Even organisms as small as bacteria can, and often do, communicate with each other through a process called quorum sensing, in which each cell releases a small amount of a certain chemical into their surroundings. When the population is large enough that the concentration of this chemical builds up to a certain level, the cells in the population change their behavior. The specifics of this change depend on the species and the situation.

But since this chemical signal is released into the environment, anything around that can sense it can listen in on the communications of a bacterial population. In this study, Justin Silpe and Dr. Bonnie Bassler find a type of virus that uses such a chemical communication as a signal to come out of stasis and hijack a whole population of bacteria at once!

Silpe JE, Bassler BL. 2019. A Host-Produced Quorum-Sensing Autoinducer Controls a Phage Lysis-Lysogeny Decision. Cell 176:268-280.E13.