Thanks. But I notice caterpillars thrive on so many other plants and in fact they are quite destructive
This can be difficult to undestand . This particualr catapillar pretty much eats ONLY this noxious toxic weed. This is a good thing for the monarch butterfly as it makes it dis-tastful and toxic for any predator that would like to eat it (the butterfly/cataplillar that is). The monarch butterfly besides being nice looking has a pretty interesting species life cycle. Adults that emerge from pupa state in my area or even up in Canada in late summer or fall will make a 3000 mile journey south to Mexico or California before it gets to cold. They will never return, their great grandchildren will the following summer.
