Think society works better when everyone is honest? You haven't met yeast. Research published  today in PLoS Biology shows that when some of these single-celled fungi cheat, they spur the growth of their entire community. Yeast secrete invertase, an enzyme that splits sucrose into fructose and glucose, their favorite food. Not all yeast secrete the enzyme, however. Some simply slurp up the glucose produced by other yeast, thus "cheating" the system. But this freeloading is actually good for the group: populations with cheaters (small colonies, above) grew 20% more than populations with none. That's because yeast use glucose more efficiently when there's less of it around. So by gobbling up the excess, cheaters are doing their comrades a favor.
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