When floodwaters strike, the fire ant species Solenopsis invicta reacts with a clever escape plan: Within minutes colony members link their bodies together to form a water-repellent raft that can stay afloat for weeks. Intrigued, Georgia Tech researchers studied in the lab how the insects, native to South America and now roaming the southern United States, interlock claws, mandibles, and sticky pads on their legs to construct the roughly circular rafts. Air bubbles trapped among the ants' bodies and hairs create buoyancy for the two-tiered structure and enable members on its underside to breathe.
Colonies of as many as 200,000 ants can form rafts measuring
up to two feet wide. And in a remarkable feat of swarm intelligence that helps
maintain the raft's integrity, ants on the bottom quickly move on top when
others succumb to encounters with debris, predators, or swift currents.
Scientists believe that studying this superorganism could provide new insights
into micro-robotics and improved water repellency. (Adapted from National