You spot a trail of ants crossing your kitchen bench, grab a can of insect spray from the cupboard, and give them a good blast. Problem solved, right? A few days later, the ants are back, only now they’re appearing in different rooms. Sound familiar? This frustrating pattern plays out in homes across New Zealand every summer, and there’s a biological reason why that spray made things worse instead of better.
How Ant Colonies Respond to Threats
Ant colonies are far more resilient than most people realise. A typical colony contains thousands of workers, but the workers you see foraging in your kitchen represent only a small fraction of the total population. The queen, or in some species multiple queens, stays safely hidden in the nest, continuously producing eggs to replace any workers that die.
When you spray foraging ants, you eliminate the visible problem temporarily. But the colony itself remains intact underground, inside wall cavities, or beneath your home’s foundations. Within days, the queen produces more workers, and new foragers emerge to replace those you killed. You’re back to square one.
The problem gets worse with certain species. Argentine ants, one of the most troublesome species in New Zealand, form colonies with multiple queens. When part of the colony is threatened, a process called budding occurs. A queen and a group of workers split off to establish a new nest in a different location. Instead of one colony, you now have two. Use enough spray in enough places, and you can inadvertently turn a single-nest problem into an infestation spread throughout your property.
Why Strong Sprays Cause Colony Splitting
The insecticides in supermarket ant sprays are designed to kill on contact. That sounds effective, but the fast-acting formula creates a problem. Ants communicate through chemical signals called pheromones. When workers die suddenly, they release alarm pheromones that warn the rest of the colony of danger.
This triggers a defensive response. Surviving ants stop using contaminated trails and start exploring new routes. In multi-queen species, the stress response can prompt budding, with reproductive individuals fleeing to establish satellite nests away from the perceived threat. The colony doesn’t just survive your attack; it disperses and multiplies.
This is why we see so many homeowners contact us after weeks of unsuccessful DIY attempts. They’ve sprayed repeatedly, the ants keep coming back in different areas, and the infestation feels bigger than when they started. In many cases, it genuinely is bigger.
When Baiting Works Better
Professional ant control takes a completely different approach. Instead of killing ants on contact, baiting systems use slow-acting formulas that foraging ants carry back to the nest. The workers feed the bait to larvae and share it with other colony members, including the queen. Over days or weeks, the toxin spreads through the entire colony, eliminating it at the source.
The key is patience. Baits don’t provide the instant satisfaction of watching ants drop, but they solve the actual problem rather than just suppressing the symptoms. For multi-queen species like Argentine ants, baiting is particularly effective because workers distribute the product to all reproductive individuals, not just the ones in a single nest.
Professional ant control services combine baiting with barrier treatments and nest location to deliver comprehensive results. A trained technician can identify the species you’re dealing with, which determines the most effective bait formulation and placement strategy. Different species have different food preferences, and using the wrong bait means ants simply ignore it.
Realistic Expectations
If you’ve already been spraying for weeks, the situation may take longer to resolve than a fresh infestation. Scattered colonies need to be addressed systematically, and any surviving queens will continue producing workers until they’re eliminated.
Professional treatment typically shows noticeable results within one to two weeks, with full colony elimination taking up to a month depending on species and infestation size. During this period, you may still see some ant activity as foragers continue carrying bait back to their nests. This is actually a good sign, as it means the bait is reaching the colony.
For ongoing protection, many homeowners opt for quarterly treatments that maintain a barrier around the property and address new colonies before they establish themselves indoors. This is particularly worthwhile if you live near bushland, have neighbours with ant problems, or have dealt with Argentine ants, which readily reinvade from surrounding areas.
At Pest Specialists, we’ve refined our ant treatment approach over nearly two decades, using low-dose professional baits that workers carry back to the queen. If your DIY efforts have stalled or made things worse, we can assess the situation and put together a plan that actually works. Contact us for a free quote or call 0800 737 877 to discuss your ant problem with our team.