Autoinducers are small signaling molecules used by bacteria to communicate with one another through a process called quorum sensing. When the concentration of autoinducers reaches a certain threshold, it triggers a coordinated response in the bacterial population, allowing them to behave collectively. These molecules play a crucial role in regulating various behaviors, such as biofilm formation, virulence, and bioluminescence. By sensing the density of their own population, bacteria can optimize their activities, ensuring survival and adaptation in their environment.