Caterpillars are not similarly colored. They are brownish-black with yellow speckling. They are also covered in spines. To further protect themselves, they flick their fecal material far from themselves in order to obscure their location. Caterpillars feed on lichens found on tree trunks, stones and even buildings. Lichens are a symbiotic organism: part fungus, part algae or bacteria. The two organisms work together and enhance their ability to survive and thrive. The fungus offers structure and water collection abilities; the algae or bacteria photosynthesize sunlight to create food. Lichens are typically slow-growing, spreading over a surface at a rate of about 1 cm a year. The Painted Lichen caterpillar has also been seen eating its smaller siblings and pupae.