How to raise monarch butterflies at home

This blog post (aside from the long-ass life story that precedes the actual instructions on how to raise monarchs) was a request from a friend seeking some help and knowledge in the area of attracting and raising monarch butterflies. I'm no expert.. I still face the troubles of disease, running out of milkweed, aphids DESTROYING my milkweed, caterpillar predation, and lack of monarchs all together just like everyone else. But one thing I do have is a variety of experience from several jobs I've had that actually included the task of rearing a lot of monarchs, and tips and tricks of the trade that were passed on to me from the many people I've met along the way of my monarch adventures.

My butterfly rearing days started when I was a wee child and my mom would buy me the send away kits of Painted Lady butterflies you feed a concoction of pre-made caterpillar "food" and watch develop and transform within a cellophane walled box. I got a "butterfly tent" for my birthday one year, where I would release my captivity raised butterflies that came from a mail order catalog each spring, and mix in some wild caught specimens such as tiger swallowtails and monarchs that I caught with my very own butterfly net in our native butterfly garden in the backyard. Having had a dad with a green thumb and passion and obsession for gardening really helped in this area (our house was the one on the block that EVERYONE would stop to gawk at every time they drove by... we knew every gardener in the neighborhood because they would stop by to introduce themselves and personally admire the gardens.. which were accompanied by multiple custom built greenhouses, "certified backyard wildlife habitat" signs, and a plethora of color all year round). Gardening was my dad's life and I'm glad the passion has rubbed off on me. As a child I studied butterfly books, let caterpillars crawl amongst manufactured bug "play-grounds", "cities", and "jungle gyms" my parents would get for me to keep me busy (and I got reprimanded in 1st grade hebrew school for insisting my caterpillar playground needed accompany me each week and sit on my desk), was always covered in head to toe with butterfly and bug gear, and never traveled anywhere without a small bug container and magnifying glass that hung from a lanyard around my neck (I was such a nerd and not much has changed since then!).

It comes to no surprise that as an adult, my butterfly-related "career" started four fall seasons ago when I nailed my job "interview" by wearing a monarch wing skirt and proving my true obsession to the individuals on the search for a monarch field technician for the Monarch Monitoring Project in Cape May NJ. After getting the job, I spent 2 solid months in the New Jersey town famous for wildlife fanatics and birders (an area so familiar to me as I spent summers and weekends at our family beach house there) counting, tagging, and rearing monarchs day in and day out, while putting on public programs and demonstrations all about them and their migration. Possibly the best job I ever had (and may ever have), the opportunity opened up my heart to what my true passion was and since then I've been working in the field of entomology. (Other monarch work since then has included work at the Florida Museum of Natural History assisting with roadside milkweed surveys, pesticide trials and rearing projects, and a contracted position doing plant and monarch surveys out in Cross Creek, FL.) Since my monarch work in Cape May, I started my collection of monarch tattoos to permanently brand my love for the species, starting with an adult monarch on my foot and a caterpillar near my ankle, turning into more monarch butterflies appearing up my leg and side of my calf. My dream came true when one of my tagged monarchs from Cape May was relocated in Mexico after the 2013 tagging season, and got even better when I actually got to go to Mexico in the late winter of 2015 to see the astounding site of overwintering monarchs (put this on your bucket list, it's an absolute MUST SEE).

The professional and recreational monarch opportunities I have experienced have introduced me to an endless abundance of monarch fanatics who taught me the little things about rearing.. varying from raising early instar larvae on milkweed cuttings stuck into a plastic wrap covered mason jar, to using dental floss to safely remove and relocate chrysalids, to the simplicity of raising larvae individually in cups. I've learned how to test for OE (a protozoan parasite) with scotch tape and a microscope and spent plenty of years after that sadly learning how to identify the signs of it with the naked eye. I've watched my own monarchs die and rot into a black melting goo, and I've watched ones in my garden get carried away and ripped apart by wasps or torn apart by ants. I've raised batches where every single one became infected with disease and I've raised successful batches where every one survived and flew away happily. Yes, I would definitely say I have a PASSION for monarchs that goes beyond just "loving butterflies" and being obsessed with their vivid and charismatic wing patterns. I've even salvaged the wings of the unhealthy ones I raised that didn't make it, or dead ones I've found, and made them into jewelry to celebrate their beauty without "killing" them for it.

