Written by Mary Free, Certified Master Gardener
One of the joys of summer is to watch butterflies flaunt their shapes and colors by flitting, floating and fluttering from flower to flower. Attracted to clustered or composite blooms that are bright, red, purple, blue, and yellow, they pick up and transport pollen on their legs and wings.
There are about 750 butterfly species in the United States. Their behavior (how they fly or perch) and physical characteristics (including wing size, shape, pattern and color) provide clues to their identity. For example, brushfoots (like monarchs, admirals, and buckeyes) vary greatly but their common family name denotes their common trait: hairy, bottlebrush-like, front appendages that are so short, it often appears as if they have only four legs instead of six.
Unlike the winged adults, butterfly larvae—caterpillars—lead a more inconspicuous existence often obscured by the leaves of their host plants. In one season, we may easily observe dozens upon dozens of butterflies of the same species; yet in one lifetime, we may never happen upon any of its caterpillars or recognize them if we do. Most butterflies use more than one plant species as host for their larvae, but monarch butterflies lay their eggs solely on milkweed leaves. [If you plant milkweed, be sure to use a native and not tropical/annual species. Learn why here: Plan to save monarch butterflies backfires.]
Monarch butterflies (Danaus plexippus) east of the Rocky Mountains overwinter in Mexico but only those born around September or October make the trip. This last generation migrates to Mexico and then returns to the United States in early spring to mate and lay their eggs before they die. The first three to four generations hatched in spring and summer live about one month each. The last generation lives 6-9 months and may travel up to 3,000 miles in their lifetime.
How do these showy insects defend themselves in an environment fraught with predators? The monarch butterfly’s bright coloration warns its enemies that it is poisonous (due to the milkweed toxin stored in its body). The southern form of the Admiral butterfly uses mimicry to keep predators like birds at bay. The coloring and pattern of the red-spotted purple (Limenitis arthemis) appear similar to that of the poisonous pipevine swallowtail (Battus philenor). Red-spotted purple larvae eat the leaves of hosts like downy serviceberry, aspen, cherry, cottonwood, scrub and black oaks and willow, while adults eat rotting fruit, sap, or sometimes the nectar from white flowers like Viburnum.
The common buckeye butterfly (Junonia coenia) uses conspicuous, target-shaped eyespots—for which it is named—found on both the upper forewing and hindwing as a defense mechanism. Experiments have yet to prove that these so-called eyespots are effective as mimics of vertebrate eyes as hypothesized; rather they have shown that it is the size and prominence of the spots that intimidate predators. [Learn more about: The evolutionary significance of butterfly eyespots.]
On the underside of the hindwing, the color depends on the season in which the buckeye is born—pale tan in summer; red/brown in fall. According to Duke University, the shortening days affect the secretion of ecdysone, a hormone that controls pigment color. Larval host plants of the common buckeye include foxglove, gerardia, monkey flower, plantain, ruellia, snapdragon, and verbena.
For skippers, their fast and erratic flight helps them evade predators. They are named for their flying habit of darting or skipping from flower to flower. Other distinguishing characteristics are their hooked antennae tips and perching stance with wings partially open in a “jet-fighter” position. The butterfly feeding on New York ironweed (Vernonia noveboracensis) is a Zabulon skipper (Poanes zabulon). Its host plants are a variety of grasses and its habitat includes woodland edges near streams as well as parks and suburban gardens.
To learn how you can attract pollinators like these to your property, read: How to Celebrate National Pollinator Week: Go Native! Don’t forget to include host plants for butterflies when you create a pollinator habitat. If you are concerned that defoliated plants will detract from your garden, then place host plants in unobtrusive places where you do not need to remove dead foliage or flowers, which may harbor eggs or developing butterflies. Then, take some time to observe and enjoy the visitors that your garden attracts. You never know what surprises and delights await you!