A termite colony is made up of very specific groups of termites that do very specific chores to enable the colony to survive.
Worker Termites
Worker termites are exactly what their name indicates: they do the work of the colony. Whether male or female, their roles in life are to build and maintain the nest; venture out to forage for food; feed, care for, and groom the other colony members, including the developing larvae, soldiers, and reproductives; build mudtubes (in subterranean species) that connect the underground nest to above-ground wood; help defend the colony when needed; and cause the extensive damage to homes and buildings in which they live.
Workers are sterile, wingless, and blind. To build and maintain the colony, the worker termites eat the wood – their hardened mouthparts are adapted for this, as well as for chewing up food which they regurgitate to feed the other termite castes.
Because they are needed to keep the colony going, there are always more workers than any other caste. And because they are so numerous, they are the termite that is most likely to be seen (except for the swarmers, but we’ll get to that below). They are white and up to about 3/8 inch in length, thus are sometimes thought to be white ants.
Soldier Termites
Soldier termites may be male or female and their job, again, as the name implies, is to protect and defend the colony. They are easily differentiated from worker termites, because they have very large, yellowish to brownish heads with long, black extended mouthparts (mandibles). They use these to fight off any predators, particularly other termites or ants, who attempt to penetrate the nest.
As described in Encyclopedia Britannica, “The attacking soldier makes rapid lunging movements, opening and closing its mandibles in a scissor-like action that can behead, dismember, lacerate, or grip a foe … In defense, the mandibles lock together and release with a loud click, like the snapping of fingers.”
Additionally, soldiers can emit an alarm pheromone to signal to the others that there is an invasion attempt. The soldier termites will even use their enlarged heads to block the entrance to the nest.
The soldier termite will also use its head to plug holes in the subterranean termite mudtubes, until they can be repaired by workers. An experiment cited at Termites 101.org, also shows that soldiers are seen as colony leaders – a group of workers were isolated at the top of a test tube and separated from wood. Until at least one soldier was a part of the group, the workers did not attempt to tunnel into the wood. Soldier termites make up only a small part of any colony, at most about 15% of the population.
Reproductive Termite Alates
Because neither the workers nor the soldiers can reproduce, there must be another caste that can keep the colony alive and growing. This caste is the "alates" or reproductive termites. These are the flying termites (sometimes thought to be winged ants) that swarm out of the nest to find a mate and reproduce.
They fly only a very short while, then land and discard their wings. If a male and female have mated, they will then burrow into the ground to begin a new colony.
Sometimes thought to be winged ants, the winged termites can be differentiated from ants primarily by their stout bodies that have no “waist”; the two body parts of ants are distinctly separated. (See more differences at: How to Tell the Difference Between Ants and Termites.)
Alates are brownish to dark black; they are the only termites that have wings.
King and Queen Termites
Although very few of the alates survive to mate and form colonies, those that do become the king and queen of the new nest. The queen will begin to lay eggs within days, and continue laying eggs throughout her life.
Initially, the king and queen care for the eggs, but once workers develop, these termites take over the caretaking chores, along with their other responsibilities (see Worker Termites above) … and the cycle begins again.