Itchy caterpillars

Australian Lepidoptera (moths and butterflies) contains several species of caterpillars that cause irritation when in contact with humans. They are armed with irritating hairs or stinging spines which serve as protection against predators. 

There are 2 types of hairs. Some can be envenomating, where they are tubular and hold a venom or irritant produced by a gland at their base. Under pressure, the tips of these hairs can break releasing their contents. 

The other type of hair is referred to as non-envenomating. These hairs do not contain venom but rather cause inflammation through mechanical irritation. 

These hairs can be easily dislodged from the caterpillar and adhere to the surface of the skin on contact or through air borne drift. Airborne hairs can land on surfaces which humans may contact such as bed linen and clothing. Disturbance of old larval skins will also cause irritation, as the hairs retain their properties long after the caterpillars have pupated.

Common NT Lepidoptera problem species

Itchy caterpillars

• freshwater mangrove itchy caterpillar
• stringybark itchy caterpillar
• bag shelter moth or processionary caterpillar

Stinging caterpillars

• cocky apple stinging caterpillar
• river red gum moth (locally) or mottled cup moth (CSIRO)

There are a number of other species of stinging caterpillars in the Top End that are usually brightly coloured with stinging tubercules on the dorsal surface similar to the River Red Gum moth larvae.