Fungus-farming termites create their own air conditioning systems that circulate hot and cool air between their mound and the outside. High-resolution scanning technology and computer simulations were used to examine the microscopic structure of the external walls of African termite nests. In slabs that look solid to the naked eye, a network of tiny, interconnected pores was found. These pores regulate ventilation, humidity and temperature within the mound and nest.
Carbon dioxide must exit so the termites don’t suffocate in their underground nests, and oxygen must enter. The mounds termites build above nests are the lungs that make this breathing possible.
Termites that farm fungus build structures with chimneys and openings that work like windows, but the non-farming termites have no apparent openings; to the naked eye everything looks blocked. But the pores are there, because the mounds are made from stacking pellets of sand mixed with spit and soil. Small spaces form inside these pellets and larger spaces between them.
Micro-CT scanners with greater resolution revealed the connections between smaller pores and bigger ones. That this micro-structure was practically the same regardless of whether it was built of sand in dry Senegal or clay in wet Guinea suggested structure, not material was the key to ventilation.
When strong winds were used in simulations, structures without the larger pores couldn’t breathe as well and accumulated more carbon dioxide. The researchers also drenched mound walls in water to mimic heavy rain. The big-pore-small-pore structure dried out faster.
“If you look at the physics of gas exchange in the lung, it’s very much the same way as the termite mound is organized,” said Dr. Turner.
Stirring from wind, much like a muscle contraction, allows gases to mix and reach important places like a termite nest or human blood. “If you think about what the mound is,” he said, “it’s literally an organ in physiology that’s constructed out of dirt by a bunch of little termites.”
If you look at the physics of gas exchange in the lung, it’s very much the same way as the termite mound is organized. Stirring from wind, much like a muscle contraction, allows gases to mix and reach important places like a termite nest or human blood.
It is possible that the pores may help regulate temperature but more research is needed to prove this.
In the capital of Zimbabwe, the Eastgate Centre holds nearly 350,000 square-feet of office space and shops. It uses 90 percent less energy than a similar sized building next door. In the 1990s, Mick Pearce, the building’s architect, took his inspiration from mounds built by fungus-farming termites he saw on a nature show. The insects created their own air conditioning systems that circulated hot and cool air between the mound and the outside.
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