Monarch butterflies used to be ubiquitous across America. Each year, billions of them migrated from Mexico to Canada and back. Along the way, they visited many types of flowers, providing valuable pollination services.
When female monarchs were ready to lay their eggs, though, they sought out a specific type of plant: a member of the milkweed family.
The reason for this choosiness is that plants don’t like to be eaten. Not being good at running or hiding, they instead deploy an array of chemical defenses to discourage would-be predators. Each species of plant has evolved its own mix of chemicals, and each toxic concoction is palatable only to the herbivores that have evolved just the right defenses against it. Thus, with few exceptions, plants can only be eaten by the animals – including insects – that have spent millions of years adapting to them.
Adult butterflies avoid this problem by eating nectar, which plants provide toxin-free in exchange for pollination services. But caterpillars eat leaves, which plants want to keep unmunched in order to produce food for themselves through photosynthesis. Milkweed is the only plant monarch caterpillars can safely consume.
And it used to be a common plant, found along the edges of farm fields all over the Midwest. Now, however, milkweed is disappearing as farmers seek to maximize yields by planting crops all the way to the edge of their property.
A monarch waystation is a little patch of milkweed – small enough to tuck into the corner of a suburban backyard – that gives butterflies a place to rest, feed, and lay their eggs. It is easy to establish, and a network of them just might save an iconic species from extinction.
More information on creating a monarch waystation can be found at this website.