Butterflies and caterpillars have distinct dietary needs that vary significantly between their life stages. The larval form, the caterpillar, has vastly different food requirements than the winged adult butterfly. Understanding these specific feeding habits is key to appreciating their life cycle and supporting their populations.
Adult Butterfly Nourishment
Adult butterflies primarily sustain themselves by drinking nectar from flowers, which provides the sugars necessary for their energy and flight. They accomplish this using a specialized mouthpart called a proboscis, a long, flexible tube that coils up when not in use. When feeding, the butterfly unrolls this proboscis, extending it deep into flowers to access the sweet liquid. This feeding mechanism allows them to extract nectar even from tubular blossoms.
Beyond nectar, adult butterflies also seek out other liquid food sources to supplement their diet. Some species are attracted to the juices of rotting fruit, tree sap, and pollen. Many butterflies, particularly males, engage in a behavior known as “puddling,” where they sip mineral-rich fluids from damp soil, mud puddles, animal dung, or even human sweat. This activity provides essential salts, amino acids, and minerals like sodium, which are often lacking in nectar and are important for reproduction.
Caterpillar Food Sources
Caterpillars, the larval stage of butterflies, have a diet that contrasts sharply with that of adult butterflies. They feed exclusively on plant matter, specifically the leaves of certain “host plants.” These host plants are necessary for a caterpillar’s growth and development, as they cannot survive without consuming the leaves of their specific plant. A female butterfly will lay her eggs only on the specific host plant that her offspring require for sustenance.
A well-known example of this specialized diet is the Monarch butterfly caterpillar, which feeds solely on milkweed plants. Milkweed contains certain chemical compounds that, while toxic to most vertebrates, are tolerated by Monarch caterpillars and even provide them with a defense mechanism against predators. Similarly, Black Swallowtail butterfly caterpillars have a very specific diet, consuming plants from the carrot family such as parsley, dill, fennel, and wild carrot (Queen Anne’s lace). Other butterfly species, like fritillaries, depend on violets as their host plants, while many types of caterpillars feed on oak trees.
Creating a Butterfly-Friendly Garden
Establishing a garden that supports butterflies involves providing both nectar sources for adult butterflies and the specific host plants needed by their caterpillars. Planting a variety of bloom times ensures a continuous supply of nectar throughout the growing season, accommodating different butterfly species and their emergence periods. Incorporating native plants is beneficial, as local butterfly populations have evolved alongside these plants.
For attracting adult butterflies, consider planting milkweed varieties, zinnias, Joe-Pye weed, asters, phlox, and sunflowers. To support the caterpillar stage, include native milkweed for Monarchs, and herbs like parsley, dill, or fennel for Black Swallowtails. It is also important to avoid the use of pesticides in your garden, as these chemicals can harm or eliminate both caterpillars and adult butterflies. Creating shallow puddling stations with moist sand or soil can also provide essential minerals for adult butterflies, enhancing the garden’s appeal.