Monarch Butterfly Life Cycle: A Fascinating Journey Revealed

Monarch butterflies are some of the most recognizable and well-researched insects of North America. Their unique life cycle consists of four main stages: egg, larva, pupa, and adult, known as complete metamorphosis.

During a monarch’s lifetime, female butterflies lay between 100 to 300 eggs, which hatch in about four days. At the larval stage, the caterpillar starts at less than 1 centimeter long and grows up to 5 centimeters, experiencing molts called instars.

The captivating transformation of monarch butterflies helps to illustrate the wonders of nature, as these creatures evolve from tiny eggs to vibrant adults.

Monarch Butterfly Life Cycle


Monarch butterflies lay their eggs on milkweed plants. A female monarch butterfly can lay 100 to 300 eggs in her lifetime. The eggs hatch in about four days.


The larval stage is also called the caterpillar stage. When they hatch, monarch caterpillars are less than 1 centimeter long. Over time, they grow up to 5 centimeters. Monarch caterpillars undergo a process called instars, where they molt multiple times as they grow.


The pupal stage, also known as the chrysalis stage, is when the caterpillar transforms into an adult butterfly. Monarch butterflies emerge from the pupa in as few as five days.

Adult Butterfly

The adult monarch butterfly is characterized by its distinct orange and black markings. Monarchs have a unique migration pattern, traveling thousands of miles between Canada and Mexico.

Stage Duration Key Features
Egg ~4 days Laid on milkweed plants
Larva Variable Instars, growth from less than 1 cm to about 5 cm
Pupa ~5 days Transformation to adult butterfly within the chrysalis
Adult Butterfly Variable Distinct orange and black markings, unique migration pattern
  • The life cycle of a monarch butterfly consists of four main stages – egg, larva, pupa, and adult butterfly.
  • Monarchs go through a complete metamorphosis, transforming from a caterpillar to a butterfly.
  • The unique migration of adult monarch butterflies spans thousands of miles across North America.

Migration and Overwintering

Eastern Population

The eastern population of monarch butterflies migrates south from Canada and the United States to overwinter in Mexico1. These migratory insects travel up to 3,000 miles, taking advantage of wind currents and stopping at specific rest areas2.

  • Unique two-way migration similar to birds1
  • Depend on milkweed plants for laying eggs3

Western Population

The western population has a different migration pattern, traveling from the western United States to Southern California4. They typically overwinter in sheltered groves along the California coast4.

  • Shorter migration compared to the eastern population
  • Overwintering grounds in coastal California4

Comparison Table

Eastern Population Western Population
Migration Distance Up to 3,000 miles2 Shorter distances
Overwintering Location Mexico1 Southern California4
Overwintering Habitat Mountain forests1 Coastal groves4

Reproduction and Mating

The life cycle of a monarch butterfly includes four stages: egg, larva, pupa and adult. Adult monarch butterflies play a significant role in reproduction and mating. Here, we’ll focus on the reproductive aspect.

When male and female monarch butterflies reach sexual maturity, they begin the process of mating. Males are slightly different from females in appearance, with narrower wing veins and scent patches. These differences can be vital when identifying and attracting a mate.

During the mating process, the male monarch butterfly transfers sperm to the female. The fertilized female monarch butterfly then goes on to lay hundreds of eggs over her lifetime. In fact, a female Monarch butterfly lays from 100 to 300 eggs during her life according to the US Forest Service. Eggs are typically laid on the underside of milkweed leaves, which serve as a primary food source for the offspring.

In certain cases, female monarch butterflies may enter a state of reproductive diapause, where they temporarily suspend their reproductive activities. This usually happens in response to environmental conditions, such as cold temperatures, which may hinder the survival of their offspring.

To better understand the features and characteristics of adult monarch butterflies, consider the following:


  • Bright orange wings with black veins and borders
  • White spots on the borders
  • Male monarchs have narrower wing veins and scent patches


  • Males and females reach sexual maturity during the adult stage of their life cycle
  • Female Monarch butterflies can lay hundreds of eggs during their lifetime
  • Reproductive diapause can occur during certain conditions and climates

When examining adult monarch butterflies, it’s important to focus on the mating process and its subsequent effects on reproduction. By understanding the unique features and characteristics of these butterflies, we are better equipped to support conservation efforts and appreciate the beauty of this natural wonder.

Feeding and Host Plants

Monarch butterflies are closely associated with milkweed plants (Asclepias spp.) for their reproduction and survival. Monarchs rely on milkweeds for two main reasons: caterpillar food source and protection from predators.

