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Green Swallowtail Caterpillars to Black and Yellow Butterflies

The Two-tailed Swallowtail Butterfly (Papilio multicaudata)

The Butterfly

The Butterfly

Can you tell a male from a female Swallowtail butterly?

Male Two-tailed Swallowtail

Male Two-tailed Swallowtail

Female two-tailed Swallowtail

Female two-tailed Swallowtail

How to tell a male from a female Swallowtail Butterfly

  • The blue spots on the hind wings are more prominent on the female.
  • The black stripes on the fore-wing on the male are shorter.
  • The abdomen of the female is fuller looking than on the male.
  • Male butterflies "puddle" which means they like to drink from puddles because they need the minerals in the muddy water. You may see them doing this in groups.
  • Females have an ovipositor (straight tube) and the end of the abdomen, males have a clasper (looks like pinchers.) These are nearly impossible for me to distinguish but perhaps you have better eyes than me.

A Yellow and Black Butterfly

Last June, my little boy found a beautiful yellow butterfly with black stripes and blue spots on the hind wings; it was just laying in the grass. Something was wrong with its wings, they were crumpled and wrinkly; the butterfly could not fly. I thought perhaps it had just emerged from its chrysalis and just needed time to let its wings dry, so we brought it in the house and set it on a flowering plant.

Sadly, the butterfly's wings did not improve with time; she still could not fly. So we decided to keep it, which turned out to be a really interesting and rewarding experience for us both.

The first thing we needed to do was find out what kind of butterfly we had. By looking through books and searching the Internet, we discovered what we had was a female Swallowtail Butterfly. More specifically, she was a Two-tailed Swallowtail (Papilio multicaudata.) There are many types of Swallowtail butterflies in Montana including the Western, Pale, Canadian and Two-tailed.

The Butterfly We Named Mary

My son named our little female butterfly "Mary." We could tell she was female because of the markings on her wings and because she had a swollen abdomen, presumably with eggs. Of course, it was her two tails (per wing) which tipped us off to the "Two-tailed" part of her identity.

What do Swallowtail Butterflies Eat?

Now that we knew what kind of butterfly we had, we started to research what she would need for food. We found lists of flowers that Swallowtail butterflies are supposed to like, including geraniums, lilacs, butterfly weed and thistle but Mary seemed uninterested in them all. We started to worry that she would not eat because she was sick, injured or dying.

My son had the idea to just try any wild flower that was currently in bloom. This made sense, why didn't I think of that? It turned out that Mary loved plain old dandelions.

It was fun to watch Mary flutter her wings excitedly when fresh dandelions drew near. Then she would extend her long proboscis, a tongue-like mouth part, to probe around the flower until she located the sweet nectar. You could actually see her abdomen grow fatter as she sipped.

Swallowtail Butterfly Eggs

Butterfly Eggs and Caterpillar Host Plants

The next thing we discovered in our research phase was that females will lay eggs singly on the leaves of the caterpillar host-trees, in this case: chokecherry, bitter-cherry, black cherry, aspen and willow. We did not know if Mary would have mated, but we decided to give her a chokecherry tree branch and see what would happen.

We cut a small but leafy branch and put the cut end into a water bottle. (Using a heavy glass or ceramic bottle helps keep it from tipping.) Then we wrapped a little plastic wrap around the bottle opening to keep any future hatchlings from going down into the water and drowning. We were able to fit the whole thing into a pop-up butterfly enclosure that we already had. (An aquarium or any other enclosed container works as long as there is some access to fresh air.)

To our great delight, within a few days we found seven perfectly spherical, bright green, tiny eggs, each at the base of a separate leaf. They gradually turned brown as they got closer to hatching.


Lifespan of the Adult Swallowtail Butterfly

For the next several weeks, we continued to care for Mary. We brought fresh flowers daily and took her outside to get fresh air. My kids loved to let her walk up and down their arms and crawl on the window screens. She seemed to like it too.

We did our best to take good care of our new pet, but Mary was aging quickly. Her wings became tattered and frayed from frequent, somewhat frantic, attempts to fly. The beautiful striped fuzz that covered her body was wearing off, leaving the shiny black exoskeleton exposed. We read that the adult Two-tailed Swallowtail butterfly's lifespan is 4-6 short weeks.

