What tools do I need in order to raise a caterpillar?

Should I leave the eggs and little caterpillars I find out in the garden or should I bring them indoors? The decision is entirely up to Y-O-U. Keep in mind that IF you do choose to hand-raise butterflies then your job as a foster parent is a BIG one! You are responsible to feed and clean them, as you will be taking care of the little ones for at least two weeks on a daily basis. If you choose to leave the ova (egg) or larva (caterpillar) outside, then there are possibilities that predators could come along...and so a butterfly may not make it to adulthood…

If you are still reading then you must have decided that you are going to become a foster parent. Okay, here goes…

Although butterfly babies (larvae aka caterpillars) are all quite different in their specific food needs, just like human babies their basic needs are very similar. Butterfly babies need a safe and clean place to live (rearing container) and good, quality food (what is called the 'host' plant). By providing these things, and being careful while doing so, your babies will grow up hopefully, to become a fantastic fluttering butterfly.

To start, you should gather some 'basics,' just like you would a baby. The basics would include:
  • small bowl
  • tissues or paper towels
  • clean paint brush (fine-tipped and wide-tipped)
  • tweezers (optional)
  • rearing container (more on this below…)
  • round coffee filters or toilet tissue
  • scissors
  • tape (I prefer packaging tape)
When larvae are really young it is best to NOT over-handle them. This is why you need that fine-tipped brush! Super-young caterpillars are at their most vulnerable when they first hatch. Too much handling is almost like manhandling (sorry for the pun!) and damage can result. Just let the caterpillar climb onto the brush or a leaf instead of actually poking or prodding it. IF a caterpillar is going to die (and many do when they are in their early instars) then don't add to the numbers because of your manhandling!

Leaving the larva on the leaf and simply moving that leaf into a container is a simple and safe way to 'handle' the baby. You can then just take that leaf and put it into a container. You can use the tweezers to move the leaf.

What type of a rearing container should you use? It isn't necessary to go out and purchase an expensive habitat or terrarium for the larvae. There are probably many things that can be recycled that will suffice (and this will also be good for the environment as well!). Those clam-shell to-go containers are great for raising caterpillars and can also be used for when they are pupating (as long as the depth of the containers is such that a butterfly has enough space to spread its wings).

Inexpensive shoeboxes from the 'dollar store' are also perfect because, again, they often don't form an airtight seal PLUS are tall enough for a butterfly to spread its wings once it ecloses (comes out of its chrysalis).It isn't necessary to make air holes in many of these containers because 1) they don't form an airtight seal, 2) there's just enough air that is contained within the container, and 3) you can easily poke holes (just do it from the INSIDE so that any burrs from the holes are on the OUTSIDE and not on the inside). For specific details on rearing containers, click Rearing Containers.

Here are some examples of containers containing Painted Lady larvae.

The paper towel on the bottom of the clamshell (picture on left) helps make cleaning the frass (poop) easier as you simply have to pick up the larvae and leaves, lift up the entire paper towel, shake the frass into a trash can, and then put the paper towel back (if it isn't soiled) or replace it.

Daily frass (poop) removal and container cleaning is ESSENTIAL. It is as important as providing your caterpillars with fresh food. Never feed your babies dried-up leaves. Never feed them leaves that are moldy, have rust, or are just plain nasty! Think of it this way: if the LEAF is sick then you caterpillar could get sick! If you leave frass in the container, it is like keeping a baby in the same diaper all day long.

The paper towel also helps to absorb moisture. Moisture is a BAD thing for caterpillars. Heat is also bad (so don't put the containers where sunlight can get in). Heat and moisture can contribute to bacteria and virus growth; just like humans can get sick from a 'bad' bacteria/virus, so can caterpillars! If you see water droplets forming on the inside of your caterpillar's container, it is time to air and dry it out!

NOTE: How can you tell if your caterpillar is sick? Some things to watch for:
1. Runny, diarrhea-like scree (poop)
2. Strange odour
3. Body turns black
4. Body elongates

If any of these symptoms appear, it is important to immediately remove the caterpillar and disinfect the container, tossing all food in the trash (I put it in a baggy first). Isolate the caterpillar from the others as the scree can contain crystals that can be ingested (eaten) by other caterpillars which can make them sick, too! Don't forget to wash your own hands as well. You can use Clorox wipes to disinfect the counter and your tools but be sure to use water to rinse everything afterwards.

Know that there are certain butterfly species can be cannibalistic (in other words, they will EAT one another!) so my rule of thumb is to keep only same-size instars ('age stage') larvae in the same container. Don't put a big guy with a little guy because you may find that the little guy has disappeared and the big guy has become BIGGER!

As your larvae nears the 2-week mark you will notice they have grown substantially in size. What once were teeny little things are now humongous! Soon it will be time for pupating (if it is outdoors, it will migrate away from the host plant, sometimes FAR away!).

For those larvae that are in a rearing container you will need to provide places for them to pupate. IF your container is large enough, you don't have to do anything more than place a paper towel or coffee filter or toilet tissue across the TOP of your container. If your container is NOT big enough, read on…

Some larvae pupate by hanging upside-down in a 'J' position. Others form a silken sling or harness and hang right-side up (like the swallowtails). The paper towel/coffee filter provides a medium for the caterpillar to pupate upon AND it serves as another purpose: you can easily transfer the pupa to another container once the chrysalis has hardened!

If you are raising swallowtails, providing sticks of some sort is always nice since they like to pupate, most of the time, on a stick. I often use chopsticks stuck in green florist's foam (the foam is called Oasis) for the swallowtails.

Although it isn't necessary to go and buy fancy butterfly pop-ups, Insectlore sells inexpensive mesh 'habitats' on-line for under $20. The shorter one is called the Butterfly Garden and comes as part of a 'kit' which includes five Painted Lady larvae. The taller one is the Pavilion and can be purchased as part of a kit or by itself. To purchase either of these items, click on the Insectlore Butterfly Kit link.

Once the pupa has hardened and the head capsule has been 'popped' off (see picture) if you want to move the chrysalis, you can do so safely. This is where the tape comes in. Simply roll some packaging tape into a loop, then tape the pupa (chrysalis) onto another rearing container. Make sure the new container (IF you are moving the pupa) has enough space for an adult butterfly to spread its wings. If the container has smooth walls, then be sure to provide a stick so the butterfly has something to climb onto.)

You just want to be sure that no matter what you do use that the butterfly can safely eclose (come out of the chrysalis) and be able to SPREAD its wings without being forced to have crumpled up wings. Having something to hold on to will also keep the butterfly from drowning in its meconium (waste fluids, often a reddish-brownish liquid) that you may see after it ecloses.

Now, all you have to do is wait for the butterfly to harden its wings (larger butterflies need more time), then you can release it when the outdoor temperatures are around 70-degrees. Whew! A piece of cake!