1st stage 2nd stage

Here are a pair of Monarchs mating. It is beautiful to see a pairing such as this in nature. Monarch matings are not brutal like some butterflies. The males will take the female down and then often fly up into a tree. The butterflies remain mated for a number of hours before the female will go off to oviposit the fertilized eggs onto the Milkweed leaves.

4th stage: the adult butterfly (imago)

Learn how to identify the gender of your Monarch next!

Life-cycle of the Monarch

The Monarch has a 4-stage life-cycle: ova, larva, pupa, and imago. The egg (ova) is laid usually on the underside of a leaf of an Asclepias plant (Milkweed family or in Hawaii, the Crownflower aka Calotropis gigantea). After about four days, the cream-coloured egg begins to darken and the dark spot is the head of the caterpillar (larva) is ready to hatch.

The following pictures show a hatchling as it emerges from the shell.


The 1st instar is somewhat beige and has a large black-ish head. Note the lack of colour in the caterpillar.

After hatching, the 1st instar Monarch will turn around and eat its eggshell. The chorion (outer shell) provides the first meal for the larva which will then go on to begin eating the fine hairs on the underside of the Asclepias leaf before it begins eating in a circular pattern.

So, if you spot small circular 'chew marks' on a Milkweed leaf, flip the leaf over and see if you find yourself a 1st instar Monarch baby.

The 1st instar is a short stage and soon, the hatchling will molt and you will begin to recognize the colours of what we think of as a Monarch caterpillar.


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1st instar

• 2–6 mm long
• beige colour
• big head

2nd instar

• 6–9 mm long
• obvious rear filament knobs
• two yellow stripes on the head

3rd instar

• 10–14 mm long
• eat leaves by 'cutting'
• yellow triangle on head is larger

4th instar

• 13–25 mm long
• white spots are visible on the prolegs

5th instar

• 25–45 mm long
• eat through the petiole of the leaf so the leaf hangs like it's broken
• body is plump and fat
• eats about one leaf per hour
• will take off to look for a place to pupate and will probably wander far away from the Milkweed

Pupa (3rd stage in the Life-cycle)

• can take time to form
• begins by larva making a silken button and hangs by the last proleg in a J-position
• final molt will include the head capsule 'popping' off
• until the chrysalis is hardened, the pupa is vulnerable
• is often well-camouflaged

The larval stage is roughly two weeks long and can vary depending upon temperature and quantity of available food. If it is warm, it is possible for the caterpillar to eat and advance more quickly to the pupating stage and if it is cooler outside, it can take longer. If less food is available, caterpillars may pupate earlier and the pupa may be smaller than normal, with the resulting butterfly a much smaller butterfly.

The 3rd stage, pupa, takes about two weeks. During this time, the butterfly continues to undergo metamorphosis. Metamorphosis begins during the larval stage and will be complete during the pupal stage. As the butterfly gets ready to eclose (emerge), you will begin to see signs of the wings through the casing of the chrysalis (hard shell of the pupa).

The 4th and final stage is the imago or adult butterfly. Since the Monarch is a fairly large butterfly, when it ecloses, it takes a bit longer for it to pump up its wings and for the wings to harden. Any orange-ish liquid that you may see dripping is called meconium and is the waste material that has accumulated during the pupal stage. It is not blood but can stain so be aware of this! (If it gets on any cloth or clothing, the use of an organic soap or detergent will easily remove the stain. Clorox Greenworks dishwashing liquid or laundry detergent will work as will any organic coconut-oil based soap.) Permit the butterfly at least four hours for its wings to harden.

Generally, the adult will eclose by 11 a.m. If the outdoor temperature is around 70-degrees, it is fine to release your butterfly. Because Monarchs are a large butterfly, it takes approximately four hours or so for their wings to dry. If you raise them, please give them plenty of time for their wings to dry before releasing them into the environment.

Monarchs are cold-blooded and as such, require warmth to help them fly. Please do not release Monarchs when it is raining. You can always keep a Monarch indoors for a few days by feeding it slices of watermelon or provide it with cut nectar flowers. Be sure your container is large enough for the butterfly to fly/flutter about. If you do not have access to fresh watermelon, the purple Juicy-Juice drink or even clear Gatorade will work. Pour some into a shallow bowl and then place a clean plastic kitchen scrubby on top. This will give the butterfly something to climb on top of and will also keep the butterfly from drowning.

For those of you who wonder when a Monarch is 'ready' to begin the reproduction process, the female is usually ready about three days after eclosing (coming out of the chrysalis).