The Adventures of a Monarch Butterfly: Milkweed, Metamorphosis, and Migration

Image of monarch caterpillar — Photo credit: Laurie Neuerburg.

Watch a video showing a monarch caterpillar transforming into a chrysalis on the Sciences Library YouTube channel! In the chrysalis, the monarch caterpillar appears to be dormant on the outside, but changes inside are happening quickly, from the breakdown of tissues no longer needed to the growth of new wings, proboscis, and compound eyes that see a range of color that is larger than most other animals can see! Prior to making the chrysalis, after hatching from an egg, a monarch caterpillar will eat around 20 milkweed leaves and increase their weight by 2,700 times! Then, the crawling caterpillar will start the process of metamorphosis into an adult butterfly who can soar across the skies! This happens when a monarch caterpillar stops eating, creates a silk button from which to hang upside down in a j-shape, and does a final molt to reveal a new form as a chrysalis. The dramatic transformations of metamorphosis underlie an amazing journey from egg to butterfly, and it is not the only incredible journey that the monarch butterfly undertakes!

Image of a monarch chrysalis — Photo credit: Laurie Neuerburg.

Each year’s final generation of Eastern North American monarch butterflies delay reproduction and undertake a long journey from as far north as Canada to spend the winter in Mexico. This trip from Canada to Mexico can be as much as 3,000 miles! In the spring, the butterflies will migrate north again. Monarch butterfly populations have been in decline for decades due to pesticide use, climate change, and habitat destruction. In response, Iowa City has taken steps to help bolster monarch butterfly populations. There are several monarch waystations across the city and they have provided a “How to Grow Milkweed” guide, which is the only type of plant that monarch caterpillars will eat, so growing more milkweed helps monarchs sustain future generations. You can attend Iowa City’s 2020 Monarch Festival virtually on Aug. 2, Aug. 9, Aug. 16, and Aug. 23. Additionally, there is a “How To Raise Monarch Butterflies At Home” guide as well as suggested ways to help monarchs on saveourmonarchs.org.