@ThylacineAlive Are they? I thought there were laws restricting trade of potential invasives, especially insects. Having worked at a butterfly house before, I know FDA is very strict on that sort of thing... If they found any sort of hole in the building to the outside they would shut it down instantly according to regulations is my understanding. Any eggs/caterpillars we found had to be killed...
This isn't some dodgy initiative of the zoo. The beetle is host-specific to Purple Loosestrife, it was tested on a large number of native American plant species before release, and they have been released throughout North America since 1992.