In Maine, monarchs are likely reaching their last generation of the season. The ones bound for Mexico usually depart by October. So you might still have time to help an egg make it into butterfly state.

But wait, is it wrong to bring monarch eggs or caterpillars into the house and raise them yourself? Not at all, says Kalyn Bickerman-Martens, a Ph.D. candidate in ecology and environmental sciences at the University of Maine Orono. She works extensively with pollinators and is the coordinator for the Maine Bumble Bee Atlas.

“We are so well trained as a society that you are not supposed to interfere with wildlife,” she said. But she said this is one case where it’s just fine, helpful even, “because when they are instars (caterpillars), they are very vulnerable.”


1) Search your milkweed for eggs. Look on the underside of the leaves – it’s rare for the monarch to lay them on the top, because she’s trying to protect the egg from heat and predators – and make sure to check the ones lower to the ground. The eggs have a distinctly globe-like shape. Snip the leaf and bring it inside. If you find an instar, a small caterpillar, congratulations, you’re that much closer to a butterfly. Snip the leaf it is on and bring it inside as well.

2) Place the leaf or leaves in a container. You can use a wide-mouthed vase and put a stick in it, to give the caterpillar a place to hang from, eventually, when it enters the chrysalis stage. Or you can buy a “critter” cage from your local farm and feed store. The important thing is, you must allow air to circulate into the cage. Add leaves for the caterpillars to eat as they go through the five stages of being an instar. (They shed their skins at each stage.) Put a moist cloth or paper towel into the container to keep the leaves moist. Or put the leaves in a florist tube. Add fresh milkweed regularly, daily if you see your instars powering through what they’ve got.

3) Prepare for your insect guest to “hang” out: If you’ve bought a container with a grid-like lid, the caterpillar will gravitate there as it prepares to become a chrysalis. They need a place to hang, so they head up. A stick will do if you don’t have a lid with openings. The instars will get into prepupal shape that looks just like a J. This stage happens in mere minutes and afterward, the future monarch looks sort of like a piece of bright green Silly Putty, hanging in a cylindrical shape. They’re done eating at this point.

4) Wait anywhere from 9 to 14 days. The pupae darken before the butterfly is ready to emerge. Typically, they emerge in the morning. They should hang with their wings pointed down, and it will take four to five hours for their wings to harden. If it is a warm, sunny day, you can release them that day. Otherwise, release them the next day.


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