monarchs and swan plants

[John Grehan]

 Man also introduced the North 
>American monarch to Australia in the mid-1800's. The monarch migration in
Australia 
>and New Zealand is thus a recent man made phenomenon. 

It was my understanding that the monarch was already in NZ and Australia
before human introduction of the host-plant, but that they were not able
to permanently establish in the absence of the hostplant. I also understand
that there is no migration phenomenon like that in America - is that correct?

John Grehan