Pheromone is a chemical substance that is produced by one animal which influences the behavior of another animal. The animal producing the pheromone may achieve this either by acting as a releaser or by building up motivation towards a particular type of behavior. The best known type of pheromones are that secreted by mammals which are used for marking out territories or attracting mates. Likewise, the chemical substance or attractants that bring the sexes together in insects, marine worms and other species are pheromones. For instance, unmated female cockroaches secrete a chemical substance from the surface of their body which stimulates males to court them. The male cockroaches are aroused even if they touch a filter paper that has been in contact with a female, which therefore contains the pheromones. In social insects such as the bees, pheromones play an important part in directing the development and behavior of the different caste in the colony.