The 5 stages of the Swallowtail butterfly caterpillar (click on a photo to enlarge)

First instar: this caterpillar is only centimeters long.  It has a white bird-like pattern across the back.

First instar: this caterpillar is only centimeters long. It has a white bird-like pattern across the back.

Second instar: the green is getting brighter and the eye-spots are starting to appear.  The white bird-pattern is still prevalent.

Second instar: the green is getting brighter and the eye-spots are starting to appear. The white bird-pattern is still prevalent.

Third instar: the white bird-pattern is gone.  The caterpillar is over an inch long at this point.  This photo shows the leaf nest in which the caterpillar hides.

Third instar: the white bird-pattern is gone. The caterpillar is over an inch long at this point. This photo shows the leaf nest in which the caterpillar hides.

Fourth instar: now they are getting big, two inches or longer.  They have a black stripe under the eye-spots which are on the "shoulders."

Fourth instar: now they are getting big, two inches or longer. They have a black stripe under the eye-spots which are on the "shoulders."

Fifth instar: at the end of the fifth instar the caterpillars turn brown.  They will become active as they search for a suitable place to pupate.

Fifth instar: at the end of the fifth instar the caterpillars turn brown. They will become active as they search for a suitable place to pupate.

Swallowtail Butterfly Caterpillars

Meanwhile, we waited for Mary's eggs to hatch. After about two weeks, we discovered one minute caterpillar on a leaf. This caterpillar was just a few centimeters long; it was brownish-green with a white bird like pattern across the back. Soon the other six hatched as well. The caterpillars' first meal was the shell of their own eggs, then they started eating the leaves.

The caterpillars made a shelter by folding the leaves in half and securing them with webbing. They grew very quickly, every few days shedding their outer skins (or molting.) Each phase between moltings is called an "instar." Two-tailed Swallowtail caterpillars had five instars. With each instar, came big changes in their appearance. They changed from brownish-green to bright green. The white bird pattern disappeared and was replaced with yellow and blue "eye-spots." They had one thick black stripe about one-third of the way down their body. Gradually, they began to resemble small green snakes, especially when they extended a special gland called an "osmateria." The caterpillar extends the osmateria from just above the head when it is threatened. It looks like the forked tongue of a snake and gives off a strange odor.

I tried to get a photo of our caterpillars extending their osmateria, but apparently they did not find us to be very threatening. They just kept eating and would not get ruffled by us at all. I even tried tickling them with the soft bristles of a watercolor paintbrush, but they seemed to like it. However, you can see a great example of what I mean by following this link:

By the time they were a week old, Mary's caterpillars could eat a leaf a day. We made sure they had plenty of fresh leaves by replacing the whole branch when it became necessary. Also, we had to clean the frass (poo) out of the habitat every other day. Otherwise the caterpillars could become ill.

Some types of caterpillars will fight with each other, but Two-tailed Swallowtail caterpillars don't seem mind each other's company. We had no problems with keeping them together their entire caterpillar-hood. (I wish I could say the same for my kids.)

They grew to be at least two inches long (some where a little bigger than others.) After two weeks, they reached full maturity. Finally, one of the caterpillars turned brown, became active, and was uninterested in food. This meant it would soon pupate.

One life ends but others have just begun...

Sadly, Mary did not live to see her children become adolescents. Such is the life of an insect. Mary died one day in mid-July. She did not have the strength to hold herself onto her favorite little perch on the flowering plant. She fell in a spiral flutter, like a leaf to the ground. The kids gently picked her up and tried to prop her back onto the plant, but her little legs curled under her and she lay still. We loved having her with us during her short life and took comfort in knowing that we could care for her little brood.

Update: I came across this fascinating and informative video:

Did you know you can fix a butterfly's wing?

The Caterpillars Pupate

Soon all of the caterpillars were brown and active. They went round and round inside the pop-up net. If you looked closely, you could see a line pulsing down the entire length of the caterpillars' backs. Eventually they each decided on a location; some chose the chokecherry branches, others chose the side of the net.

Swallowtail caterpillars do not hang upside-down as other butterfly caterpillars do. Instead, they attach a "girdle" or a thread of silk around themselves so that they hang sideways.

Swallowtail Butterfly Pre-pupae and Pupae

You can see the girdle about 1/3rd of the way down the caterpillar.  This thread holds the caterpillar parallel to the branch.

