What Do Cabbage White Butterflies Eat? Brassicas, Then Nectar
What do cabbage white butterflies eat? The answer depends entirely on which life stage you’re looking at. Pieris rapae caterpillars chew through cabbage, kale, and other mustard-family leaves, while the white-winged adults switch to sipping nectar through a coiled proboscis. The two diets barely overlap, and that split is exactly why this species does so well in both vegetable gardens and open meadows.
Four Stages, Two Very Different Diets
Cabbage whites go through a complete metamorphosis: egg, larva, pupa, and adult. Only two of those stages actually eat.
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Egg: Females glue single pale-yellow eggs to the underside of Brassicaceae leaves, usually one per leaf rather than in clusters, and a female can lay several hundred over her lifetime.
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Larva (caterpillar): The velvety green caterpillar is the feeding machine of the life cycle, eating almost continuously for two to three weeks.
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Pupa (chrysalis): Caterpillars pupate on stems, fences, or nearby structures and take in nothing while they reorganize into a butterfly, a process that can take one to two weeks in summer or last through winter in colder regions.
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Adult: The emerged butterfly drinks nectar exclusively; it has no chewing mouthparts left to eat leaves even if it wanted to.
What the Caterpillars Actually Eat
Cabbage white larvae feed almost exclusively on plants in the Brassicaceae (mustard) family. Purdue University’s Vegetable Crops Hotline notes that their caterpillars do significant damage to plants in the Brassica family, including cabbage, broccoli, cauliflower, and collard greens. In gardens and farm fields, the short list of favorite hosts includes:
Cultivated Crops
- Cabbage: The namesake host and still the most heavily damaged crop.
- Kale: A frequent target, especially young, tender leaves.
- Broccoli and cauliflower: Larvae chew through both leaves and developing florets.
- Brussels sprouts: Young leaves draw egg-laying females before the sprouts even form.
Wild Hosts
Away from vegetable beds, caterpillars also survive on weedy relatives: wild mustard, shepherd’s purse, and peppergrass all grow along roadsides and field edges and can sustain a population even where no crops are planted.
Why Mustard-Family Plants Specifically
Brassicaceae leaves contain mustard-oil compounds called glucosinolates, which break down into isothiocyanates that repel most insects. Cabbage white caterpillars are one of the few species with the enzyme to neutralize that defense, so a plant that poisons other herbivores is simply food to them. That biochemical workaround is the main reason the caterpillars are locked onto this one plant family instead of feeding more broadly.
How Caterpillars Feed
Young larvae often start out feeding side by side on the same leaf, then scatter to feed alone as they grow larger. They eat the soft leaf tissue between veins first, leaving a skeletonized, ragged leaf behind, and a single caterpillar can strip a young seedling in days.
What the Adults Drink
Once the butterfly emerges, its diet shifts entirely to liquid. Adults use a long, straw-like proboscis to probe flowers for nectar, which fuels flight and egg production.
Preferred Flowers
- Composite flowers (Asteraceae): Asters, daisies, and dandelions are regular stops.
- Lantana: A reliable nectar source in gardens through the warm months.
- Butterfly bush (Buddleja): Its dense flower clusters draw cabbage whites along with many other species.
- Verbena and red clover: Both are common low-growing nectar sources in meadows and lawns left to flower.
Feeding Behavior
Cabbage whites tend to favor purple, blue, and yellow blooms over white or red ones. A single butterfly visits many flowers in one outing rather than lingering at one plant, spreading pollen as it goes.
Why Adults Also Visit Mud and Wet Soil
Nectar is rich in sugar but nearly empty of sodium and amino acids, so adult butterflies top up on minerals by a behavior called puddling. The Coastal Georgia Botanical Gardens describes how butterflies use their proboscis to absorb essential nutrients from the substrate, including salts, amino acids, and minerals like sodium, because nectar lacks many of these essential nutrients. Males puddle more often than females, and the minerals they gather are passed to females during mating, which can improve egg viability.
What This Means for Gardeners
Knowing the diet split changes how you manage cabbage whites. Caterpillar damage is a leaf and crop problem; adults are pollinators you generally want around.
Reducing Caterpillar Damage
- Floating row covers: Physically block egg-laying females from reaching young brassica transplants.
- Companion planting: Interplanting with strong-scented herbs can make it harder for females to locate host leaves by smell.
- Parasitic wasps: Braconid wasps such as Cotesia glomerata parasitize the caterpillars and are a major natural check on populations.
Working With the Adults
Handpicking caterpillars off leaves is still the most direct organic control, and it does nothing to discourage the nectar-feeding adults. Planting asters, verbena, or lantana nearby keeps adult butterflies (and other pollinators) fed without adding more egg-laying targets near your brassicas.
