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Wasps are forever? The potential to eliminate an invasive pest in New Zealand; permissions withstanding

By Gemma McLaughlin, University of Otago PhD candidate

Invasive social wasps have long plagued New Zealand’s beech forests and suburbs. Now, a  genetic technology holds the potential to stop such wasps in their tracks. But one major issue lurks: are scientists even allowed to explore this option?

Wasp

New Zealand summers are a great thing. We have our kiwi classics: the barbecues, the beaches, the roadie. But we also have a less than welcome visitor that can serve as a source of irritation or just a downright disruption to the festivities; the social wasp.

These winged nuisances thrive in our environment, with densities higher here than anywhere else in the world – not really something we can brag about!

And while they can be an annoyance for us, they are a much bigger problem for other species residing here. Native caterpillars and spiders have pretty much zero chance of surviving in a beech forest during wasp season. Wasps’ domination of the honeydew produced by scale insects in beech trees leaves other insects and birds out in the cold, and may be responsible for poor breeding seasons of kākā in beech forests.

Additionally, they love to rob the honey from beehives, to the detriment of our honey production.

Typically, these wasps exist in their high densities for the summer only, then nests die down while new queens hibernate over the winter. But with climate change we can expect to see more overwintering nests surviving for multiple years with up to a million workers occupying such nests.

Wasp control options

So what can be done to counter these ravenous pests?

Gemma McLaughlin

Gemma McLaughlin

The insecticide Vespex is a great creation, capable of reducing wasp densities by up to 98% in a 24 hour period. However, Vespex is not a feasible solution for beech forest populations due to the intense number of traps needed in the area.

Also, the poison used in Vespex is fipronil, which can cause mass death to bees with a single small application. Fipronil is banned as an insecticide in many countries including the US, where it is classified as a possible human carcinogen. The harmful effects of fipronil could lead to another public outcry of its application akin to the #ban1080 movement.

One novel technique recently developed could be a great contender for wasp management or even possibly elimination.

The use of gene editing/gene drives can work by removing undesirable genes from an individuals’ genome, with these changes being passed on to the individuals’ offspring and across future generations. Such gene editing could be used to produce wasps incapable of producing one sex, so the species would slowly die off without mates to produce the next generation. This is arguably a more humane method to control a pest than poison.

While yes, gene editing is technically genetic modification, this new technique outstrips previous methods in its cost, efficiency and labour intensity. This technology is already being investigated in many countries for pest control, mainly targeting mosquitoes that are the vectors of malaria.

It is somewhat odd that New Zealand is happy to use pesticides which are banned overseas, but reluctant to employ the gene editing research that those countries are embracing. Currently our scientists are not allowed to even research the potential of this technology. Gene editing research is banned in New Zealand, with no politicians willing to endorse it.

While we are aiming for a Predator Free 2050, current measures are not sufficient to eradicate our possum, stoat and rat populations from the mainland.

While nothing in science is a silver bullet, we need to be bold and consider adding new weapons into our armoury if we truly want to eradicate pests in this country, or at least, be given access to research the potential of these new technologies unencumbered.