I have assumed this is a Helena gum moth. Am I correct? They are currently being savaged by something that isn't necessarily eating them. They end up on the ground full of larvae (I assume fly of some sort).
I have heard gum moths larvae are susceptible to parasitic insect attack by introduced insect species but I have yet to see authoratative research on the topic. Someone reading this may be able to help with a reference. A NZ paper on Polities (genus) wasps shows data saying they have most impact on native Lepidoptera: https://link.springer.com/article/10.1007/s10530-022-02739-0
Do you reckon the black spots on my specimen are necrotic? I can photograph the larvae that were in the one I found yesterday. I had assumed they took over once whatever had attacked the moth caterpillar had killed it. But it could be a wasp being (well) just like a wasp.
Just looked at the paper on wasps. That seems to be two species of paper wasp neither of which we have here as far as I know. And actually we don't even have native paper wasps. Also they seem to be wasp species that take larvae home for their offspring to consume rather than wasp species that lay eggs in other animals' larvae. Images of the larvae of the two wasps do not match the larvae in the O. helena that I have.