  • Caterpillars depend on milkweed plants for their diet.
  • Monarchs lay their eggs only on milkweed plants.
  • Glycoside toxins from milkweed plants provide protection from predators.

Adult monarch butterflies feed on the nectar of various flowering plants, which supply the energy they need for activities like flight and reproduction. Some examples of nectar plants that monarchs utilize include:

  • Coneflowers
  • Asters
  • Lantanas

Monarchs and Milkweed: A Comparison

Feature Milkweed Plants Nectar Plants
Role Host plants for caterpillars Food source for adult monarchs
Toxins Contains glycoside toxins No glycoside toxins
Monarch Lifecycle Stage Egg, caterpillar Adult
Examples Common milkweed, swamp milkweed, butterfly weed Asters, coneflowers, lantanas

In conclusion, milkweed plants are essential for monarch caterpillars, while adult monarchs rely on a variety of nectar-producing plants to meet their energy needs. This close relationship between monarchs and milkweed plants is a remarkable example of nature’s interconnected web of life.

Threats and Conservation


Monarch butterflies are highly sensitive to pesticides. Exposure to these chemicals may lead to decreased populations.

Endangered Status

While not yet classified as endangered, monarch populations have experienced a significant decline. This decline increases concern for their conservation.

Plant Milkweed

Monarchs rely on milkweed plants for feeding and reproduction. Planting milkweed is essential for supporting monarch populations and their habitats.

  • Milkweed species: Over 100 different types of milkweed exist, providing various options for planting.
  • Planting locations: Gardens, parks, and other green spaces can benefit from the addition of milkweed plants.

Habitat Loss

Habitat loss is a major threat to monarch butterflies. Urbanization, agriculture, and deforestation contribute to the decreased availability of suitable habitats.

Climate Change

Climate change affects monarchs by altering their migratory patterns and the availability of food sources.

Comparison Table: Threats

Threat Monarch Impact Conservation Actions
Pesticides Decreased populations due to direct exposure Limit the use of pesticides; Integrated Pest Management
Endangered Increased concern for survival Monitoring; Conservation efforts
Plant Milkweed Provides essential food and breeding grounds Plant native milkweeds in gardens, parks, and other suitable locations
Habitat Loss Decreased availability of suitable habitats Habitat restoration and protection
Climate Change Altered migratory patterns; Reduced available food sources Monitoring; Research to better understand long-term effects on monarchs

Physical Characteristics

Colors and Patterns

Monarch butterflies, scientifically known as Danaus plexippus, are known for their distinct appearance. Their wings display:

  • Bright orange color
  • Black veins
  • Black border with two rows of white spots
  • White dots around the border edges

These colors are not only for aesthetics but also serve as a warning to predators that the butterflies might be toxic.

Wingspan and Size

When it comes to the wingspan and size, there are differences between male and female monarchs:

Gender Wingspan Distinct Features
Male Slightly larger than females Narrower wing venation and scent patches
Female Slightly smaller than males Broader and darker wing veins

Both male and female monarch butterflies have a wingspan that can range between 3.7 to 4.1 inches (9.4 to 10.4 centimeters). The size difference and other gender-specific features are integral to their sexual dimorphism.

Adaptations and Behaviors

Monarch butterflies exhibit unique adaptations that contribute to their survival and reproduction. One of these adaptations includes the presence of scent glands that helps males attract females during mating.

These butterflies undergo a fascinating metamorphosis process. When transforming into a chrysalis, they develop a protective casing that serves as a shield during their vulnerable pupal stage.

Comparison between Western and Eastern Monarch butterflies:

Feature Western Monarchs Eastern Monarchs
Migration Pattern California coast Central Mexico
Overwintering Sites Forests in California Oyamel-fir forests
Migration Distance Shorter Longer

Within their life cycle, there is a specific generation called the “migrating generation” which is essential for the species to survive over vast distances. These migrating monarchs make remarkable two-way migrations, similar to birds.

A crucial adaptation to their survival is their toxicity. Monarch caterpillars feed on milkweed plants that contain cardenolides, which make them toxic to predators.

Here are some features of monarch butterflies:

  • Cardenolides consumption
  • Distinctive appearance: warns predators of their toxicity
  • Long-distance migrations

Some common plants monarch larvae feed on:

By understanding the adaptations and behaviors of monarch butterflies, we can better appreciate their extraordinary life cycle and the importance of conserving their habitats.

