Monarch Fostering
- Oct 1, 2021
- 3 min read
Updated: Feb 13, 2024
Citizen Science Project - Monarch Butterfly,
7.15.21 - 9.13.21
Monarch Caterpillars
I love butterflies and caterpillars and have always wanted to learn more about their lifecycles and metamorphosis. After some research I learned about the monarchwatch.org caterpillar rearing/citizen science opportunity. I placed my order and Monarch caterpillars were delivered on July 15th. This post is a brief overview of my experience.
Monarch caterpillars exclusively feed on Milkweed leaves. Common Milkweed is abundant in my area so I knew I would have plenty of food for the 14-16 caterpillars I was expecting. Every day for the next 15 days, I collected milkweed leaves.
I ended up with 14 out of 16 caterpillars that went into chrysalis. Unfortunately 1 didn't make it to the 3rd instar and the other didn't make it past 4th instar. I am not sure what happened. Possibly too many caterpillars were together and they couldn't get enough food, or, they had a parasite from the egg larvae stage. I also ended up with 3 additional caterpillars that we saved from a Milkweed plant that had been sprayed with weed killer. But, they lived to become butterflies!
Growth & Development - Instars
This may vary, but it seemed like the caterpillars developed through each instar about every three days with the 4th instar being the longest stage at 4 days. I did get to witness the molting a few times. Learn more about instars here: https://monarchjointventure.org/monarch-biology/life-cycle/larva/guide-to-monarch-instars
J-hang to Chrysalis
On 7/27 two caterpillars climbed to the top of the enclosure to J-hang, forming a chrysalis 7/28. In the next group, a total of 8 caterpillars formed a chrysalis on 7/29. On 7/30, 3 more. Then finally on 7/31, the last guy made it into a chrysalis. Like clockwork, each monarch emerged 11 days after they went into the chrysalis stage. This can vary based on temperature. On August 8, 2021 the first monarch emerged. It was beautiful to witness.
Steps
Here is what I did:
Monarchwatch.com for Caterpillars & Tagging Kit
Enclosure (reptile enclosure from Amazon) lined with paper towels
Flower tubes
PLENTY of Milkweed
Cut leaf around small caterpillars and place on to fresh leaf using tweezers as needed
As they grow, you can help them climb onto a new leaf
Use paper towels to catch the frass, replace daily
Keep enclosure clean to prevent bacteria (replace the paper towel and spray with water + 10% bleach mix to clean)
REPEAT until the caterpillars J-hang
Once in chrysalis make sure they have enough room once they emerge
You can create a "Charlie Brown' Christmas tree using an old planter filled with rocks to support a dead tree branch to hang each chrysalis
To detach the chrysalis from a "bad location" (close to the wall or too close together) use a straight pin (or a paperclip works) to pull up the silk around the cremaster. Once loose, you can pull the silk to remove the chrysalis.
Gently place on a soft washcloth and use about 6 inches of dental floss to loop around into a knot around the silk just above the cremaster. Tie another knot at the top of the dental floss to create the hanging loop. Hang on the tree. Wait...
Here is a list of the resources I used to learn how to rear Monarchs:
Results
In total, 16 Monarchs emerged. I was able to tag about half once my tagging kit arrived (visit MonarchWatch.org to learn more about this). Overall, this was an incredible learning experience. Feeding and watching the caterpillars grow was time-consuming but a lot of fun. Metamorphosis is fascinating.
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