You can see the girdle about 1/3rd of the way down the caterpillar. This thread holds the caterpillar parallel to the branch.

After the pre-pupa has transformed into the chrysalis, the girdle can still be seen.

After the pre-pupa has transformed into the chrysalis, the girdle can still be seen.

How to Overwinter Butterfly Pupae

In this part of the world (Montana) the Two-tailed Swallowtail butterflies only have one brood per year and they overwinter in the pupal stage. This meant that we had to wait nearly 10 months for the adult butterflies to emerge or "eclose." We had to keep the chrysalides somewhere cold so that they would emerge at the same time as others of their species. It seemed like keeping them outside would work, but exposure to direct sun could kill them and we did not want them to blow away or be buried under 10 feet of snow.

Another option was to keep them in the refrigerator but they would need a continual humidity source or they would dry out and die. You can keep them in the refrigerator if you place them in a plastic container with a lid. Then keep a bottle of water with a cotton wick in the plastic container as well. You must check it regularly to ensure that the wick is still wet enough to be releasing moisture into the container.

Instead, we decided on the garage. Our garage is not heated and provides shelter from sun, wind, and snow. I hung the butterfly habitat on the wall near the door so that we would see it everyday. That way, we wouldn't forget about our little pupae. The only trick with using the garage was knowing when to move them back into the house (or to a safe spot outside) in the spring. The garage would not get warm enough to trigger them to eclose, but bringing them in too early or too late would mean that they would miss any chance to mate with their kind.

We looked to the dandelions to tell us when it was time. Knowing that dandelions were Mary's preferred food, we did our best to time the eclosure with the blooming of these flowers. We brought them into the house when the dandelions where close to blooming. Once inside, it took exactly 10 days for the adult butterflies to emerge.

Letting Go...

Because the adult Swallowtail has such a short lifespan, it is important to release them right away. After waiting for 10 months to see these beauties, it was not easy to let them go, but let them go we did. Here are some tips for releasing butterflies:

  • Release butterflies in the morning and moths in the evening.
  • Do not release butterflies into a rain shower, they need time to find shelter before it rains.
  • If you release them near their host plant, they may stick around for a while, that way you can observe them a bit more.
  • Let them crawl onto your hands and then release them by hand. This is especially fun for kids.
  • Release them the right time of year for that species.
  • Remember, it's OK to cry. Heehee..

Butterfly Wings

This is Mary, a beautiful Swallowtail butterfly with a crippled left hind-wing.

This is Mary, a beautiful Swallowtail butterfly with a crippled left hind-wing.

I welcome Comments and Questions.

Mrs. Menagerie (author) from The Zoo on July 29, 2015:

Hi Kales, we love animals and bugs too! Thank for leaving you kind comments!

Kales on July 28, 2015:

Loved the story! We are from canada and where IN Montana for Evel Kinevel days, and while walking I seen a catipillar in its 5th stage in the rocks. We had never seen anything like it. After A LOT of photos I put him back in a bush. I LOVE ANIMALS AND BUGS. You never hear of a 13 year old that loves bugs but I do. I am watching my pet grasshopper as I write this. Thank you for writing such a informational hub.

Steve Andrews from Tenerife on December 19, 2014:

This is one of the best hubs I have read! Well done on helping Mary too!

Pharme534 on August 21, 2012:

Hello! ffdbcae interesting ffdbcae site! I'm really like it! Very, very ffdbcae good!

illillcinueda on August 19, 2012:

illillcinueda on August 14, 2012:

Brandon Lobo on March 23, 2012:

Oh another butterfly hub, Great :) I used to keep caterpillars and watch them turn into butterflies. I remember they used to take 12 days from the cocoon stage to become a butterfly (The species that I used to have).

Sheila Brown from Southern Oklahoma on March 23, 2012:

This is a wonderful hub! I enjoyed the entire story from beginning to the sad ending. How wonderful that you and your children shared the life of your butterfly, Mary. Voted up and awesome and sharing! Wonderful job! Have a great day! :)

Mrs. Menagerie (author) from The Zoo on July 12, 2011:

Oh Laura, I totally understand. (I'm glad I'm not the only one who gets emotional about these things.) Don't beat yourself up...your choice was made with heart.

I read recently that the crumpled wing thing is caused by a bacteria. I think that was on the "live Monarch Foundation" website.

