If you’re trying to figure out how to raise monarch butterfly caterpillars at home, you’re in the right place! Our family has many years of experience successfully raising monarch butterflies and this guide will help you do the same!
This is a very detailed guide intended to help you successfully raise monarch butterflies at home while answering every relevant question you might have about the process. Hopefully, we answer any general questions you might have about the majestic monarch butterfly as well.
Table of contents
This guide contains the following sections:
1. Context: the charismatic monarch butterfly and why they matter
2. Does raising monarchs help or hurt the species?
3. Why raise monarch butterflies?
4. How to raise monarch butterflies in your home: a step-by-step guide
5. Monarch butterfly FAQs
We highly recommend you read the entire article before attempting to raise monarch butterflies at home.
Part 1. Context: the charismatic monarch butterfly & why they matter
Ecologists express mixed feelings about charismatic species. If you’ve never heard the term before, “charismatic species” are the ones that human beings tend to care the most about due to some combination of their beauty, impressive physical traits/athleticism, or endangered status.
While it’s great for people to care about a beautiful or fast-running species, why not care about the little “ugly” ones too? After all, in the interconnected web of life, isn’t an endangered American burying beetle as important as a monarch butterfly?
In our minds, the answer is yes. However, charismatic species can serve a critical role: they help draw us humans into a state of greater empathy, connection, and concern about the natural world. And that’s a good thing.
Monarch butterflies: the attractive and threatened spokesmodel for butterflies and insects
Likewise, the charismatic monarch butterfly (Danaus Plexippus) is beloved because of its exceptional beauty and its extraordinary, long-distance migration pattern. In fact, Eastern North American monarch butterflies undergo the longest two-way migration of any insect on earth, which is also the reason they have such huge wings.
These attributes have earned them their name: “monarch,” the king of butterflies. There are also similarly colored Viceroy, Queen, and Soldier butterflies that don’t get as much popular attention as monarchs do.
Monarch butterflies’ populations have declined by 80% in North America in the past 20 years, and they are now considered an endangered species. This population decline has further boosted public awareness, concern, and love of monarch butterflies.
No insects, no people.
Perhaps you’ve heard headlines from around the world about the insect apocalypse, massive population declines across virtually every species of insect. What’s causing this terrifying trend?
According to recent research, insect population declines in the US are largely being driven by the fact that today’s agricultural landscape is nearly 50 times more toxic to insects than it was 25 years ago. New classes of synthetic pesticides in use today — namely neonicotinoids and pyrethroids — are the primary culprits behind this heightened acute insecticide toxicity loading (AITL).
Coincidentally, the typical American lawn is actually just as bad or worse than our agricultural landscapes – all to grow a monoculture of grass. Shrinking habitat + more extreme weather + higher toxicity loads is creating the perfect deadly storm for all insects, including monarch butterflies.
Why should you care whether insects live or die? Because you care about whether you live or die.
As Harvard entomologist E.O. Wilson and others have pointed out, if insects disappear, so too will most terrestrial life — including humans, due largely to food shortages. Whether we like it or not, our fates are intertwined with insects.
Part 2. Does raising monarchs help or hurt the species?
You know the saying, “the road to hell is paved with good intentions”? Well, here’s some bad news: captive breeding monarch butterflies may well be having a harmful effect on the species.
Several studies have found that the survival rates, migration success rates, and other fitness metrics such as strength, color, wing shape, etc are significantly worse in captive-raised monarch butterflies relative to wild-raised monarch butterflies.
Why? We’d strongly encourage you to read about this issue directly from the lead researcher of one such study at University of Georgia. More research is needed to get a conclusive answer, but his hypothesis is that the problem is due to a combination of:
a) caterpillar stress caused by repeated handlings by humans during milkweed changes and cage cleanings, and
b) weaker caterpillars surviving to adulthood rather than being eaten by predators.
