Updated: Jul 19, 2020
Whether you are a casual butterfly gardener or an avid lepidopterist, if you raise butterflies long enough, you will experience a fallen chrysalis.
This can happen for several reasons and across many species. For one, the caterpillar may be weak or sick. However, there are plenty of times when it is perfectly healthy and something mechanical simply goes wrong. Leaf abscission (falling off), loosened silk or an accidental knock off can all cause a pupa to fall. Hopefully the fall wasn't too hard or long, and if not, the pupa may still be perfectly viable.
If the chrysalis is punctured or if liquid is coming out, it may not survive.
Greeny greenies contend that if a pupa is not reattached, not suspended as it would normally be, it won't survive.
This is bogus.
They can still emerge just fine as long as a few conditions are met. I have done this many times and so have other professionals. For example, in butterfly houses where they can be receiving shipments of dozens of chrysalides at a time, they don't always re-hang them. It is too time consuming and not necessary.
So what is the proper way to reattach a chrysalis?
There is more than one way to skin a chrysalis, oh wait, I mean hang one. This can be done with several household supplies that you already have. With endless ingenuity, there are certainly more ways than this post describes. Lastly, there is no "right" way, despite the demands of the dogmatic.
As you may know, each family of butterflies makes a specific style of chrysalis. Those in the Brushfooted family usually have longer cremasters, which is like a stem on the top of the chrysalis that it hangs from. They only attach to their substrate in one place. These kinds of butterflies can be easier to rehang because of that elongated stem. Monarchs are a fine example of this.
Sulphurs and Swallowtails can be a bit more complicated because they don't have a long cremaster. Plus, they attach in not one place, but two. They make silk girdles that go around their thorax for back-up hanging support. Luckily, if we reattach them only at the tail end, they will emerge successfully. We don't need to recreate the girdle.
The Cloudless Sulphur below is still connected by both its cremaster and its silk girdle.
The Gossamer-winged family doesn't use a cremaster at all, so they may be the most challenging to rehang.
You will need some type of netted cage or container that you are going to attach the chrysalis to. I use strawberry or cupcake containers, cages, modified Tupperware containers and more.
With these common supplies, you are prepared for various types of rehanging.
1. Tape can be used in the most basic types of rehanging. This is the fastest and I think, easiest way, but it is not always possible. If the silk is still attached to the cremaster (in applicable species) then you can simply tape the glob of silk to the top of a new container. Or, if a leaf has fallen from its plant with a chrysalis attached, just tape the leaf to the container as seen below.
2. Q-tips or micro-fiber cloths can be used in lieu of their silk. If you have a pupa with a cremaster (Brushfooted, Swallowtail, Sulphur) you can hold the pupa against the q-tip or micro-fiber cloth and wiggle it around. The tiny hooks will attach. Watch this video for a visual.
Then tape the q-tip or cloth to the top of the container you are using to suspend the chrysalis.
3. Dental floss works not only to rehang a pupa, but it can help to remove a pupa from a bad location. Once the floss is tied around the cremaster, you can either tie it directly on a twig if you wish to leave the chrysalis outside. Or, to bring it in, trim the excess and tape the floss to the lid of the container. Be sure to trim it because any long floss pieces hanging down may interfere with the butterfly drying its wings when it emerges.
4. Pins can be used to attach a chrysalis that still has its silk connected to it. Professional butterfly houses use this quick method. But, they often receive chrysalises with silk still attached, so that is the prerequisite to using them. Or, you can re-create the silk using the q-tip method above.
Of course, you need something to pin it to. A net cage will work because you can simply pin to the side or top of it. You can pin it to a screen. Professional houses use strips of styrofoam or other soft material, but this is because they are regularly pinning dozens at a time.
Use extreme caution when pinning because if you poke the chrysalis it will die. We only want to pin the silk, never the chrysalis itself.
The photo below shows Swallowtail chrysalises at a butterfly house that were reattached in only one place. There is no need to re-create the original silk girdle. Using just the cremaster will suffice.
5. Low Temperature Hot Glue is another option. Some folks use other types of glue, but I prefer hot glue because of its fast dry time. This is perhaps the trickiest to use because you don't want to burn or kill the chrysalis. Yet, I use this often because it can work for any type of chrysalis, with or without a cremaster. For example, Atalas.
A small drop of glue should be placed on a piece of paper or cardboard, or the top of the container, and GIVEN SEVERAL SECONDS TO COOL before pressing the very tail end of the pupa into it.
A professional butterfly house glued pupae to strips of paper and then pinned the paper to a cork board as seen below.
Now you are all set to rehang a chrysalis.
Butterflies release liquid meconium when they emerge from their pupa. You may wish to place a paper towel under the chrysalis on the bottom of the cage for easy clean-up.
Also, if you use a slick-sided container like plastic, be sure to put a paper towel on at least one side of it so they can climb up it if they fall from their chrysalis too soon, before their wings are formed. Their feet cannot grip a smooth sided container.
This video explains the details.
If you DO NOT wish to reattach a chrysalis. Simply place them on the bottom of a container with a paper towel lining the bottom and at least one side, or put them in a netted cage. After they emerge, they will climb up the side of the container (gripping the net or the paper towel) to dry their wings.
Be sure the container is large enough for their wings to expand.
Hang well and prosper.
Jessica Morgan McAtee