The Venomous 'Mad Hatterpillar': A Crown of Old Heads

The Gum leaf skeletonizer, also known as the Mad Hatterpillar, is a caterpillar found in Australia and New Zealand that wears its old head capsules as a crown. This macabre adornment serves as a defense mechanism, confusing and deterring predators. The caterpillar is covered in venomous spines that can cause caterpillar dermatitis in humans. It feeds on eucalyptus leaves, often in groups, and can slow the growth or kill eucalyptus trees. To control their population, a parasitoid wasp has been introduced as a biological control agent in New Zealand.