Here are some questions and speculations we have on this topic:
- If a predatory insect or bird happens to kill a wild monarch caterpillar, is that due more to chance or to the caterpillar’s lack of genetic fitness? After all, the caterpillars can’t run away or fight back. They simply have to rely on good luck, camouflage, and the hope that the molecules in their bodies that make them taste unpleasant to predators are effective.
- None of the caterpillars in these studies received unfiltered natural sunlight. What impact might that single factor have on their fitness as adults given the importance of de novo vitamin D synthesis for such insects at all stages of their life cycle? Would exposure to the sun also help them develop better directional orientation? (Lab-grown monarch caterpillars are also less adept than their wild peers at direction.)
- Similarly, would raising monarch caterpillars in protected outdoor cages where they experienced natural environmental variability such as wind, humidity fluctuations, temperature fluctuations, sunlight, etc yield more fit adults?
- If stress caused by human handling during their larval stage is indeed a primary cause for decreased fitness as adults, would raising monarch caterpillars on living potted milkweed plants (as we sometimes do) yield stronger adult butterflies since human handling would be greatly reduced?
These are questions we hope can be answered by future research. However, current research certainly causes us to question whether captive breeding of monarchs is a good idea. We now only raise a few monarchs each year, mostly for educational purposes for our child.
What are the best ways to “help” monarch butterflies?
- Focus on providing safe, non-toxic, food-rich outdoor habitat first. In short: plant native milkweed varieties in your yard and don’t use pesticides, especially synthetic pesticides. Also, be very careful that any flowering plants you buy from nurseries are untreated.
- Support certified organic and regenerative farms. These farms don’t use synthetic pesticides.
- If you do decide to captive breed monarchs, raise no more than 5-10 per year. When doing so, do your best to provide ideal habitat and conditions that closely mimic those experienced by wild monarch caterpillars, as we’ll detail below!
Part 3. Why raise monarch butterflies?
Successfully raising monarch butterflies requires a considerable amount of knowledge, resources, work, and time. However, there’s an indescribable joy you experience when you release an adult monarch butterfly into the wind and watch it joyfully use its new wings for the first time.
Here are a few good reasons to raise monarch butterflies:
- as a school project/children’s hands-on educational project;
- to help children or fully grown adult humans gain more of a connection to the natural world;
- because it’s fun, interesting, and rewarding.
Again, as detailed in the previous section, raising captive-reared monarchs may not actually be helpful to the species. So we do NOT recommend that you raise hundreds or thousands of monarchs, have over-crowded conditions which foster disease, or buy monarch chrysalises from commercial vendors. Doing so is likely to actually hurt the species as well as hindering scientists’ efforts to monitor their population numbers and health. Read more about this topic from Xerces Society.
If you’re determined to raise monarchs, we recommend a small-scale, thoughtful, and careful approach.
What is the success rate of raising monarch butterflies indoors vs outdoors?
In the wild, monarch butterfly eggs and caterpillars have a narrow road to success. A female monarch butterfly will lay 300-400 eggs. Of those, it’s estimated that at least 90% will not live to become an adult butterfly. (Yes, monarch eggs and caterpillars are a food source for many predatory species.)
Over multiple years and between three different households in our family raising monarch butterflies, our overall success rate raising monarch caterpillars indoors is well over 90%. The caterpillars that die are often due to our accidents.
However, the higher success rates of captive-breeding could be problematic if the butterflies you release are weaker or diseased, so caution must be taken.
First, you’ll need to do some learning, get the necessary material/equipment, and dedicate yourself to properly feeding and cleaning up your indoor monarch enclosure.
We’ll show you exactly how to accomplish all of that to successfully raise your own monarch butterflies.
Part 4. How to raise monarch butterflies in your home: a step-by-step guide
1. Preparing for monarch butterflies
Proper preparation is critically important for successfully raising monarch butterflies.
