- News Home
6 March 2014 1:04 pm ,
Vol. 343 ,
Magdalena Koziol, a former postdoc at Yale University, was the victim of scientific sabotage. Now, she is suing the...
Antiretroviral drugs can protect people from becoming infected by HIV. But so-called pre-exposure prophylaxis, or PrEP...
Two studies show that eating a diet low in protein and high in carbohydrates is linked to a longer, healthier life, and...
Considered an icon of conservation science, researchers at World Wildlife Fund (WWF) headquarters in Washington, D.C.,...
The new atlas, which shows the distribution of important trace metals and other substances, is the first product of...
Early in April, the first of a fleet of environmental monitoring satellites will lift off from Europe's spaceport in...
Since 2000, U.S. government health research agencies have spent almost $1 billion on an effort to churn out thousands...
- 6 March 2014 1:04 pm , Vol. 343 , #6175
- About Us
A Game for Three Microbes
31 August 2001 7:00 pm
AMSTERDAM--Microbes can play rock-paper-scissors just like children, a new study has shown. Under the right circumstances, three strains of Escherichia coli can co-exist because each has a strategy that beats one competitor but loses to the other. Researchers think this kind of situation may be much more common in the real world than was once thought, and it may contribute to biological diversity.
Ecologists often depict the rivalry between organisms vying for the same niche as all-or-nothing struggle: there are clear winners and losers. But more recently, some ecologists have suggested that such final reckonings are rare, and competition in the real world keeps going. They say the separation of organisms in space often allows them to co-exist.
At the International Symposium on Microbial Ecology here on 28 August, Stanford University ecologist Brendan Bohannan presented a striking example. Bohannan, grad student Benjamin Kerr, and their colleagues used three strains of E. coli. Strain C grows slowly but is armed with a toxin. Strain S is susceptible to the toxin. Strain R is resistant to the toxin, but grows more slowly than S, although faster than C. When the strains were grown in contiguous hexagonal patches on a petri dish, something akin to rock-paper-scissors developed: C killed adjacent patches of S with its toxin, fast-growing S colonized patches of R, and R overran patches of slowpoke C. All three strains persisted in a waltz of circular competition.
The elegant balance broke down, however, when the three strains were grown in a shaking flask. Without home turf defended by growing borders, all of strain S fell victim to strain C's toxin. Then R won by outgrowing C. The bottom line? "Simply allowing for spatial interactions is sufficient for diversity," says ecologist Paul Rainey of Oxford University in the U.K. And biological games like rock-paper-scissors may be under way in all ecosystems, Rainey says. If so, studying them could help solve one of ecology's enduring puzzles: nature's staggering biodiversity.