Milky's World

Monarch Butterflies Need Our Help

Raising Monarch Butterflies from egg to flight.

by Roland Kriewaldt

In July of 2018, I counted ten Monarch Butterfly caterpillars crawling around on the newly planted Milkweeds outside. A few days later, something had eaten them all. And so, I went into action.

That sudden massacre was my rude introduction to the dangerous and predatory world that the already stressed Monarch Butterfly population must survive from the time of hatching until they are ready to fly. It also explains why it is estimated that only 2% of those Monarch Butterfly hatchlings make it to adulthood in the wild.

Among the more gruesome of their natural predators, one whose handiwork I witnessed first-hand, is the Spined Soldier Bug. This insect waits on plants, then thrusts a sharp, spear-like tube into the body of its caterpillar victim, whereupon it injects a deadly poison in preparation for its feast.

In the meantime, the squirming caterpillar may be left dangling mid-air while slowly losing it ability to move from the nerve numbing chemical cocktail being dispensed through this long, needle-like appendage; a kind of death-row lethal injection experience. At times like this, I often wonder "Where is God in all of this?" when I see how much one animal is being asked to suffer so that another might live.

But let's "look on the bright side of life," as the Monty Pythons suggested, and delve into how I remedied this situation of the dying caterpillars by turning their outdoor 2% odds of survival into a 100% indoor success rate for dozens of Monarch Butterflies in my care. Also, make sure to click the orange image links along the way to see photos of my progress.

The Indoor Butterfly Enclosure

I was somewhat limited in terms of setting up a safe enclosure outdoors for the Monarch caterpillars to grow up in. We have raccoons, opossums, skunks, squirrels, feral cats, coyotes, and just about anything you can imagine that noses around here night and day, so the enclosure would probably get breached within a few days. What I chose to do instead was to set up an old aquarium in a well-lit room as both a feeding and pupation site.

My plan was to allow the caterpillars to feed on the bottom until maturity, then climb up and attach themselves to the screen mesh cover. There they could hang out in their newly formed chrysalis for a further 10 more days until they were ready to fly. Naturally, removing the lid required extra care not to disturb my pupating roof tenants. Many people will move all chrysalises to a separate cage — it's easy, but requires care. I took a more "all in one" approach, except when hatching eggs.

(View image of Monarch chrysalises)

The aquarium I had available was about 13" (W) X 32" (L) X 13" (H); a descent size. I then lined the bottom of the glass aquarium with newspaper. This is important because you want to keep the caterpillars on a non-conducting surface to keep them from losing heat, which is essential to their growth. The newspaper also catches the caterpillar poop, known in the science world as "frass" — which would make a catchy product name for this 100% organic, all-natural meat substitute. ;)

The lid I used was improvised; an old screen window that was both light and wide enough to cover the edge gaps and prevent my "cat" prisoners from escaping. However, to avoid having the tiny hatchlings crawl out through the mesh, I housed them separately in a small jar for the first week. I covered this jar with a piece of cheesecloth to allow for air circulation, while the lid discouraged these habitual climbers of all things vertical from getting out and dying of dehydration somewhere in a corner. An elastic band served as a fastener for the cheesecloth; I also aired out the jar once a day and removed the frass — caterpillar shit by any other name.

(Yes, raising Monarch caterpillars does require an investment in time and effort, but it's worth it in the end when you watch them fly away).

Maintaining A Milkweed Food Supply

Raising Monarch Caterpillars indoors also requires bringing their food source indoors. That's a problem for a few reasons.

First of all, when you take Milkweed out of the wild, you're taking away egg laying and feeding habitat from the outdoor population of Monarch Butterflies and caterpillars. Ideally, I would suggestion having two plots of Milkweed with perhaps twenty plants in each. This way you can harvest individual leaves as needed without clear-cutting the entire ecosystem away. Moth caterpillars will also feed on Milkweed, so it's better to have "too many" milkweed plants if you want better results.

A WORD OF CAUTION: When harvesting Milkweed leaves, ALWAYS check for Monarch eggs on both sides. They are tiny pinhead-sized white sacks. If you find one, cut around it with scissors and put it in a jar with other newborns and their food supply, or take the entire leaf and place it in a hatching jar. Lightly spray mist the leaf and keep the jar aerated but covered with cheesecloth. Three days later, you should find a hatchling. Or not. This is also how I collect eggs for indoor hatching — however, most of my caterpillars are taken from outside at sizes from newborn to fully grown and ready to pupate. My main objective is to improve their chances of survival at every stage in their development.

