I can attest to the fact that the Oleander caterpillar infests, defoliates and yet doesn't kill the plant. Here in central Florida many municipalities and even the federal government used this plant as an attractive large shrub in public areas like parks, library grounds and in the medians of highways. The practice has been stopped as it was discovered that all parts of the plant are toxic to humans including smoke from burning plants. Nerium oleander is probably mediterranean in origin (it is mentioned in old roman texts) but cultivated all around the world. It was introduced into Florida by Spanish explorers and the Oleander moth (likely a caribbean native) soon followed. Amazingly, the moth and its caterpillars seem to prefer Adenium to Nerium when both are available. I say this from my own experience. If the adenium in my yard are actively growing then the moth ignores the Nerium and the Adenium get all the eggs. I do have two only two oleander but hundreds of desert roses so maybe my experience would be different if the numbers were reversed. One last thing, the toxic chemical compound in Nerium is the same as that which causes Adenium to be toxic.
Here's a site that covers the Oleander Moth in Florida. Note that it doesn't mention Adenium
https://entnemdept.ufl.edu/cre...
