Scribbly gum (Eucalyptus haemastoma) is an Australian tree that is named after the 'scribbles' on its bark. The intricate zigzag tracks are tunnels made by the larvae of the moth Ogmograptis scribula. These photos were taken in the Conjola National Park, south of Sydney.
Eggs are laid between layers of old and new bark. The larvae burrow into the new bark and, as the old bark falls away, the trails are revealed.
The diameters of the tunnels increase as the larvae grow, and the ends of the tracks are where the larvae stopped to pupate.
Together with the bark peel markings and other trunk features, the patterns take on a playful character.