What Do Caterpillars Eat? Host Plants

Spicebush Swallowtail Caterpillar eating on Camphor Tree

Spicebush Swallowtail caterpillar
eating a Camphor leaf

The plants that caterpillars eat are called host plants while the plants that adult butterflies eat (actually they “drink” nectar from the flowers) are called nectar plants. Each species of butterflies has specific host plants on which the adult butterflies lay their eggs.

Listed below are several popular butterfly species and the host plants that their caterpillars eat.

The butterflies are particular about where they lay eggs because their caterpillars must have that distinct host plant to survive. The caterpillar will not eat if it does not have access to one of its specific host plants and will die.

Some caterpillars are so picky that there is only one plant type that will support them. Many caterpillars will eat from more than one plant types.

Giant Swallowtail caterpillar with osmeterium

Giant Swallowtail caterpillar on one of its host plants, Rue

You may find that in one region of the country the butterfly caterpillars may prefer to eat a specific variety of their host plant more so than in other regions. I’ve read that this can even vary from garden to garden and may be due to changes in soil types, pH, etc. So it is hard to say which is the “best” host plant for a certain butterfly.

If you are raising caterpillars indoors and you happen to run out of caterpillar food, you will probably be successful in changing their food source as long as it is in their group of host plants. Many caterpillars will easily eat from several food plants within their normal host plant range.

For example, we have had success with switching between fennel, parsley, dill or rue for a Black Swallowtail caterpillar. We have also had success in raising a Monarch caterpillar while switching out different milkweed varieties. Hopefully the table below will help you find something to feed your caterpillar if you happen to run out of food.

zebra longwing caterpillar

The Zebra Longwing butterfly/caterpillar is found in the deep south. The spikes are soft and do not hurt
Source: DeadEyeArrow reproduced under
Creative Commons

An excellent book that will help with choosing what caterpillar food plants to grow in your area is The Family Butterfly Book by Rick Mikula. It has a section about best butterflies, host plants, and nectar plants, broken down by regions of the US including Hawaii, Alaska and parts of Canada. It is well illustrated with a lot of good information about raising butterflies.

Here is a list of some common and/or popular backyard garden butterflies and what their caterpillars eat. Joyful Butterfly sells several of these plants and seeds. All of our plants, and of course, seeds are safe for caterpillars and butterflies. Some of the plants listed below can be found in local nurseries but ask about pesticide use if you are planning to buy them to feed caterpillars.

What Caterpillars Eat:

BUTTERFLY SPECIES HOST PLANTS
Anise Swallowtail anise, parsley, carrot, dill, fennel, rue
Eastern Black Swallowtail_________ parsley, carrot, dill, fennel, rue
Giant Swallowtail citrus, hop tree, prickly ash, rue
Pipevine Swallowtail dutchman’s pipe, pipevines (not the exotics), Virginia snakeroot
Spicebush Swallowtail spicebush (primarily), sassafras, camphor tree (Cinnamomum camphora), various bays (Persea spp.)
Eastern Tiger Swallowtail many broadleaf trees and shrubs, lilac, willow, birch, tuliptree, cherry
Zebra Swallowtail pawpaw
Monarch Milkweed (Asclepias)
Viceroy willow, poplar, aspen, apple, cherry, plum
Red-Spotted Purple apple, aspen, cherry, hawthorn, hornbeam, poplar, willow
Great Spangled Fritillary violets, (Viola tricolor)
Variegated Fritillary Violets, (Viola tricolor), pansies, stonecrops, passionflowers, plantains
Meadow Fritillary violets (Viola sororia, Viola pallens)
Mourning Cloak elm, poplar, willow
Question Mark elm, hackberry, hop, nettle, false nettle (Boehmeria cylindrica)
Green Comma rhododendron, azalea, birch, willow
Red Admiral nettle, false nettle (Boehmeria cylindrica), hop
Painted Lady members of the mallow family, Malva sylvestris, Tree mallow (Lavatera), thistles, goosefoots
American Painted Lady daisies, everlastings, other composites, Hollyhock (Alcea rosea)
Buckeye plantain, snapdragon, stonecrop, verbena, (Verbena bonariensis), other garden flowers
Baltimore Checkerspot turtlehead, false foxglove, plantain, white ash
Pearly Crescentspot asters New England Aster (A. novae-angliae)
Great Purple Hairstreak mistletoes
Gray Hairstreak cotton, mallows, strawberry, legumes, mints
American Copper sheep sorrel, curly dock, mountain sorrel
Tailed Blue clovers, beans, peas
Spring Azure blueberry, California lilac, dogwoods, meadowsweet, viburnums
Cloudless Sulphur senna, clovers, other legumes
Clouded Sulphur clovers and other legumes
Orange Sulphur white clover, alfalfa, vetch, lupine
Dogface false indigo, clovers, lupine, vetch, leadplant
Checkered White crucifers, Cleome
Cabbage White Cabbage, Mustards, other crucifers, nasturtium
Zebra Longwing passionflowers
Gulf Fritillary passionflowers, (Passiflora caerulea)
Malachite yerba papagayo

 

Monarch butterflies and Black Swallowtail butterflies (Anise Swallowtail butterflies in the West) are popular, easy, and beautiful caterpillars/butterflies to raise indoors. They are found throughout most of the US and beyond. If you are new to raising butterflies then you may want to start by planting what these caterpillars eat. Parsley (curly or flat leaf) and common rue are my personal favorites for Black Swallowtail caterpillars in my Southeast area and Tropical milkweed (Asclepias curassavica) is my current favorite for the Monarch caterpillars.

These plants are attractive and well behaved in a garden setting and the Milkweed has the added advantage of being a popular nectar plant as well. Parsley can be found in most local garden centers (but ask around about pesticides that may have been used on the plants – it will kill the caterpillars). The common rue plant is a perennial and will start easily from seeds or cuttings. Tropical milkweed starts easily from seed and is a quick growing annual. You can harvest the seed in the Fall to start your new plants next Spring.

Many people already have nectar plants in their gardens that attract some butterflies. By adding what the caterpillars eat you will greatly increase the number and duration of butterflies and this gives you the opportunity to watch the amazing life cycle of a butterfly in your own garden!