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by Tony Gomez

4 years ago

Raising Butterflies Blog

How to Raise Eastern Black Swallowtails- Butterfly Life Cycle Photos

Raising eastern black swallowtails from tiny egg to beautiful butterfly with lots of colorful photos + helpful raising tips

4 years ago


By Tony Gomez

How To Raise Eastern Black Swallowtails through the Butterfly Life Cycle

by Tony Gomez

4 years ago

A Photo Journey Raising Eastern Black Swallowtail Butterflies

Raising the Eastern Black Swallowtail Butterfly- A Photographic Adventure from Black Swallowtail Egg to Beautiful Butterfly

When we first started the butterfly garden, I believed that eastern black swallowtails were regular visitors to our Minnesota butterfly garden. But after years of research and networking with other butterfly enthusiasts, I realized this was not the case.

A bird’s eye view of the abdomen distinguishes a true black swallowtail from its close relatives…

What's the easiest way to tell that this is NOT an eastern black swallowtail butterfly? Compare abdomens for a definitive ID...
Don’t be Tricked by a Tiger

Eastern Black Swallowtails (Papilio polyxenes) are one of the most abundant swallowtail species across North America. Click here to see if they’ve been sighted in your region?

Common host plants include common rue, curly parsley, carrot tops, golden Alexander, bronze smokey fennel, dill, celery, asparagus, and Queen Anne’s Lace.

In our garden, we’ve had the most success attracting them with fennel, but we stopped planting it because it attracted too many wasps. Wasps are beneficial pollinators, but in large numbers they can wreak havoc on the caterpillar population in your garden. Currently, we have rue and Golden Alexander.

If you’re interested in learning more about (or purchasing) black swallowtail host plants, get more info on my butterfly plants page

The Eggs

One of the pros of fennel is that it contrasts beautifully with black swallowtail eggs to make finding them easy, considering their small size…

Finding tiny black swallowtail eggs is a little easier on the dark green leaves of bronze smokey fennel. Raise black swallowtails from egg through butterfly life cycle
Glowing Needle in a Haystack

Unlike monarchs, eastern black swallowtails will often lay eggs on the tops of leaves, which can make them a little easier to find. However, they tend to blend in with their host plants.

The Caterpillars

Eastern black swallowtail caterpillars can feed on a variety of host plants, including common rue. Discover other host plants you can grow in your garden to support them...

Our most recent black swallowtails were brought in as small caterpillars. I was not expecting to find them on our golden Alexander plant, but they were easy to see against contrasting yellow blooms. So, we took stem cuttings (with caterpillars) and placed them in floral tubes.

Tube Tip: take long cuttings so that the stem goes to the bottom of your floral tubes. That way you’ll have to refill less often.

Find Floral Tubes on the Raising Resources Page

Golden Alexander is a native host plant for eastern black swallowtails. It's a superior plant for stem cuttings if you plan to raise and release them back to nature. More info here...
A Golden Opportunity

Common rue is also easy to use with floral tubes and is also a host plant for Giant Swallowtail Butterflies.

Some people have allergic reactions to rue so you may want to handle this plant with gloves.

Ruta graveolens is a host plant for two swallowtail butterfly species...giant and black. Find out more about raising eastern black swallowtails...
A Host Plant for TWO Swallowtail Species

Fennel is a top host plant for attracting eastern black swallowtails and the feathery foliage is beautiful addition to the garden landscape…

Bronze smokey fennel is a preferred host plant for black swallowtail caterpillars. The anise/licorice flavored plants and seeds are also used for seasoning sausage and certain liquors. Find seeds or plants here...

Other host plants for black swallowtails include curly parsley, dill, and carrot tops.

Monarchs go through their metamorphosis almost twice as quickly as their swallow mates. I’m often asked if they can be raised in the same enclosure. I’m not aware of any disease or in-fighting issues, but I’d suggest raising them on elevated stem cuttings to keep them separated. We also use separate mesh enclosures, but did introduce these two briefly:

is it OK to Raise Black swallowtails and Monarchs together in the same Raising Cage? This is what we do...
I’m not too sure about this parsley?!

As eastern black swallowtails grow, they also became more colorful. Many confuse monarch caterpillars with black swallowtails, but if you compare the caterpillars below, with the large monarch above, you can see the differences.

