{"65778":{"#nid":"65778","#data":{"type":"news","title":"How Fire Ants Build Waterproof Rafts","body":[{"value":"\u003Cp\u003EIt\u2019s a naturally occurring phenomenon that has puzzled biologists for\ndecades: \u0026nbsp;Place a single fire ant in\nwater and it will struggle. But a group of fire ants will bind together and\nfloat effortlessly for days. \u0026nbsp;\u003C\/p\u003E\n\n\u003Cp\u003EGeorgia\nTech researchers \u2013 \u0026nbsp;Nathan Mlot, mechanical engineering graduate student; Craig Tovey, professor of industrial and systems\nengineering; and David Hu, joint professor of mechanical engineering and biology\u0026nbsp;\u2013 have solved the mystery of how fire ants self-assemble\ninto a waterproof raft.\u003C\/p\u003E\n\n\u003Cp\u003EUsing\ntime-lapse photography and mathematical modeling, the Georgia Tech team found\nthat fire ants act collaboratively rather than individually to form a\nwater-repellant, buoyant raft. \u0026nbsp;\u003C\/p\u003E\n\n\u003Cp\u003EA\npaper describing the research, titled \u201cFire ants self-assemble into waterproof\nrafts to survive floods,\u201d was published April 25 in the early edition of the\njournal \u003Cem\u003EProceedings of the National\nAcademy of Sciences\u003C\/em\u003E.\u003C\/p\u003E\n\n\u003Cp\u003E\u201cIt\u2019s\na real thrill unraveling what at first looks like chaos,\u201d Tovey said. \u201cTo\nunderstand what the individual behaviors are and how they combine in order to\nachieve the function of the group is the central puzzle one encounters when\nstudying social insects.\u201d\u003C\/p\u003E\n\n\u003Cp\u003EAn\nindividual ant\u2019s exoskeleton is moderately hydrophobic. But fire ants enhance\ntheir water repellency by linking their bodies together, a process similar to\nthe weaving of a waterproof fabric, researchers said. \u0026nbsp;\u003C\/p\u003E\n\n\u003Cp\u003EBy\nfreezing the ants, the Georgia Tech team observed that fire ants construct\nrafts when placed in water by gripping each other with mandibles, claw and\nadhesive pads at a force 400 times their body weight.\u003C\/p\u003E\n\n\u003Cp\u003EThe\nresult is a viscous and elastic material that is almost like a fluid composed\nof ant \u201cmolecules,\u201d researchers said. The ants spread out from a sphere into a\npancake-shaped raft that resisted perturbations and submergence techniques.\u003C\/p\u003E\n\n\u003Cp\u003ETo\ndetermine how this is possible, Tovey and the team tracked the ants\u2019 travel and\nmeasured the raft\u2019s dimensions. They found the ants move using a stereotyped\nsequence of behavior. The ants walk in straight lines, ricocheting off the\nedges of the raft and walking again until finally adhering to an edge, Tovey\nsaid. The ant raft is water repellent because of cooperative behavior.\u003C\/p\u003E\n\n\u003Cp\u003EThe\nant raft provides cohesion, buoyancy and water repellency to its passengers. Even\nmore remarkable, it is self-assembled quickly, in less than 100 seconds. It is also\nself-healing, meaning if one ant is removed from the raft, others move in to\nfill the void.\u003C\/p\u003E\n\n\u003Cp\u003E\u201cSelf-assembly\nand self-healing are hallmarks of living organisms,\u201d Hu said. \u201cThe ant raft\ndemonstrates both these abilities, providing another example that an ant colony\nbehaves like a super organism.\u201d\u003C\/p\u003E\n\n\u003Cp\u003EThe\nresearch could have application to logistics and operations research and\nmaterial sciences, specifically the construction of man-made flotation devices.\nIt also could impact the field of robotics, the team said.\u003C\/p\u003E\n\n\u003Cp\u003E\u201cWith\nthe ants, we have a group of unintelligent units acting on a few behaviors that\nallow them to build complex structures and accomplish tasks,\u201d Mlot said. \u201cIn autonomous\nrobotics, that\u2019s what is desired\u2014to have robots follow a few simple rules for\nan end result.\u201d\u0026nbsp;\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EUsing time-lapse photography and mathematical modeling, the Georgia Tech team found that fire ants act collaboratively rather than individually to form a water-repellant, buoyant raft.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Georgia Tech researchers have solved the mystery of how fire ants self-assemble into a waterproof raft."}],"uid":"27462","created_gmt":"2011-04-26 08:17:19","changed_gmt":"2016-10-08 03:08:38","author":"Liz Klipp","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2011-04-26T00:00:00-04:00","iso_date":"2011-04-26T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"65777":{"id":"65777","type":"image","title":"Fire ant raft","body":null,"created":"1449176884","gmt_created":"2015-12-03 21:08:04","changed":"1475894582","gmt_changed":"2016-10-08 02:43:02","alt":"Fire ant raft","file":{"fid":"193262","name":"Ant_raft.jpg","image_path":"\/sites\/default\/files\/images\/Ant_raft_1.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/Ant_raft_1.jpg","mime":"image\/jpeg","size":1179897,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/Ant_raft_1.jpg?itok=K-pyBNvj"}}},"media_ids":["65777"],"related_links":[{"url":"http:\/\/antlab.gatech.edu\/antlab\/Home.html","title":"Georgia Tech Ant Lab"},{"url":"http:\/\/www.pnas.org\/content\/early\/2011\/04\/20\/1016658108","title":"PNAS article"}],"groups":[{"id":"1183","name":"Home"}],"categories":[{"id":"135","name":"Research"}],"keywords":[{"id":"12938","name":"Fire ants; water repellant raft; college of engineering; david hu; craig tovey; nathan mlot"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Cstrong\u003EGeorgia Tech Media Relations\u003C\/strong\u003E\u003Cbr \/\u003ELaura Diamond\u003Cbr \/\u003E\u003Ca href=\u0022mailto:laura.diamond@comm.gatech.edu\u0022\u003Elaura.diamond@comm.gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-894-6016\u003Cbr \/\u003EJason Maderer\u003Cbr \/\u003E\u003Ca href=\u0022mailto:maderer@gatech.edu\u0022\u003Emaderer@gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-660-2926\u003C\/p\u003E","format":"limited_html"}],"email":["Klipp@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}