Ant Colony Structure and Behavior

Foraging, Feeding and Communicating

Forager ants leave nests in search of food. Once they locate a food source they return to the nest, marking the trail with a special chemical to lead other foragers from the nest to the food source and back. These chemical markers are called trail pheromones and new foragers using the trail reinforce the pheromone until the food source is no longer exploited. These trails often follow natural and manmade structural guidelines such as tree limbs, the edges of sidewalks, building edges and mortar and expansion joints.

Adult ants can only eat liquid food. They also temporarily store liquid food in their crop (an expanded portion of the digestive tract) and regurgitate it in small amounts to feed nest mates. In some species, solid food brought back to nests may be processed into liquid form by older larvae and then shared with nest mates. This process of food sharing and distribution within a colony is called trophallaxis.

In addition to trail pheromones, ants use chemicals for many of their other communication needs. For example, alarm pheromones send a signal that the colony is being threatened, and workers immediately react in a defensive or evasive manner. This alarm pheromone is most notable in imported fire ant behavior in which workers pour out of disturbed mounds to attack and sting intruders. Sex pheromones are typically used for mating purposes by female and male ants.