By: Tanya Lewis, LiveScience Staff Writer
Published: 03/28/2013 02:04 PM EDT on LiveScience

The "artists" behind bizarre, barren, grassless rings dotting the desert of Southwest Africa have been found lurking right at scientists' feet: termites.

Known as fairy circles, these patches crop up in regular patterns along a narrow strip of the Namib Desert between mid-Angola and northwestern South Africa, and can persist for decades. The cause of these desert pockmarks has been widely debated, but a species of sand termite, Psammotermes allocerus, could be behind the mysterious dirt rings, suggests a study published today (March 28) in the journal Science.

Scientists have offered many ideas about the circles' origin, ranging from "self-organizing vegetation dynamics" to carnivorous ants. Termites have been proposed before, but there wasn't much evidence to support that theory.

Finding patterns in circles

While studying the strange patterns, biologist Norbert Juergens of the University of Hamburg noticed that wherever he found the dirt patches (the barren centers inside fairy circles), he also found sand termites. [See Photos of the Bizarre Fairy Circles]

Juergens measured the water content of the soil in the circles from 2006 to 2012. More than 2 inches (5 centimeters) of water was stored in the top 39 inches (100 cm) of soil, even during the driest period of the year, Juergens found. The soil humidity below about 16 inches (40 cm) was 5 percent or more over a four-year stretch.

Without grass to absorb rainwater and then release it back into the air via evaporation, any water available would collect in the porous, sandy soil, Juergens proposed. That water supply could be enough to keep the termites alive and active during the harsh dry season, while letting the grass survive at the circles' rims.

Juergens conducted surveys of the organisms found at fairy circles. The sand termite was the only creature he found consistently at the majority of patches. He also discovered that most patches contained layers of cemented sand, foraged plant material and underground tunnels — telltale signs of sand termites.

 The scientist found a few other termite species, as well as three ant species, at fairy circles in areas that get rain during the summer or during the winter, but not at all the sites he studied.

Teensy engineers

The termite behavior provides an example of "ecosystem engineering," Juergens wrote in the Science paper. The insects appear to be feeding on the grass roots to create the characteristic rings, the study suggests. As to why the termites would create circular-shaped patches, Juergens doesn't say.

"The paper is a useful addition to debating the origin of the fairy circles," chemist Yvette Naude of the University of Pretoria, South Africa, who was not involved in the study, told LiveScience in an email. But, Naude added, the study "does not address the key question as to what is the primary factor that causes sudden plant mortality, i.e. the birth of a fairy circle."

The soil in fairy circles seems to be altered so that plants can't survive, whereas termites usually enrich soil, making it more hospitable to plants, she said. (Juergens actually thinks the termites chew up the plant roots, and that's what leads to the barren patches.)

It is possible the termites don't cause the fairy circles, but merely live in them. However, Juergens found the insects were present even during the early stages of patch formation, before the grass had died off on the surface. Over the termites' lifetime, they munch on the grassy borders and gradually widen the circles.

Follow Tanya Lewis on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Also on HuffPost:

Loading Slideshow...
  • Assassin bug

    <em>Triatoma infestans </em> Look out for it in: Mexico, Central and South America Why you should fear it: Assassin bugs transmit Chagas disease, a long-term, chronic disease that can ultimately cause serious cardiac and digestive problems. Notorious victim: Charles Darwin met one on his first trip to Argentina.

  • Fire caterpillar

    <em>Lonomia obliqua </em> Look out for it in: Brazil, Argentina, and neighboring countries Why you should fear it: The caterpillars release a powerful toxin that can cause internal bleeding and massive organ failure. Notorious victim: A young Canadian tourist walked barefoot through a resort and stepped on five. Although local hospitals carried an antivenin, she didn't seek treatment until she returned home--a mistake that cost her her life.

  • Biting midge

    <em>Culicoides spp. </em> Look out for it in: Everywhere. Why you should fear it: Also called no-see-ums, biting midges are a serious annoyance in the Scottish Highlands--so much so that tourists check the Biting Midge Forecast before heading out for a round of golf or a trek to a distillery. In Brazil and around the Amazon, they transmit Oropouche fever. Notorious victim: According to a community study, the biting midge broke up marriages in Hervey Bay, Australia, presumably because couples were forced to spend more time indoors together.

  • Paederus beetle

    <em>Paederus sp. </em> Look out for it in: Most of the world. Why you should fear it: The beetle lands on the skin but doesn't bite. People tend to want to slap it, which releases a nasty poison called pederin that causes horrible blisters and welts. Notorious victim: Our troops stationed in Iraq. The beetles tend to swarm around the bright lights at military bases.

  • Asian giant hornet

    <em>Vespa mandarina japonica</em> Look out for it in: Japan, China, Taiwan, Korea Why you should fear it: Stings deliver a powerful neurotoxin that could be fatal. Notorious victim: Dr. Masato Ono, the world's leading expert on the giant hornet, said the sting felt like "a hot nail through my leg."

  • Pork tapeworm

    <em>Taenia solium </em> Look out for it in: South America, Africa, Asia, and parts of Europe and North America Why you should fear it: While modern livestock management here at home has practically eliminated tapeworm-infested pork, the tapeworm eggs can be spread directly from one infected person to another. How? Let's just say that it's really, really important to wash hands after going to the bathroom-- and leave it at that. Notorious victim: A woman in Arizona went into surgery thinking she had a brain tumor, and woke up later to learn that the cause of her problems had been a tapeworm, not a tumor.

  • Deer tick

    <em>Ixodes scapularis </em> Look out for it in: Eastern United States (other species that transmit Lyme are found in the West and in Europe) Why you should fear it: The nymphs transmit the miserable and difficult-to-treat Lyme disease Notorious victim: Polly Murray, a resident of Lyme, Connecticut, battled the disease for decades and led the fight to get it properly identified, diagnosed, and treated.

  • Chigoe flea

    <em>Tunga penetrans </em> Look out for it in: Tropical beaches in Latin America, the Caribbean, India, and Africa. Why you should fear it: Tiny fleas burrow under toenails and lay eggs, creating awful sores and possible infection Notorious victim: Members of Christopher Columbus' crew were made so miserable by chigoe fleas that they cut off their own toes to get rid of the bugs.

  • Scorpion

    <em>Centruroides sp. </em> Look out for it in: Southern United States, Central and South America Why you should fear it: The venom can cause severe pain, difficulty breathing, and can be fatal to small children. Notorious victim: A little boy vacationing with his family in Mexico stepped on a scorpion in his shoe. He was flown to a hospital in San Diego, placed on life support, and did survive.

  • Bed bugs

    <em>Cimex lectularius</em> Look out for it in: Your bed Why you should fear it: After hearing about all these other nasty creatures, you aren't still worried about bed bugs, are you? Bed bugs may be annoying, but they are not known to transmit disease. They may cause a dreadful allergic reaction, but you'll survive. Bed bugs have always been around; overuse of toxic pesticides drove them away for a few decades, but fortunately, we now realize that the chemicals were far more dangerous than the bugs. Notorious victim: You.