The passion vine hopper has lovely lacy wings – and that’s the only nice thing I know about this little Ozzie overstayer. For the PVH, as it is known to the cognoscenti, is the real fly in the ointment (well, bug in the honey) in the latest poisoning episode in the Coromandel.
If ever an ecologist needed an example to illustrate the interdependency of humans and their natural environment, then the toxic honey story is a graphic example. Consider the elements needed in this tragic drama:
- a long, dry autumn – frequently experienced on the East Coast of New Zealand
- tree tutu – a poisonous native shrub
- PVHs – greedy, sap-sucking insects
- honey bees – to collect the toxic wastes from the PVHs to transform into honey
- humans – to consume the toxic brew.
Remove one element and there’s no problem: in parts of New Zealand where tree tutu is uncommon or where temperatures are too cool for PVHs, toxic honey is not produced. If there is plenty of rain during summer and autumn, the poisonous drops from the bums of the PVHs are washed off the leaves of the tutu bushes and honey bees search for another food source.
One of the tragedies of this recent poisoning episode is that some people seem to have forgotten that toxic honey poisoning is not uncommon and has a well-documented history in New Zealand. Up until 2008, 294 cases of toxic honey poisoning, including six deaths, had been notified (see page 16 of Supply of and demand for pollination hives in New Zealand).
In the late 19th and early 20th centuries there were probably other poisoning episodes that were never officially notified. This article from 1902 (in Te Reo Māori) records the deaths of some young men who chanced upon a beehive and sampled its honey.
Scientists worked out the links between the insects, climate, tutu and poisonous honey in 1947, and the following year the government brought in regulations preventing beekeepers from placing their hives in the Coromandel and eastern Bay of Plenty areas during December–May. These regulations have now been relaxed, but commercial beekeepers are required to check that their bees are not gathering honeydew from toxic sources.
Toxic honey isn’t the only problem with PVHs. They’ve also been implicated in spreading diseases to cabbage trees, flaxes and strawberries, and are responsible for producing the honeydew that feeds the sooty moulds that ruin kiwifruit.
It’s time for these little hoppers to pack their swag, pick up some of their possum cobbers along the way and head back home.