Another problem with bringing milkweed indoors is that it begins to dry out once detached from the main plant stem and its water supply. What I did was invent a system that allowed me to keep leaves moist for longer. Much of this was learned through personal experience, while my initial learning came courtesy of other websites. I'd recommend you also search online to find particular answers not found here. There are also butterfly kits available, with some websites reviewing them for quality; always a good way to buy.

As for harvesting, cutting the leaf is important. You do not want to TEAR it from the plant because that is damaging. Instead, use scissors or a knife to cut the leaf at its stem and quickly wrap it in wet paper towel or an air-tight container to seal in the freshness. Also take note: Milkweed latex, the white substance that comes out of the plant, can leave you effectively blind for a week if it gets in your eye. So never wipe your eyes with your Milkweed picking fingers, unless you have a week's vacation planned. :)

So, in summary, I would advise to first rinse off the leaves with ordinary tap water to remove all debris, and then, after feeding your caterpillars, wash your hands thoroughly with soap. Again, pay attention not to leave latex residue on the faucet or other surfaces where kids or pets can touch it. That's why I wash my leaves outside and in my plastic collection jar.

The number of leaves to harvest depends on the number of caterpillars you have to feed. If you are at home all day, be very conservative; watch how much is being eaten so you don't wind up throwing half your milkweed away after having dried out.

If you have 3-5 tiny hatchlings, one medium sized leaf can last for two days. But in order to keep it moist, it should be inside a jar (with some air circulation) and sprayed with a misting bottle once a day to keep it fresh. The danger here is in drowning these tiny caterpillars, which are so small that you may hardly see them at times. So be careful — they don't wear life jackets!

View image of caterpillar hatchling

A helpful tip is to keep your freshly washed milkweed leaves stored in a covered container with a few air holes to discourage mold. This way you can layer leaves one on top of the other like sheets of paper, allowing them to stay moist and last at least a couple of days. It also saves you having to forage for Milkweed outside in the dark if you should run out of caterpillar food close to midnight.

So the process I recommend is to cut the leaves, wash them immediately (to remove traces of disease, aphids, or parasitical insects), then store them wet in a suitably sized sealed jar with a few air holes in it. This has worked well for me; it should also work well for you. But note, it's always worth visiting other websites to see if someone has better ideas.

(Oh c'mon, who are we kidding here? I've been getting five star reviews from all my caterpillar clients). :D

Feeding and Keeping Milkweed Leaves Fresh

Milkweed leaves are often thick and durable and will hold their moisture for a decent amount of time (a full day). However, I will often wrap a wet piece of paper towel around the bottom of the cutting to keep moisture in, and then I push that stem into a hole I've predrilled into the plastic lid of a small pill or supplement bottle filled with water. This way, the caterpillars can climb vertically on leaves being supported at the bottom and kept fresh by standing in water. This also makes it easier to mist leaves with a spray bottle. 

On the internet you can find various upright "beaker" style milkweed holders that you can fill with water. This is where I got the idea, and I think it works well to keep Milkweed leaves from drying out too fast.

However, I also place full sized leaves, spray moistened, into plastic containers for caterpillars to forage in at their leisure.

(View image of caterpillars feeding)

This is now my second year of raising Monarchs and both upright and horizontal feeding approaches seem to work well. I also never shred or cut the leaves as this would dry them out quicker. If you're not a do-it-yourselfer "Macgyver" type, you may find it easier to order prefab feeding kits online. Caterpillars seem not to care either way. :)

The Caterpillar Maturing to Pupation Process

The hatchlings will be large enough after a week to move in with the larger caterpillars. If you move them into the general population (sounds like a prison theme, doesn't it?) too early, you risk the danger of the larger caterpillars EATING the smaller ones. That's right, these little cuties are also mindless zombie cannibals, it would seem. So that's why you also should keep them separate, because a couple of times I was left to wonder "Where did little Ernie go?"

(Ernie, it appears, was on that day's lunch menu).

Once Monarch Butterfly caterpillars start to grow — THEY REALLY START TO GROW! It's amazing how fast they get all big and juicy. In my experience, from the time of hatching until the time of pupation (when they begin to climb up and look for a place to hang from the ceiling) is usually about 10 days in warm weather. After that, they will usually emerge from their chrysalis in another 10 days or so. However, the full term growth cycle can vary from between 21 to 30 days, so be flexible with your expectations. All is probably well.

