How to Prepare Your Classroom for a Manduca Project

Rearing Containers

Manduca can be raised in just about anything that will keep the moisture reasonably high and let air in. We use clear plastic tupperware style containers (butter tub size) while the Manduca are eggs until they entering the wandering stage.

 

Once Manduca enters the wandering stage it will stop eating, smash its food and restlessly wander around the plastic container. For more detailed information on this stage check out the Larva Stage page under All About Manduca tab. At this point a clear, two liter soda bottle will serve as an excellent container for Manduca ready to burrow.

 

Follow the instructions depicted in the diagram to the right of this paragraph.

 

 

 

 

If you miss the window where the larva can burrow on its own, it can be placed into a toilet paper or paper towel roll that has tape sealing one end and a removable plug (wade of paper towel) in the other.

This will provide the insect with a semiround surface that is needed for pupation. If the insect is allowed to pupate on a flat surface, the wings will not unfold properly.

 

After the pupa has formed its thick outer cuticle (redish brown in color), it can be transferred back to the original soda bottle. We recommend placing a pencil-sized stick in the bottle so that when the pupa emerges, it can climb up on the stick and unfold its wings. Without the stick the Manduca moth will not be able to spread its wings properly.

 

Rearing Conditions

Manduca is a robust insect that does well under classroom conditions. If classrooms are kept between 68 degrees Fahrenheit and 80 degrees Fahrenheit (20 to 27 degrees Celcius), larval development should take about 3 to 4 weeks. Since insect growth is temperature dependent, the warmer the room, the faster the insect grows. Direct sunlight is to be avoided as the containers can become quite warm from the radiant heat.

If the insects receives more than 13 hours of light per day, they will not undergo diapause (hibernation in a sense). They should emerge as adults in one month or less. If they receive less than 12 hours of light per day, they undergo diapause and will not emerge as adults for as long as 8 to 9 months.

Teachers report that keeping the insects under fluorescent lights 16 hours per day will yield large robust larva that develop in about 3 weeks. If the animals are constantly handled, there will be delays in growth.

Each stadium is marked by an active feeding period and a quiescent period (not feeding) in which the insect undergo molting. Thus, do not expect to see the insect feeding continually.

However, if the insect does not feed or move for more than 3 days, it has probably died. Don't handle the insect as it probably harbors pathogens that can spread to the rest of the insects. Discard the insect and container and make sure that the student washes their hands. Insect diseases can be transferred from one insect to another by students so be vigilant.

Diet

Insects, for the most part, need about the same nutrients that we need. Thus, the artificial diets contain protein, lipids, carbohydrates, minerals, and vitamins. The diet we use is composed of wheat germ, casein, vitamins, minerals and agar. Agar is used to solidify the mixture into a solid cake. The commercially available diet was originally designed for Gypsy moths but works quite well for Manduca.

If you choose to purchase the diet, we recommend you can obtain it from ICN. It comes as a dry mix and can be purchased in 4 liter packages. The mix comes with the agar packed separately. The current cost is about $30. This will sustain a class of 25 for the entire life cycle if the food is used judiciously. You need not make the entire 4 liters at once, rather it can be made up in one liter batches; the remainder can be stored in the refrigerator. A kitchen blender will serves as the mixer.

The diet can be purchased from:

ICN Pharmaceuticals, Inc.
Gypsy moth diet Catalog number 960293
ICN Pharmaceuticals, Inc.
Biomedical Research Products
3300 Hyland Ave.
Costa Mesa 92626
1-800 854-0530

Kitchen Preparation of Commercial Diet
Materials needed: measuring utensils, kitchen blender, 12-inch x 9-inch plastic container with air-tight lid, hot pads, Gypsy moth diet.

Procedure:

  1. Measure out 20 grams (approx. 1/4 cup) of agar and 258 grams (approx. 3 cups) of dry diet mix.
  2. Boil 1,250 ml (approx. 5 1/4 cups) of water. Pour boiling water into blender and turn the blender to the lowest setting.
  3. Carefully add the agar to the hot water. To avoid causing an eruption, add small amounts of agar at a time.
  4. Slowly add the dry diet mix.
  5. After all of the dry diet mix has been added, allow the mixture to blend for approximately 5 minutes on medium setting.
  6. Using hot pads, carefully pour the liquid diet into clean, flat containers (plastic air tight containers work well) and let cool. Cover and refrigerate overnight. Once the food mixture has hardened, it can be cut into pieces.

The diet can be kept covered in the refrigerator for about 2 weeks. It produces an off-smell as it ages but the insects will eat it. When brought to room temperature, the food quality ages rapidly. We have found that if the diet is changed at least twice a week, the insects are quite happy. You should note the color of the new diet and when it become either gray, very moist or very dark brown, that it be discarded and new food placed in the container. The insects tend to stay on the old food so it is a good idea to move it to the new food; don't expect it to move. The insect does not drink water, therefore their food must be kept reasonably fresh.

A Homemade Recipe for Manduca Diet

We have developed a diet composed of ingredients that are readily available in a large supermarket. Diet preparation requires only a kitchen blender and a microwave oven. The finished diet, having the consistency of tofu, can be easily sliced into any shape or size and the quality of the diet can be modified by adding or subtracting various chemical components.

1 cup (100 g) of non-toasted wheat germ (Bobs Red Mill, Milwaukie, OR)
1/3 cup (25 g) of nonfat dry milk (Sanalac, Fullerton, CA)
4 tablespoons of agar (generic)
1 teaspoon pure raw linseed oil (nonboiled, Sunnyside Corp., Wheeling IL)
1/2 tablespoon nutritional flake yeast (generic)
1 vitamin C tablet (1000 mg) (generic)
2 vitamin B tablets (generic)
2 multivitamin tablets (generic)
1 tablespoon of table sugar (generic)
2 1/2 cups water

  1. Place vitamin tablets in blender and reduce to a powder. To this powder, add the wheat germ, powdered milk, and sugar and blend until the dry components are well-mixed.
  2. Remove the dry mix from the blender and add 2.5 cups of boiling water. While mixing at low speed, add the agar. Be careful to replace the lid on the blender before turning it on. Blend for one minute and then add the dry mix and continue to mix.
  3. Add the linseed oil and increase blender speed. You may need to manually blend the diet while the blender is running. The diet gets rather viscous at this point.
  4. After blending for about 5 minutes, add the nutritional yeast flakes and continue blending for another minute. Components in the yeast are heat labile, thus, yeast is added as late as possible.
  5. Once the diet is thoroughly mixed, pour it into a plastic tray that has a sealable airtight lid. The diet will solidify and remain usable for about 7 to 10 days if kept refrigerated.

Some teachers report mold growing on the diet after being left at room temperature for several days. It's best to change the diet every other day to avoid spoilage.

Despite the large body of scientific information about Manduca, teachers and students often bring to our attention new information. We appreciate your comments and questions and can be contacted via email at: or by phone at (608) 262-6919. Happy observing.