Research shows that ants, and also honeybees and other species of social insects, use several pheromones or other signals in organizing their foraging system. Two important and connected questions, therefore, are to determine why multiple signals are needed and how they work together. Some progress has been made in the honeybee, where four dances and a pheromone are known to be involved. The role of most of these signals is known. The waggle dance directs foragers to food and recruits them to foraging, the vibratory dance prepares foragers for work by causing them to move into the dance floor area where returning foragers make waggle dances, and the tremble dance recruits additional workers to the task of unloading nectar foragers. But what is not known is precisely how they work together and why five signals (and maybe more) are needed. Why not four?One possibility is that some of these signals are fine tuning. Multiple signals may be needed because of inherent limitations in the signals used. For example, the short-lived attractive and repellent trail pheromones used by Pharaoh's ants can direct foragers to the rewarding branch at a trail bifurcation but a single one of these pheromones can only direct about 75% to the rewarding branch. Perhaps the presence of two pheromones can increase this to 90%.We also need to understand communication mechanisms in relation to the foraging method. The solid substrate upon which ants walk from nest to food is suitable for depositing trail pheromones to guide nestmates. A trail pheromone is obviously less useful for flying social insects, such as honeybees. However, some stingless bees do mark routes to food with pheromone, which they deposit on vegetation as discrete beacons rather than a continuous trail. The use of a trail pheromone means channels of communication may be continuously open for ants, because they are capable of a continual, reactive exchange of information with nestmates whilst foraging. This is in marked contrast with the honeybee, where the signals used to organize foraging are communicated in the nest. Foraging is a dynamic process and an important role of communication is to recruit or direct nestmates rapidly to a food source. But the need to do more than this, for example to retain a longer term memory, may require additional pheromones or signals.The multiple signals used in social insect communication provide shared information and enable the colony (or system) to be more responsive or better regulated, so that it functions better. Similar complexity is found at other biological levels, such as cell signalling pathways, where positive and negative feedback provide the capacity for control at multiple levels and enable greater flexibility in system responsiveness. A major interdisciplinary challenge in modern biology is to understand how complex adaptive systems function, and how they function robustly yet flexibly. One goal in this research is to determine if there are any general principles underlying adaptive biological systems. The focus of this research, and the funding, is usually directed at the organismal level or below, particularly cells in a multicellular organism, or molecules within cells. Insect societies provide another level of organization for comparison.