Gi-Ants

Giant ants. They live in dug tunnel complexes, led by a queen the size of a big chariot whose only purpose is laying eggs. They communicate mostly by using different types of pheromones, and to some extente by body movements.
Size increase made them require more food as well, so the colonies usually range from 50 to 100 individuals, and eggs take longer to reach a fully developed stage, about a year. Besides the queen there are marked phenotypes: workers, soldiers and drones.
Workers are infertile females, they vary in size, from the size of a small mutt to the size of a donkey, their mandibles are not so large.
Soldiers are also infertile females that are larger, they have larger heads with larger mandibles that have mild poison. They have more chitin armor, and their main purpose is defending the colony.
Drones are fertile males. They are the most dangerous of all, but luckily they are short-lived. In the old world, males usually had wings to move to other colonies for mating purposes. Since they mutated their weight made them incapable of flying, instead, they developed very nasty adaptations to make them able to survive the mating trip. Most of them are large and heavy as an ox or large horse, they are covered in very thick chitin, they have serrated mandibles the size of longswords (mild poison), and a sting the size of a shortsword (paralyzing poison), their feet are serrated, and they are also capable of attacking with their frontal legs. They usually travel alone, voraciously foraging for plants and hunting for prey while looking for another colony. They will fight to the death with any other drone they encounter. When they reach another colony, the whole colony aggresively attacks them, and only the ones that manage to reach the queen chamber are allowed to mate, but they are usually so wounded that they die very soon.

Domestication:
It is possible to generate domesticated worker ants. They are very valuable because they are extremely hardy and resilient, they can eat almost anything and require little water, and most importantly, they are capable of carrying several times their own weight. Even though they are not very intelligent, they are loyal to the death.
Workers can be domesticated if eggs are stolen, and their larvae are subjected to a strict dietary strategy that is usually kept a secret by the breeders. This diet somehow warps the development of their pheromone system, and they are not able to communicate with wild Gi-ants. If this diet is not followed, the adult specimens with pheromone systems will run away and join wild ant colonies.
Gi-Ants are bonded to a single master, and won't obey anyone else. Domesticated Gi-Ants must be fed by their future master for a full month before the larvae experiences the metamorphose into a fully grown specimen, and the master needs to be present whan metamorphose ends. Hence, Gi-Ants can't be traded freely, if you want one, you need to commission the breeding of one and partake in the process. Since it requires commitment and effort, in places where domestication of Gi-Ants is common, some people make specialize, and make a living by commanding many Gi-Ants, using the whole collective as highly coordinated work animals, to plow, clear fields, and as pack animals in caravans.