CATERPILLAR STAGE

This page shows photos and videos taken of Monarch caterpillars raised inside, and of some found outside in the garden.
Sometimes caterpillars will gnaw at the base of a flower stem in order to partially detach it from the stem, and leaving it there hanging down, as if this would make it easier for them to eat the flowers.
Caterpillars go through five stages of growth or instars, and each time they shed their skin for a bigger one and eat the molt for its nutrients.
When they are ready to turn into a chrysalis, they stop eating and search for a suitable location to pupate, sheltered from predators and the weather.
They then weave a silk pad to hang from. As opposed to spiders that secrete their silk thread from the tip of their abdomen, caterpillars secrete their silk thread from their mouth.

FEEDING
MOULTING
SEARCHING A SUITABLE SPOT TO PUPATE
THE ‘J’ PHASE
TOO CLOSE FOR COMFORT
COLOR VARIATIONS

FEEDING

Monarch caterpillar eating milkweed fruit envelope - Aug. 16, 2018 - © Denise Motard
Monarch caterpillar eating milkweed fruit envelope – Aug. 16, 2018 – © Denise Motard
4 Monarch caterpillars on different parts of Swamp milkweed - Aug. 18, 2018 - © Denise Motard
4 Monarch caterpillars on different parts of Swamp milkweed – Aug. 18, 2018 – © Denise Motard
Monarch caterpillar munching on Swamp milkweed pod - Aug. 16, 2018 - © Denise Motard
Monarch caterpillar munching on Swamp milkweed pod – Aug. 16, 2018 – © Denise Motard
Monarch caterpillar munching on one side of a Swamp Milkweed leaf - Aug. 16, 2018 - © Denise Motard
Monarch caterpillar munching on one side of a Swamp Milkweed leaf – Aug. 16, 2018 – © Denise Motard
Monarch caterpillar on a Swamp milkweed stem - Aug. 15, 2018 - © Denise Motard
Monarch caterpillar on a Swamp milkweed stem – Aug. 15, 2018 – © Denise Motard
Two Monarch caterpillars on a Swamp milkweed flower stem - July 31, 2018 - © Denise Motard
Two Monarch caterpillars on a Swamp milkweed flower stem – July 31, 2018 – © Denise Motard

Monarch caterpillars will readily feed on immature seed pods:

MOULTING

This Monarch caterpillar just moulted - Aug. 18, 2018 - © Denise Motard
This Monarch caterpillar just moulted – Aug. 18, 2018 – © Denise Motard
This newly moulted Monarch caterpillars has funny-looking leg and head colors - Aug. 18, 2018 - © Denise Motard
This newly moulted Monarch caterpillars has funny-looking leg and head colors – Aug. 18, 2018 – © Denise Motard
The Monarch caterpillar is now eating its moult - Aug. 18, 2018 - © Denise Motard
The Monarch caterpillar is now eating its moult – Aug. 18, 2018 – © Denise Motard

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SEARCHING FOR A SUITABLE SPOT TO PUPATE

I had two particularly ‘restless’ or fussy caterpillars (nos. 14 and 15 out of 17 raised) that kept crawling for hours before finally settling on a screen I had to arrange especially for them. (I was starting to get concerned they were wasting energy for nothing.)
The caterpillar below on the Swamp milkweed stems, then on the fern leaf, was seemingly unable to find a suitable spot, so I decided to move it into a nearby lilac, where it quickly turned into the ‘J’ phase (see further below).
EXTENDING THEIR BODIES: When exploring around for a suitable spot to pupate, Monarch caterpillars can extend their bodies without support quite a bit (see below photo and video).

This Monarch caterpillar ended up in window frame corner to pupate - Aug. 2, 2018 - © Denise Motard
This Monarch caterpillar ended up in window frame corner to pupate – Aug. 2, 2018 – © Denise Motard
These 2 caterpillars started weaving their silk pad - Aug. 22, 2018 - © Denise Motard
These 2 caterpillars started weaving their silk pad – Aug. 22, 2018 – © Denise Motard
This Monarch caterpillar is crawling down Swamp milkweed in search of a location to pupate - Aug. 1, 2018 - © Denise Motard
This Monarch caterpillar is crawling down Swamp milkweed in search of a location to pupate – Aug. 1, 2018 – © Denise Motard
Their silk pads are now visible - Aug. 22, 2018 - © Denise Motard
Their silk pads are now visible – Aug. 22, 2018 – © Denise Motard
The same caterpillar is now crawling on ferns under the Swamp milkweed - Aug. 2, 2018 - © Denise Motard
The same caterpillar is now crawling on ferns under the Swamp milkweed – Aug. 2, 2018 – © Denise Motard
Monarch caterpillar searching a spot to pupate - Aug. 22, 2018 - © Denise Motard
Monarch caterpillar searching a spot to pupate – Aug. 22, 2018 – © Denise Motard

The seemingly endless search for a suitable spot to pupate:

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THE ‘J’ PHASE

When the silk pad is ready, the caterpillar attaches itself to it from it last proleg pair, and slowly lets go of its 4 other pairs of prolegs, one by one.
It then hangs head down in a ‘J’ shape, a stage which lasts around 10-12 hours before it turns into a chrysalis.

These two caterpillars are in the 'pre' J phase - © Denise Motard
These two caterpillars are in the ‘pre’ J phase and are starting to let go of their prolegs – © Denise Motard
Monarch caterpillar now in lilac in 'J' phase - Aug. 2, 2018 - © Denise Motard
Monarch caterpillar now in lilac in ‘J’ phase – Aug. 2, 2018 – © Denise Motard
Caterpillar has let go 2 pairs of pro-legs - July 30, 2018 - © Denise Motard
Caterpillar has let go 2 pairs of pro-legs – July 30, 2018 – © Denise Motard
Monarch caterpillars nos. 14 and 15 FINALLY into 'J'phase - Aug. 23, 2018 - © Denise Motard
Monarch caterpillars nos. 14 and 15 FINALLY into ‘J’phase – Aug. 23, 2018 – © Denise Motard
The caterpillar has now reached the 'J' phase - July 30, 2018 - © Denise Motard
The caterpillar has now reached the ‘J’ phase – July 30, 2018 – © Denise Motard

This video (a bit blurry, sorry) captured the moment the caterpillar lets go of its last pair of prolegs to get into the ‘J’ position.

Here’s why it’s crucial for the Monarch caterpillar to attach itself securely to its silk pad:

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TOO CLOSE FOR COMFORT

Monarch caterpillars don’t appreciate being touched by another caterpillar, and will lunge at them. Yet they don’t show that reaction when we handle them.

The lower Monarch caterpillar just lunged at the caterpillar above - July 31, 2018 - © Denise Motard
The lower Monarch caterpillar just lunged at the caterpillar above – July 31, 2018 – © Denise Motard

Here’s another video of an ‘altercation’ between Monarch caterpillars:

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COLOR VARIATIONS

Not all Monarch caterpillars are created equal in terms of color, as can be seen below. Some have more prominent black stripes and for others it’s the other way around, more prominent white stripes.

Monarch caterpillar with more black stripes
Monarch caterpillar with more black stripes
Monarch caterpillar with more white stripes
Monarch caterpillar with more white stripes

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