Scientific Study and Cultural Significance


In recent years, the study of the monarch butterfly life cycle has gained increased attention in the scientific community. Researchers have observed that monarchs go through a process called instars, which are the stages between larval molts. This is important because it sheds light on the butterfly’s unique development process and heredity aspects.

For instance, some key facts about their life cycle include:

  • Female monarchs lay 100 to 300 eggs during their lifetime
  • Eggs hatch in about four days
  • Larvae grow from less than 1 cm to about 5 cm

Literature and Art

The beauty and transformative nature of the monarch butterfly have made it a symbol of inspiration and metaphor in various forms of art, such as literature and visual arts. It represents themes like change, growth, and the delicate balance of life. The intricate patterns of the butterfly’s wings have also led to their incorporation into different artistic expressions.

Some examples include:

  • Monarch butterfly-inspired paintings
  • Poems about the butterfly’s transformation
  • Books illustrating the monarch life cycle

In summary, the scientific study and cultural significance of the monarch butterfly life cycle showcase the value of this incredible creature. Both researchers and artists alike find inspiration in the monarch’s journey, further enriching our understanding and appreciation of nature.


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Reader Emails

Over the years, our website, has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Monarch Caterpillar attacked by Tachinid Fly


Monarch Caterpillar under Attack
location:  St. Augusta, Minnesota
August 20, 2012
Hi Daniel.
I’m editting photos now, and just came across something interesting.  This fifth instar monarch caterpillar may be under attack by a fly.
Although the photo isn’t as clear as I’d like, if you look near the caterpillar’s head you can see what appears to be a small fly.  I assume it was attracted to the droppings left from the caterpillar’s overnight binge.  I wish I’d noticed it when I was doing the photo.  This seems to be a smaller species than the one I previously noted (August 14th).
This has been a very difficult year for the monarchs and other butterflies here; many many predators and parasites and now, drought.  The spring was spectacular for bug nuts like me, seeing species not usually seem this far north and large numbers of monarchs on our milkweeds.  But it quickly dropped off as we got into the more normal summer season.
Cheers.  And thanks again for your incredible service!
Don J. Dinndorf
St. Augusta (central), Minnesota

Monarch Caterpillar preyed upon by Tachinid Fly

Hi Don,
While we cannot make out details, we can be relatively certain that this Monarch Caterpillar is being preyed upon by a Tachinid Fly, perhaps even the same species of Tachinid Fly from your August 14 submission.  What a marvelous addition to our Food Chain tag despite the sorrow of you losing one on your Monarch Caterpillars to predation, or rather, parasitization.

Thanks, Daniel.  Next time, maybe I’ll get a clearer shot.
The flies have just been murder here.  I lost four metamorphosing caterpillars just today.

Letter 2 – Monarch Caterpillar


What is this caterpiller?
Found on wild lantana in Ramrod Key, Florida
Beryn Harty

Hi Beryn,
It is a Monarch Caterpillar feeding on milkweed, not lantana.

Letter 3 – Monarch Caterpillar


New London, NH USA
Can you tell me what these caterpillars are? I think one is a swallowtail but don’t know the other one. Thank You

Your caterpillar is a Monarch, not a swallowtail. It is on a milkweed pod, the larval food plant.

Letter 4 – Monarch Caterpillar


Dear Bugman,
I found this Caterpillar in some vine on my fence in the backyard. I live in central Illinois. Can you help me figure out what kind it is? Can I possibly watch it change? Thanks!

Hi Blaire,
The vine must be a climbing milkweed since this is the larva America’s (if not the world’s) most beloved butterfly, a Monarch Buttefly Caterpillar.

Letter 5 – Monarch Caterpillar


Monarch Caterpillar Success
Location: Hawthorne, CA
October 18, 2011 8:43 pm
While watering out back today, I spied this beauty and thought I should share it with you. It’s common, but ”new to our yard” and I’m so glad to see that our efforts have yielded yet another gem. Don’t think I would have even looked for this had it not been for you!
Signature: Thanks, Anna Carreon

Monarch Caterpillar

Hi Anna,
Thanks for sending us your lovely photos of a Monarch Caterpillar on Milkweed in your garden.  Do you know if this is a native milkweed?

Monarch Caterpillar

Hi Daniel,
Thanks very much.  This is  Asclepias curassavica – Mexican Milkweed, a native of the American Tropics.  It was in a “Butterfly Mix” packet of seeds that we bought at a local nursery last year.  Should I discourage it from reseeding this year and try to get native milkweed started instead?

