 weeks in advance
Stop feeding predators 1-2 days prior to the beginning of the lesson (so they will be "hungry" during the Research Project.

Plant Note
Depending on your plant growing conditions, infested plants will survive for about two weeks after initial infestation with aphids.  When plants start to deteriorate, place them next to fresh 2-week old plants so that the aphids can migrate onto healthy foliage.  Dispose of the dying plant, wash and reuse the pot.

Management Strategies
Depending upon the availability of equipment, this lesson can be completed by individual students or in teams of three to four. The best time of year for this experiment is spring through autumn as both predators and prey are readily available and most active. Adult ladybird beetles, in particular, are sensitive to photoperiod and temperature and will not eat during late fall through winter months.

Note that Activity 1 depends on spontaneity. The student will be given something to look at which will immediately stimulate his or her interest. To be most effective, preliminary preparations should be completed in advance of the activity.