Some notes first
- Wash everything thoroughly. Caterpillars are highly sensitive to chemicals, so if you’re recycling a container you’ll need to make sure it’s clean.
- Caterpillars need natural light and temperature. Plan to keep your caterpillar outdoors, out of direct sunlight. More about it here.
- Mesh is great as it gives them something to grip while they climb.
- Plan on a container large enough to accommodate your butterfly when it emerges.
What you will need
This is complicated because a lot of it depends on your individual situation. There are a million and one ways to raise monarchs, and no one right method. But, generally speaking for a small operation you’ll need an enclosure, a milkweed holder, and a jungle gym. Larger operations will need additional containers to separate the cats by instar (age).
–Enclosure: you’re going to want a mesh enclosure, unless you’re strictly observing nature. You can find these on Amazon (click here) or Insect Lore (click here), or you can make your own using regular household items. A dollar store will also have great options, just note: the key is that you want fine mesh. Not the wide holes that a lot of pop-up laundry hampers have. Even if you are only putting the larger caterpillars in the enclosure and it’s clear they wouldn’t be able to fit through the holes, there are a lot of tiny wasps, flies, and spiders that could. Your enclosure is not just to keep cats in, but also predators out.
–Additional containers: If you only have a few caterpillars, this really isn’t necessary. But if you have a lot of cats and they’re all at different stages, you’re going to need to give the tiniest ones extra protection. Which is to say, you’ll need to protect them from the usual predators and also from the larger caterpillars. The big cats are voracious eaters, and they aren’t eating at a table using delicate China with intricate designs. Their mouths are like a shovel and they will devour an entire leaf, including baby cats and eggs.
Again, there are a lot of methods out there, and you’ll probably want to do a little Pinteresting, but for the baby cats a plastic cup with lid is sufficient. At first they don’t even need air holes, and they are so tiny they could escape from even very small holes. You’ll be opening the lid to give milkweed and clean out frass, so they’ll get enough air. Once they get a bit bigger though, they really need airflow and mesh is the perfect way to make sure they get it.
Note: usually how small operations become large operations is by finding eggs while gathering leaves for your larger cats! But a word to the wise: you cannot save them all. Do not feel guilty or that you have to take in every single one that you find. Caterpillars are part of the food chain, and you are not obligated to raise more than you are comfortable with. This should be an enjoyable hobby, not causing stress or financial strain. If you have reached your limit for the season, leave the rest to nature and feel pride that you did a wonderful thing. The cats you do not bring in will either survive on their own, or bless another one of God’s creatures with a meal. Planting milkweed, spreading awareness, and enjoying the sight of these beautiful creatures is Enough. Period.
–Milkweed holder: Okay, this can be done any number of ways. It can be as simple as laying a paper towel down and placing washed, individual leaves washed on top. Just know, caterpillars poop a lot. However much you are thinking is “a lot,” you need to double. When you have leaves lying on the ground, the cats will be pooping on them, while continuing to eat, and then they’ll eat and poop some more. It can be very time consuming to keep their food clean, but keeping it clean is crucial. If caterpillars are eating poop (“frass”), disease and sickness can spread like wildfire.
Another option is to use floral tubes with lids. I found one with a rack holder (click here) this year and I really like it. Milkweed wilts quickly once it’s cut, but if you stick cuttings in water they will stay fresh for days. Any container will work, but cats are notorious for falling into open containers of water and drowning. You could use a plastic cup with lid and put the stalk of milkweed through the straw hole, or even make your own lid with plastic wrap and a rubber band (just poke holes for the stem). Experiment and figure out what works for you.
–Jungle Gym: Haha, just kidding. A few sticks will do. Caterpillars like to climb, and seem to prefer leaving the milkweed to molt or pupate. They hold very still during this time, which can be 12-36 hours! It is imperative not to disturb your wandering cats… They know what they’re doing and rarely get lost.
Location
There are a lot of passionate opinions out there amongst the hobbyist community regarding the best location for your habitat. Many will insist that they’ve been raising caterpillars indoors for years with no issues. Some people say that raising them indoors is harmful. I have been reading up on the subject and have come to my own conclusions:
I strongly believe it is best to keep your cats in a place that is as close to their natural conditions as possible.
Caterpillars are cold blooded. When it’s 90 degrees outside, humans are looking for shade and an icy drink, but that’s when caterpillars thrive! Our 68 degree home is a bit brisk for them… Butterflies can’t even fly when it’s less than 55 degrees. So even though you’re miserable, please don’t bring your cats indoors “where it’s nice.” What is nice for a human is not ideal for a caterpillar.
I adamantly believe that best practice is a porch out of direct sunlight and protected from extreme wind.
Make sure to anchor your enclosure and containers in a way that they can’t blow away in a strong wind, but your cats should still feel wind and temperature changes through the mesh.
How to set up a DIY habitat
If you want to create a habitat without spending a lot of money, or if you’re in a pinch, take a look around your house and you’ll probably be able to find what you need.
First find something to use as an enclosure such as a mesh hamper or aquarium. Size is important; when your butterfly emerges from its chrysalis it must be at least 6″ above the ground. They will hang and flap their wings, and if it’s too cramped their wings will dry crimped and curled and it will not be able to fly. So your container needs to be at the very minimum 8″ tall and 4″ wide for a single caterpillar, and preferably larger. If you have more than one caterpillar you really don’t want anything smaller than 10″H x 10″W x 10″D so they’re not too crowded.
It is best, but not absolutely necessary, to use something that is breathable (as opposed to glass or plastic). Mason jars really are just too small to accommodate the butterfly after it emerges; it doesn’t have enough space to fully extend their wings.
If your container is round (such as a jumbo food container), you can makeshift a lid with an old pair of pantyhose and a rubber band or ribbon. Make sure the pantyhose have not been washed with fabric softener or detergent… Soak and re-wash it in diluted vinegar and rinse it as best you can before use.
Your caterpillar will need fresh milkweed daily until it pupates. A small container or a complicated lid will hinder this process!
Speaking of milkweed: it is very, very important not to get the white sap from milkweed in your eyes. You don’t need to wear a hazmat suit or anything, and you don’t need to be afraid of it… It’s not like poison ivy. The leaves are harmless to touch, and the sap doesn’t hurt your skin or cause a chemical burn or anything like that, so don’t panic if it gets on your skin. But if you’re sweaty, make sure not to wipe your forehead because it could run into your eyes. Always wash with soap and water after handling it.
Okay, back to the habitat. Get a few sticks, place the enclosure in a protected area outdoors and out of direct sunlight (this is why), and now you can add your caterpillar.
Simply Sunlight 