ThunderCavalier said:
Surprising. I wasn't aware that animals could form societies where they recognize and care for their own that have genetic abnormalities, as well as using them for the betterment of their colony. I thought that they operated on the Darwinism, "You screwed up somewhere, so you die." type of system.
If you think about it, the ants' entire caste system is based on the fact that societies with a certain percentage of useful genetic aberrations work better than others. Soldier ants may suck at foraging, but they're good at fighting; queens are "only" good for sitting on their enlarged abdomens and pooping out eggs, which means the whole colony lives and dies with them; the only purpose in a male's life lies in that one ejaculation into a future queen.
And those are just the basic ones - some known ant species [http://en.wikipedia.org/wiki/Eciton_burchellii] have multiple worker castes as well as completely badass übersoldaten with razor-sharp hook-like jaws, while others have workers that use their abdomens as living honeypots [http://en.wikipedia.org/wiki/Honeypot_ant].
Really, that's often how evolution works: Not on an individual, but on a societal/genetic level. It would be inefficient for the ants to have to run their own eugenics program and identify/cull the "defective" ones - since there is only a single individual responsible for the procreation of the hive (and thus one genetic template), it is only appropriate that evolution weeds out that information with the entire hive.