Humans aren't the only species that have had to deal with the issue of slavery. Some species of ants also abduct the young of others, forcing them into labouring for their new masters.
They found that the [slave]workers clearly care for the larvae, and nearly all of them were raised until their pupated. But at that point, the slaves' behaviour changed dramatically, taking on a more homicidal bent.
Two-thirds of pupae died before they hatched. The mortality rate was even higher (83%) for pupae containing queens, but very low (3%) for those containing males. The duo saw that the captives were deliberately killing the healthy pupae. In about 30% of cases, as in the photo, the workers would gang up to literally pull the developing ants apart. Another 53% of the pupae were killed by neglect, by workers who moved them out of the nest chamber.These murders were solely the acts of the slaves. No P.americanus worker ever lifted a mandible against its own pupae.