Sometimes we accidentally damage the pupation chamber of our beetles. If no rectification is done, the beetle may not emerge successfully. In this article, I will show you how to save your beetles after the pupation chamber is damaged.

Semi Artificial Pupation Chamber

An excavated pupation chamber exposing the vulnerable beetle pupa.
If you damage only a portion of the pupation chamber, you can still fix it!

Semi artificial chamber is the easiest to do. It should be your first choice whenever possible, because the size and shape of the chamber is already being optimized for the beetle by itself.

The prerequisite for this is that only a portion of the original pupation chamber is damaged. You do not need to remove the chamber from its housing. Do ensure there are no mites in the housing.

Gently break the pupation chamber like how u peel the shell of a hardboiled egg. You should start from where the chamber is broken, until the opening is big enough to take out the pupa. Then, carefully take out the pupa and gently brush off the substrates that fell onto its body.

After that, put the pupa back into the chamber. Be gentle when you lay it down to minimize any impact that may hurt the pupa. Make sure no more substrates drop onto the pupa’s body.

Prepare a wet (but not dripping) paper towel. You can use either a face or hand paper towel sprinkled with water. Avoid using commercial disposable wet towels as they may contain ingredients that harm the pupa. 

Cover the opening of the chamber with the wet paper towel. Make sure the towel does not touch the pupa. If the paper towel is too thin and may break easily, you should add a few more layers of towel.

Spray the paper towel with water using a bottle sprayer every few days before it gets dry. It is crucial to make sure the towel is not wet till the extent of dripping as that may harm your pupa by promoting the growth of molds

Foam Pupation Chamber

Foam pupation chambers can be easily made and are reusable. It is suitable for bigger beetles such as the goliath beetles and the hercules beetles. You need a florist foam for this. A florist foam is the foam that is used in flower arrangements. 

First, use a compass drawing tool to draw 2 circles – 1 with 2” and another with 1.5” in radius on the foam. Connect the 2 circles with 2 lines (as per the picture below). The distance between the center of the 2 circles (red dash line in the image) should be around 5” to 8” depending on the size of your pupa (eg. 5” for goliath beetle and 8” for hercules beetle).

Drawing on the florist foam for cutting
Top down view of the drawing on the florist foam. Red dotted line is the distance between 2 circles.

Carve the foam out using a spoon. You can start by working from the center of a circle outward, then work on another circle. After that, connect both circles by carving out the middle portion. 

Cross-section side view of the florist foam. Red area is the area to carved out. Blue area can be cut off to achieve 20-25° (optional) if that cannot be done by carving the red .

I prefer to make the chamber slightly slanted (~20-25 degree) by carving the smaller circle slightly deeper than the bigger circle. This will help the pre-pupa (if your grub has stopped moving but yet to pupate) to pupate better. Alternatively you can cut out a portion of the foam at the bottom to make it slanted (blue portion in the picture above).

Soak the cut foam into cooled boiled water. Drain off some water so that it is not dripping. Put the foam into a container and place the pupa into the foam. The abdomen of your pre-pupa or pupa should be facing downwards while the head should be facing upwards in a slanted setting. Make a few ventilation holes on the lid and cover the container. Add some water onto the foam every few weeks to prevent it from drying.

Paper Towel Pupation Chamber

Paper towel chamber is easy to make and can save you a lot of space. It is suitable for smaller beetles.

First, prepare a small disposable plastic container. Take a handful of paper towels and lay 5-10 layers of towels at the bottom and around the wall of the container. The resulting space in the container should be around 3-4 times the size of the pupa.

Spray the towels with cooled boiled water to make it wet but not to the point of dripping. Gently brush off the substrates on the body of the pupa. Then, place the pupa into the wet towel and cover it with a lid with ventilation holes. From time to time, add a few drops of water onto the tissue when it dries up.

Caring of Artificial Pupation Chamber

Pupation is a very crucial stage in the development of beetles. During this stage, the pupae are not able to move and cannot defend themselves. That’s why they hide themselves by building a pupation chamber. 

Whichever artificial pupation chamber you build, make sure it is safe from ants or other insects which may attack the pupa. Do not put the chamber at places where you see ants are foraging. By ensuring the container is intact and using a lid to cover the chamber, you should be able to prevent pests intrusion. 

The housing should be placed in a dark, undisturbed place. Regulate the temperature according to the recommended temperature of the beetle species. 

While you need to keep the pupation chamber moist, do not make it too wet. Otherwise, you may find your pupa covered with molds or start rotting. Ventilation helps to reduce the chances of mold to a certain extent. Never spray water directly onto the pupa. 

When Should I Use an Artificial Pupation Chamber for My Beetles?

You should move your beetle to an artificial pupation chamber if the original pupation chamber is damaged. This usually happens if you change the substrates without realizing there is a pupation chamber. 

To avoid this, always check for the presence of a pupation chamber before changing the substrates. Simply hold the housing with both hands and slowly rotate it. Since the pupation chamber is hollow, you should hear the sound of the pupa hitting the wall of chamber as you rotate. This is not 100% accurate though.

If you are not sure, always remove the substrates layer by layer when changing substrates. Avoid digging with a sharp object. You can start digging out the substrate clockwise or counter clockwise. If you hit something hard, stop digging that part. Instead, dig around the hardened substrates. If the hardened substrates seem to form an oval, likely it is the pupation chamber. Leave the pupation chamber alone if you discover it when trying to change substrates. 

Other occasions where you need to move your pupa are when the substrates start rotting/growing molds, or if you deliberately break the pupation chamber to observe the development of the pupa. I don’t recommend deliberately breaking the chamber for observation especially for beginners. 

There is a risk where the metamorphosis fails if you use an artificial pupation chamber, due to factors such as the size, shape, and moisture. Hence, whenever possible, always let your beetle pupate and emerge in the pupation chamber which it builds. 

The Size of the Pupation Chamber

Whenever you make a pupation chamber for your beetle, make sure the chamber is more or less the same size and shape as the original chamber dug by your beetle. 

If the chamber is too small, the beetle may die as there is not enough space for it to emerge. If the chamber is too big, the beetle may not be able to turn its body around when it molts, which may cause malformed wings and even death.

Do note that some beetles build a vertical instead of a horizontal pupation chamber. Always refer to the original chamber built by your beetle before building your artificial pupation chamber.

Next Step after Adult Beetle Emerged

After the beetle has emerged in the artificial pupation chamber, it will remain dormant for a period of time. You should transfer it into a housing for adult beetle set up according to the species requirement, and take care of your beetle during the dormant period as outlined in this guide.