Information efficiency of bacterial chemotaxis*

Organisms acquire sensory information to guide behavioral decisions. Past studies have used information theory to understand the maximum amount of information biological sensing systems can transmit, showing that in some cases they can approach the theoretical limits. However, how information constrains the ability of organisms to perform behavioral tasks remains unknown. Here we show that the information a bacterium’s sensory system acquires during navigation sets an upper limit on how fast it can climb a chemical gradient. Then, we quantify how much information E. coli cells acquire by measuring swimming statistics, signal transduction responses, and noise fluctuations in single cells. Finally, measuring their gradient-climbing speeds and comparing to the theoretical limit, we determine how efficiently E. coli use information to navigate.