What happens if ants are given caffeine? Scientists performed the experiment, and here’s what happened

Caffeinated Ants? A Tiny Dose Could Help Banish Them (Image: Canva)

If you’ve ever battled ants in your kitchen, you're not alone. These tiny pests might seem harmless, but they’re clever and relentless. And now, scientists might have found help in a surprising place—your coffee cup.

Ants with a taste for sugar and trouble

Ants are expert travellers. They sneak across the globe inside cargo, settle into new places, and chase away local bugs. One of the worst troublemakers is the Argentine ant (Linepithema humile). It’s no bigger than a grain of rice but builds colonies that stretch thousands of miles. They’re especially common along the coasts of the U.S. and the Mediterranean.

These ants aren’t just a nuisance in homes. They push out native insects, raid hummingbird feeders, and even cause damage to electrical wires. Many people use poisoned bait to get rid of them. But there’s a problem—the ants lose interest in the bait too quickly. That means they don’t carry enough back to poison the rest of the colony.

A caffeine fix for better memory

This led scientists to a strange question: What if ants had caffeine? Could it help them remember where the bait is? According to new research published in iScience, a little caffeine can make a big difference—just not too much.

Researchers created a mini obstacle course for ants using Lego bricks and a plastic platform. Each ant had to cross the setup to find sugar water. Some drops had no caffeine, while others had small, medium or high doses.

A total of 142 ants took part, each completing the task four times. Without caffeine, they wandered slowly and didn’t improve. But with small or medium doses, they performed better. They remembered the way and walked straighter paths to the reward.

Lead author Samuel Galante said a small caffeine boost improved learning. At 250 parts per million (ppm), ants reached the sugar 38% faster. For instance, an ant that needed 300 seconds at first could reach the reward in just 54 seconds by the fourth try.

Interestingly, the ants didn’t move faster—they simply focused more. “They’re not moving faster; they’re just being more focused on where they’re going,” Galante explained.

Too much caffeine? Not so sweet

There is a limit, though. At 2,000 ppm, the ants showed no improvement. That level might also pose a risk to helpful insects like bees. The key, scientists say, is finding the right amount.

The idea of caffeinated bait could one day help manage ant infestations. It might keep bait interesting long enough to reach the heart of the colony. But experts warn it needs careful testing before use.

For now, your morning brew might just offer a clever solution—to a very tiny but widespread problem.