The moth is named after the red mineral cinnabar because of the red patches on its predominantly black wings. It feeds mainly on Ragwort plants. Cinnabar moths are about 20mm long and have a wingspan of 32 to 42 mm (1.3-1.7 in). They are day-flying insects and like many other brightly coloured moths, it is unpalatable due to its food source. An exception is the Cuckoo which eats hairy and poisonous caterpillars including cinnabar moth larvae. Cinnabar moths are about 20mm long and have a wingspan of 32 to 42 mm (1.3-1.7 in). They are day-flying insects and like many other brightly coloured moths, it is unpalatable due to its food source. An exception is the Cuckoo which eats hairy and poisonous caterpillars including cinnabar moth larvae. Females lay up to 300 eggs, usually in clusters of 30 to 60. The larvae are pale yellow, but later larval stages develop the jet black and orange/yellow striped colouring. They can grow up to 30mm, and are voracious eaters; large populations can strip entire patches of ragwort clean, a result of their low predation. The cinnabar caterpillars can turn cannibalistic. This can be due to lack of food, but they can eat other cinnabar larvae for no apparent reason.
