Science reports that ants use smells and sounds to communicate:
Scientists have known for decades that ants use a variety of small chemicals known as pheromones to communicate. Perhaps the most classic example is the trail of pheromones the insects place as they walk. Those behind them follow this trail, leading to long lines of ants marching one by one. However, the insects also use pheromones to identify which nest an ant is from and its social status in that nest. Because this chemical communication is so prevalent and complex, researchers long believed that this was the primary way ants shared information.
However, several years ago, researchers began to notice that adults in some ant genuses, such as Myrmica, which contains more than 200 diverse species found across Europe and Asia, made noise. These types of ants have a specialized spike along their abdomen that they stroke with one of their hind legs, similar to dragging the teeth of a comb along the edge of a table. Preliminary studies seemed to indicate that this noise served primarily as an emergency beacon, allowing the ants to shout for help when being threatened by a predator. [...]
Further analysis of this noise showed that it was a simplified version of the more complex(h/t Marginal Revolution)
adult sound . It was as if the mature pupae were saying, "Help!" while the adults were saying "Hey, I'm over here! Please come help! It's your friend!"
