Trope-a-Day: Ape Shall Never Kill Ape
Ape Shall Never Kill Ape: For the most part, thoroughly averted. With some statistically insignificant exceptions, no fully-individual species is entirely united (and even those exceptions still have criminals and dissidents), and generally have no greater inhibitions against killing their own kind than against killing anyone else, given a reason to.
Played straight in the case of hive minds (although many of those have no problem with euthanizing obsolete, sick, or even redundant members – but then, that doesn’t kill anyone, by strict rules) and collective consciousnesses (with, remember, individuality-preserving member minds, but which don’t attack each other for the same reason that, say, your hippocampus doesn’t beat up your cerebellum). But they’re a specially constructed exception to the general rule.