Scribbly Gums

You’d be forgiven in think that the fairy children have had at it with crayons on their walls, the scribbles on the trunks of certain Eucalyptus trees look just like a kid has had a delightful time. The wiggly lines scratched into the bark are actually scars left by the scribbly gum moth larvae. There are several Eucalyptus species that are commonly called scribbly gums - as with many common names, it isn’t specific to any one plant, but simply any gum tree with scribbles on the bark! Some of the species include Eucalyptus racemosa, E. rossii and E. haemastoma, which are all found up and down the East coast of Australia (E. rossii is found further inland).

A scribbly gum at Indigiscapes

There are a few different species of the moth, all with their own characteristic patterns. The moth lays their eggs in the bark of the tree, and the larvae hatch, meandering their way around between the bark layers, eating the cambium layer - or the part of the tree trunk that has the growing cells - the cells that make new bark. The tree fills these tunnels with even more new cells, trying to heal the initial tunnels. Eventually the moths turn around(!), and eat their way back through the tunnel again, which has been conveniently filled with nutritious delicacies (in larvae world). The last part of the larvae grow fast and once they’re satiated, emerge, forming cocoons at the base of the tree.

Not long after the larvae have finished their feast, the trees are ready to shed their bark. The top layer of bark falls off and reveals the scarred scribbly artwork of the moth larvae.

The bark hardens, the cocoons hatch, and the new moth generation lays eggs to start next year’s masterpieces.

The same gum. So majestic!