Nepotism of the ant colony uncovered

Workers in an ant colony are more likely to help close relatives than more distantly related ants, according to a study that shows nepotism exists in the insect world.

Scientists found that when ant colonies had more than one queen, the female workers preferred to help their own sisters rather than the offspring of the second queen.

The research is the first time nepotism has been demonstrated in animals other than honey bees, say Minttumaaria Hannonen and Liselotte Sundstrom, from the University of Helsinki.

The scientists studied 10 laboratory ant colonies that were led by two queens. In each case, they found that the workers – which are all females – singled out the eggs and larvae of their own queen for preferential treatment.

The scientists found that the queen most closely related to her workers was more likely to have her brood well tended by the workforce. "This indicates that workers can discriminate their own kin and selectively favour a brood of closer kin," the professors write in the journal Nature.

Social insects have been invaluable in testing predictions about the evolution of altruism – unselfish acts that seem detrimental to an individual's survival.

"Nepotism is kept in check in the interests of keeping the colony going," Professor Sundstrom said.