Colossia Moth: The Giant Leopard Moth and Its Caterpillar
Learn about the giant leopard moth, from its harmless "woolly bear" caterpillar to its striking, spotted adult and its role within its ecosystem.
The Colossia moth, more commonly identified as the giant leopard moth (Hypercompe scribonia), is a large, visually distinct insect in the tiger moth family found across North America. This species is notable for both its unique adult form and its equally recognizable caterpillar stage. While widespread, it is an uncommon sight, which makes an encounter with one a noteworthy event.
Identification and Appearance
The adult giant leopard moth has bright white wings covered in a pattern of black or iridescent blue spots. Many spots are hollow, resembling open rings, while others are solid black. This distinct patterning gives the moth its common name, and its wingspan can reach up to three inches. These moths are nocturnal and often drawn to artificial lights.
When at rest, the wings conceal a vibrantly colored abdomen. The top side is dark, iridescent blue with orange or yellow markings, while the underside is white with solid black spots. This flash of color is revealed when the moth is disturbed. Males are larger than females, reaching about two inches in body length compared to the female’s 1.2 inches, and may have a thin yellow line on their abdomen.
As the moth ages, its wings can lose scales, causing the edges to appear translucent. The legs also feature distinct black and white bands.
The Woolly Bear Caterpillar
The larval stage is a “woolly bear” caterpillar with a thick coat of stiff, black bristles called setae. Reaching up to three inches long when fully grown, it is one of the largest woolly bear species. The dense, spiny-looking hairs cover its entire body in a deep black color.
Beneath the bristles, the caterpillar’s body has bright red or orange bands between its segments. These colorful rings become visible when the caterpillar feels threatened and curls into a tight ball. This defensive posture protects its vulnerable underside and presents a difficult shape for predators to handle.
The stiff bristles are not venomous or urticant and do not cause irritation for most people. While they may feel prickly, they are considered harmless to touch. The caterpillar’s defense relies on its coiled posture and unpalatability, not venom.
Life Cycle and Reproduction
The giant leopard moth undergoes a complete metamorphosis that can span up to two years. After emerging, adult moths mate, and following mating, the female lays her pearly gray, spherical eggs, often on the leaves of host plants.
Once hatched, the caterpillars feed and grow, molting several times. The caterpillar is the longest stage of the moth’s life, and it is in this form that the insect overwinters. It seeks shelter under decaying tree bark, in woodpiles, or within leaf litter.
In the spring, the caterpillar emerges to feed again before it pupates. It spins a thin cocoon, incorporating its own setae into the structure. Inside, the pupa develops for several weeks before the adult moth emerges. In southern parts of their range, they may complete two broods a year, while in the north, there is only one.
Habitat and Diet
The giant leopard moth is found from southern Canada through the eastern and southern United States, extending into Mexico and Central America. Its habitats are diverse, including forests, open woodlands, fields, and suburban gardens. The caterpillars can be found searching for food or overwintering sites on the ground.
Only the larval stage of this species eats, as adult moths live only to reproduce. The caterpillars are generalist feeders, consuming the leaves of many broad-leaved plants. Their host plants include:
- Dandelions
- Violets
- Plantains
- Sunflowers
- Willows
- Maples
- Cherries
- Magnolias