You spread ant poison and suddenly there are more? Experts explain what is happening

The summer season brings with it unwanted guests: long lines of ants in the kitchen. The automatic reaction of most of us is to pull out the gel bait or poison trap, spread it in strategic points, and expect an immediate curbing of the nuisance.

Often something frustrating happens: instead of disappearing, the next morning it seems the situation has only worsened. Individual ants wander with hyperactivity around the sink, climb the windowsill, and look as if they have completely lost their direction. The immediate feeling is that it is a defective or ineffective product. However, a new and unusual study presents a fascinating perspective that changes everything we knew about this behavior.

"As if they received an overdose of neural stimulation": what happens inside the nest?

A new study from the University of California, Riverside (UCR), published in the scientific journal Insects, examined in depth how Argentine ants — the main invader in many homes — react to two common pest control methods: boric acid and a substance called Thiamethoxam.

The results point to dramatic differences in how the chemicals affect their functioning. When substances focused on the nervous system are used, the insect's biological activity goes out of control.

"Their nervous system was damaged by the pesticide, and they develop hyperactivity that causes them to go out and wander in visible areas before the final collapse," explained the head of the research team, Prof. Dong-Hwan Choe.

Why does the house look like a zone of increased activity?

The study distinguishes between two main effects depending on the type of material:

1. Neural pesticides (such as Thiamethoxam): cause ants to lose motor control. They leave the nest in droves, searching for food in prominent areas like the sink or windowsill, and exhibit increased movement for a day or two. Effect on the ground: it seems the infestation has worsened, even though the poison has already begun to act inside their bodies.

2. Boric acid: produces a completely opposite reaction. The ants completely stop searching activity and gather in high density inside nesting areas, usually near water sources due to damage to the digestive and regulatory system. Effect on the ground: it seems the house has been cleaned in an instant, but this is often only a temporary relief as the survivors may return later.

The bottom line

The researchers' main message to the public is unequivocal: do not be alarmed by increased activity in the first 24 hours after application. The appearance of visible ants in the immediate term does not indicate a failure of the pest control, but is an indication that the substance has penetrated the system and is making its way to eliminating the nest.