Laura McClellan on July 12, 2011:

That is a great story. I am so sad since I started to raise one and had two failed attempts at the caterpillar stage to finally have one emerge but with crumpled wings on Friday. I tried to put him on some plants in case they would straighten out but it was windy and he was being tossed everywhere. I brought him back to my balcony, not ever thinking he could live with me indoors and hysterically I looked on-line and the first many things I found was that he had no future and it would be humane to euthanize. Unfortunately being so upset that he would not get to live out his destiny and might be in pain from the falls, that is what I did. I have been heart broken ever since. Now more than ever because I would have gladly taken him in as an indoor butterfly. I pray he had a happy first half and that he is flying freely on the other side.

Mrs. Menagerie (author) from The Zoo on July 11, 2011:

Thanks Craftdrawer, I love learning about butterflies too!

craftdrawer on July 08, 2011:

Great hub! I always enjoy learning something when I read and butterflies are one topic that catches my interest. This is very informative!

Mrs. Menagerie (author) from The Zoo on July 08, 2011:

Thank you carolinemoon! Now we are raising some tiny Azure butterflies. We love butterflies!!!

carolinemoon on July 08, 2011:

Awesome hub! It is very informative and well-written. Nice post.

Mrs. Menagerie (author) from The Zoo on June 18, 2011:

Why, thank you rorshak sobchak!

rorshak sobchak on June 17, 2011:

Great hub Mrs. Menagerie. Very insightful and full of detail. Great job!

Mrs. Menagerie (author) from The Zoo on June 17, 2011:

I checked out your hub and you're right, they do look similar! Great hub btw, and thanks!

Charlotte B Plum on June 16, 2011:

Hey Mrs Menagerie!

I loved this hub! Especially loved the photographs of the caterpillars. I wrote a hub about keeping caterpillars too, and like you, i tried to put in photographs - it's amazing that the lime butterfly caterpillar looks so similar to your swallowtail caterpillars!


Mrs. Menagerie (author) from The Zoo on June 12, 2011:

Hello Butterfly Girl...the "red stuff" is just waste material from the pupal stage. It is actually called meconium. It is not blood and is totally normal.

butterfly girl on June 08, 2011:

I have a question what is the redstuff that came out of the butterfly when it hached

Mrs. Menagerie (author) from The Zoo on June 06, 2011:

Thank you RTalloni and thanks for the vote!

RTalloni on June 05, 2011:

What a wonderful journey you had with your son. Good job of journaling it on HP. Thanks so much for sharing with us! Voted up!

Mrs. Menagerie (author) from The Zoo on May 26, 2011:

Thanks so much Denise ...it was a real learning experience!

Denise Handlon from North Carolina on May 23, 2011:

What a phenomenon experience for you and your son. And, what a wonderful recording with photos and information of the events that you share here on Hubpages. Thanks for the superb write up.

Mrs. Menagerie (author) from The Zoo on May 23, 2011:

Hi Kashmir! Great to hear from you again and thank you for the votes!

Thomas Silvia from Massachusetts on May 23, 2011:

Hi Mrs. Menagerie, WOW what a very interesting and fascinating hub ! I really love butterflies they are so beautiful !

Awesome and vote up !!!

Mrs. Menagerie (author) from The Zoo on May 23, 2011:

Hahaha, rescued with a pizza peel. I love it. I like bats too, people seem to find them creepy but I think they are fascinating.

Stephanie Bradberry from New Jersey on May 22, 2011:

Mrs. Menagerie, another great hub (voted up). I thought it was useful and beautiful. Like Susan, I had no clue you could repair butterfly wings. The closest I have come to helping wildlife in my yard is a bird that knocked itself out on my screened in back porch, unless you count the catch and release of a bat from my house using a pizza peel and garbage can.

DoItForHer on May 22, 2011:

I bet your kids will remember this better than they will remember their videos games. They will probably grow to appreciate this experience more as they get older, too.

Mrs. Menagerie (author) from The Zoo on May 22, 2011:

Thanks Susan,

You're so right, we learned a lot and had fun doing it. I thought maybe one day I might try to write a children's story based on this real story. Kids usually love bugs...I think.

Susan Zutautas from Ontario, Canada on May 22, 2011:

Wow what a fantastic hub. I have learned so much from your article. I never realized one could even go about doing any of this with a butterfly. What a learning experience this must have been for you and your son. Up useful beautiful and awesome.

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