Hi Anna,
No, we would not recommend discouraging it.  We were simply curious.  You can try some native milkweed as well.  You have a cultivated garden and if something is happy with the habitat you are providing and that thing is attracting native species of insects, we can think of no reason to discourage it.


Letter 6 – Monarch Caterpillar


Subject: Daniel – Monarch Caterpillars
Location: Hawthorne, CA
December 4, 2014 6:40 pm
Hi Daniel,
Hope all is well with you and yours. I haven’t been able to get out in the back much lately, but things are looking up and I want to share with you some late season Monarch Butterfly caterpillar shots. We have many Monarch Butterflies out there right now also, which tends to brighten the mood!
Signature: Anna Carreon

Monarch Caterpillar
Monarch Caterpillar

Thanks for an update on your Monarch population Anna.  We cannot remember a year when we have seen more Monarchs in our Mount Washington neighborhood than we have this past year.

Letter 7 – Monarch Caterpillar and Chrysalis


Monarch larvae & chrysalis
September 27, 2010
Hi Daniel,
I’ve sent you a few pix over the last couple of months, one of which you featured as September’s Bug of the Month.
Thought you might be interested in this monarch larvae. I found it munching on milkweed, which I have growing all around my property and in my yard. (For this very reason!) I decided to try bringing it in and making a “perfect spot” for it to make its chrysalis. Well, the photos show the progression: it continued to eat for another full day after I brought it in, which was September 22. On the evening of September 23, it started making its way up the branch. I figured I’d find a chrysalis the next morning. Instead, it had disappeared, no where to be found! On the 25th, I found the larvae on my wall, way down by the heat baseboard. I debated on moving it, but left it there and went to do errands. I came home in the mid afternoon to find the chrysalis hanging from the wall! Now, will a butterfly emerge?!
K L Thalin
Saxtons River, Vermont

Monarch Caterpillar

Dear KL,
The adult should emerge in a few weeks depending upon the temperature.

Monarch Chrysalis

Letter 8 – Monarch Caterpillar: Best Letter in a Long Time!!!


Lesson Learned in Florida
Last spring, I tried in vain to keep eight, young, butterfly plants alive in my modest flower garden. “How wonderful it would be to attract beautiful butterflies”, I thought. To my dismay, fat, yellow, aphids appeared by the dozens on each little plant. They were herded by fire ants from a nearby nest. For weeks, I squished aphids, always marveling at the protectiveness of the ants and sheer numbers of aphids they managed. While walking in the cattle pasture one day, I saw an entire plant covered with aphids. I was horrified that the source of these bugs was a weed that had appeared in our pastures in record abundance, presumably due to a long drought experienced here in northern Florida. Since we raise natural beef cattle, I picked many of these weeds by hand out of our pastures, but to my dismay, as I picked them, their seed pods were already releasing fluffy seeds for next year. This spring, the population of these plants was even higher than last year! So, I began picking these plants early this year, well before they could complete their seed pods. I didn’t get far before I noticed a caterpillar on one of the plants. It was a monarch! (See pictures below). I looked at my hands and noticed the milky substance from the few plants I had already picked. How ironic that I waged a (thankfully) unsuccessful war against what turned out to be a milkweed native to Florida because I wanted to save a few measly butterfly plants! How completely human of me. Little did I know that I had several hundred or more plants in the pastures that were the perfect diet for the very creature I was seeking to attract. I have learned my lesson and sworn off meddling with milkweeds or anything else unless I know for certain that it is a threat to native wildlife.

Hi Alicia,
Thank you for writing one of the best letters we have received in a long time. We are excited to post your photo of a Monarch Caterpillar.

Glad you enjoyed it! I’m researching when these caterpillars will complete their pupa stage and emerge as butterflies. We plan to rotate the cattle in our other pastures until then to keep the monarchs safe. We already made changes in our livestock management to accommodate two other threatened species: gopher tortoises and Sherman fox squirrels. Gratefully,

Letter 9 – Monarch Caterpillar, but is that Milkweed??? Yes, it is!!!


