The Monarch Butterfly Life Cycle (technically called metamorphosis) is the series of four developmental stages that insects go through to become adults: egg, larva (the caterpillar stage), pupa (the chrysalis phase), and adult.
I have been lucky enough to witness this process, and I wanted to share it with you. I hope you enjoy it as much as I do. Taking nature shots is so much fun for me, you can also check out my backyard birding tips. By the way, I often share my nature photography on Instagram. If you would like to see more, please be sure to follow me there.
It takes a Monarch butterfly about 30 days to complete its life cycle. Let’s start with the egg stage.
Egg developmental stage
Adult female monarchs lay their eggs on the underside of milkweed plant leaves. She can lay from 100 to 300 eggs during her life.
How to tell the difference between a female and a male monarch butterfly?
Males have a small black spots on the top surface of the hind wing. Females do not have these spots. It’s easy to see the spots when the wings are open. Sometimes it’s faintly visible on the outside when the wings are closed, too.
Males also have thinner wing veins than females.
Females tend to be slightly darker than males.
And, the tip of the abdomen of males and females are visibly different.
Back to the eggs
Monarch butterfly eggs are very small, about the size of a pin head, and are white in color.
Each egg is attached to the leaf by an adhesive fluid that is applied to the egg as it is being laid.
A day or two before the egg hatches, it appears to turn gray in color. Actually, the egg case (or shell) has turned transparent, and you can the caterpillar inside the egg.
About 3 to 8 days after the eggs are deposited, they should hatch into caterpillars. When larvae first hatch they are less than 1 centimeter long.
The caterpillar (or larva) stage
The caterpillar has eight pair of legs: 3 pairs of true legs on its thorax and 5 pair of prolegs on its abdomen.
It also has a mouth it can use to bite off and chew its food (monarch butterflies do not have this). Milkweed is the only food monarch caterpillars eat, and they eat a lot!
About 2 weeks after it hatches, the Monarch caterpillar is fully grown, at about 2-inches long. A monarch grows 2,000 times bigger while it is a caterpillar.
When the caterpillar is fully grown it usually leaves the milkweed plant, sometimes crawling 20 to 30 feet away, until it finds a safe place to pupate (or turn into a chrysalis).
The caterpillar will spin a silk-like mat and then attach itself to the mat with its cremaster (a hook-like apparatus located on the tail end of the caterpillar).
The caterpillar allows itself to drop and then it hangs there, upside down in a “J” shape, for about 24 hours.
Just before the caterpillar pupates, the caterpillar will shed its skin for the last time as it passes from the larval (caterpillar) stage to the pupa stage of metamorphosis.
Under the caterpillar’s skin this time is a jade green casing, called a chrysalis, that is only about an inch long!
The chrysalis phase
A monarch is a chrysalis for about 10-15 days.
Inside the chrysalis the Monarch is going through many changes, not the least of which is that it’s growing wings!
But also, the Monarch’s mouth parts are reconstructed so that the emerging butterfly will have no chewing mouth parts but, instead, a proboscis (a straw-like apparatus which will be used to sip nectar). Never again will it eat solid foods.
The butterfly will have 3 pairs of legs, not eight like the caterpillar.
Reproductive organs will form; they were absent in the larval stage.
About 24 hours before the Monarch butterfly is ready to emerge, the chrysalis will begin to darken and become transparent so that right before the butterfly emerges you will be able to see the wings inside the chrysalis.
Detailed pictures of the emergence
If you would like to see video of the monarch emerging, I have some lovely videos for you to watch. Please feel free to hang out and watch all three of them. They are short, but so amazing!
The first video is of the monarch emerging from the chrysalis. Second is of her drying her wings by allowing air to pass through them. And the third video is of the butterfly expelling fluid after it has emerged.
Look at the top rounded part of the chrysalis. Can you see that the pleats have started to expand and separate like a slinky? That indicates that the butterfly is soon to emerge.
The chrysalis has cracked open and the butterfly is soon to emerge.
Her little leg is sticking out!
The abdomen and both antennae are out of the chrysalis, as are most of the wings.
You can see the proboscis (or what I might call the tongue) is now sticking out and a little curled. And, you see that it’s two parts? Later, the butterfly will pat those two parts together to form the proboscis (straw-like appendage used to take in nectar).
Its wings are small and crumpled, and its abdomen is plump and filled with fluids. Over the next minutes, hemolymph from the abdomen is pumped through the wings, until the butterfly starts looking more like a big beautiful butterfly.
The butterfly is completely out of the chrysalis. Next she will find a comfy spot to hang and allow her wings to plump and dry. You can also see the four distinct wings really well in this photo.
Waiting for her wings to dry
The Monarch Butterfly Life Cycle is so fascinating to me. I sat outside watching this butterfly for almost 8 hours this day!
Her abdomen is so plump. And, you can see her mouth parts, called labial palps, that she will use to fuse together the proboscis from two thin pieces into one large straw to drink nectar.
The emergence process only took about 10 minutes from first crack of the chrysalis to this point. She will hang here another hour or two before her wings are fully dry enough to fly away.
The video above is of the butterfly expelling a red-brown fluid called meconium; it’s metabolic waste that’s built up while the butterfly was inside the chrysalis and is completely normal.
Moving her wings so they dry
The above video is of her moving her wings in and out to allow air to pass through them and help them dry.
You can see in these next photos that she’s moving her wings to allow the air to come in and out.
When your butterfly is ready to try flying it will flap its wings. And, the first flight may not be the most graceful. This is a great time to get the butterfly to crawl on you.
Within days, the males and females mate, the female lays her eggs, and the life cycle begins again.
Some butterfly fun facts for you
Butterflies sleep upside-down
Butterfly wings are transparent. The wings of a butterfly are covered in thousands of miniature scales (I used to call them powder when I was a kid). And those colors you see when a butterfly flits across your yard are the reflection of various colors through the scales. The wings themselves are made up of a protein called chitin, which is the same protein that forms an insect’s exoskeleton. And much like an exoskeleton, chitin is transparent. Therefore, the wings themselves are transparent.
Butterflies taste with their feet
They can’t fly when it’s cold
Butterflies have four wings, not two
I love going out into nature, learning new things, and seeing new things. Sometimes I share some of the nature experiences we have, like Glass Beach and Fort Casey State Park. I hope you have enjoyed watching this butterfly as much as I did! Thanks for being here with me!
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