I came across these two ants facing each other and they appeared to be almost motionless. This provided a good opportunity to get a macro shot. Upon close inspection its apparent the ant on the left is secreting fluid from it’s head and the ant on the right is using it’s antennae to determine what is being communicated.
From wikipedia “Ants communicate with each other using pheromones. These chemical signals are more developed in ants than in other hymenopteran groups. Like other insects, ants perceive smells with their long, thin and mobile antennae. The paired antennae provide information about the direction and intensity of scents”.
“Ants use pheromones for more than just making trails. A crushed ant emits an alarm pheromone that sends nearby ants into an attack frenzy and attracts more ants from further away. Several ant species even use “propaganda pheromones” to confuse enemy ants and make them fight among themselves.”