I've only had one pupae be D.O.A. and had a couple of caterpillars die on me in mid-growth. However, things went well for the most part and taking care of them required little effort except to clean the cage(s) and keep them well fed.

NOTE: Never disturb caterpillars as they're hanging from the mesh lid by their silk and beginning to pupate. It usually takes 24 hours of transition time for them to enter the green pupal state. During this time their jaws also fall off, so you'll see little black things on the ground. Don't eat them...

This 10 day waiting period has become my favorite time because I no longer have to play waiter to a bunch of hungry, out of control caterpillars from out of town. Now I can just sit back, watch and wait as each butterfuly begins to emerge. And wait. And wait. And...

You will know when a butterfly is ready to hatch because the chrysalis will turn from bright green to transparent, revealing the dark form of a caterpillar with folded up wings. That transition, from my experience, occurs about 24 hours before the actual butterfly emergence, so that gives you some time to hire caterers and buy champagne to usher in this new addition to your family.

WARNING: NEVER handle the butterflies when they are emerging, nor for at least two to three hours afterward. This is the time when they pump fluid into their wings, stretching them and drying them out in preparation for their first flight. If you interfere with this process, you may permanently damage their wings, effectively cancelling their winter vacation plans to visit Mexico. So be careful not to get too excited and make the wrong move. Otherwise, you're going to have to walk that butterfly to Mexico yourself.

Once the emerged butterfly appears to be getting restless and bored with hanging upside down, you'll know that it's time to take them outside to the international flights runway. (It's just a metaphor, not another expense.) I have a number of methods for removing butterflies from the cage. What you don't want is for the butterfly to fly through the house, so think about using a light plastic strawberry container or something similar for the process of taking them outside.

Removing butterflies from the cage can be interesting. I have a piece of frayed rope a few inches long that I may dangle next to the Butterfly's legs. This often coaxes them to climb aboard so you can gently carry them outdoors that way. Holding your finger next to their feet also works. However, there may be times when you have to be a little more proactive in convincing them to leave home.

If the butterfly is stubborn or afraid of your hand, GENTLY cup your hand over it's entire body. Usually they will then latch on to one of your open fingers and let you carry them out that way.

Once outdoors, put the Monarch Butterfly in a sheltered area where they are safe from predators (birds) and hazards such as sprinklers or rambunctious dogs and cats. I have found that they may sit in the sun for hours before taking flight. Some also suggest releasing them in the evening so they can rest for the night before testing their wings out. I've experienced this with one Monarch who stayed in the same spot overnight and then flew off early the next morning. So the message is to get them somewhere where they are protected enough to sit for many hours so they can fly off at their own leisurely pace.

Once back indoors, you can then sit down at your computer and think about documenting your own experiences. Who knows, maybe it'll help someone else to feel more confident in rising to the challenge of helping Monarch Butterflies beat the odds in their short and long term survival. Thank you at least for trying, if you do make the effort.

View image of Butterfly release.

A Word About Monarch Butterfly Diseases

In the two years since I began raising Monarch Butterflies, I have encountered a few mortalities. Thankfully, none of them appeared to be related to any obvious communicable diseases. In other words, if one caterpillar died, it did not seem to affect the rest. However, there are some diseases that can spread within the caterpillar colony, so I would suggest checking online if you encounter any situation where more than one caterpillar appears to be affected by the same symptoms.

Also note, because you may be new to this, as I am, there will always be periods of doubt as to what is the right thing to do, or whether something truly represents a hazard. My best advice is to use this article and others like it to create your own approach, and then simply keep your eyes open — and your CATS, DOGS and BABIES away! — as you go through your own process of learning and getting better at doing this. Above all, keep the cage clean; remove the "frass" daily, and also change any water in the leaf holder jars or beakers every two days if using them. I think that's about it. Good luck, fellow nature lover and defender of the wild.

Good Online Resources:
Monarch Watch (Monarch Butterfly info, tagging, annual counts and milkweed sales)

Author's note:

Thanks for reading my article, and if you'd like to support my work — or maybe help me feed a roaming feral cat — you can either make a donation here or better yet, buy my book Reality Checks for Everyday Life and we'll both win. :)