To rear Monarch butterflies you will need Monarch eggs or caterpillars, healthy milkweed (Asclepias) plants, and a rearing chamber. A small aquarium with a screened lid will serve this purpose. A clear plastic habitat for small animals also works well as a rearing chamber.
Common Milkweed (Asclepias syriaca), Swamp Milkweed (Asclepias incarnata), butterfly weed (Asclepias tuberosa), or Tropical Milkweed (Asclepias curassavica) can be utilized as a food source for your caterpillars. Since the caterpillars will require fresh milkweed leaves every day, your milkweed source should be near by.
To begin your rearing project, cut a few leaves from a milkweed plant. Rinse the leaves under clean water and then pat them dry with a paper towel. Wash your hands after handling milkweed foliage. Its sap can be harmful, especially if it comes into contact with your eyes. Put the milkweed leaves in the rearing chamber and then carefully add the Monarch caterpillars. Apply the lid so the caterpillars cannot get out.
Replenish the caterpillars’ food supply (milkweed) daily and be sure they have an adequate supply of fresh leaves at all times. Caterpillars do not require a source of water as they get all the water they need from the foliage they consume.
Caterpillar feces (droppings) should be cleaned from the rearing chamber on a daily basis to limit the chance of disease. Even in a very clean rearing environment, watch your caterpillars closely for signs of bacterial infection or virus. If any of the caterpillars turn black or appear deflated, remove those caterpillars immediately and dispose of them. Bacterial infections and viruses kill the infected individuals and they are highly contagious.
Monarch caterpillars grow fast and shed their skins several times during their growth. After reaching their full length of about 2¼” (usually 10 to 14 days after hatching from their eggs), the caterpillars stop eating and generally crawl to the top of the rearing chamber. There each spins a silken pad to secure itself to the lid and then it hangs upside down in a J shape until the next day.
The transformation from caterpillar to pupa (chrysalis) must be one of the most fascinating displays nature has to offer. It begins shortly after the caterpillar’s antennae begin to look zigzagged (wrinkled). By the time the caterpillar is ready to pupate, it looks somewhat collapsed. At this point though, the deflated look is to be expected.
When the transformation from caterpillar to chrysalis is complete, the chrysalis will be only about 1” long. You will wonder how a 2¼” caterpillar could fit inside such a small container. The chrysalis will be jade green with a metallic gold band and metallic gold dots.
Motionless, the chrysalis hangs for 10 to 14 days. Inside a remarkable change is taking place though: a not-so-cute caterpillar is becoming a beautiful Monarch butterfly. The green chrysalis turns a transparent blackish color and you can actually see the Monarch’s orange and black wings inside. The change in chrysalis color occurs a day or two before the butterfly emerges from its chrysalis.
Once the chrysalis cracks open, it takes less than 30 seconds for the butterfly to completely emerge from its shell. Immediately following emergence, the Monarch’s wings are small and its body is short and plump. Within 90 minutes or so, the Monarch is full-sized and able to fly. Weather permitting, it should be set free outdoors within a few hours.
Copyright © 2001 [Rose Franklin's Perennials]. All rights reserved.
Revised: January 18, 2015