I'm creating a story with a biological caste system based on different species of ants. There are soldiers, farmers, and builders, each with biologically different bodies in order to keep factions separate. Would this work? A group of royals rules over the factions, attempting to keep the groups separate in order to avoid war or riots that could be caused if the factions united.
To be clear, the different factions cannot breed with each other, and only speak to each other when necessary. Their jobs also prevent them from interacting with each other. The royal faction reigns supreme. Sorry if I didn't make that clear. If the castes united, they'd rebel against the Royals in order to make the society a capitalist democracy.
The royals stopped genetic manipulation a long time ago. Since then, they've lost the technology. There are multiple societies like this, hence the need for soldiers. Members are non-reproductive. A machine creates the members using pre-existing and cloned reproductive "stuff" in various combinations. Every so often the royals collect new "stuff" to input into the machine, but they've lost the knowledge of how to interface with most of the technology that makes up the machine. The members do have some level of self-determination. There is an economy between factions and governments.
The machine does not breed between castes, because the members literally cannot breed with each other without the help of the machine, as they have become different species. As for mating, the instinct to breed has been genetically engineered out of them, or otherwise prevented. For example, all soldiers are nearly identical clones of each other, with only slight differences like markings that represent rank.