Male and female cabbage whites are white with dark wingtips. Females have two black spots in the center of the forewings; males have one. The dark markings may be faint, especially in spring. The underside is yellow-white.
Larvae (called cabbageworms) are green with yellow lines along the top and sides.
Wingspan: 1¼–1¾ inches.
Statewide.
Habitat and Conservation
Any type of open habitat, ranging from fields and roadsides to urban lawns. They occasionally fly in heavily wooded areas before trees leaf out in spring. The larvae are well camouflaged and typically rest on the undersides of leaves of their host plants.
Food
Larvae feed on plants in the mustard family, both wild and cultivated. The latter group includes cabbage, kale, broccoli, cauliflower, radish, and horseradish, making this species an economically significant pest. Adults do not feed on vegetation, and their foraging for nectar from flowers helps to pollinate them.
Status
Breeding resident statewide; often a pest species on commercial plants in the mustard family. Accidentally released in Quebec in 1860 (probably from imported cabbages), this species spread rapidly and reached Missouri by 1877.
Life Cycle
Adults fly from March through October, and there are continual broods throughout this time. Eggs are laid singly on the leaves of host plants. Although remarkably cold-hardy, cabbage whites generally overwinter in the pupal form, and they are among the first butterflies to emerge in spring.
Human Connections
This nonnative butterfly has become so common that we scarcely think of it as “exotic” anymore. Although pretty to behold, and butterflies generally cheer us up, especially in early spring, the cabbage white is also an agricultural pest.
The great 19th-century French entomologist J. H. Fabre studied a close relative of this butterfly and marveled at the egg-laying female's ability to select not just plants in the cabbage family, but certain species that seem to be special favorites. He noted that a botanist would have to examine flowers and seedpods to make such fine identifications, but the mother butterfly instinctively "knows this group to perfection." Later, entomologists would learn that butterflies "taste" plants with sensory organs on their legs.
Ecosystem Connections
The caterpillars are herbivores that graze on vegetation, including wild mustards. The adults serve a role in pollination. All stages provide food for predators that range from other insects to birds, reptiles, and mammals.
