Environmental fluctuations do not select for increased variation or population-based resistance in Escherichia coli.

Little is known about the mechanisms that enable organisms to cope with unpredictable environments. To address this issue, we used replicate populations of Escherichia coli selected under complex, randomly changing environments. Under four novel stresses that had no known correlation with the selection environments, individual cells of the selected populations had significantly lower lag and greater yield compared to the controls.

ANIMAL COGNITION. Comment on "Number-space mapping in the newborn chick resembles humans' mental number line".

Rugani et al. (Reports, 30 January 3015, p. 534) tested 3-day-old domestic chicks using an innovative experimental setup and demonstrate the presence of the mental number line.