Christmas beetles (the Australian Anoplognathus and related species) mainly feed on the leaves of eucalyptus trees during their adult stage. In some cases they may also nibble other tree or shrub foliage, including rose leaves, but eucalyptus leaves are their primary food source. The larvae (grubs) live underground and feed on grass roots and decaying organic matter.

If you’re dealing with them in your garden or yard:

• Expect adults to appear in midsummer, sometimes in large numbers, and they can defoliate eucalyptus trees or other leafy hosts briefly as they feed.

• For captive or educational observations, adults typically eat fresh eucalyptus leaves, and sometimes other soft foliage like rose leaves.

• Control or mitigation in planted areas can focus on promoting tree health and managing grasses where larvae reside, though natural predators in the environment (birds and certain wasps) can help keep populations in check.

If you’d like, I can tailor this to your location or specific plants you have, or help with non-harmful ways to observe their lifecycle.