Among social insects, individuals excel at easy decisions and colonies do better at subtle distinctions — but big swarms may snag the best options.
When house hunting, Temnothorax ants (pictured) recruit each other to potential new homes. Takao Sasaki at Arizona State University in Tempe and his colleagues forced isolated ants and whole colonies to choose between two nest sites. When one site was only slightly better than another, the colonies did better than individuals at picking the best site. When site differences were larger, the ants performed better as individuals.
But big colonies are better when there are more choices to be made. Timothy Schaerf and colleagues at the University of Sydney, Australia, used mathematical models and field experiments to compare how honeybees (Apis mellifera) picked out a new nesting site. Swarms of 15,000 bees chose ideal locations more often than those with 5,000 bees. Huge swarms contain more scouts, and so can collect and compare more options for potential digs.