Scientists tested two Argentine ant baits; one sent them roaming, other drove them near water

The study from the University of California, Riverside, found that two common ant-bait insecticides can cause very different changes in Argentine ant behaviour before the ants die.

Thiamethoxam made affected ants unusually active and sent them roaming outside the nest, while boric acid caused ants to stop foraging and gather inside.

The findings show that unusual ant activity after treatment does not necessarily mean the pesticide has failed.