Dear Timothée,
Think of all the ways the people you know get your attention. An adult might shout your name across the yard. Your friend might wave his arms from down the sidewalk. Your teacher might tap you on the shoulder.
Humans use way more than words to communicate. Animals like ants have many ways of communicating, too.
To learn more, I asked my friend Dowen Jocson, who is earning her doctorate in entomology at Washington State University. Entomology is the study of insects.
Many ants can release special chemicals into the air that other ants can sense and respond to. These chemicals are called pheromones (FAIR-UH-MONES). Ants are famous in the world of biology for using pheromones to warn other ants about danger or guide them to food.
But ants communicate in other ways, too. Pheromones can’t always travel quickly through a nest of ants, Jocson said. Not too long ago, scientists discovered that some ants get their colony-mates’ attention with another type of communication: vibration.
Imagine a big speaker hooked up to a computer or radio. If you played a song really loud, you wouldn’t just hear it—you’d feel it shaking through the floor and into your body.
When some species of ants realize that their nest is under threat from a predator like an anteater, they can release pheromones. But they might also drum their mouth-parts, called mandibles, or use their abdomens to make a vibration. The vibration shakes through the nest, and other ants feel it with hair-like organs on their legs called sensilla.
“When they hear and smell that alarm pheromone and the alarm signal, some of them start being aggressive. They start attacking whatever they can see that is not part of their nest,” Jocson said.
Some species of ants even have special “door guard” ants that sense these signals and rush to the door of the nest to block it with their wide, flat heads.
Other types of ants have body parts they can rub together to make a noisy vibration called a stridulation. You might have heard crickets or grasshoppers “sing” in the same way. This is another way of communicating!
For example, leafcutter ants can make stridulations or drum vibrations on the leaves they’re cutting to let their colony-mates know they have leaf pieces ready to carry back the nest.
Jocson studies how a different type of insect called a pear psylla uses vibrations to communicate. Since pear psylla can damage pear trees, Jocson’s research helps people protect crops for food and develop more sustainable ways to manage pests.
But, she said, it’s still cool to learn about how animals behave, even when you don’t know exactly how that knowledge could help humans.
“As humans we are naturally curious, and just knowing something gives us a sense of where we belong in the world,” Jocson said.
So next time you spot an ant, follow it and pay attention to where it goes, how it behaves and how it acts around other ants. Who knows, maybe you’ll discover another amazing way that ants communicate.
Sincerely,
Dr. Universe