Adult Monarch Butterfly feeding off of milkweed.
August is a good time to keep an eye out for butterflies. By planting native plants in your yard like coneflowers, spicebush, yarrow and milkweed, you can attract a number of species. This is because butterflies have multistage life cycles in which their larval stage (the caterpillar) is dependent on a particular set of host species on which to feed.
The butterfly’s life cycle includes: going from egg; to larvae (the caterpillar); to chrysalis (the pupal stage-in which a complete rearrangement of organs and body parts occurs through metamorphosis); to adult (butterfly). Host plants are vital for ensuring butterfly populations persist. These plants are used by adults to lay their eggs and the caterpillars then feed exclusively off these plants. Host plants are native plant species that the butterfly species have evolved with and which the caterpillars primarily feed off of. By planting these native host plant species you will have higher success attracting butterflies. Some butterfly species' caterpillars will feed on non-native species such as Queen Anne’s Lace and Dill but these plant species are generally closely related to the butterfly’s native host plant so the butterflies do not seem to mind too much.
You can still attract butterflies to your yard even without native species, as the adult butterfly spends most its time searching for nectar. One of my favorite flowers to plant are zinnias and butterflies seem to like them pretty well too. Zinnias are not native to Missouri but are native to the southwest US through South America.
Monarch Caterpillar feeding off of common milkweed. See the caterpillar poop or frass! (Fun fact! Frass is the technical term for caterpillar poop)
Many butterfly species will migrate to wintering sites when it gets too cold. The most famous migratory butterfly is the Monarch (Danaus plexippus), the only species of butterfly to migrate over 2500 miles to reach their wintering grounds. Concern about Monarch population declines has led some people to raise monarch butterflies in captivity, but a recent study finds that these butterflies might not be able to migrate; suggesting that conservation efforts should be in habitat conservation (both in the winter and summer range). https://www.npr.org/2019/06/24/735389108/monarch-butterflies-born-in-captivity-have-trouble-migrating-south-study-says
If you are interested in helping monarch, grow native milkweeds – their host plants, and look into citizen science programs. MonarchWatch (https://www.monarchwatch.org/) allows you to catch, tag and release Monarch butterflies on their fall migration. With the data they collect MonarchWatch is able to keep track of population changes. I participated a few times and even got a certificate telling me that one of my tagged butterflies was found in Mexico!
What about the butterflies that do not migrate? How does the species continue to persist?
Spicebush (Papilio troilus) and Black swallowtail (Papilio polyxenes) butterflies will overwinter in their chrysalis stage. The caterpillars, after getting their fill of their host plant, can then be found crawling on the ground looking for a good place to bury before it gets too cold. They bury under leaf litter where they will pupate (form a chrysalis) and stay like that until spring. Once spring returns, metamorphosis occurs and the adult form emerges from the chrysalis and looks for a place to climb and hang upside down. Once they reach a safe location, they may not look much like an adult butterfly because their wings are all folded and crinkled. They then pump fluid through their wings making them rigid and ready for flight. Because many butterfly species overwinter and bury under leaf litter, you might not want to worry about removing all the fall leaves in your yard. Biodiversity ...making your life easier!
Black Swallowtail (Papilio polyxenes) feeding off of a coneflower.
Spicebush Swallowtail (Papilio troilus) just chillin'...or maybe plotting to take over the world.