The relation between structure and function of the exocrine and endocrine system of social insects is crucial in our research. Emphasis is put on glands (pheromone- and toxin-producing ones) and on their dependency of the fat body. This research should be seen in the broader context of queen-worker dimorphism, and hence in a reproductive context. By means of histochemistry and immunocytochemistry we will try to elucidate the organinteractions mentioned. We therefore use a functional approach.