MURDEROUS SLAVES. “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.”
http://scienceblogs.com/notrocketscience/2009/04/01/the-rebellion-of-the-ant-slaves/