What work they do seems unclear, but it is assumed that they do menial tasks that would be equivalent to a working class Sim. Colony Drones are the workers of alien society.
It appears that whoever impregnates them has no marital attachment to them, and that the sole purpose of a birth queen is to breed. Birth Queens are the central, and seemingly only, reproductive system of the aliens, except for the work of the Pollination Technicians. At least to an outside observer, their society appears to be structured in a way not unlike that of bees or ants, where individual aliens have roles parallel to the functions within a hive. From what little information is given from the family history of Pollination Tech#9 Smith, a player can see what appears to be a complex culture on their home planet based on a hive mind.