A. OUTDOOR preparation for monarch butterflies and caterpillars
Monarch caterpillars feed exclusively on various species of milkweed (Asclepias). That means you’ll need to either:
- grow LOTS of milkweed in containers and/or in your yard or garden (without using any pesticides);
- have access to LOTS of nearby wild milkweed that is NOT sprayed with pesticides;
- or both.
We recommend both (growing and foraging milkweed) because it’s always nice to have backup. Monarchs caterpillars are voracious eaters, and if they run out of food, they will die. You can’t have too much milkweed around when you’re raising monarchs.
Even better: you could grow native milkweed varieties in nursery pots and use those potted plants to provide food for your caterpillars. That way, you won’t have to swap out cuttings every 1-2 days, which reduces the frequency with which you have to touch (and potentially stress) the developing caterpillars.
Once the caterpillars have eaten the leaves down to the stems, put the plants back outside to recover, then replace them with another plant or freshly-clipped milkweed stems/leaves.
Warning: Milkweed plants you find at a local nursery may be sprayed/treated with pesticides. If you buy milkweed plants for your monarchs, make absolutely certain that no pesticides have been used or you’re likely to kill your caterpillars.
How much milkweed do you need to raise monarch butterflies?
For each monarch caterpillar you raise, you’ll need to plan to have about 1′ of mature healthy milkweed plant, which equates to about 20 mature average-sized milkweed leaves.
Leaf size varies by milkweed variety/subspecies, so it may take more than 20 leaves for small-leafed varieties and less for large-leafed varieties. Common milkweed (Asclepias syriaca) is the species that produces the largest leaves that we know of and its a common native throughout most of North America.
We also grow a lot of milkweed in-ground throughout our yard from which we gather leaves. These are also the plants from which we collect monarch eggs and caterpillars to raise.
There are a number of online resources from which you can get free milkweed seeds. Do a bit of research to determine the specific species or subspecies of native milkweed that grows in your area. Don’t use non-native or tropical milkweed, especially if you live in warmer regions where the milkweed will not die or freeze back in the winter. (This can lead to harmful disease/pathogen buildup on the plants.)
Monarch butterflies’ favorite flowers: attracting monarchs to your yard
Female adult monarch butterflies can smell milkweed from great distances away. If you only have a little room in your butterfly garden, just plant milkweed. Chances are, a female monarch will pass close enough by to smell it, visit, and lay eggs. Monarchs have wide foraging ranges and can travel up to 25 mph per day in favorable wind conditions.
Ideally, you have enough room in your garden/yard that you can also grow other flowering plants so your visiting monarchs can forage pollen and nectar in your yard in addition to laying eggs on your milkweed. Yes, milkweed also produces flowers that provide a good food source for pollinators as well. However, the following flowers seem to be particular favorites for monarchs in our yard:
- Mexican sunflowers,
- cosmos, and
If you need more help with flower selection, Xerces Society has an excellent monarch nectar plant list broken down by region.
No pesticides – including herbicides
As mentioned earlier, pesticides are not good for insects. This means you should stop using insecticides as a starting point, but also stop using herbicides like RoundUp as well. Yes, poisons designed to kill plants are also harmful to insects (and humans too for that matter).
If you collect milkweed from the wild for your monarch caterpillars, you’ll need to be careful to gather it from a spot where pesticides have not been used.
B. INDOOR preparation for monarch butterflies and caterpillars
To raise monarch caterpillars indoors, you’ll need to have the following:
- Location – A designated spot to raise your caterpillars. Ideal spot: a covered or screened porch that gets natural sunlight without getting hotter than the outdoor temperatures while providing protection from storms. Otherwise, you’ll need to at least have an indoor room that gets a lot of natural light (ideally 6+ hours daily).
- Enclosure – A protected, easy-to-clean enclosure/cage where the caterpillars can eat before crawling to the top to form chrysalises. This enclosure needs to be thoroughly sanitized before and after each use to prevent disease buildup.
