Dick called me out to see this clump of writhing larval caterpillars
they are the the larva of a wasp related to the Cherry and Pear Slug.
This particular clump is of the Eucalyptus Sawfly (Perga Kirbyi)

When disturbed larvae tap their abdomens up and down and regurgitate a thick,
greeny-yellow juice. This is a very effective deterrent for would-be predators and parasites.


Eucalyptus trees have a great ability to recover quickly after the initial attack
unless such factors as drought or other insects further weaken the trees.

Predators, many birds find the larvae distasteful but currawongs and cuckoo-shrikes will eat them.
Pardalotes, honeyeaters and fantails will occasionally feed on the eggs and several birds will eat the adults.
Larvae will also be eaten by lizards and frogs.

[Info via Primary Industries and Resources, S.A.]