A floating raft of fire-ants combines structural ants with "free" ants to create bridges that can help them reach drier areas.Fire ants work in teams to survive floods. They build rafts from their bodies that float until the water recedes. A time-lapse video now shows how these clever insects create living conveyor belts to transport riders to dry land.This footage showed how ant-rafts transformed in just a few hours. The slender extensions of the ants that grew from the main sections of antrafts looked like tentacles. These bridges were formed by the combined activity two groups of ants: structural ants insects which pack tightly together to keep the colony floating, and surface-ants insects that move freely on top of the heaps.Similar: Image gallery: Ants around the WorldThere are over 20 species of fire-ants in the world, but only one species, Solenopsis invicta, is well-known for its large colonies that can number 300,000. According to North Carolina State UniversityFire ants can form floating rafts if their underground tunnels flood. These rafts can keep the colony together for several weeks or more, and carry them until the waters recede. The exoskeleton of a fire ant repels water and traps air bubbles. Live Science previously reported that tightly knitted ant bodies can create a buoyant foundation for floating rafts.In southern Texas, there were many fire-ant-ant rafts in the wake 2017's record-breaking hurricane Harvey. People fleeing floodwaters from Hurricane Harvey were advised to avoid the rafts as the bites of fire ants can be extremely painful. Live Science reported this year.Prior research showed that even after an Ant raft's structure was stabilized, it continued to change in shape. Scientists didn't understand why questing tentacles extended in multiple directions.Researchers wrote that these protrusions had not been documented or explained in the existing literature to their knowledge in a new study published in the Journal of the Royal Society Interface June 30, 2013.Moving ants climb over stationary ants to build a fire-ant boat. Image credit: Robert Wagner/University of Colorado BoulderThe scientists collected between 3,000 and 10,000 fire ants at once and placed them in water containers with a rod in their center. Around the rod, the ants formed rafts. The scientists then recorded the ant-raft formations and their shape changes, taking both time-lapse footage and real-time footage. Computer modeling and image-tracking data revealed which parts of an ant raft were stationary and which were moving, and where the different layers of the raft were going.Study authors discovered that the raft's exploratory tentacles had been shaped by ant movement, which they called "treadmilling." Free-walking ants could burrow into lower structural levels as structural ants crawled to the surface. This cycle created a raft that contracted and expanded, creating narrow bridges of ants that reached outwards to find land where they could safely disperse.Other factors, such as the time of day, the season and the colony's environment can also influence ant behavior. These variables could also impact the dynamics that create fire ants' rafts. These variables were not explored in the experiments but could be in future studies, scientists concluded.Original publication on Live Science