- Baby container (maybe)- A smaller container to house any milkweed leaves with eggs or small first and second instar caterpillars until they grow large enough for your primary enclosure. Otherwise, your eggs and small caterpillars might get eaten by your larger caterpillars (more on this below). However, if you’re only raising a few monarchs and they’re all starting at roughly the same stage in their life cycle, you don’t need a baby container.
- Milkweed – Access to a constant supply of milkweed (see above for quantity of milkweed you’ll need per caterpillar).
- Caterpillar-safe water containers (maybe) – Containers to hold any milkweed cuttings upright without drowning your caterpillars. A heavy pot or glass with floral tubes works well. However, if you’re using living milkweed plants in nursery pots, you don’t need to worry about this preparation.
Best butterfly enclosure?
You might think that a lightweight mesh polyester laundry hamper can serve as your monarch butterfly enclosure. However, here are the problems you’ll run into:
- You can’t easily see in to enjoy caterpillar gazing.
- You can’t easily reach in and out to clean, change out milkweed, etc.
- Since there’s no way to completely secure the opening, when your monarch caterpillars are ready to form a chrysalis, some of them will likely get out of their enclosure and form chrysalises in undesirable spots in your house. Or, if the enclosure is on an open porch, predators will be able to come in to dine on your developing monarchs.
Instead, we’d recommend you purchase the following supplies:
- RESTCLOUD Butterfly Habitat Cage – A lightweight mesh cage that collapses flat for easy storage | smaller sized cage 15.7 x 15.7 x 23.6 inches (this is the one we use) or larger sized cage 24 x 24 x 36 inches.
- Floral tubes – These help hold up, water, and preserve any milkweed leaves/branches you trim off to feed to your monarch caterpillars
Now that you have all your outdoor and indoor preparations in order, let’s go through what you’ll need to KNOW and DO to raise monarch butterflies at home!
2. Understanding monarch butterfly generations and life cycles
Two important things you need to know about monarch butterflies before raising them, are: a) the different generations of monarchs, and b) their life cycle.
A. Monarch butterflies typically have four generations per year.
Unlike many other insects, monarch butterflies do not overwinter or lay eggs to overwinter. The monarch butterflies you see in spring are NOT the same butterflies you see in late summer.
Instead, every year usually equates to four distinct generations of monarch butterflies, and the cycle repeats:
- First generation/super generation – These are the final super generation that migrated south the following year. Warming weather in February and March triggers overwintering monarchs in Mexico to mate and begin their migration north and east. This generation dies soon after laying eggs on milkweed in their early migration ranges.
- Second generation – In May and June, the second generation of monarchs emerges. They live for about four weeks and continue traveling to new migratory areas, laying eggs on milkweed as they go.
- Third generation – The third generation (born in July and August) also lives for about four weeks before reproducing and dying.
- The fourth “super generation” – This generation is usually born between late August through mid-September, with some variability by climate region. This fourth generation of monarchs is typically the “super generation,” due to some rather extraordinary differences. Rather than only living for four weeks and having a limited flying range, the super generation travels thousands of miles to its southern overwintering ranges in the mountains of Mexico and live until the following spring (about eight months) when they restart the migration back north/east. (This migratory pattern only applies to Eastern monarch populations, not Western monarchs.)
- Exceptions – The number of generations of monarchs may vary by location and whether it’s an unusually hot or cold year. In cold summers in northern climate regions, the third generation may become the migratory super generation. On the other extreme, there may even be a fifth generation of monarchs in very warm years, which become the migratory super generation. Also, there are areas of the world where monarchs don’t migrate at all, and breed year round.
Which generation of monarch butterflies should you raise?
There’s no right or wrong answer here, and it may depend on your goals. If you’re just raising a couple of monarchs for fun or as a project with your child, it doesn’t really matter which generation you raise.
