A caterpillar is the larval stage of an insect in the order Lepidoptera, which includes all moths and butterflies. Caterpillars are dedicated to consuming and storing energy before their transformation. A white caterpillar will always turn into an adult moth or butterfly through a process known as complete metamorphosis.
The Process of Change
The transformation from a caterpillar to a winged adult is a biological process involving four distinct stages. The life cycle begins with the egg, which hatches into the larva, or caterpillar, the stage dedicated to growth and foraging. After reaching its maximum size, the caterpillar prepares for the third stage, the pupa.
During the pupal stage, larval tissues are broken down and reorganized into the adult structure. For butterflies, this protective shell is called a chrysalis, which is typically smooth and hangs from a silk pad. Moth caterpillars usually spin a silk covering called a cocoon, often incorporating debris or leaves for camouflage, to protect the pupa inside.
The adult insect emerges from the pupal casing. The adult’s purpose is reproduction and dispersal, completing the cycle. The duration of this pupal stage varies greatly, sometimes lasting only a few weeks, but occasionally extending for months to survive winter conditions.
Common White Caterpillars and Their Adult Forms
The identity of the adult insect depends on the specific species of white caterpillar observed. One common white-colored larva found in gardens is the Imported Cabbage White butterfly (Pieris rapae). Though often pale green, these larvae can appear whitish while feeding on cruciferous plants like cabbage or broccoli. They mature into a familiar white butterfly with one or two black spots on each forewing.
Many white, hairy caterpillars belong to the moth family, specifically the tiger moths. The Virginian Tiger Moth (Spilosoma virginica) is frequently encountered in its larval form, often called a white woolly bear. This caterpillar, which can range from white to pale yellow, transforms into a white moth that has a small pattern of black dots running down its abdomen.
The Hickory Tussock Moth (Lophocampa caryae) caterpillar is covered in fuzzy white hairs and features distinct black tufts or “pencils” near the front and rear. This larva becomes a rusty-brown moth with cream-colored blotches across its wings. These adult forms highlight that a white caterpillar can become either a moth or a butterfly, with moths being the more common outcome for fuzzy white larvae.
Identifying Key Features of White Larvae
To determine what a white caterpillar will become, observation of its physical features and habitat is necessary. Hairy or “woolly” white caterpillars are almost always the larvae of moths, such as the numerous species of tussock or tiger moths. The density and arrangement of these hairs, whether in tufts or evenly distributed, are important distinguishing characteristics.
Conversely, caterpillars that are smooth-bodied, or have only sparse, fine hairs, are more likely to be butterfly larvae. The presence of specific markings, such as subtle stripes, dark spots, or unusual structures like a tail horn, can narrow the possibilities. The Catalpa Sphinx caterpillar is pale yellow-white with dark markings and a black horn, and it exclusively feeds on catalpa trees before turning into a large, grayish-brown moth.
The host plant or environment where the larva is found provides another key piece of evidence. A white larva found burrowing in the soil and curled into a “C” shape is typically a white grub, which is the larva of a beetle, not a caterpillar, and will become a Japanese beetle or a similar scarab. Combining the creature’s appearance—hairy or smooth—with its feeding location allows for a more accurate prediction of its adult form.