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Lifecycle of the Painted Lady Vanessa cardui butterfly

Life-cycle of the Painted Lady

The life of a Vanessa cardui begins when the female oviposits (lays an egg) onto the host plant. Eggs are laid, usually, singularly on the tops of the host plant leaves. Now, keep in mind that there can be a mama who might lay an egg, one on top of another, for some odd reason! OR, she might lay clusters of eggs on a leaf instead of one egg per leaf. Just like people, each butterfly is unique…


Eggs are a light green colour and somewhat barrel-shaped. They have horizontal lines that go from tip to bottom. The Painted Lady egg often reminds me of a light-coloured watermelon.

In about four days or so, a little caterpillar will hatch from this green egg. After it has emerged, it will turn around and go back to eat the chorion or outer eggshell. This provides the larva's first meal of protein. It will then go on to begin feasting on the leaf upon which the egg had been laid.


1st instar Painted Ladies are extremely tiny; in fact, they look an awful lot like little ants! For those who are raising these little ones for the first time, be wary as these little ones are super fast and can quickly escape if you aren't on YOUR toes!


It isn't long before their bristles become noticeable. That big black head has shrunken a bit now, and is more proportional to the rest of its body. Note this little 2nd instar as it hangs onto the side of the paintbrush…it has the beginnings of little bristles.


Here is a topview as it is walking aross the top of a Malva sylvestri (Cheeseweed) leaf. Watch for the the change in the little white 'dots' at the base of some of the bristles in the next instar…With each successive molt (shedding of its skin as it grows larger and is unable to fit into its body), larval features are distinctly different. By the end of the two-week larval period, the changes are amazing!


In these next two pictures, you can see how much more bristley the caterpillar has become. This is the 3rd instar. Note the white bristles in this particular instar. This wasn't a feature in earlier instars. Remember those little white dots from the 2nd instar?


The drastic changes are obvious as we near the end of the larval stage. There is a distinct thickening; a lot of food has been consumed!

The 4th instar is very bristley. There is a white stripe along its side and you can clearly see the spiracles. The spiracles appear as little spots on the caterpillar's sides and are part of its respiratory or breathing system. It may be easier to see them in the pre-pupal picture below.


Soon, the larva will be ready to pupate. As do most brush-foot butterflies, the Painted Lady is one that will find a spot usually a distance away from its host plant, upon which to pupate (so as to deter predators, more than likely).

A silken button will be made and the caterpillar will suspend from its last prolegs in a 'j' position with its head hanging downward. It can take upwards of 24-hours for this final larval molt. You will probably find a little black blob either attached to the chrysalis or on the ground nearby. This is the remaining exuvia…the final 'molt' from the caterpillar stage. It will include the head capsule of the caterpillar. It is rather cool to look at under a magnifying lens!

The chrysalis or pupa (NOT a cocoon!) is a non-descript brownish or tan colour with gold flecks. Close inspection and you can spot the spiracles and other features of the soon-to-be butterfly.

OH, you should be forewarned that the pupa of the Vanessa cardui does have a rather unique characteristic that is not to frighten you. It is intended to scare PREDATORS but is often a shock the first time it is observed. When you least expect it, the pupa may start doing a very strange rapid jiggly dance. I mean, a quick and fast rat-a-tat-tat that will make you wonder if it is going to fall from its perch! Don't worry…it won't fall.


In about ten days' time, the pupa will begin to change colour and soon, a lovely Vanessa cardui butterfly will eclose. It will take about an hour for the butterfly to fully expand its wings. The wings also will require the time to 'harden.' Think of it as laundry that has been in the washing machine…it needs to be dried on a line outdoors in the breeze.

An orange-red liquid will often be found either in the exuvia (chrysalis 'shell') or on the ground. This is called meconium and is the waste material from the pupa. It is NOT blood as butterflies do not have blood; they have what is called hemolymph.

During the time the wings are drying, the proboscis (tongue tubes) will uncoil and recoil, as the imago (adult butterfly) readies itself to go out into the world to begin its 2-week or so life to procreate.


2010 Learn about Painted Lady butterflies

Sherry Skipper Spurgeon

2010 Learn about Painted Ladies
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