There are a few well-meaning people out there who are negatively affecting monarch butterflies through their efforts.
We get to see instances of people with sunscreen on their hands handling caterpillars, or covering plants with dirty nets which probably carry all sorts of diseases. Plug-in insect controls, pets with flea collars on, or using seedlings with pesticide residue for food are other concerns.
In California laws have recently been passed against “captive rearing” because it is harmful to the species . “…decreased fitness, poorer overall condition and reduced migratory propensity compared to wild monarchs” has been proven. Handling can also increase stress in monarch larvae and pupae and has the potential to spread Oe.
The migration of monarchs in North America has been negatively impacted over many years by human intervention. You can read more at this link:
Of course, the NZ government won't introduce laws as monarchs are not endemic but the MBNZT can spread the message about best practice.
From time to time you will see our messages in social media. Please share them and encourage others to adopt best practice too. Here's one: