Are you interested in raising monarchs at home? Butterflies are very important garden pollinators and the monarch butterfly population in particular has been rapidly declining for a number of years. Monarchs (and butterflies in general) really are the most remarkable creatures. The caterpillar has this incredible potential for transformation. They spend their days nourishing their bodies until it’s time for the next stage. Each transition (the literal shedding of their old exterior) carries with it the potential for even more growth. These stages occur in succession until the caterpillar is ready for its final transformation— completely deconstructing and rebuilding themselves from the inside out. The experience of being able to observe this life cycle up close is truly unique.

This guide is based on our own personal experiences from successfully raising and releasing monarchs in our home and garden, as well a lot of research along the way and guidance from experts that I have been lucky to have connected with. I am by no means an expert myself, and my intention for sharing this information is to hopefully encourage you to raise a small number of monarchs yourself. I’d love for you to learn about them, which will hopefully inspire you to then become involved in monarch conservation. I want to emphasize that we raise our monarchs in an extremely controlled environment and that in general, experts do not recommend rearing large numbers of monarchs in captivity as a conservation strategy, as it can have quite the opposite effect. I’ll cover more on this below. This guide will go over the general methods that we use ourselves to raise our caterpillars so that you have some information to get started. If you’re interested in more details, a comprehensive how-to guide that will cover the methods outlined within this guide in-depth, as well as plans to build our wood enclosure is in the works for next Spring!

Concerns about Raising Monarchs in Captivity

As I had mentioned earlier, researchers and experts do not recommend rearing large numbers of monarchs in captivity as a conservation strategy— there are several known risks to this such as increase of disease and parasites and it is argued that over time generations of captive-bred monarchs may be less likely to actually migrate. This is in large part due to lack of control over several factors. Unfortunately the average hobbyist is likely not sanitizing their enclosures properly, or are rearing and releasing large amounts of monarchs without providing them with enough habitat to breed and enough food to sustain all of the eggs the adult butterflies will lay. We raise our monarchs in an extremely controlled environment where we take a lot of precautions to sanitize our enclosures, clean them frequently and test adults for OE to make sure we are raising a generally healthy population. We will also stop collecting eggs at some point based on the amount of food and shelter we can provide. I am only recommending to raise a small amount of monarchs for learning purposes— in hopes that this will spark your awareness and interest in monarch conservation.

Monarch conservation

Research shows that in the wild, 90% of monarch eggs that are laid do not survive to adulthood— monarch butterfly populations have been rapidly declining due to environmental factors that are both within and out of our control such as drought, loss of habitat, pesticide use and natural predators. The most critical reason for their rapid decline, however, is the lack of host plants (milkweed) available for them to keep reproducing. Adult female monarch butterflies lay their eggs on milkweed, which is their only host plant. So, what else can you do? Plant native milkweed and provide nectar-rich plants! Create a habitat in your garden to attract butterflies and other beneficial pollinators. Garden organically and do not use pesticides. Support monarch conservation organizations. Tag your monarchs and test for OE if you are raising them. Something great that you can do is to become a monarch waystation, which is where you have your habitat certified by Monarch Watch. There are a few requirements, mostly that you provide an ample amount of food and habitat for monarchs to sustain them on their migration journey. Our garden is a registered monarch waystation!

Milkweed

I recommend planting native milkweed in your garden to attract monarch butterflies to naturally come and lay eggs. Planting milkweed is the best (and easiest) way to ensure that monarchs come and visit your garden. Your local nurseries will be able to point you in the direction of the native milkweed that is most ideal for where you live and help you to obtain it. Make sure that you ask for milkweed that has not been treated with pesticides. Better yet, if you plan ahead you can order seeds online and plant them yourself. What about tropical milkweed? Tropical milkweed is what you’ll find most commonly sold in nurseries— we had some in our garden last year before we learned that it was debated by experts if it was an ideal choice. There’s a lot of concern regarding a higher rates of the parasite OE with tropical milkweed as well as a lot of debate that the presence of it may interrupt migratory behavior since the plant does not die back in winter like native milkweed does and usually people do not cut it back. If tropical milkweed is your only option, make sure that you cut it back during winter very close to the ground and remove all of the leaves.

