Infectious Selflessness: How an Ant Colony Becomes a Social Immune System

Ants work together to battle a deadly fungus by diluting the infection across the colony
By Ferris Jabr | April 3, 2012, Scientific American

"When a deadly fungus infects an ant colony, the healthy insects do not necessarily ostracize their sick nest mates. Instead, they welcome the contagious with open arms--or, rather, open mouths--often licking their neighbors to remove the fungal spores before the pathogens sprout and grow. Apparently, such grooming dilutes the infection, spreading it thinly across the colony. Instead of leaving their infected peers to deal with the infection on their own and die, healthy ants share the burden, deliberately infecting everyone in the colony with a tiny dose of fungus that each individual's immune system can clear on its own. Such "social immunization" also primes the immune systems of healthy ants to battle the infection. These are the conclusions of a new study in the April 3 issue of PLoS Biology."