Of Monarchs and Milkweed

As someone who spent many years working as an educator and naturalist at a variety of parks and facilities in Colorado and Seattle, I am always interested in learning more about the animals and plants I see while occasionally walking on trails.

My partner and I recently went for a walk on a trail close to town where we were surprised by a variety of different butterflies and moths. I am always very attached to my binoculars in hopes of seeing some birds who got up late for the breakfast buffet, but I am fortunate that my partner sometimes brings his camera to snap photos of things we see along the way so we can identify them later. 

Monarch caterpillar on milkweed plant,  J. Gray, Ecology Margin Notes

Monarch caterpillar on milkweed plant, J. Gray, Ecology Margin Notes

A crowd favorite in the world of butterflies is the monarch butterfly (Danaus plexippus), which seems to range across most of North America, from southern Canada down through most of the U.S., Mexico, and even part of South America and the Caribbean. We live on the eastern side of the Rocky Mountains, which means the monarchs we see here usually winter in Mexico. The smaller population of monarchs to the west of the Rocky Mountains winter in southern California. 

Monarchs depend heavily on the availability of milkweed (Asclepias spp.). Not only do they need to lay their eggs on milkweed, but their caterpillars survive solely on the consumption of this plant. Their bright exterior colors mixed with eating only this toxic plant makes the monarch less vulnerable to predators.

Wasp drinking nectar from Penstemon spp., J. Gray, Ecology Margin Notes

Wasp drinking nectar from Penstemon spp., J. Gray, Ecology Margin Notes

Monarchs are not the only ones to benefit from the existence of milkweed plants. The nectar from the flowers is used by many other butterflies and honeybees, while hummingbirds may use milkweed floss (seed fiber) to help build their nests. 

According to the National Wildlife Federation, monarch butterfly populations have decreased by over 90% in the past 20 years. The main cause for this dramatic drop includes loss of habitat in both the United States and Mexico -- particularly the loss of native milkweed species and other nectar plants that feed monarch adults. 

Photo by U. Leone under  Creative Commons CC0

Photo by U. Leone under Creative Commons CC0

One of the best ways humans can help is to plant native milkweed species and nectar-rich flowers in their own yard. The Xerces Society for Invertebrate Conservation has a Monarch Nectar Guide that allows people in the U.S. to click on where they live to find which plants are best for that area. It is important to keep in mind that milkweed plants are toxic and may not be appropriate for areas where there are livestock or unsupervised pets and children. 

There are still so many other butterflies we encountered on this walk that I hope to share with you in the future. I'd love to know your favorite caterpillar or butterfly adult that you find near your home. I'm gathering inspiration for a future art piece and would love to hear some of your personal favorites -- leave a note in the comments!