Life of a Pale Swallowtail Caterpillar

Newley Emerged Pale Swallowtail Caterpillar

Newley Emerged Pale Swallowtail Caterpillar

This post is a follow-up to two earlier posts I wrote titled “Pale Swallowtail Butterfly Eggs” and “Butterfly Egg Hatches“.

The life of a pale swallowtail caterpillar is not only rare to experience, but extremely slow and methodical compared to other caterpillars I’ve raised.

The tiny pale swallowtail caterpillar hatches from it’s egg in only 4 days, spending most of it’s first day eating it’s own egg shell before setting out to explore it’s new surroundings.

If you’ve read my previous posts, you know the egg was mistakenly laid on a common fruit bearing peach tree in my neighbors back yard (peach trees are not considered to be a host plant for the pale swallowtails, although peach trees are in the prunus family).

Pale Swallowtail Caterpillar 2nd instar

Pale Swallowtail Caterpillar 2nd instar

I had offered the newly hatched pale swallowtail caterpillar a smorgasbord of host plants to eat.  Finally settling on the coffeberry (Rhamnus californica), taking only a small bite on the edge of the leaf, then returning to the center of the leaf to rest for the remainder of the day.

After watching the pale swallowtail for a couple of weeks now, I’ve started to realize there is a mythological pattern in it’s behavior.  First of all, this is a very long time for a caterpillar to still be a caterpillar and the time it takes to molt (intsar) is much slower than other caterpillars I’ve raised. I have rarely seen my pale caterpillar move, let alone eat.  I check on it first thing in the morning, noticing that the coffeeberry has been munched upon and frass (caterpillar droppings) are in the bottom of the container, but the caterpillar is in the exact same position as the day before.  I’ve realized the actions of my pale swallowtail caterpillar are all done privately, in the middle of the night.

Pale Swallowtail Caterpillar 5th Instar

Pale Swallowtail Caterpillar 5th Instar

The larger and more mobile a caterpillar becomes, the more visible and tempting it is to potential predators. Newly interested parties including birds, lizards and spiders are among the large list of dangers a caterpillar can face. Such luxuries as claws, beaks and venom are not at a caterpillar’s disposal. Nor can a caterpillar scamper, hop or fly away quickly from a perilous situation. Fortunately, however, over time these amazing creatures have adopted and learned to survive despite the incredible challenges they face each day.” Excerpt from Butterfly Dimension by Kristen D’Angelo.

Day after day, moving slowly, molting, pooping and eating only at night, he grows. My methodical pale swallowtail caterpillar is in it’s 5th instar, almost ready to pupate into a chrysalis.  I’ll keep you posted.  ~ Vickie

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3 Responses to Life of a Pale Swallowtail Caterpillar
  1. […] life stages of the Pale Swallowtail caterpillar are shown here, and for the Anise Swallowtail here. Caterpillars can have quite different appearances, as they […]

  2. Mandy
    November 21, 2009 | 8:48 am

    Wow, this butterfly blog is wonderful and is another great website to visit. Thanks!

  3. Glenn Richardson
    August 10, 2009 | 5:49 pm


    This is behaviour is typical of other single brooded swallowtails. For example the Canadian Tiger Swallowtail caterpillar behaves similarly and takes almost the entire summer to develop.

    Canadian Tigers fly in Listowel in early June…then about a month later the Eastern Tiger Swallowtail flys in July. We are about on the edge of the range of each butterfly in here…

    If you drive 160 miles south to Pelee Island (which is much closer to Ohio than the rest of Ontario) there are at least two broods of the Eastern Tiger Swallowtail and sometimes there are three broods.

    OR… If you drive 70 miles noth to Port Elgin and the Bruce Peninsula, then the Canadian Tiger Swallowtail is common (flying in late May-June) but there are no Eastern Tigers at all.


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