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A study showing how ants tunnel their way
through confined spaces could aid the design of search-and-rescue
robots, according to US scientists.
A team from the Georgia Institute of
Technology found fire ants can use their antennae as "extra limbs" to
catch themselves when they fall, and can build stable tunnels in loose sand.
Researchers used high speed cameras to
record in detail this behaviour.
The findings are published in the journal
PNAS.
Dr Nick Gravish, who led the research,
designed "scientific grade ant farms" - allowing the ants to dig
through sand trapped between two plates of glass, so every tunnel and every
movement could be viewed and filmed.
"These ants would move at very high
speeds," he explained, "and if you slowed down the motion, (you could
see) it wasn't graceful movement - they have many slips and falls."
Crucially, the insects were able to gather
themselves almost imperceptibly quickly after each fall.
To see how they managed this, the team set
up a second experiment where, to move from their nest to their food source, the
ants had to pass through a labyrinth of smooth glass tunnels.
"We could watch these glass tunnels
and really see what all the body parts were doing when the ants were climbing
and slipping and falling," said Dr Gravish.
Tune
the environment
Finally, the researchers wanted to look
inside the hidden labyrinths that the ants constructed underground, so they put
ants into containers full of sand or soil and allowed them to dig.
They then built a "homemade X-Ray CT
scanner", just like a medical scanner, to take 3D snapshots of the tunnels
that the ants dug in different types of soil.
"We found that ant groups all dug
tunnels of the same diameter, [no matter what the] soil conditions were,"
said Dr Gravish.
"This suggested to us that fire ants
are actively controlling their excavation to create tunnels of a fixed
size."
Keeping their tunnels at approximately one
body length in diameter seemed to ensure that the ants could catch themselves
when they slipped and allowed the creatures to continue to dig.
Prof Dan Goldman, who was also involved in
the study, explained that these remarkably successful insects were able to
manipulate their environment - using it to control their movement.
His overall aim, he explained, was to
distil "the principles by which ants and other animals manipulate complex
environments" and bring them to bear in the design of search-and-rescue
robotics.
"The state of the art search-and-rescue
robotics is actually quite limited," he told the BBC.
"Lots of the materials in disaster
sites - landslides, rubble piles - are loose materials, which you're going to
potentially have to create structures out of.
"You might want, for example, to create
a temporary structure for people buried down beneath."
Fire ants, he explained, could build stable
tunnels in sand or soil with almost no moisture to bind it together, so
learning from them might enable designers to build and programme robots that solve
these same engineering problems.
（source：bbc）
