Insects that walk in the soil will get dirty and need cleaning. For ants, their antennae must be kept clean because it is used to detect odors of all sorts- from food odors, to pheromone trails and nest odors. To clean its antenna, an ant needs a brush. Fortunately, ants have a brush built into their front leg. Between the tibia and the tarsus (leg segments) of the front leg is a spur that arises from the tibia. The spur is covered with bristles. Opposite the spur, the tarsus also has bristles. When an ant grooms, it will lift its front leg and place the antennae into the gap between the tibial spur and the tarsus. As the antenna is pulled through the bristles, it is brushed clean of dirt and other particles.
The ant cleans the brushes on its leg by passing the leg and the dirty bristles through its mouth for a spit shine.