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 Geographic)