Caterpillar (is it a Monarch?)
Location: Leitchfield, Kentucky
May 5, 2011 11:31 am
I am an avid Monarch fan. I have Milkweed in my flower bed for them. I also have several Butterfly Weed plants for all butterfly…I noticed several Monarch caterpillars on my milkweed…was so delighted at this sight. Couple of days later as I was stalking up the Butterfly Weed, I saw to my amazement what appeared to be lots of caterpillars that look to be Monarch. I thought Monarchs only(strictly) ate Milk Weed…
Signature: JoAnn

Monarch Caterpillar

Dear JoAnn,
This is most certainly a Monarch Caterpillar, and we are not entirely convinced that your “butterfly weed” is not a Milkweed.  We are not botanists, though we are also not entomologists and that doesn’t stop us from trying to identify insects, but we do know that there are many species of Milkweed.  The plant in these photos has a developing flower head that seems to resemble the inflorescence of a milkweed.  Check with the nursery where you purchased the Butterfly Weed to see if they can provide a scientific name and then check that it may be in the milkweed subfamily Asclepiadoideae.

Monarch Caterpillar

Dear Daniel
I did some checking as you suggested.  You are 100% correct.  My Butterfly-Weed is Asclepias tuberosa. It is a member of the Common Milkweed family.  It does not have the milky sap as the others or the opposite whorled leaves.  This is what threw me for a loop (absence of the milky sap) when I saw the caterpillars.
I thought the Butterfly-Weed was just one of the plants that all butterflies loved for nectar.  Never entered my mind to check it out further.  To my delight, I now have another plant for the Monarch to feast upon.  As I have the other types of milkweed readily available to me, I plan on expanding my garden.  The fragrance of the common Milkweed is heavenly and the plants can be controlled by removing the fruit(follicle) right before it pops open or immediately after.   Should your bed get to big, as it will in time…just dig up the straggling plants moving outside your bed in the spring.
Thank You very much for you rapid reply.
Have a Great Day!

Letter 10 – Monarch Caterpillar libeled on "Bug-B-Gon" label


Hi Daniel,
Husband Marty showed me this article yesterday and I immediately thought of you.  You’ve probably already read it, but here’s a link just in case:,0,7448108.story
Anna Carreon

Monarch Caterpillar photo by Anna from our archive

Thanks Anna,
I was going to scan the article and post it, but this is even better.  I am illustrating the posting with one of your photos of the Monarch Caterpillar.

Monarch Caterpillar placed on insecticide label!!!
Monarch Caterpillar vindicated!!!


Letter 11 – Monarch Caterpillar meets Red Milkweed Beetle


Subject: Tetraopes tetraophthalmus? Inter-species love?
Location: Niagara, ON
September 3, 2013 9:15 pm
Hello WTB,
Loving the site as always. I wanted to share this photograph I managed to capture last week near Port Colborne, ON (Niagara region). I found this monarch caterpillar and red milkweed beetle (Tetraopes tetraophthalmus, I think?) sharing an intimate moment on a common milkweed along the Lake Erie shoreline. I hope this was a friendly encounter!
Signature: Alison

Monarch Caterpillar meets Red Milkweed Beetle
Monarch Caterpillar meets Red Milkweed Beetle

Hi Alison,
We love your photo and we can predict that our readership is going to love this photo as well.  We have no idea what is going on and we suspect it is just a chance meeting, but it sure makes for interesting and provocative viewing.  Neither the Monarch Caterpillar nor the Red Milkweed Beetle is a predator, so we don’t believe either is going to make a meal out of the other.

Letter 12 – Monarch Caterpillar Metamorphosis and Tachinid Fly Parasites


Monarch Bodysnatchers
Hello, Bugman,
I recently placed 2 large monarch caterpillars in an terrarium with some milkweed, so I could watch them go through metamorphosis. All was well… at first. One morning, I found one of the caterpillars hanging from under a branch, as though ready to pupate, but it was dead, shriveled, and and clear strands hanging from it. There were two small, yellow maggots in the tank, as well as a red pupa. After a bit of searching, I found this site /research/PNE/creasey.aspx . Apparently, an introduced tachinid fly, Lespesia archippivora, was brought over to control cutworms, but attacks non-target species like monarchs as well. Fortunately, the other caterpillar seems to have dodged the bullet, and has formed a lovely chrysalis. Regards,

Monarch Caterpillar Monarch Chrysalis

Hi Emily,
Thank you for your wonderful letter, excellent photos, precise documentation, and technical research. Though we approve of biological control methods over pesticides, we always question the introduction of biological agents before the total ramifications of the actions are made apparent.

