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A rule from bacteria to balance growth and expansion
Bacteria move along gradients of chemical attractants. Two studies find that, in nutrient-rich environments, bacteria can grow rapidly by following a non-nutritious attractant — but expanding too fast leaves them vulnerable.
Bacteria can sense chemical attractants and use that information to navigate towards resources or away from harm — a process called chemotaxis. But why bacteria chase signals that often do not have much nutritional value has been a long-standing puzzle. Writing in Nature, Cremer et al.1 show that bacterial populations can use non-nutritious attractants as cues for rapidly expanding through nutrient-rich areas, ensuring that plentiful nutrients are available for their future growth. In a second paper, Liu et al.2 build on this work to reveal an unanticipated rule of bacterial evolution: the safest way for a bacterial population to colonize a habitat is not necessarily to expand as fast as possible, because rapid expansion can leave the population vulnerable to invasion by competitors.