However, if you raise back-to-back generations, be sure that you’ve thoroughly sanitized your enclosure and all materials used before starting anew.
B. Monarch butterfly lifecycle: egg > larva > pupa/chrysalis > adult
Monarch butterflies’ life cycle is as follows:
Small white monarch butterfly eggs are laid on the underside of milkweed leaves by adult females. A single female monarch butterfly can lay between 300-500 eggs over her lifespan.
Duration: It takes about 3-5 days for the tiny monarch larva to form inside the egg, eat the egg, then emerge as a first instar larva/caterpillar.
There are five “instars,” which are the growth stages of monarch caterpillars/larvae. Each instar represents a larger-sized caterpillar, and a shedding of the previous instar’s skin. Monarch caterpillars typically eat the shed skin when transitioning to the next instar.
Duration: The larval stage of a monarch lasts 9-14 days.
At the end of the fifth instar larval stage, a monarch caterpillar will stop feeding and go off in search of a spot to form its chrysalis. In the wild, this might be the underside of a nearby leaf or branch, but it’s very unlikely to be on the milkweed plant they fed on.
In a home enclosure, monarch caterpillars will typically crawl to the top of their enclosure at the end of the fifth instar stage. Then, they’ll excrete a silken cremaster, attaching their backend to the ceiling before going into “J”. This simply refers to their J-shape as they hang down in preparation to form a chrysalis.
Monarch chrysalises look like a beautiful piece of jade jewelry with gold dots.
Duration: Monarchs will remain in their chrysalises for about 8-13 days.
At the end of the pupal stage, a monarch chrysalis will turn black in color. However, it’s still translucent enough to see the dark wing veins and colorations inside.
Your first time watching an adult monarch emerge from its chrysalis (eclose) is a magical experience for children and adults alike! After emergence, it will take 3-4 hours for its wings to properly dry.
They’ll do quite a bit of flapping and walking around during the drying process to help dry and get proper blood flow to their wings. You should not touch them as they’re readying their wings for flight.
After first flight, an adult monarch will spend its days flying, consuming nectar, and mating, similar to a human airline pilot. (Gotta throw in a joke to make sure you’re paying attention.)
Duration: An adult monarch butterfly will live anywhere between 4 weeks and 8 months, depending on what generation it falls in. (Remember the “super generation” lives much longer than earlier generations.)
3. Step-by-step: How to raise monarch butterflies at home
Now that you have all the background information you need, let’s dive into the step-by-step process of raising monarch butterflies!
Step 1: Set up your butterfly enclosure.
Set up your indoor butterfly enclosure/habitat (see above sections).
On the bottom of the enclosure, we place:
- a layer of aluminum foil (which will stay there throughout the entire process), and
- a layer of paper towels on top of the foil (which we change out at least daily or more if needed).
Step 2: Gather monarch butterfly eggs (or young caterpillars).
Now, it’s time to go to your milkweed patch to get monarch butterfly eggs and/or first or second instar caterpillars.
Carefully inspect the underside of the milkweed leaves for small white monarch butterfly eggs. Early instar monarch caterpillars are often on the undersides of the leaves, but larger late-stage instar caterpillars will often be on the top side of the leaves, stems, and milkweed flowers as well.
Very carefully gather the eggs and YOUNG caterpillars – the smaller, the more delicate. This often means cutting/pinching off entire leaves so as not to crush the eggs or small caterpillars. Place the eggs and caterpillars into a breathable container.
Larger, late instar monarch caterpillars can and will eat monarch eggs and young caterpillars while eating milkweed leaves, so try to gather either: a) all eggs, or b) all first instar caterpillars.
Another reason to only collect eggs or young caterpillars? A common predator that parasitizes monarch caterpillars is tachinid flies, whose larvae live inside the caterpillar before emerging and finding a new host. The older the caterpillar, the higher the likelihood they’re a host for tachinid flies, which could then attack other caterpillars in your indoor enclosure.
