"The cooperation displayed by social insects has intrigued evolutionary biologists since Darwin. However, the harmonious appearance of their societies hides many conflicts of interest that exist between individuals in the colony. Social insects are also perpetually engaged in competition over resources such as space, food and mating opportunities. The study of cooperation, conflict and competition in social insects continues to be instrumental in testing evolution and ecology theory. Social insects, particularly ants, mediate these three fundamental biological interactions via pheromones, but the precise mechanisms and evolutionary consequences of these chemical messages are just beginning to be understood. The purpose of the proposed work is to investigate the role of pheromones in cooperation, conflict and competition throughout the lifecycle of an ant colony. I will characterise the pheromones of reproductive ants and determine whether these substances signal an individual’s value as a mating partner (e.g. the quality of a male’s sperm, or a queen’s ability to resist disease) and allow mate choice. This research focuses on the least-studied form of competition in social insects: sexual selection and competition between males. I will also investigate the pheromones produced by queens in developing colonies. Queen pheromones are thought to signal fertility and elicit care from the workers (facilitating cooperation). The same chemicals may also inhibit worker reproduction (a potential conflict), but no previous studies have identified queen pheromones in ants and determined their effect on workers. The proposed research is highly likely to discover the first queen pheromone in any social insect apart from the honey bee. This research is highly multidisciplinary, utilising chemical analysis, electrophysiology, microscopy, immunology, genotyping and behavioural studies, and focuses on evolutionary questions that have received considerable recent attention."