Fire ants build tunnels like they’re playing Jenga

Chuck Bednar for redOrbit.com – @BednarChuck

The invasive red fire ant may be nature’s best excavator, seemingly drawing inspiration from the popular game Jenga by grabbing onto grain particles impeding their progress and carefully moving the obstacles out of their way in even the tightest of spaces.

As Daniel Goldman, a physics professor at Georgia Tech, reports this week in the Journal of Experimental Biology, the red fire ant or Solenopsis invicta is capable of digging a series of mounds and tunnels with great precision in nearly any type of soil. They can even adapt and change tactics based on the type of soil they’re digging in, according to BBC News.

“You can get them to dig in anything,” Goldman told Discovery News. “When the particles are big, they grab a grain and remove it. It’s not a trivial task. They have to carefully to hold the particle in their jaw. They have another mode of digging where they can rake and scrape the soil into a pellet, and use their mandibles and antennae in a new way to help shape that pellet.”

Learning from the “master excavators” to build better rescue robots

He and his fellow investigators conducted a series of lab experiments in which they placed fire ants in different sizes of sand and soil (small, medium, and large) and used both different levels of moisture and tiny glass pellets that served as obstacles. Groups of 100 ants were placed in the different environments to dig as the researchers monitored them for a period of 40 hours.

Using x-ray technology, Goldman’s team watched as the ants carefully built tunnel walls as if they were using Jenga blocks, with each particle supporting the one above it, Discovery News said. When the researchers used a metal rod to probe the tunnels, they collapsed. (All that hard work!)

The authors also noticed that the ants built tunnels faster in coarser soils and performed better in wet ground than in dry ground. As BBC News explained, the reason is likely due to the fact that water particles generate forces that stick soil grains together, causing the structures to be more robust. Goldman said that the ants will dig in anything above five percent moisture content.

The study authors believe that data collected from analyzing the building habits of fire ants could one day be used to design search-and-rescue robots designed to save people from structures that have collapsed. The machines could work together in large teams, manipulating the environment in order to rescue those trapped in the rubble of buildings or tunnels, Goldman explained.

“Swarming robots that operate in crowded environments are going to need to know how to excavate a disaster site,” he told Discovery News. “You might learn some things from how the master excavators are doing it.”

Do you think they’re as good as this cat?

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