Common milkweed produces a sticky, milky white sap. The plant's latex contains large quantities of glycosides, which renders the leaves and seed pods toxic.
Sheep and other large mammals cannot eat it, but there are several insects that have developed immunity to the "milk" of milkweed. The most famous of which is the monarch butterfly (Danaus plexippus). The females lay their eggs on young milkweed plants and when they hatch, the caterpillars have something to munch. Like most caterpillars, they are little eating machines. They are incessant.
Some caterpillars eat as much as 27,000 times their body weight to support their lives as flying insects. I was a seven pound baby. That would be like me eating 94.5 tons of food my first few weeks of life, which I do not think I did. But I'd better ask my mother.
Look for milkweed and monarch caterpillars in the plaza in front of the Visitor Center.
- Text and photo by Stephen Lyn Bales