Saturday, August 23, 2014

The Life of a Black Swallowtail Caterpillar--updated

On July 31, I watered my parsley plant and noticed this small caterpillar wiggling when the water splashed on him...

Black Swallowtail Caterpillar          July 31, 2014

I missed a lot of instars (earlier caterpillars) before I saw him--some naturalist I am! 

July 31, 2014

This is a close up view where you  see the water drops from my watering can.  He looked like he hadn't eaten much of my parsley thankfully.

 Black Swallowtail Caterpillar          August 6, 2014

The caterpillar grew big and fat as he quickly ate the parsley.  I noticed he would eat voraciously and then rest for awhile.  I wished he would eat the outer leaves since it would not have been so noticeable.  I hoped he would not eat all of it since I only planed this one pot of parsley.  Yet, there was no way I would get rid of this fascinating caterpillar.

August 10, 2014 
On August 10, the caterpillar got into this position I had not seen before.

This close-up shows how he attached himself to the stem.  Then I knew he was going into a pupa.   I checked on him a lot that day and the next.

August 12, 2014

He finished making his pupa on August 12.  Maybe he had done it overnight I am not sure but I missed the process.   I saw that he had only eaten about 3 or 4 parsley strands so there is plenty left for my cooking.

August 17

I am amazed that the pupa has survived the many rainstorms with just that single strand of silk holding it. It appears to be smaller than the diameter of fishing line.

Today is August 23 and the pupa looks pretty much the same.  I worry that a bird might get him or that strand might finally break.    I am awaiting the birth of a black swallowtail butterfly and am afraid I won't be there to see it.   The life of a naturalist is sometimes fraught with worry! 

I am going to make a note in my gardener's journal to plant lots of parsley next year.  I may plant with native flowers so the newly hatched butterflies will not have to go far for nectar. 

UPDATE:  The pupa turned brown.  I had heard from a biology professor on Facebook that the pupa might overwinter so I put under chicken wire (hardware cloth) to protect against birds and the weather.  Today (Sept. 4) I noticed a distinct change in the pupa.  I thought the butterfly had emerged since the pupa looked empty but it is translucent and no opening noted.  I think the butter fly will emerge soon!


  1. What fun! Great photos, too. Can't wait to see the adult ... i have faith in your naturalistic talents.

  2. I have been raising Monarchs and Queens in a Butterfly House on my porch. I now have Gulf Fritillariys in it also. Guess I'm not the only one who is fascinated with caterpillars. The pupating process is always amazing.

  3. I do hope you get to witness it when it happens!

  4. Awesome work.Just wanted to drop a comment and say I am new to your blog and really like what I am reading.Thanks for the share

  5. so ... what happened? we found these same caterpillars today on our parsley.

  6. Denise G--I have one also on my parsley. Last year, I didn't see when the butterfly emerged but it did. This year, I cut some parsley to cook and noticed a very small caterpillar, no more than 1/4" and black. I cut the sprig and then put it back on the plant. It is now doubled in size and clearly a black swallowtail. I will try to trust some photos.