If you want to eliminate the possibility of having any tachinid flies, only gather eggs, not caterpillars.
How many monarch caterpillars should you raise?
It bears repeating that you should only raise a small number of monarchs for the sake of the species. No more than 3-5 at a time.
If future research provides conclusive evidence for how to improve the fitness of captive-bred monarchs, then consider raising more under those recommended protocols.
Step 3: Gather milkweed
Assuming you’re not using potted milkweed plants to feed your caterpillars…
When gathering milkweed as food for your indoor caterpillars, it’s critically important to make sure you’re not bringing predators or diseases into your indoor cage/habitat.
Remove all other insects such as:
- Aphids – We’re very comfortable with insects, so we simply smush and/or hose spray off any aphids on the plants by hand. Aphids aren’t predators but they also eat the milkweed and may have parasitoid wasps inside them that can hatch and parasitize your indoor monarch caterpillars.
- Spiders – Arachnids, not insects, but you don’t want them in your monarch enclosure… Simply shoo spiders off the leaves while you’re outside.
- Other predators and predator larvae – The most common predators we see on our milkweed are adult and larval ladybugs (larvae look like red and black alligators), syrphid fly larvae (look like brown or green worm slinkies), and lacewing larvae (look like little alligators). Don’t kill them! Simply blow them off onto an outdoor plant and let them continue hunting.
Once all predators have been removed and you’ve inspected the milkweed plants/leaves to make sure there are no remaining monarch caterpillars and eggs, give the plant material a good rinse in tap water to reduce pathogen loads.
Then, immediately place stems of milkweed into floral tubes that are placed into empty glasses/jars for support. Those are then put in the monarch enclosure.
For milkweed you’re not going to use immediately: wrap the cut stems in damp paper towels, then place it all into plastic bags stored in your fridge. (Milkweed lasts for many days properly stored in the fridge.) Bring the cuttings to room temperature before providing it to your caterpillars.
Step 4: Raise monarch butterflies in your enclosure.
Now the monarch caterpillars do a lot of the work for you: eating and growing. Take time to observe them and enjoy the view. They’re fascinating creatures. And their antennae are adorable!
Don’t get lazy! Daily maintenance of your growing monarchs is required:
You’ll need to clean the frass (aka poop) out of the bottom of the cage on a daily basis to reduce the potential for diseases/pathogens. This means changing out the paper towels on the bottom of the cage, carefully making sure you’re not also getting rid of any caterpillars who might be hanging out on the bottom. (Frass makes great plant fertilizer!)
Monarch caterpillars can starve to death, and often do in the wild when they run out of milkweed leaves. When using cuttings rather than potted milkweed plants, we typically change our milkweed leaves/stems/plants out every 24-36 hours.
If your leaves have been eaten and/or the caterpillars appear irritated and exploring around the cage, you may need to change your milkweed immediately, regardless of how long it’s been.
Do monarch caterpillars need supplemental water in addition to what they consume through milkweed leaves?
Generally no, but it depends:
If your milkweed leaves are relatively dried out and limp and you are unable to immediately change them out for fresh leaves, you’ll want to spritz the plants with water in the morning so your caterpillars get the hydration they need. If your milkweed leaves are normal and perky, there’s no need to spray your plants with water. Keep in mind that wet conditions and damp paper towels in the bottom of your cage can encourage diseases.
Eggs and first instar caterpillars will benefit from a supplemental early morning water spritz on the leaves they’re consuming.
However, as long as your milkweed is in good condition, your monarch caterpillars should be fine without supplemental water spray.
WARNING: One thing you do NOT want to do is place bowls of water in your cage. This will likely lead to drowned caterpillars.
Step 5: Monitor the pupae/chrysalises.
After 9-14 days as a caterpillar, your monarchs will spend another 8-13 days in the pupal stage inside of their chrysalises, wherein they’ll metamorphose into adult butterflies.
