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An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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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.