Parasitized Monarch Caterpillar Tachinid Fly larvae and pupa

Letter 13 – Monarch Caterpillar Metamorphosis and Tachinid Fly Parasites


Monarch Bodysnatchers
Hello, Bugman,
I recently placed 2 large monarch caterpillars in an terrarium with some milkweed, so I could watch them go through metamorphosis. All was well… at first. One morning, I found one of the caterpillars hanging from under a branch, as though ready to pupate, but it was dead, shriveled, and and clear strands hanging from it. There were two small, yellow maggots in the tank, as well as a red pupa. After a bit of searching, I found this site /research/PNE/creasey.aspx . Apparently, an introduced tachinid fly, Lespesia archippivora, was brought over to control cutworms, but attacks non-target species like monarchs as well. Fortunately, the other caterpillar seems to have dodged the bullet, and has formed a lovely chrysalis. Regards,

Monarch Caterpillar Monarch Chrysalis

Hi Emily,
Thank you for your wonderful letter, excellent photos, precise documentation, and technical research. Though we approve of biological control methods over pesticides, we always question the introduction of biological agents before the total ramifications of the actions are made apparent.

Parasitized Monarch Caterpillar Tachinid Fly larvae and pupa

Letter 14 – Monarch Caterpillar: Metamorphosis into Chrysalis


chrysalis formation of monarch caterpillar
September 14, 2009
Hi! A few weeks ago, my kids and I collected some monarch eggs and caterpillars from a local park. After weeks of collecting fresh milkweed every day and watching the caterpillars grow, we were rewarded by seeing them turn into beautiful green chrysalids. One morning, we happened to be watching when a caterpillar started to shed its skin to reveal the green chrysalis underneath. I took some photos of the process that I thought you might like to see. It took about four minutes for the caterpillar to become a pupa. So far, five of the butterflies have emerged and been released. We have two more that should emerge in a few days. We are already looking forward to raising monarchs again next summer, and even plan to tag them for the Monarch Watch program.
Thanks for such an awesome website! We are big fans!
The Ganino Family
Madison, CT

Monarch Caterpillar Metamorphosis
Monarch Caterpillar Metamorphosis

Dear Ganino Family,
Thanks for the awesome images showing the transformation of the Monarch Caterpillar to the Chrysalis.  Your first image shows the caterpillar skin splitting and the second image shows the Chrysalis while it still maintains the more elongated shape of the caterpillar.

Monarch Chrysalis Metamorphosis
Monarch Chrysalis Metamorphosis

Letter 15 – Monarch Caterpillar transforms into Chrysalis


Detailed series of pics of monarch caterpillar to pupa
Location: Central Wisconsin
September 7, 2011 11:22 pm
Hi! First of all, I want to thank you for your time and devotion to this site. I’ve been lurking for a few years, and have identified a few critters with the help that you give others. From my own failed attempts to keep a site/blog going, I know how much work it is, and I’m so glad you don’t have the same problem I do of letting it slide into oblivion. 🙂
My new hobby lately is to collect caterpillars. Some of my first have been monarchs–they’ve been really active at the caterpillar stage around Central Wisconsin. This is actually the first year I’ve ever seen one, but that doesn’t mean much since my attention has been elsewhere. I’ve brought a total of 7 home over the last week and a half, and within the first 3 days, all of my original 5 turned into pupa, and the latest 2 additions from the last field search has one as a pupa and the other currently finding his spot for his J.

Monarch Caterpillar prepares for metamorphosis

I was amazed at how fast the transformation was, and was disappointed with the first 4 turning into their cocoons before I could capture them with the camera. Finally I noted the signs I’d read about in one of my J’s, and sat like a hawk for hours to capture the following series of photos and video. I thought you may be interested, but understand if this is a rather common submission.
Since there are multiple photos all in my album, I’ll give the main link of the album along with using the form fields below for a few of them.
Main/full album:
Signature: ScribbleMuse

Monarch Caterpillar begins transformation

Dear ScribbleMuse,
Thanks for the lovely documentation.  Common insects are often quite new to our readers who have logged onto our site for the first few times, and we always try to post timely submissions that new readers might encounter.  Your series of photos is quite wonderful, and we hope our readers visit the link you have provided so they can view the entire transformation process.

Monarch Chrysalis

Thank you for the compliments!  I’ve been finding that common components of nature often have quite extraordinary details when I take the time to look at them, and have had quite a few rewarding experiences.  Usually I’m hoping to capture just a nice still shot of something and then find something fascinating in the actions (or sometimes inactions) of the subject.
Thanks again for your time not only to me, but in general to provide this helpful website!

