I have an idea for this alien race that is birthed from a non-sentient (hive queen-esque) organism, thus eliminating the need for sexual reproduction by its populace. But I wanted there to be different "types" or "classes" to fill specific societal roles that have different attributes for their role (ie increased speed for a warrior class). So, my question is, what are the most important 3-4 social roles that my alien race needs to function smoothly?
There are really only 3 social roles a society needs to be successful
1 - Farm/gatherer class these will be your society's food producers. For example, they could grow food and develop long sharp claws for harvesting, they could be gatherers with strong skeletal structures for supporting heavy loads, or even be photosynthetic and generate fruit-like things over time.
2 - Builder class this class will be responsible for constructing your society's buildings, maintaining existing structures, etc. They should have dexterous appendages to manipulate building materials such as wood planks or stone blocks, and should also be able to lift heavy loads and collect these materials (strong skeleton, maybe one or more arms solely designed to chop down trees or cut stone).
3 - Warrior class: these would be the members of society responsible for protecting your society from outside invaders. They should be resilient to damage, with maybe a tough exoskeleton or a thick hide, preferably resistant to temperature changes both hot and cold.
Now, depending on how advanced you want your society to be you could develop sub-classes for each grouping. For example, a sub-builder class that can mine for iron ore or rare materials, or a sub-warrior class that can take on aerial enemies with wings and honeycombed bones. And if you want to get really advanced, you could have certain organisms with larger than usual brain capacity and a degree of autonomy from the hive mind, allowing them to learn and design new ways for the hive to operate (think engineers to design new buildings or scientists to design new weapons).
- Breeder. Your non-sentient hive queen-esque organism is absolutely essential to the colony. Plot point: will humans or other enemies try to kill it? How easy is it to replace?
- Food producer. Other classes gotta eat. Whether they're farmers, hunters or gatherers is flexible
- Warrior. Protection from outsiders, predators, rival colonies
- Builder. If your race lives in structures, someone has to build them.
Worker class: It is most importance as it keep the colony survive. Someone have to produce something. Become sentient, the worker class work in difference ways, such as they have mean of production (yeah, capitalism). However, they are the main force to create wealth (food, tool, weapons, ...) for the colony. Worker class cannot be omitted in any ways.
Queen: The queen is necessary because of biology dependency (hive queen-esque). The queen are required to give birth to baby. She may be the one who control the swarm (if you are hive-mind) like the Formic in Ender's game.
Next, depend on biology, you will decide who is a 'citizen'. If a queen only give birth, but her child can functional on their own.
No hive-mind or weak hive-mind. This example is ant, bee. Queen give out order, her child carry out. However, they may react to unexpected situation without the queen guide step-by-step. You may related with the medieval setting in human history. Then, anyone (including worker, of course) can become citizen.
Single hive-mind: the Formic in [Ender's game], Zerg in Starcraft. Who can independent thinking is a citizen. For example, The [Formic] queen herself is a citizen. Her worker is just her arms and legs, part of her body. There are/is a/some queen individual who is wise/powerful lead other queen.
Swarm hive-mind: it is a difficult case. It is purely fictional. Depend on your imagination. Here is some idea: 1/ a swarm identified themselves as a individual and communicated with others as an individual. In this setting, you must omit all personal of any single 'thing' because all the biomass (no matter they stick together or not) is an individual. 2/Organism need to stick together to gain IQ. If they separated, they become stupid. In this case, you may keep personality of each organism. (refer to my question here)
Updated: In case of the Formic, a queen is a worker class. She create thing with her 'arms' and her 'legs'. Another queen, who dedicate only to use her 'arms' to invade earth is warrior class.
Using social insects and naked mole rats as examples, you'd need:
1) female breeder(s)
2) male breeder(s), aka drones
3) workers (who would probably all be sterile females), who would comprise:
3a) builders/diggers, 3b) foragers/hunters/farmers, 3c) nursery maids;
These would have 4 body types. The workers might specialize, but usually go through a rotation of the three worker jobs as they age.
If you want this to be an advanced society, then you'd need thinkers in there someplace. They could be a type of worker, or a separate class.
Also, some ants have a "food storage" class. But you asked for a bare minimum.