Communication in bacteria

The term quorum sensing (QS) is used to describe communication between bacterial cells, whereby a coordinated population response is controlled by diffusible signal molecules. QS has not only been described between cells of the same species (intraspecies), but also between bacterial species (interspecies) and between bacteria and higher organisms (interkingdom). This chapter compares the evolutionary literature on animal signalling and cooperation with the microbiological literature on QS, and discusses whether bacterial QS can be considered true signalling. From an evolutionary perspective, intraspecies signalling can be explained using models such as kin selection, but explanations become more difficult when communication is described between species. It is likely that this often involves QS molecules being used as 'cues' by other species as a guide to future action or as coercing molecules whereby one species will 'coerce' another into a response.