A grumpy letter by Jessica Maxwell of Havelock North drew my attention to the invasion of Argentine ants into the village … and with it a vexing policy problem.

The Argentine ant is placed by the World Conservation Union in the top 100 worst invaders. Originally from the Parana River basin of Argentina, they have spread rapidly across the world, surpassed in this respect only by humans. Great hitch hikers, they are often referred to as ‘tramp ants’ and are well-adapted to living with humans.

These ‘Argies’ got to Auckland in 1990 and sadly weren’t eradicated then. They arrived in Hawke’s Bay between 1998-2002 and – as willing travellers – haven’t stopped moving.

Their DNA varies little, enabling them to intermingle, which means they can form super colonies sometimes covering many kilometres, unlike most other ants where each colony will defend its own turf. Each Argentine ant colony has multiple queens and when faced with danger the colony splits as a protection mechanism. Resilient buggers.

They are omnivores, eating nectar, seeds, other insects and honey dew. They have been reported to attack nesting birds, skinks and will likely displace native ants to protect their food source. They are resourceful and determined. There are reports of them getting into screw top jars by following the turn of the screw and back.

Although not poisonous they have a bite that some react to strongly. In large numbers they can invade outdoor social events as unwelcome gate crashers, swarm over food, people and pets. They invade kitchens, fridges and pantries in their quest for sugar for the workers and protein for the queens. They can make outdoor areas almost unusable.

Facing such a threat, why haven’t we, the smartest here, simply dealt to the ant?

There are a number of reasons. The range of effective poisons for the Argentine ant is limited and expensive. But they are effective, more so on industrial land where there are limited food sources. Private land is more problematic because more food sources are available and there are more individual land-owning parties to gain cooperation from.

With an estimated 5,000 properties affected from Waipukurau through Havelock North to Wairoa, the size of the challenge multiplies.

Jessica writes that property owners lament the cost of attending to their properties, $150 to $200 each, with no certainty that their neighbours are going to do the same. The obvious problem is that having fixed your own backyard, amassing beyond the fence is a reinvasion force itching to reclaim lost ground.

Jessica believes, not unreasonably, that the Regional Council should embark on a mass eradication programme of the Argentine ant. The ants are a destructive pest and a public nusiance; they will create an economic loss and an environmental cost. But is their pestiness so great that we should put them ahead of pests like possums, mustelids, feral cats, rabbits and other enemies of the Regional Council? Probably not.

How might we resolve this policy issue?

The first issue is cost. The Regional Council subsidises the bait for the ants with a 15% discount. Is this too little? If it were increased what would the likely uptake be? Jessica writes that she canvassed her neighbours for collective action, good on her. But while they agreed the ant was a pest they were not prepared to spend that amount of money.

Secondly, the more people involved, the less chance of effective action being taken. If we are not confident our neighbours will take action, why should we spend the money and make the effort? The Regional Council works with a few groups who do work collaboratively, but this is only a tiny fraction of the households affected. What could be done to lift public confidence and improve this cooperative participation rate?

Thirdly, there seems to be a communication issue. The Regional Council wrote to Jessica in December, telling her the time to start baiting for these ants was in the spring. The late notice didn’t impress or provide confidence about the advice.

So where to from here? Some public engagement? Currently, it seems that neither the Regional Council nor the general public are willing to take sole responsibility for dealing with the Argentine ant. Divide and conquer – this is probably the ants’ preferred option. Only a joint approach has a chance of success.

Are the ants such a pest that they will move the people of Havelock North into action? No one knows because the people of Havelock North have not been asked.

Will we stamp out the Argentine ant? Well that’s in your hands. I’d welcome your views. Email me at rickjbarker@gmail.com

Meanwhile – while we dither – the ants march on!

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