Because this is a hobby I've literally been doing since I was a kid, I feel confident enough to tell you that yes, anyone can raise monarchs, yes, it's rewarding and fun and that releasing healthy, captive-raised monarchs can help the wild populations of monarchs too. Even though I've worked with monarchs in so many ways, like I said, I wouldn't consider myself an expert, and everyone who raises them has their own tricks of the trade. I will however provide suggestions and ideas for monarch rearing.

How to attract monarchs to your butterfly garden:

Two things- host plant and flowering nectar sources.

Adult butterflies feed on the nectar of flowers, so if you want them to come enjoy your garden and have a meal, you should provide a variety of colorful flowering plants with lots of nectar. Pentas and lantana are a couple of (many many) popular favorites.

Adults lay their eggs and caterpillars will only feed on host plants, which for monarchs is milkweed. Look up what native species of milkweed are common and easy to care for in your area (natives will do best with your climate, soil type and likely require less water) and plant a ton of it! I personally have a love/hate relationship with "tropical milkweed" for a few reasons. It's beautiful, hardy, easy to grow and a popular favorite amongst butterfly gardeners. BUT it's not native. Die hard monarch fans may prohibit its use.. despite the fact it's often the only species of milkweed you can easily obtain from garden centers and plant sources. The reason for this is that although a great food source for both caterpillars and adults that feed on its nectar, it doesn't die back in the winter when native species do (which normally signals for migrating monarchs to stop reproducing and laying eggs and to go focus on getting to Mexico! Monarchs feeding on an everlasting tropical milkweed plant into the late fall and winter months will stay behind, miss their "flight" to Mexico when all of their peers are migrating there, and freeze with the first frost and die because the plant itself will not. In addition to this, since tropical milkweed is hardy and will not always die back in the winter, it can continuously harbor the OE virus (you'll read more about this later) that is spread through protozoan spores that can land on the plant. If the plant is always growing and never dies, it will always harbor this disease once infected. The good news? If you love tropical milkweed, just get it to "die back" like native species by trimming it way down to the ground when the other species of milkweed begin to die in the fall. It WILL grow back with vengeance, often times in the middle of winter when you do NOT want to attract monarchs. Keep it trimmed no matter how tempting it is to let it grow.. and wait to let it grow wild again in the spring. I'm guilty of having a garden full of it myself. I have several species of milkweed growing in my yard, but tropical is the hardiest and easiest to grow... so I do have a lot of it and love it when it's properly managed for the monarchs' health and well-being.

In general, for attracting monarchs.. just keep the milkweed growing and flowers blooming! If it's a tough year you may not see many but if they're around, be patient and they will come!

Where to get monarchs to raise:

Outside in nature of course! You can send away for them in butterfly kits but the best way is to collect them from outside where you can (hope) they're healthy, and know when they are released that they are from an existing local population. There are also several butterfly farms where you can mail order them in any stage varying from egg, to caterpillar, to pupa or adult if you cannot find your own or prefer them to have been hatched/raised in captivity.

I recommend looking for the eggs when you're collecting wild caught monarchs so you can start from the beginning and it's also the best way to ensure they don't get brought in with disease. Look on the undersides of milkweed leaves for an off-white dimensional egg. If you observe a female monarch lingering in a patch of milkweed, you can even witness her laying the eggs on the underside of the leaves with the tip of her abdomen. Take the whole leaf containing an egg, or the part of the leaf surrounding it, do not try to remove the egg. Have fresh food ready for the caterpillar when it hatches. Usually takes about 10 days from the day it was laid to hatch, but timing can vary on temperature. You can also collect caterpillars at varying stages off wild milkweed plants and then continue to raise them in captivity.

Monarch rearing set up:

Yes, you can "raise" monarchs out in your garden, but they are very prone to predation when outside. If you want to raise them outside in the garden and want to see them reach adulthood easily, consider making a protected area shielded with a make-shift shelter made of screen or mesh netting to prevent intruders from coming in, or an upside down flight cage over the plant the caterpillars are feeding on. An outdoor "enclosure" is a lower maintenance way to protect your monarchs as they grow.

