Emperor Gum Moth
PHOTO CAPTION: Elachista rufocinerea (Photo taken by Keith Edkins)
The Elachistidae are a family of Lepidoptera (moths). Their larvae have a wide variety of habits including leaf tiers, seed borers, and leaf or stem miners. The Emperor Gum Moth (Opodiphthera eucalypti) is a species native to Australia, and can be easily found in all the states except for Western Australia, South Australia and Tasmania.
The eggs are laid on a leaf either singly or several in a row usually on native eucalyptus trees although they can sometimes be found on introduced species such as the peppercorn, silver birch, liquidamber and apricot trees. They are pale cream in color and are approx 2mm in length. They hatch between 7-10 days after being laid.
Caterpillars can typically be found on young adult leaves between October and March (the Australian Spring and Summer). When the caterpillars hatch they are black with short hairs on top of little nodes on their bodies called tubercles. These hairs are not poisonous and will not sting. As the caterpillars mature they change color each time the shed their skin (which totals to 5 stages in the caterpillars appearance). By the final stage before pupation the caterpillars have develop striking coloration, having a yellow/cream stripe down their bright green/blue body and nodes of red and blue. Despite this they are still surprisingly hard to spot. The caterpillar stage in the Emperor Gum Moths life cycle can last for many weeks, depending on the temperature and weather conditions.
When the caterpillar is fully mature it spins a dark brown silken cocoon on a branch which usually has a leaf to protect it with. The moth emerges from the cocoon the following year (in Spring or early Summer). However, depending on weather conditions, the moth can stay in the cocoon from anywhere between 2 and 5 years. One case has even been recorded of a moth emerging out of the cocoon after 10 years! When the metamorphosis is complete, the adult moth regurgitates a fluid to soften the tough cocoon and then cuts a hole using sharp hooks on the base of each forewing. After this is done, the moth emerges and rests while its wings dry and expand.
The Emperor Gum Moth does not feed after it emerges from the cocoon, relying solely on the energy they stored as caterpillars. Their adult life span is limited to a couple of short weeks in which they mate, lay eggs and die. The moths, like the caterpillars, are very striking. The Emperor Gum Moth is a very large moth, having a wingspan of 120mm-150mm. Females are generally larger than males. The furry wings and body are multi colored, but are in overall tones of pale reddish/brown. The wings are decorated with four prominent “˜eyes’ and various other markings in a symmetrical formation. The antennae of the males are feathery, while the females are thinner and with less hairs.