What does life look like for butterflies and moths before they reach adulthood? In a word: eating!

One of my favorite childhood books was The Very Hungry Caterpillar by Eric Carle (you can watch a charming animated version of the book HERE). In the story, a caterpillar eats and eats before undergoing metamorphosis and emerging as a butterfly. While Carle captured the essence of a caterpillar’s insatiable appetite, he made a small mistake: the book mentions that the caterpillar makes a cocoon, but in reality, caterpillars that become butterflies form a chrysalis, while those that become moths spin cocoons. But I’m getting ahead of myself—if you’re curious about the difference, you can read more HERE.

Photo of a monarch caterpillar eating narrowleaf milkweed leaves by “zjn1” on Inaturalist.org.

What Carle got absolutely right is that caterpillars eat voraciously to prepare for their magnificent transformation into adulthood. Unlike the fictional caterpillar, though, real caterpillars have a much more specific diet. They rely on particular plants known as “larval host plants.”

Many people are familiar with the Monarch caterpillar’s highly specialized requirement to consume milkweed. This diet makes Monarchs an unappealing meal for predators because milkweed is toxic to most wildlife. In the 10-14 days they spend as caterpillars, Monarchs will consume up to 200 times their body weight in milkweed leaves!

Monarchs aren’t the only butterflies with host plant requirements. While some species have a broader range of food options, they still have specific needs. If you’re interested in attracting butterflies to your garden, consider the food for their larval stage too!

Here’s what some of our local butterfly and moths with their host plants: 
A green caterpillar on a willow plant

Photo of a Glover’s silkmoth caterpillar by ESLT staff.

The Glover’s Silkmoth is a striking and rather large caterpillar that transforms into a magnificent red moth and can be found on willow species, bitterbrush, and wild rose. This particular caterpillar stopped us in our tracks at Conway Ranch during a mullein pulling stewardship day earlier this summer.

Photo of a swallowtail caterpillar by Tsu Dho Nimh

Western Tiger Swallowtails are common and abundant in the Eastern Sierra. The caterpillars feed on many common tree species including willow, cottonwood and quaking aspen.

Photo of white-lined sphinx moth caterpillar, known as a hornworm, by Joseph Berger, Bugwood.org

White-Lined Sphinx Moth caterpillars are well-known to many gardeners as “hornworms.” They have a varied diet and favor nightshades, like tomatoes and potatoes, in vegetable gardens. Other host plants include Evening Primrose, apple, grape, and many more.

Photo of a painted Lady caterpillar by Julien Piolain.

Painted Lady butterflies are one of the most widespread species in the world. The caterpillars feed on many species in the Aster family including sunflowers, sagebrush, mugwort, thistles, hollyhock and many many more!

We hope you have learned something about life before flight and will consider planting larval host plants for your favorite butterflies and moths! If you only choose one- we recommend Showy Milkweed or Narrowleaf Milkweed for monarchs. If you don’t live in the Eastern Sierra- be sure to research your local milkweed species. The highly specialized diet of these charismatic migrating butterflies makes it especially difficult to find the food they need to survive. Learn more about monarchs and how you can help from our friends at Monarch Joint Venture.