Raising Monarch Butterflies

Some years ago I learned about rain gardens. The logic is that instead of directing rainwater into sewer systems, why not put it to work growing things and give the infrastructure a break. One of the plants that does well in wet conditions is the swamp milkweed, Asclepias incarnata. For a plant with a questionable sounding name, it is very pretty. See here. It is not at all like common milkweed.

Both common milkweed and swamp milkweed are host plants for Monarch butterflies. That is they lay their eggs on it and the resultant caterpillars eat it and grow up to be big, strong caterpillars.

The female Monarch lays a single egg on the underside of a leaf. They are very small white globes.

Monarch populations rise and fall but this seems to be an especially good year. I cut off this stem because it got broken off by my clumsiness and there was an egg.

Only about 2 out of every hundred eggs develop into an adult Monarch butterfly. They are preyed upon by ants, spiders, and birds. So I bring them inside and raise them in a plastic shoe box. It is best if you find just-hatched caterpillars because I am not sure how long the leaves remain viable before they dry out too much.

When they are very small caterpillars it takes them quite a while to get going but once they get to be, say, 3/4 inch long you have to check on them a couple times a day to see if more leaves are needed. The amount of leaves in the above photo is actually more than is typical.

If you find several eggs near the end of a stem, cut a few inches of it and put it in a vase inside.

By the way, I will expand on certain points of caterpillar husbandry in later posts but, for now, I just what to present the basics.

So to raise these guys you just add leaves each day as needed. Keep the box covered (it is nice to use a box with a clear lid) because when they are ready to pupate they will climb to the top and do it there. As they grow they produce a lot of poop (called fras). You will need to clean this out but I will cover that in a later post.

Again, I'm just providing the basics here... After they pupate it will take 10 to 14 days to develop. When they are within a day of emerging the pupa will begin to look transparent (darker). Make sure you take the box lid outside and support it with a clamp or something that leaves the underside clear for them to fly away. My videos, below, will give an example of this.