At some point, you’ll notice your large fifth instar caterpillars stop eating and begin wandering around the walls and top of your enclosure. (The smaller caterpillars do this as well when they’re shedding skin between instars.)
Soon, they’ll excrete silk from their tail ends to form a cremaster, and hang the front of their bodies down into a J-shape. After 6-12 hours or so, they’ll then rapidly form a green chrysalis in a matter of a couple minutes, which is an amazing process to watch!
Over the next 1-2 weeks, they remain inside their green chrysalises, forming full wings and adult body parts. You can see these changes taking place through the semi-translucent chrysalis walls.
What should you do if a monarch forms a chrysalis in a spot you don’t want it? Or you want to move a chrysalis?
Using scissors, cut the top of the silken stem where it attaches to whatever object it’s hanging on. Then attach a clip to the top of the stem – tie the clip to the top of your cage and you’re all set! Obviously, be careful throughout this process to put as little pressure as possible on the chrysalis.
Finally, your chrysalises will turn black, signaling that adult butterflies will be emerging within ~24 hours!
Step 6: Release your adult monarch butterflies into the wild.
Out pops a beautiful adult monarch butterfly from a small chrysalis! Another exciting moment — especially for their human caregivers.
Now, your monarchs will need to dry and stretch their wings, while getting their wings’ circulatory system up to speed. This will take a few hours.
If you want to transport your monarch over a short distance when it’s time for the release: extend your index finger immediately in front of the monarch’s legs, and get them to walk on to your finger. Then (without touching or pressing on the wings) slowly and calmly bring the monarch out of the enclosure.
How do you know when it’s time to release your monarch butterflies into the wild?
Temperature – First, keep in mind that monarch butterflies are cold blooded, so warm external temperatures are essential to them being able to fly. If it’s below 55°F (13°C), monarch butterflies can’t fly. So don’t release them outside on a cool morning when temps are below 55°F and expect them to fly!
Weather – A warm, sunny day is ideal for your monarch release. Do not put your adult monarchs out for their first flight on a rainy or windy day. Doing so could injure or cripple them. Instead, hold them indoors until storms have passed.
If you need to feed them in the interim, use a honey water mix (1 part honey to 9 parts water). Soak a cotton swab in this mixture so it’s damp but not soaking wet. Then tie it to the inside roof of your cage/enclosure so the monarchs can hang on it while drinking.
Signs your monarch is ready for first flight…
A few hours after eclosing, a ready-to-release monarch will start taking short flights around its enclosure. At this point, you can release it. Ideally, you can take your whole enclosure outside (if it’s not already outside), open it up, and let the adult butterfly find its way out.
Wish your babies a good life and safe travels! It’s thrilling to be an intimate part of a monarch butterfly’s life — from egg to adult — and to cultivate a relationship with another of earth’s extraordinary species.
Part 6. Monarch butterfly FAQs
1. Do monarch caterpillars eat their skin?
Yes – at least usually. monarch caterpillars go through five instar stages before forming a chrysalis. Between stages 1-4, they typically consume their old skin while transitioning.
2. I think one of my monarch caterpillars died. What should I do?
First, note that when transitioning between instar stages, your monarch caterpillars will crawl off to shed their skin. During part of that time, they may appear to be dead since they’re not moving.
However, if you definitely have a caterpillar that has died, you’ll want to remove it from the cage asap in case it has parasites or a disease that could spread to other caterpillars.
How much milkweed does a monarch caterpillar eat?
We answer this question above, but it bears repeating since it’s critical that a monarch caterpillar have adequate food to survive. For each monarch caterpillar you raise, you’ll need to plan to have about 1′ of mature healthy milkweed plant, which equates to about 20 mature milkweed leaves.
There is variability in leaf size by milkweed variety/subspecies, so it may take more than 20 leaves for small-leafed varieties and less for large-leafed varieties. Common milkweed (Asclepias syriaca) is the subspecies that produces the largest leaves that we know of and it’s native throughout much of North America.