Black swallowtails become quite colorful as they grow to their larger caterpillar instars. Many confuse them with monarch caterpillars. Compare to the monarch photo on this page and you'll see the differences...
We’re Golden

Also, monarchs only eat milkweed so you’ll never seem them feasting on your dill or fennel…or zizia!

Once the caterpillars are ready for the next stage, they are kind enough to let you know in advance 💩 😉

The Chrysalides (or Chrysalises)

Before the caterpillar searches for that perfect spot to form its chrysalis, it will purge any remaining food all over the cage floor. Thankfully, we had our poo poo platter inserted on the cage floor so they purged inside that. Otherwise, it can stain the cage floor, as our eastern tiger swallowtails did multiple times in this cage:

Once a swallowtail caterpillar is finished feeding, it will purge out one final frassy mess of undigested food. Never fear, this is a normal part of swallowtail what comes next?
Explosive End

Swallowtails will attach themselves to the cage wall, cage ceiling, stick, or host plant in two places: at the base with a silk pad and with a silk girdle around the mid section of the caterpillar:

This diseased (possibly parasitized) black swallowtail caterpillar did not survive to the chrysalis stage of the butterfly life cycle. See what a healthy caterpillar looks like here...
Not Looking So Good

So it looks like we’re good to go? Not so fast…

This poor swallowtail was compromised by disease or parasites. This photo was taken several seasons ago, and the caterpillar never did form its chrysalis. We’ve never had any diseases (I’m aware of) affect swallowtails. However, we’ve had caterpillars parasitized by the Trogus Pennator Wasp. If you know what happened to the caterpillar pictured above, please post a comment a the bottom of the page…

Here’s a healthy eastern black swallowtail, to take us to the next stage of the butterfly life cycle:

Black swallowtail caterpillars spin a silk girdle which allows them to lay back to form their chrysalis. See more of their amazing butterfly life cycle...

This caterpillar formed a chrysalis directly on its golden Alexander host plant. Green chrysalides are more common during the spring and early summer. Many believe this is a defense mechanism against predators that helps them blend in with their surroundings…

Eastern black swallowtail chrysalises are often green in spring, which many believe is a defense mechanism against predators which allows them to go unnoticed against the spring background. See what emerges...

In the late summer and fall, the chrysalis colors are more likely to blend in with the tree branches that will hide them from predators over winter.

The overwintering generations of eastern black swallowtails often form brown chrysalides, which help them to blend in with the barren trees of winter. Learn more about raising and overwintering swallowtails through their life cycle...

A monarch chrysalis will hatch reliably in 7-10 days, but the swallowtail family is on a European vacation schedule. They can take 2-3 weeks, or longer if they see fit. If you’re raising toward the end of the season, they may even decide to overwinter until next spring.

The Butterflies

Before your butterfly emerges, the chrysalis will turn dark (with yellow accent spots) revealing the butterfly inside. It’s easy notice this change with a green chrysalis, but the change is more subtle when the chrysalis is formed brown.

Shortly before a black swallowtail chrysalis emerges, you will be able to see the black butterfly and its contrasting yellow markings inside. This is the same green chrysalis pictured above...

When the adult butterfly emerges, it will come out of the top of the chrysalis, and find a place to hang down to expand and dry its wings properly:

Eastern black swallowtails must hang down for their wings to dry properly after emerging from a chrysalis. This is a vulnerable part of metamorphosis, so make sure they can dry in a safe place if raising them.
Drying Off

As with monarchs, I suggest placing eastern black swallowtail butterflies outside in a closed mesh cage for a couple hours to sunergize 🌞 them. This insures they will have plenty of energy to elude potential predators upon release.

Females typically have more blue hue in their hindwings, and less prominent yellow wing markings:

The female eastern black swallowtail has less prominent yellow markings, and more blue hindwing hue than her male counterpart. Check him out here...

Males typically have less blue hue in their hindwings, and more prominent yellow wing markings:

The male eastern black swallowtail has more prominent yellow markings, and less blue hindwing hue than his female counterpart. Check her out here...

Eastern black swallowtails don’t spend as much time in the butterfly garden as some others in the swallowtail family, but zinnias and obedient plant are two plants they have favored in our northern garden over the years.

An eastern black swallowtail adds more beauty to the butterfly garden- learn how to raise them through the butterfly life cycle and release them in yours...
Black Beauty in the Butterfly Garden

Would you like to start raising eastern black swallowtails through all 4 stages of the butterfly life cycle? Click here for butterfly cages and helpful raising supplies. Happy Raising!