I wrote in an earlier post that I was volunteering at Beaver Creek Reserve’s Butterfly House Lab. This is a followup on that experience. Prepare to learn about raising monarch caterpillars!
Step 1: Locate Eggs or Caterpillars
Monarchs love milkweed! This is a very common plant and you can find it growing in patches of brush near parks, lawns, and roadsides. Collecting eggs or caterpillars should really be done in places with high disturbance where they would have a low survival rate anyway, that way you won’t disturb the local population with your collection. I didn’t carry out this part of the work at Beaver Creek, but finding milkweed is fairly easy. Locating eggs and young caterpillars requires a bit of inspection. Often they’ll be located in the upper part of the plant on the undersides of leaves.
Step 2: Newborn Caterpillars
Beaver Creek’s method for caring for very tiny, young caterpillars is simply to keep them in plastic baggies sandwiched between milkweed leaves. They’ll survive in this manner until they become large enough to not escape through a screen, at which point they can be placed in a caterpillar container.
Step 3: Caterpillar Stage
I learned a simple technique for housing caterpillars. You can use an empty ice cream pail to contain them. Cut out most of the lid (leaving the rim), and then place a square of mesh screen over the pail and close the rim of the lid over that. No more than six caterpillars should be kept in one ice cream bucket, with fewer animals in smaller containers.
Caterpillars should have fresh milkweed leaves given to them every day. Once they are very large (an inch or more in length), one caterpillar can eat three to four 3 inch leaves per day, so collecting milkweed daily is important! Every time their food is freshened, they should be switched to a fresh container as well, with all of the old leaves and caterpillar waste (frass) dumped out and the old container cleaned and disinfected. Living in close quarters, disease can spread quickly between animals, so it’s important to keep their habitat and your workspace clean.
Cautions: If a caterpillar has moved away from the milkweed and is on the side or top of the container, do not switch it to a new container. It is probably molting and mustn’t be disturbed during this delicate process.
Step 4: Chrysalis
Once you’ve taken care of your caterpillars long enough and they’ve reached a large size, they’ll migrate to the top of the container (the underside of the mesh screen). There, they will hang from the mesh and curl their bodies in a characteristic “J” shape. At this stage, do not disturb them until they have finished creating their chrysalises. Then they can be moved to a larger container (Beaver Creek uses ones which are screen sides on a wooden frame) to await their transformation.
Step 5: Butterfly
The chrysalis begins as a seafoam green color with spots of metallic gold. When the butterfly is close to emerging, the chrysalis becomes clear and you’ll be able to see the colors of the wings within. Eventually it will crack open and the butterfly, still folded and wet, will emerge. Give it plenty of time to unfold and dry out. Once it is actively flapping its wings, perhaps even fluttering around its container a bit, it’s time to release your metamorphosed friend! Do so in a quiet location, away from busy areas, near flowers and brush. Butterflies require food, but also sunlight and areas to hide.
Raising monarchs is a fantastic project to do with children, as it is quite simple to only raise one or two at a time. They don’t require much upkeep. Consider it as a science fair or other school project, or just as something to do at home.
To the reader: feel free to share experiences or resources on raising monarchs and other kinds of caterpillars! What do you like or dislike about the methods on display here?