Last week’s post on raising Monarch butterflies at home sparked a a slew of questions, comments and emails. I figured I’d better get back here and clarify a few things.
First, I left out the part about what to do with the egg, once you bring it inside.
I usually tear off the leaf that the egg is on and put it in a jar or plastic container with the lid on. This keeps it moist and at a stable temperature. Sometimes the leaves will start getting moldy or condensation will form on the sides of the jar or lid. If that happens, just open the container and let the fresh air in. You might even wipe off the condensation. Too much humidity may cause mold to grow and is not a good thing.
But often as the torn leaves decay, they smell “ripe”–that is, you can tell they are starting to degrade. The eggs usually hatch within three – four days, so hopefully they will show themselves as tiny caterpillars before that happens. That said, it seems that caterpillars don’t mind that earthy aroma as much as we humans do.
Once the egg hatches, you can start the process discussed in last week’s post. There, I shared photos and info mostly about raising caterpillars in a vase-like setting with cut milkweed set in water and caterpillars munching happily on the leaves. But when you have LOTS of caterpillars, that’s hard to do.
When I have more than two-three caterpillars at once, I use the contained “caterpillar condo” approach I alluded to but didn’t describe in detail last week. I will do that now.
I like to have a large stalk of milkweed that I place inside the container. Taking a small piece of dampened paper towel and wrapping it around the end of the milkweed helps keep it fresh and assists in extending its appeal to the caterpillars. Like us, caterpillars prefer fresh greens.
As the caterpillars get bigger and indulge in their 10-14-day feeding frenzy, massive amounts of caterpillar poop, or frass, result. The problem compounds with more caterpillars. When I have several caterpillars, a paper towel in the bottom of the plastic container helps to absorb dampness and makes for easy clean-up.
When the caterpillars reach their third instar, or stage, you’ll find you may need to supply fresh milkweed daily, sometimes more than once a day. Of course it depends on how many caterpillars you are raising. NOTE: When there’s nothing to eat, caterpillars can become cannibalistic. We don’t want that.
Some people may struggle with moving the caterpillars around. Often you can simply lift what remains of the stem and put the caterpillars aside while you wipe down the container. If a caterpillar is stuck in an inconvenient position, take a leaf and slide it under her. Usually she will climb right on, getting out of your way. I’ve used a spoon or paintbrush to move the caterpillars. Handling with your fingers should be discouraged. Usually they will ball up and drop to the ground and it can be difficult to get a grip on them.
Sometimes, the caterpillar is in the middle of shedding its skin and won’t want to move. In that case you should try to wait til the process is complete. Caterpillars seem to gravitate to the roof of the containers, too. I just let them hang out there while I clean up, then put the roof back on.
When it’s time to go chrysalis, I will move all these caterpillars to a chemical free milkweed plant. They will wander off and find a good place to transform themselves. As stated previously, I’m not squeamish about caterpillars in my house.
You can also put them inside the pop-up cages that I mentioned last week, and they will form a chrysalis on the side of the netting or the roof of the cage.
Good luck, and let us know how it goes!
For more information, check out the Monarch Larvae Monitoring Project page on raising Monarchs or Monarch Watch.
- FOS Monarch Lays Eggs in San Antonio Urban Garden
- Tropical Milkweed: To Plant it or Not is No Simple Question
- Oh Those Crazy Chrysalises: Caterpillars in Surprising Places
- Butterfly FAQ: Is it OK to Move a Chrysalis? Yes, and here’s how to do it
- Should You Bring in a Late Season Caterpillar into Your Home?
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