"Weed early and often" is the key to a productive garden. Interestingly, certain species of ants are also avid gardeners, a practice they've refined over 50 million years. They too weed their underground fungus gardens, but how they know what to weed out has been a mystery. Now, a multidisciplinary team of scientists report in PNAS on June 15 how ants distinguish the good fungus from the bad.
