From last month's journal Evolution, a fascinating tale of slave rebellion among ants kidnapped by other ant species and forced to work for the rival colony:
When these youngsters mature, they take on the odour of their abductors and become the servants of the enslaving queen. They take over the jobs of maintaining the colony and caring for its larvae even though they are from another species; they even take part in raids themselves. But like all slave-traders, P.americanus faces rebellions.
Some of its victims (ants from the genus Temnothorax) strike back with murderous larvae. Alexandra Achenbach and Susanne Foitzik from Ludwig Maximillians Universty in Munich found that some of the kidnapped workers don't bow to the whims of their new queen. Once they have matured, they start killing the pupae of their captors, destroying as many as two-thirds of the colony's brood…
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. Nor are the deaths a reflection of a generally poor standard of care on the part of Temnothorax. In their own colonies, the majority of pupae hatched, with just 3-10% dying before that happened.
(Image: Ant Actions, a Creative Commons Attribution-ShareAlike image from CharlesLam's Flickr stream)