Scientists gave ants caffeine—what happened next would blow your mind

Time of India

18-05-2025

Ants might be tiny, but they cause big problems. These little insects are smart, quick, and super organized. They travel across the world hidden in cargo ships, build huge colonies, and push out local bugs and animals.
They're not just in your kitchen—they're everywhere.
One of the worst offenders is the Argentine ant (Linepithema humile). It's only about one-tenth of an inch long, but it builds massive colonies that stretch for thousands of miles, especially along the U.S. and Mediterranean coasts.
These ants can:
Push out native insects
Rob hummingbird feeders
Even cause electrical problems by crawling into wires
People often try to get rid of them using poison baits.
But the problem is: the ants lose interest in the bait too quickly. They don't take enough of it back to the colony to kill the others.
So scientists asked a weird but clever question: What if we gave ants a little bit of caffeine? Could it help them remember where the bait is? The study, published in the journal iScience, says yes, caffeine can help—but only in small amounts.
How the experiment worked
The scientists built a tiny 'ant course' using Legos and a plastic platform.
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Each ant walked across the platform to find a drop of sugar water. Some sugar drops had no caffeine, while others had low, medium, or very high levels of caffeine.
They watched 142 ants, and each one did the course four times.
Without caffeine, the ants walked around slowly and didn't improve.
With a small or medium dose of caffeine, the ants remembered where the sugar was. They walked straighter and found it faster each time.
'We found that intermediate doses of caffeine actually boost learning – when you give them a bit of caffeine, it pushes them into having straighter paths and being able to reach the reward faster,' Galante said.
Here's what they found:
At 25 parts per million (ppm) of caffeine, ants got 28% faster on return trips.
At 250 ppm, they got 38% faster.
For example, if an ant took 300 seconds to find the sugar the first time, it could take only 54 seconds by the fourth time if given the right amount of caffeine!
But they didn't walk faster—just more directly.
That means they were focused and remembered the way. 'They're not moving faster, they're just being more focused on where they're going,' Galante explained.
What about too much caffeine?
At the highest dose (2,000 ppm), the ants didn't improve at all. In fact, it might even be dangerous to helpful bugs like bees.
So the key is using just the right amount—not too much, not too little.
'The lowest dose we used is what you find in natural plants, the intermediate dose is similar to what you would find in some energy drinks, and the highest amount is set to be the LD50 of bees, where half the bees fed this dose die,' Galante said.
Ants use chemical trails to lead their nest-mates to food. When one ant finds bait and remembers the way quickly, it lays a stronger trail, and more ants follow. The team is already testing caffeinated bait in Spain. They also plan to see how it works with regular poisons like spinosad and hydramethylnon.