Raising Black Swallowtail Butterflies

If you’ve seen a Black Swallowtail in your yard, you’ll probably want to find out how to have more of them. They are gorgeous.

The male and female Black Swallowtail butterflies are very different. The males are mostly black with a lot of yellow while the females are mostly black with a lot of blue (see photo of the female I raised below). Their host plants are several plants in the parsley family, including cultivated, weedy and native species.

If you find these critters on your plants, know that they most likely Black Swallowtail caterpillars of some kind. If you need more of these herbs for yourself, just plant extra for them!

Can you spot the black caterpillar on this parsley?
Can you spot all of the eggs on this dill?

If you let them be, they will continue to grow in size until they are ready to pupate.

Can you spot the tiny black caterpillar on this fennel?
Near full grown black swallowtail caterpillar on fennel.
I’ve noticed that if you try to touch them, two orange “horns” come out as they try to fight you off.
Getting ready to pupate.

Here is one that has made it to the pupa stage. It looks very different from the Monarch butterflies chrysalis. It looks like part fo the tree or a leaf. It’s held on with a fine string.

This is the pupa form of the Black Swallowtail butterfly.
Female Black Swallowtail butterfly in Crescent, Iowa.
The empty chrysalis after the butterfly left.

I have had many, many caterpillars eating on my plants. Initially, I was trying not to interfere and let nature run its course. However, I’ve found that the caterpillars eat ALL of the dill and then most don’t make it into their chrysalis. I keep planting more and more dill but then the caterpillars disappear (too early to pupate).

I decided to purchase this butterfly enclosure on Amazon to help them. I feel like this is minimal interference with nature but at the same time protecting them from those horrible parasitic wasps and other predators.

The right side has door that swings out.
I found all of the eggs and small caterpillars on all of my plants and gathered them inside of the protective screened cage.
We found this cow skull in the woods and I put in in the enclosure to add some weight.

So while I was setting this up, a butterfly came into the patio area. At first I thought it was another Black Swallowtail…. but upon closer inspection, I knew it wasn’t. As you can imagine, I got REALLY excited, grabbed my camera and started following it around.

UPDATE: September 1, 2019

Chalcid Wasps
My experience with chalcid wasps in Eastern Black Swallowtail butterflies.

Everything was going great. I had probably 30+ swallowtail chrysalis. I thought that if they made it to the chrysalis stage, we were safe. I was feeling so great!

Then I noticed these small gnats hanging around each chrysalis. I would pick them off and shoo them away by hand. I noticed that the chrysalis (yes they move) were trying to shake them off too. After a few weeks of this went by, I realized maybe this was a real problem and dug into the internet to try to find out what these ‘gnats’ were. Everything LOOKED FINE except the gnats.

I found this great Facebook group called Simply Swallowtails where people share their experiences raising East Black Swallowtails (EBS) along with other swallowtails. They have a wide variety of resources to help people and it’s been a great place to learn through their ‘files.’ Through that site, I learned that the ‘gnats’ were actually chalcid wasps. I went through the parasitoids article one by one and figured it out, I would not have guessed they were wasps.

So basically, almost all of my chrysalis are infected. I even broke one open and sure enough it looked just like the one in the video below. I have maybe five that don’t look infected so I have brought them in to our uninsulated front porch. I’ve emptied my enclosure and just put my dill, fennel and parsley plants outside on my back patio. It’s a miracle that any of these butterflies survive at all.

The reason I was so convinced I should keep my enclosure outside is because of new articles (see Monarch Watch’s response) out about the importance of sunlight and natural light to Monarch butterflies. (Except EBS do not migrate so its irrelevant). If I do this again next year, I will bring them inside to my uninsulated front porch and NEVER bring in a chrysalis that I found outside as it was probably already infected. That is potentially what happened in my situation.

Back to the original blog before my 10/1/19 update:
After I came back inside and read through my Kaufman Field Guide to Butterflies of North America book, it is a Red-Spotted Purple. They believe it mimics the Pipevine Swallowtail, a butterfly that is distasteful to birds. It is mostly black with blue iridescence with red-orange spots near margin and hind wing base. It’s host plants are willows, cottonwoods, poplars and related trees.

Red-Spotted Purple Butterfly

So exciting! It’s not every day that I find a new kind of butterfly (new to me).

Red-Spotted Purple Butterfly

Isn’t it beautiful? Have you ever seen one in the wild?

One Comment Add yours

  1. Cathy Kennedy says:

    I have been raising ebs inside and move them to a large cage until I move them outside to release. Lots of times one of their wings break on the tip and also the tips on the hind wings will break off. Depending on how many I have to release that day, I will put several in the same cage. Am I doing something wrong or do they need to go earlier than what I release them?Sometimes because of weather, I will wait to release them.


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