If you choose to raise monarchs in captivity, which is my preferred method to protect them from predation, keep them clean and keep them protected, you can use anything varying from:

A glass aquarium/vivarium/terrarium with a snug fitting lid that caterpillars cannot escape from-- if there are large gaps or holes, try using plastic wrap or getting creative to block the areas of escape. Just make sure there are tiny air holes!

Tupperware or plastic box-- again make sure there are small air holes available to not only provide air but prevent the inside from getting too moist/humid.

Plastic cups-- great for an easy and disposable way to clean and also to separately house each caterpillar and prevent spread of disease.

Flight cage-- harder to "clean", but good for raising caterpillars because of the space and airflow, allows them to pupate at the top and emerge into adult butterflies that will have space to stretch their wings and fly around until being released.

Get creative! Anything that can safely house monarchs, be secure and be cleaned works!


Monarch feeding:

Monarchs feed on milkweed. All species of milkweed are acceptable host plant and this is all the adult butterflies will lay eggs on, and that larvae will feed on until they pupate. One of the only known substitutes to milkweed for feeding larvae is twin vine (I do not remember the scientific name---- working on it!), which is not a "true" host plant because the adults will not be attracted to it to lay their eggs, but if the caterpillars have access to it in captivity or in the garden, they will feed if they run out of milkweed (for this reason it's a great back up plant to have in the butterfly garden for when the caterpillars run out of food, and it prevents the adults from laying extra eggs when you're running low on host plant!). We got ours from one of the big plant sales at the Florida Museum of Natural History.

The other substitute which only really works for larger instars (bigger caterpillars) is pumpkin, cucumber or squash, organic, raw and chopped, just like how I like my own food :)  (read more about my experience with this here!). These veggies will not work on smaller and younger caterpillars though, just for big guys when you're really stuck. All in all, milkweed is the best and should be used.. Twin vine is just as good if you have it, and the mentioned veggies-- only in an emergency.

Milkweed can be fed to caterpillars several ways:

1. Feeding individual leaves, that are hand picked daily on slightly moist (NOT sopping wet) paper towels, and replaced 2x a day to prevent wilting and drying out. This option is favorable for flat and shallow housing containers, and also works well in plastic cups.

2. Providing fresh cut stalks of milkweed with stems in water to prevent wilting and drying out. The challenge here is to keep the milkweed in the water and the caterpillars out. Caterpillars can't swim and don't float- they will drown; so to prevent this, try putting a piece of plastic wrap tightly over a mason jar filled with water, and held on by a rubber band or metal screw top ring. Stick the milkweed stem into the plastic so it's snugly supported and there's no wiggle room for a caterpillar to sneak through to take a deadly "dip" in the water. Water should be changed every other day or so, or as needed when it gets dirty. Replace milkweed stalks as they are completely eaten or leaves are no longer fresh. For this option you will need a housing container that is tall enough to support the height of the milkweed cuttings.

3. Putting a whole plant in your monarch habitat. This is by far the easiest option if you have a milkweed plant in a pot. If you grow from seed or purchase milkweed plants, leave some in the pots if you plan on rearing and have the space for them in your rearing habitat.. this option is best in a very large housing container or flight cage. Plant may need to be replaced as it gets eaten up (just trim it down and it will soon regrow and be "bushier" the second time around, good for future batches of rearing in the same season), and keep in mind that many caterpillars may pupate (make a chrysalis) on the branches and may need to be relocated before another caterpillar eats around it and knocks it down.

Cleaning and disease:

Spot cleaning every day is important. Remove old frass (caterpillar poop), replace paper towels, and remove old food items and replace plant water as much as you can. Disinfecting and cleaning the container helps prevent disease, and proper ventilation will also prevent mold and (some) diseases from developing. Another secret/tip of the trade I learned is that caterpillars that may have been exposed to a sick caterpillar or infected plant can actually be "dunked" VERY BRIEFLY in a diluted (1:10) bleach-water solution and then gently dried. Crazy huh?

If you suspect disease, it's always smart to start off with separate containers and always wash hands or wear gloves in between handling. Doesn't hurt to do this any way to be safe. Keep in mind that caterpillars are SO finicky.. they are so sensitive to diseases and if this happens it is NOT your fault. In the wild, between disease and predators only about 1 out of every 100-200 eggs laid survives into adulthood. Disease is a sad subject, but if you wish to explore it further and learn what signs to look for, here is a good resource on common monarch diseases/parasites you may come across when rearing (there's TONS of resources if you google them-- but this one seems to cover a wide range and I found it really helpful). Also... here's another blog post I made a while ago when I had my worst OE epidemic ever.

