Ants prefer not to make a collective raft when on water. However, once there are 10 insects near each other, the so-called Cheerios effect pushes them together and is too strong to counteract
Fire ants can form rafts, but they would rather not
Andre L Magyar and Candler Hobbs/Georgia Tech
Fire ants can form impressive rafts made up of hundreds of ants. However, rather than this being the result of collective social behaviour as was previously thought, experiments suggest the insects are forced together by a fluid phenomenon called the Cheerios effect. If there are 10 or more nearby ants on water, the effect becomes too strong to overcome.
When an ant nest gets flooded, ant colonies can survive by banding together to form rafts. These are buoyant enough to float …