Letter 16 – Monarch Caterpillars


Monarch – Different Instars?
Location: Fort Myers, Florida
December 20, 2010 11:10 am
Greetings from sunny (but cold) Florida! I was suprised to find I still have monarch caterpillars even after the almost freezing weather this past week. However, I also noticed another caterpillar that looked very similar – but the black, yellow, and white bands are different. They are both on the milkweed, but the look-alike’s black bands seem more prominent. I’ve watched over the last couple of days, and the look-alike doesn’t seem to be changing the bands as he gets bigger. Is this a different butterfly, or just a different stage of the monarch I haven’t seen before?
Signature: Catherine

Monarch Caterpillars

Dear Catherine,
Just as some people have brown hair and others red or blond hair, there is often individual variation among insects of the same species.  We do not see anything unusual in the variations you point out and it is our opinion that these are two Monarch Caterpillars.  Thanks for your question and also for your wonderful photograph.

Letter 17 – Monarch Caterpillars


Daniel, We have baby monarchs

Location: South Pasadena, CA
January 3, 2011 12:44 am
Since I planted the milkweed a few years ago, I’ve had occasional monarch butterfly visitors, and a single caterpillar last summer. Then a few days ago I started finding these. I counted at least eight of them in two different sizes. This is pretty exciting for me. It doesn’t seem like the right season, but I guess they know better.
Signature: Barbara

Monarch Caterpillar

Hi Barbara,
This is really exciting.  Congratulations on your good fortune.  We would love to know what species of milkweed you are growing in Southern California and where you acquired your plants.

Monarch Caterpillar

I got the milkweed at a Huntington Library plant sale.  I’ve lost the tag, and I don’t remember what species it is, but it has nice red and yellow flowers and seeds like crazy.  The birds and bugs like it, and it’s quite pretty most of the time if I trim off many of the seed pods.  I’d be happy to give you some seedlings which pop up everywhere there’s a little water.

Monarch Caterpillar

Hi Barbara,
I in no means mean to disparage the Huntington which is a marvelous garden and resource for the public, but if they have milkweed, it is probably an exotic species from a faraway land.  I was hoping to hear that you got your milkweed from the Theodore Payne Society, a non profit organization in Sun Valley that sells native plants.  I may do a book signing there this spring.  I am currently working towards trying to preserve our local milkweeds.  Clare Marter Kenyon, a local activist who was behind the City of Los Angeles’ Protected Native Tree Ordinance, formerly the Oak Tree Ordinance, informs me that there are three species of native milkweeds in Elyria Canyon Park in Mt Washington, and I plan to try to propagate them.  I have never seen a Monarch on the milkweeds in Elyria Canyon Park, but there are always Large Milkweed Bugs on them.

Ed. Note: January 5, 2010
Clare Marter Kenyon just sent us this link:

Update: May 3, 2011
Obtaining Native Milkweed
May 3, 2011 9:44 am
Dear Bugman,
I was reading your tag on Monarchs and milkweed (asclepias).  If you havent found sources yet, there are some great native nurseries throughout the state (check for a thorough list).  One near LA is Las Pilitas Nursery,, they have great photos and information.  The SF Bay area has Annies Annuals (where I purchased my milkweed).  Both of these companies are responsible propogaters and have excellent mailorder service. I have my first crop of Narrow leaf milkweed (asclepias fascicularis)growing in this year.  We may only get a few monarchs drifting in but many insects enjoy it. Kudos and thank you for getting out the word that our monarchs need Native milkweed to thrive.  I consider it far lovelier than the tropical variety.  Before I knew better I had tropical milkweed planted and all it attracted was flies!
Signature: Colleen Clark

Letter 18 – Monarch Caterpillars


Subject: Daniel – Monarch Butterfly Caterpillars
Location: Hawthorne, CA
December 3, 2013 7:34 pm
Hi Daniel,
We have seven Monarch Butterfly caterpillars as of today and wanted to share some photos with you. There were more, but we can’t figure out what happened to them. Maybe wasps, or goldfinches?
Signature: Thanks, Anna Carreon

Monarch Caterpillar
Monarch Caterpillar

Good Morning Anna,
What a nice cheerful posting you have provided for us this morning.  We believe Goldfinches are seed eaters, so if there is predation, we would suspect wasps to be the culprits.  We planted some cosmos seeds already and they are beginning to sprout.

Wonderful!  Thanks for letting me know that the goldfinches aren’t eating my caterpillars.  I so enjoy putting out Nyjer seed for them in the winter.

