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The swallowtail pupas take anywhere from 10 days to several months (if they over-winter) to hatch. In our experience, it seems that heat and Spring/Summer are the primary speeder-uppers of the process: keep them warm and if it's May, June, or July, they will usually hatch within 2 weeks. Unfortunately, some never hatch, and it is not yet clear why they don't.

When the pupa gets within a day or so of hatching, the pupa's covering will become more translucent--you can easily recognize the wing patterns and the abdominal stripes. In the shot below, the wing pattern is clear, but the abdominal stripes are not in view. The translucency is more apparent in a green pupa than in a grey-brown pupa.

The pictures in this series are all of the above pupa and the butterfly that emerged about an hour after the above photo was taken. At the bottom of this page is a video of a butterfly emerging form its pupa.

When the butterfly decides that the time is right to emerge, the pupa splits open at "chest" level (below), and the butterfly very rapidly climbs out---if you're looking the other way for 10 seconds, you'll miss it! And there's no sleepy staggering around after the emergence; the butterfly is wide awake, as if it had been waiting impatiently for the perfect moment to emerge. And once out, it's "Go! Go! Go!" to find an appropriate place to perch while its wings unfurl, fill, and dry.

This guy is upside down at the moment, but that'll soon be fixed:

He flips himself upright and gets on his feet while his back half is still encased in the pupa...caught in the process and hence the blur.

He then quickly climbed the rest of the way out of the pupa before I had a chance to snap another pic, and headed confidently across the paper towel. No messing around or dawdling.

I picked up the paper towel and held it so that he had a vertical surface to hang onto: 

Look at those tiny scrunched-up wings!! This is the most notable aspect of a new butterfly---in fact it's a bit distressing to see it for the first time---it looks like something is terribly wrong! But no---the wings have to be scrunched up in order to fit in the pupa. 

Newly-hatched butterflies need to hang at least vertically, and preferably somewhat upside down so that as their wings inflate, gravity pulls them away from the butterfly's body and they can inflate without interference. If there isn't sufficient space for the wings to unfurl and stretch fully, they will, when they dry, retain whatever bends or other abnormal shape they had while drying. Not good.

Above, he has walked to the upper-most tip of the paper towel and is paddling the air with his front legs in an attempt (presumably) to find the next higher surface he might grab. Seemingly frantic flailing/paddling of the front legs is standard on-foot butterfly behavior when they've reached the top of whatever they are climbing up. After a while it dawns on them they're as high as they're going to go and the paddling stops and they settle in.

Above, a minute or so after emerging from the pupa, he has settled in at the upper edge of the paper towel and is immediately getting on with the main business at hand...inflating his wings.

The butterfly inflates its wings by "pumping" fluid from its body into the hollow structural framework of the wings. It's not a very rapid process, and takes about 15 minutes for the pumping, and at least an hour for the wings to fully dry and harden. Each of the next few shots were taken 1-5 minutes apart. The initial inflation happens fairly rapidly--a few minutes.

Still looking a bit tangled up.


Above, the view from the side---starting to look more like wings now, at least from this viewpoint.

Fuller yet...6-8 minutes into the inflation.

And now, above, 15 minutes or so into the process, starting to look stretched and taut the way they should be.

At this point, the view from the side would lead you to think that the inflation is about finished...but there's more to go, and very importantly, the wing structural members are still very soft and vulnerable to damage.

Here's the view from above again--notice that the wings are actually still soft and droopy. The "leading edges" of the wings (the front edges) are soft and bendable and more curved than they will be when fully hardened, and it's very important not to scare the butterfly at this stage, because the wings are easily broken if it reflexively flaps its wings to escape. If a leading edge gets crimped and bent, the butterfly will never be able to fly.

Above, showing off his fabulous wing colors...

You may have noticed that I have been referring to this fellow as "he" rather than as "she". The reason is because he is clearly a fellow! In the shot below, notice the claspers at the end of the abdomen...these are for grasping the female during mating, and this is a much clearer picture of claspers than is found in the section on sexing butterflies.

Below, about an hour after emerging, the wings are fully inflated and are looking normal. They still need to dry and harden some more, however, so it's best to let the butterfly sit quietly for a couple of hours before letting her/him climb up on one of your fingers.

By the way, a newly-hatched butterfly will generally not be afraid of you at first. But as they get older (measured in hours from emergence), the more they tend to panic if you approach them. Moving slowly helps keep them calm. Still, when you have one walk up on your finger for the first time (described below), the butterfly will, perhaps out of nervousness at being picked up, usually squirt some creamy brownish liquid (apparently intestinal contents, and it is sometimes a clear liquid). But don't worry, it's harmless and mostly odorless stuff and rinses off easily with plain water. I like to think of it as the butterfly dumping some ballast before the maiden flight!

A contained butterfly: What if your butterfly emerges in a small container and unbeknownst to you? Will he or she beat him/herself to death flapping against the container walls trying to escape? Answer: probably not. They will usually perch quietly, having somehow realized that flapping is futile. Especially true if the container is stored someplace that's not well-lit. Still, it's best to check on them regularly, whether they're in a closed container or not. If they're in an open container in a well-lit location, they likely will decide to test the wings after a couple of hours, and may end up doing something foolish--like settling on the floor where the cat can easily reach them! Cats tend to play rough with their new butterfly friends, at least from the butterfly's perspective.

Release: About 2 hours after emerging from the pupa, our guy started getting frisky, so I put my index finger in front of him and gently nudged his front legs. He obligingly climbed aboard, and we walked out the back door...where he immediately launched himself and flew to the nearest fennel plant...and landed a little less than gracefully. More of a "thunk" than a delicate alighting (takes them a while to get the hang of it).

I then nudged his front legs to get him to walk onto my finger again, and below he is shown about 3 seconds before he flew straight up and over the house behind us...this one is a strong flier!

Enjoy your week or three, little guy, and please help make lots more caterpillars, OK?

A few after-thoughts:

They don't all zoom skyward immediately: Not all butterfies are anxious to take flight ASAP. If you are releasing one in the cool morning, it very likely will prefer to sit on a branch or leaf until it gets warmed by the sun. Direct sunlight really seems to charge them up, and sometimes they will sit for 15-20 minutes in the sun, warming, and then suddenly burst into the air and zoom away.

Rescue may be required: If you or something else startles a butterfly before it is sufficiently charged up to fly strongly, it may still attempt to take refuge in the air but end up a few feet away on the ground or on a low piece of vegetation. That makes the butterfly vulnerable to predators such as cats or dogs that may be in the area. If you're concerned in that regard, it's probably a good idea to slowly approach the butterfly and nudge its front legs with a finger to get it to climb aboard so you can place it high enough off the ground to be safe.

No-sun release: If you are releasing a butterfly on a sunless day, or before the sun is high enough to reach the butterfly, or when the sun is too low in the afternoon or evening to reach the butterfly, don't be surprised to find that the butterfly waits until it gets some sun. This may well mean the butterfly waits all night before launching itself. They are very patient.

Below is a video of a butterfly emerging from its pupa. The hand-held camera (Canon SX260 HS) is jiggling and there's not enough light, and this vid will be replaced by a better one ASAP, but it's worth a look. It shows how wide-awake and active the butterfly is immediately upon emerging. Also note the leg-flailing as its front legs come out of the pupa. It was upside down and needed to right itself. The butterfly climbs to the top of the container and this provides its wings with plenty of space to unfurl and extend themselves and dry in the correct shape.

You can also see the butterfly flexing its proboscis after it arrives at its perch.