Related read: Common milkweed: How to eat your monarch butterfly garden.
Do monarch caterpillars eat each other?
Typically no, but this can sometimes happen. For instance, large monarch caterpillars may inadvertently eat monarch eggs or first and second instar caterpillars when eating milkweed leaves.
Also, when food supplies are exhausted, the caterpillars can sometimes eat each other or even nibble on other monarch chrysalises.
To reduce the likelihood of this happening:
- make sure you provide a steady supply of quality milkweed;
- don’t place milkweed leaves with eggs or first stage instar caterpillars in an enclosure with larger caterpillars;
- don’t overcrowd your enclosure.
Can you touch monarch caterpillars?
Yes, but do so as little as possible to reduce stress, which may translate to less fit adult butterflies. (We detail this earlier in the article.)
Also, the smaller the caterpillar, the more likely you are to damage it. We recommend NOT handling first or second instars unless absolutely necessary. The larger fourth and fifth instar caterpillars are able to be handled more safely.
Be sure your hands are clean before handling them to reduce the likelihood of giving them a disease you carried in from outdoors, and return them to their milkweed plant as soon as possible.
Can monarch caterpillars eat anything other than milkweed?
Monarch caterpillars should be raised on a diet of 100% milkweed – ideally a milkweed native to where you live. However, if you’re desperate and trying to bridge a gap between replacing your old milkweed with new milkweed, you can supplement the diet of FIFTH INSTAR caterpillars (not the younger ones) with slices of cucumber or pumpkin/winter squash.
If you have to do this, just be sure you use organically-grown produce (no systemic pesticides) and scrub the heck out of them with soap and warm water BEFORE you cut into them. Organic growers often use a soil-borne bacterium called Bt (Bacillus thuringiensis) to control caterpillars on their crops, and this can also kill monarch caterpillars.
Let us repeat: monarch caterpillars should only be fed milkweed; other food sources should only be used temporarily during emergencies.
What triggers monarch butterflies to migrate?
Monarch butterflies are triggered to produce a super generation and/or migrate by the following environmental cues:
- decreasing number of daylight hours,
- cooling temperatures,
- decreasing quality of aging milkweed,
- decreasing nectar sources.
How can you tell the difference between a male and female monarch butterfly?
The easiest way to distinguish between male and female monarch butterflies is that the males have two distinctive black spots on their hind wings.
My monarch’s wings are deformed and it can’t fly. What should I do?
A common disease that effects monarchs — especially in warmer climates — is OE (Ophryocystis elektroscirrha). This is a protozoan parasite that monarch caterpillars get while eating milkweed. Heavy OE infection in caterpillars is the main cause of wing deformity in emerging monarch butterflies.
If you have a monarch butterfly whose wings are still crumpled and unable to fly 4-6 hours after eclosing, you’ll want to euthanize it to prevent the spread of OE. Dispose of the body in the trash rather than outside. If you have an OE infection, you’ll also want to use more extreme cleaning methods of your hands, enclosure, etc to prevent its spread.
How can you tell a “super generation” monarch butterfly apart from other generations?
The super generation of monarchs usually starts in the north in late August. In our area (Greenville, South Carolina), it usually starts in early-mid September.
In addition to the time of year, you can tell the super generation of adult monarch butterflies by their wingspan. Most early generation monarchs have a wingspan of 3.5 – 4″. The super generation has a larger wingspan over 4″.
What else can I do to help monarchs?
You can tag your monarchs and report the data of other tagged monarchs that you capture and release via the Monarch Watch Tagging Program. University of Michigan’s M3 Monarch Migration Study may have volunteer/citizen scientist opportunities as well.
We hope you enjoyed this guide to raising monarch butterflies at home! If there’s a question we didn’t answer or you want to add some of your own tips, please let us know in the comments below!
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