Letter 19 – Monarch Caterpillar Update from Anna


Monarch Butterfly Caterpillars
Location:  Hawthorne, CA
December 12, 2012
Hi Daniel,
Here are some shots from the past four days.  While I was sitting out back on Sunday, a Monarch Butterfly came by to plant some new eggs on the Mexican Milkweed.  I actually got to watch her leave the one on the seed pod!  We’re watching eagerly for new hatchlings.  The oldest of the caterpillars is now eating the seed pods.  If things go as last year, it will pupate in a few days.  There was another that hatched at the same time, but we lost it.  The others in between egg stage & what I understand to be the fifth instar and final stage before becoming a chrysalis are well and eating away.  I counted 8 in the back today.
Hope all is well you with you on this gloomy, soon to be rainy day.

Monarch Ovipositing

Hi Anna,
Sorry for the delay.  Your submission caught us at the end of the semester and at the end of the week.  Thursday and Friday are particularly heavy work load days for us.  We are thrilled with your latest round of photos and the ongoing Monarch Caterpillar documentation you are providing to expand on the Bug of the Month posting.

Monarch Egg

We love the photo of the egg.  Your Mexican milkweed, though not native, is well adapted to Southern California weather and the Monarchs obviously love it.  When choosing plants for the butterfly garden we are working on in Elyria Canyon Park, we need to stick to native plant species.

Monarch Caterpillar

We look forward to receiving photos of your first Monarch chrysalis of the season.

Monarch Caterpillar

Hi Daniel,
Thanks very much.  I thought maybe you were immersed in end of semester goings-on.  I don’t know that I will find a chrysalis, couldn’t last year.  We didn’t have as many caterpillars then, though, so maybe will get lucky this year.

Update:  December 18, 2012
Hello Daniel,
Still no pupating, but I got these shots of the oldest surviving caterpillar today and just wanted to share them with you.  This and one other ventured onto one of the Cigar Plant bushes a few times yesterday.  They may pupate there, who knows?  I’ll keep my eyes peeled.

Monarch Caterpillar

Reader Emails

Over the years, our website, has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Search Engine Problems Resolved!!!


Subject: Lack of Images
July 26, 2013 12:57 pm
I must say that the new design is not user-friendly.  I type, for example, “small yellow bug” into the search field and only links come up.  I then have to click on every link to see an image.  Find myself using your site less and less.  So sorry to complain.  Anna Carreon
Signature: Anna Carreon

Monarch Caterpillar by Anna
Monarch Caterpillar by Anna

Dear Anna,
We are really sorry to hear that as you have been such a faithful contributor over the years.  We will bring this to the attention of our webmaster to see if we can return to the former way the search engine worked.  Our editorial staff doesn’t particularly like the way the search engine is currently working either, and we have taken to using google and selecting images after typing in what we want to find, followed by “” if we want to search our own archives.  Again, thanks so much for your input and we will try to remedy this problem.

UPDATE:  July 27, 2013
We just learned the problem has been corrected.  Images are once again appearing when using the search engine.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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11 thoughts on “Monarch Butterfly Life Cycle: A Fascinating Journey Revealed”

  1. We were excited to see that we had smallish caterpillars eating on our milkweed, thinking that they were Monarch. But, after viewing your pictures, I see that ours are smaller and have lots of sparse long “hairs”. They have the colors of a Monarch; What could they be?

  2. i have some caterpillars that looks exactly like a monarch butterfly except that these have like small spikes that kinda look like a bunch of pimples is it the same thing or just a different type of caterpillar i haven’t seen before

  3. Hey this is somewhat of off topic but I was wanting to know if blogs use WYSIWYG editors or if you have to manually code with HTML. I’m starting a blog soon but have no coding knowledge so I wanted to get advice from someone with experience. Any help would be enormously appreciated!

  4. I have twice witnessed a similar event in my garden. In each case, though, the beetle had a death grip with its mandibles on a monarch caterpillar and was dragging it away. Once I went quickly to the house to get a jar to catch it, but unfortunately it was gone by the time I returned. I could not find the beetle, nor the caterpillar. I do not see the beetles when there are no caterpillars present, but I have never seen a Monarch chrysalis on any of my plants, nor any where in the garden and I have been searching for them every year since 1985, so I have presumed that the beetle finds erery monarch larva the appears in my garden!

  5. If you can find the monarch seeds bring them in and help – hatch them feed the cats and they will make a pupa. When the monarch is born let them free.


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