Invasive ants are smarter

Amazing stuff!

"... While ants are famously social creatures, they aren’t exactly considered brainy. So, it came as a surprise to scientists in Argentina when they devised a test to see whether ants could learn to avoid a toxic bait trap—and the ants passed. Given the choice between a normal sugar feeder and one laced with a toxin, the ants started avoiding the toxic one after only a few hours. A lab test revealed that six hours after eating the tainted food, only seven of 120 ants died, suggesting that the ants hadn’t stopped visiting the toxic feeder because they’d succumbed to its poison. ..."

From the abstract:

"Invasive ants, such as the Argentine ant, pose a severe economic and ecological threat. Despite advancements in baiting techniques, effectively managing established ant populations remains a daunting challenge, often ending in failure. Ant colonies employ behavioural immunity against pathogens, raising the question of whether ants can collectively respond to toxic baits. This study investigates whether ant colonies actively abandon palatable but harmful food sources. We provided two sucrose feeders, each generating a new foraging trail, with one transitioning to offering toxic food. Six hours later, ant activity on that path decreases, while activity on the non-toxic food and the trunk trail remains unaffected, excluding factors like population decline or satiation as reasons for the activity decline. Laboratory experiments confirmed that ants remained alive six hours after ingesting toxic food. Ant presence remains low on the toxic food path for days, gradually decreasing along the nearest section of the trunk trail. This abandonment behaviour minimises the entry of harmful food into the nest, acting as a protective social mechanism. The evasion of toxic bait-treated areas likely contributes considerably to control failures. Understanding the behavioural response to toxic baits is essential for developing effective strategies to combat invasive ant species."

Why don’t ants always fall for toxic bait? They may learn to avoid it | Science | AAAS

Ants evade harmful food by active abandonment (open access)

Fig. 1: Temporal dynamics of ant foraging activity on bridges over days.