White-stemmed Gum Moth

Introduction

The White-stemmed Gum Moth is one of the largest common moths found in Sydney. With females reaching a size of 16 cm, they have sometimes been mistaken for bats.

Identification

The wings of the female White-stemmed Gum Moth are attractively patterned with soft grays and browns. The male is slightly smaller and is darker, with more strongly contrasted markings. Both sexes are active at night. They sometimes fly to lights where the large females have been compared to bats as they move around the light source. As in many moth species, the males have large bipinnate (feathery) antennae, while the females have narrow, simple antennae.

The large, thick caterpillars are grey-black with yellow bands and are covered with tufts of reddish-brown spiky bristles. The bristles can penetrate human skin and cause painful skin irritations, even after the larvae have been preserved in alcohol.

Habitat

The White-stemmed Gum Moth lives in urban areas, forests and woodlands, heath.

Distribution

The White-stemmed Gum Moth is found in southern Queensland, New South Wales and Victoria. There are more than 70 other described Australian moths in the family Anthelidae, with many more species yet to be described. Anthelids are found only in Australia and Papua New Guinea and are most closely related to silk moths (Bombyciidae) and emperor moths (Saturniidae).

Feeding and diet

The caterpillars of the White-stemmed Gum Moth feed on gum trees.

Life history cycle

The White-stemmed Gum Moth has an annual life cycle. The pupal stage lasts over late summer and most of autumn before the adult moths emerge in May.

The females lay eggs that hatch into small caterpillars. The caterpillars feed on eucalypt leaves and grow throughout the rest of the year until they reach their maximum size before pupation.

In summer, when the caterpillars are fully grown and are ready to pupate, they spin cocoons. As the caterpillar changes into a pupa, the bristles from its skin are pushed through the walls of the cocoon from the inside. The projecting bristles protect the pupa inside the cocoon in the same way that they protect the caterpillar. Pupation usually takes place under the loose bark of trees.

Adults are short-lived (two to three days) and mate soon after emerging. They do not feed because none of the anthelids have functional mouthparts as adults.

Danger to humans

The bristles of the White-stemmed Gum Moth's caterpillars are difficult to remove and although they are not known to contain toxic chemicals, handling of caterpillars and pupae of this species will cause irritation to humans. Medical attention may be necessary in some cases.

As a general rule it is not wise to handle hairy caterpillars, as many species are known to cause irritation. Irritation to skin by hairs is sometimes referred to as 'urticaria', meaning 'nettle-like'.