Highlights from the American Physical Society meeting
Highlights from the APS March Meeting, Baltimore, March 18-22, 2013
By Science News
Fire ants need damp soil
Despite its name, the fire ant isn’t afraid of a little water. In fact, the insects need just the right amount of moisture in soil to build superior nests, new experiments show.
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Researchers from Georgia Tech in Atlanta filled 14.5-centimeter-deep aluminum tubes with an artificial soil made up of tiny glass beads and various amounts of moisture. The team then gave the stinging, invasive insects 20 hours to get their nest on. CT scans revealed that at about 10 percent moisture content — a medium amount — the ants (Solenopsis invicta) built tunnels twice as long as they did in parched soil. The researchers speculate that the dash of water makes the soil particles glom together in a manner that makes for easy digging.
“If you keep your backyard dry, they may leave and dig in your neighbor’s backyard,” said Daria Monaenkova, who presented the research on March 21 at the American Physical Society meeting. When the researchers tried varying the size of the soil particles, it didn’t influence nest construction: The fire ants chugged along fine with small or large grains, at least until the soil particles became as big as small worker ants. — Rachel Ehrenberg