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Green Speak

Adventures in Babysitting – Monarch Caterpillars

A co-worker is headed out on vacation this week and asked me to babysit her twenty babies. By babies I mean monarch caterpillars. I have built rearing cages, taken classes, learned all about the lifecycle of the monarch butterfly, but I have never raised them before. I've gone back to the materials taken from the Monarch Teacher Network Class to make sure I don't kill these tiny caterpillars entrusted to me. Here's what I've learned:

  • Once the caterpillars hatch they need fresh milkweed. It is best when collecting monarchs in the wild to also bring in a cutting of the milkweed plant they are on. Monarch caterpillars only eat milkweed, and it should be fresh at that.
  • When you observe a newly hatched monarch caterpillar it is tiny and shouldn't be handled until they are four days old. Avoid handling caterpillars as much as possible.
  • Though they start small monarch caterpillars will grow exponentially. Lots of milkweed will be required to fuel this massive amount of growth. I need to make sure to have plenty of milkweed on hand to feed twenty caterpillars! To have a constant supply of milkweed on-hand harvest cuttings ahead of time and keep them in a plastic bag in the fridge.
  • Caterpillars will die. There is some mortality in the larval stage of monarchs. When infected with a common bacterial disease, caterpillars will darken in color and die. And sometimes monarch caterpillars will just stop eating. Researchers aren't sure why. Keep the caterpillar's container clean and you will minimize the loss of larva.

Here's hoping to a successful adventure of babysitting.

There's a lot of great information out there on raising monarch caterpillars. But the best way to learn is to do it yourself! Here are some resources to get you started:

Rearing monarchs from Monarch Watch http://monarchwatch.org/rear/

University of Minnesota Monarch Lab http://monarchlab.org/biology-and-research/monarch-rearing