Basic monarch stuff:

So monarchs have 4 life stages (egg, larva/caterpillar, pupa/chrysalis, and adult/butterfly) and 5 instars as larvae (5 sizes of growth, each separated by the caterpillar shedding and eating its skin as it grows). The 1st instar is the tiniest that is freshly emerged out of an egg, 5th is the biggest size the caterpillar will get before pupating.

Caterpillars can gently be handled. I like using a small, clean paintbrush for moving small instars around as they're really tiny and delicate. You can also move them by transferring the leaf they're currently on to a new leaf and resting the old leaf on the new one. Big ones are safe to pick up carefully but just don't squeeze them! They're tough, but not invincible. They're harmless and can crawl all over you if you want. They're super cute and make fun little friends.

Caterpillars produce a lot of FRASS. That's poop. It's literally just the milkweed leaves coming out the other end. Makes great fertilizer.. just throw them out in the garden. It's safe to touch them they won't hurt you. Definitely clean out the frass often though, especially as it gets larger because it will grow mold and can make your caterpillars sick.

The "J". Once the monarch forms a "J" at the top of the rearing container or on a plant, it should not be touched, moved or disturbed as some magic is going on inside to help it develop into a pupa. The lime green color of the pupa is actually inside the caterpillar already.. as you see it move and twitch around after it's a J, you can watch carefully as it shed it's skin a final time.. was described to me once as someone "shedding" a long, tight, striped sweater, to reveal the green gem underneath that will then harden over several hours into the beauty embellished in gold detail containing the inner workings of the true metamorphosis stage. After 24 hours, the chrysalis will be slightly hardened on the outside and can be carefully "moved" if need be.. perhaps it's in an inconvenient or unsafe location and needs to be relocated. Do not grap or touch the pupa itself as it's still soft and can easily be squished or crushed killing the monarch. Take a piece of dental floss, make a loop knot bigger than the width of the pupa and put it around the pupa and up above it where it is attached by a "cremaster" (see diagram below). Close in on the loop making a "knot" around the cremaster tightly, and gently tug to remove the pupa from where the cremaster is attached. You can now tie the dental floss to anything (with the pupa hanging from it), such as a screen lid of a container, onto a stake or pole used to hang several pupae from, etc. Get creative!

(Taken from Monarch Watch)

Adult butterflies can be released when they emerge. They need almost a full day to "dry" their wings when they first come out of the chrysalis. Let them be.. don't touch them as their wings are still fragile and they can't fly yet. Once they are dry, you can handle an adult butterfly by gently pinching it's wings together when closed, and moving them where you need to. You can even throw them into the air and they will fly. I usually like to place them on a flower outside so they can feed right away. After the first 24 hours the adults need nectar to feed on, so please let them go as soon as you can or if you need to keep them or are protecting them from harsh weather conditions you can provide fresh flowers (cuttings in water or a whole plant) to drink from, sugar water, or gatorade (temporarily).. but fresh flowers are best.. after all that's what they naturally feed from!

If your caterpillars, pupa or butterfly show unusual coloring, signs of disease, or unusual behavior (ie- adult gets stuck in pupa when emerging), it's likely that your monarch is unhealthy and SHOULD NOT be released as it can spread disease into the environment. The best and most humane option is to euthanize, which can be done by putting the caterpillar, pupa or adult into a ziplock bag or envelope carefully, and then putting into the freezer where they will "go to sleep" before they die. Monarchs are tropical species so when they are exposed to cold weather their metabolism cannot handle it and they do not survive. This sounds horrible, but is better than spread the disease into the wild population where it will harm and kill many more monarchs.

Did I cover enough here? Yes you've heard much of my life story (well not all of it... but the butterfly realm of it) and learned a bit about rearing monarchs, and I'm sure I left a ton out.. after all I could go on and on and on about every subject and sub-subject about monarchs. Feel free to comment here or reach out to me if you have any other questions. You can reach me by email at sammwehman@gmail.com. Good luck and happy rearing!