monarch eating exuvia

You found an egg under some Milkweed…and now, you want to know what to do next OR, you found a Monarch caterpillar and want to successfully raise it so that will 'grow up' to be a butterfly. Just how is this done? Read on…

I found an egg!

You can do several things with the egg that you've found on the leaf.

1. You can cut and leave a bit of the leaf around the egg intact.
2. You can carefully roll it off with your fingers or flick it off with your fingernail.
Supplies needed for rearing caterpillars

You probably have all the stuff you need in your house already so check for the following:

toilet tissue or coffee filters
clean paintbrush
paper towels
small plastic container with lid
plastic shoebox or mesh clothes hamper
clothespins (optional)

Put your eggs into a small container. Little half-ounce condiment cups are great for eggs.

Initially, you won't need air holes but as the caterpillars grow, you will want to add a few holes to provide air circulation. Do this by poking the holes from the inside of the lid so that the burrs from the holes are on the outside of the lid and won't cut the delicate caterpillar skin.

It will take about four days or so for the caterpillar to hatch so you have time to get the rest of the supplies in order. For specifics on the actual life-cycle, go to the Life-cycle of the Monarch.


As the caterpillars grow, you will need to watch them carefully and begin to separate them so that you don't have more than five larvae in one container. There is a very good reason for this: health of the developing larvae! Overcrowding is one of the worst things that can be done to a Monarch; it invites nothing but problems. It also restricts you from observing any unusual behaviours or characteristics of each individual caterpillar.

• Clean the frass (poop) at least once a day
• Feed only fresh leaves from organically-raised Milkweed plants, removing dried out leaves daily
• Keep the rearing container away from sunlight to eliminate moisture build-up
• Limit quantity of larvae to no more than five per container
• Sanitize containers, instruments, and surfaces to reduce potential for bacterial and viral problems
• Remove and euthanize unhealthy caterpillars immediately
• Overhandling can lead to problems, particularly in the early instars. Less handling is best.
• If the caterpillar isn't moving, it is probably ready to molt so leave it alone
• Wash your hands!
Key Elements when Raising Monarchs

If you've changed from a small container to a larger one, you will need to place either a few sticks (chopsticks work well and can be broken into varying size lengths) into the container and/or place a sheet of paper towel/toilet tissue/coffee filter across the top of the container. Monarchs pupate by hanging head down in a 'j' position, and forming a silken button attaching their final pro-leg to a surface. I've found that they prefer the toilet paper/coffee filter I place across the top of the container but have had others pupate along the sides of the container, too.





2010–2013 Sherry Skipper Spurgeon All Rights Reserved.

Raising Monarchs: From Ova to

I prefer to flick the egg off with my fingernail.

Or just cut around the egg & leave part of the leaf.

Keep similar-sized caterpillars together as this will help to limit the potential for accidental cannibalism. Although Monarchs generally are not known to eat one another, a big caterpillar may accidentally eat a smaller one that just happens to be on a leaf!

Once the chrysalis is formed, the next phase of the life-cycle begins. It is now about two weeks before you will have an adult Monarch butterfly eclose. As a pupa, many changes are taking place, changes that began while it was a caterpillar. If the caterpillar was undernourished, then the adult will show the effects of malnutrition and the pupa may be small. It is while a pupa that I watch for unusual colour changes as this is when you will more than likely spot predation issues such as those dealing with the Tachinid Fly and/or Oe parasitization.

So, after four days in the egg, the 1st instar hatches. This begins the roughly 2-week larval phase. After several days, it will have shed its skin and will begin its eating spree. It will be very important to have fresh leaves for the little guy. In the first week, the caterpillar will not eat all that much; one fresh leaf for two days is about it. This is one leaf PER caterpillar.

Before getting ready to molt (shed its skin) the caterpillar will stop eating and will often move to the lid of the container. It won't move but will remain still and this is when most people feel the larva has died. Do NOT poke it or move it around! This is a critical time as it is shedding its skin and moving to its next growth stage.

I prefer to move all pupae into a pop-up habitat instead of keeping them in the smaller containers. This is a personal preference. Some people will raise their caterpillars completely in plastic shoe boxes. The choice is yours. Pop-ups can be purchased but collapsible clothes hampers can also be used; simply make a covering to go over the opening and use clothespins to seal it

Pop-ups from Insectlore


Although you may not see this happen, the Monarch caterpillar, after molting (shedding its skin) will turn around and EAT the exuvia (the shed skin)! Oooh! It is quite a cool thing to behold, if you do get the opportunity to see it happen. Usually, it occurs and you just don't get the chance to see it…so you wonder, "Where did that leftover skin go?

By the 3rd instar, the caterpillar will begin to consume many more leaves. Be prepared for rapid growth during this second week. During the 4th instar, expect the caterpillar to begin eating about one leaf per HOUR. As you notice the size increase start getting set up for the next stage in the life-cycle; pupation.