Finding eggs and caterpillars

We have native milkweed planted in our garden (mostly Narrowleaf) and that is how we obtain all of our eggs. You’ll generally find monarch eggs on the underside of the leaves and to collect them I pull the entire leaf and bring it inside. The eggs are very tiny and you’ll have to look closely and be careful for little caterpillars when searching the leaves. After that, we just keep the leaves from drying out inside of a sanitized container until they hatch and then we transfer the tiny caterpillars onto sanitized milkweed cuttings. I sometimes also collect very small caterpillars off the outside milkweed plants and bring them inside. Any larger than that and I just leave them to live naturally outside on the milkweed plants. It’s important to make sure that only collect the amount of eggs where you can comfortably feed those caterpillars through adulthood. A single caterpillar will eat A LOT and I can’t stress that enough.

Taking care of your caterpillars

What you’ll need:
1. An enclosure
I am asked often about the wood one that I built, so building plans for it will be released next year. I highly recommend the mesh reptile cages if you’re just starting out because they’re very easy to sanitize/clean and are lightweight and easy to store. We have a few different sizes that we use ourselves. Make sure that your enclosure is large enough, has good air flow and is sanitized. We have and use both of these sizes: small / large. You can also use the standard pop-up enclosures like these.
2. Containers to hold your milkweed cuttings
Make sure that you can completely seal off the water so that caterpillars can not fall into it. We use glass yogurt jar containers like these with tight holes cut into the rubber tops. The milkweed cuttings fit tightly into the holes and the lids fit tightly on the glass jars so there is no way that the caterpillars can fall into the water.
3. Milkweed
Enough milkweed to feed your caterpillars. A single monarch caterpillar can easily devour a one gallon milkweed plant before the chrysalis stage.

How-to care for caterpillars:
I recommend keeping your enclosure outdoors in indirect sunlight if possible— we keep ours indoors only because it is extremely hot where we live during these months and I don’t currently have a protected area outside to put it. Our indoor enclosures are located next to a glass sliding door where they are exposed to indirect light and outside air a majority of the time. Place your caterpillars on the fresh milkweed cuttings (that are held tightly in the jars with tops) and place those jars into the enclosure. They eat constantly which means that you’ll also need to remove frass— caterpillar poop throughout the day. Change out milkweed cuttings as they are eaten down. We use several enclosures to keep caterpillars separated by size/stage. Make sure that you are sanitizing each enclosure by wiping it down with a diluted bleach mixture (we generally do not use bleach here, but it’s necessary in order to minimize disease). In general we separate into the following groups: (1) the smallest caterpillars, (2) the medium sized caterpillars, (3) large caterpillars that will be forming their chrysalis soon + ones in chrysalis that will be emerging soon and (4) caterpillars that were found outside.

Forming the chrysalis + eclosing

During the final 5th stage the monarch caterpillar spins a silk pad to hang from (inside of our enclosure they usually choose the underside of the top screen or under this large horizontal branch) before hanging upside down in “in J” shape. After a day or so they begin their transformation, completely deconstructing themselves from the inside out to rebuild themselves into something brand new over the course of roughly two weeks. When they are ready to emerge, they prepare to undergo their final monumental change.

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Right before they emerge the green chrysalis will turn dark before becoming transparent and thin. At this point you’ll be able to see the pattern of the monarch’s wings through the chrysalis. Monarchs eclose (emerge) in the morning and I usually have to wake up early if I want to catch them in action. The monarch emerges by expanding their wings to break through the paper thin outer layer. Over the course of the next couple hours they hang upside down and pump the fluid through their wings to make them expand as well as let them dry. It’s important that they are able to hang upside down undisturbed.

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Identifying Male vs. Female Monarchs

How to tell the difference between a male and female monarch: Males have a black spot on each hindwing (lower wing) and females do not! If you look closely at the veins in their wings you’ll also see that the male’s are also thinner. Overall size does not seem to be an indicator of size as we’ve had both small and large males and females.

Releasing Monarchs

We generally keep our monarchs for about a day and release them the following morning after they eclose. They need to be released on a warm sunny day as they will have trouble flying if it is cold and/or windy. If the weather is unfavorable and it’s necessary to keep them past 24 hours, you can feed them an artificial nectar or fruits such as orange or banana slices. When it’s time to release them, we let them go in our garden near their favorite nectar flowers.

Some Monarch Resources:
– Monarch Watch – Tagging , Become a certified Waystation
– North American Butterfly Association
– Monarch Joint Venture
– Xerces Society
– Milkweed seed finder
– OE testing- Project Monarch Health , Journey North

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