A single-celled protist reacts to threats in surprisingly complex ways
Being single-celled doesn’t necessarily doom a creature to a simple life. A fresh look at a long-dismissed, century-old experiment suggests that so-called primitive organisms can behave in surprisingly complex ways. Stentor roeseli, a tiny trumpet-shaped protist, can dodge, duck or flee in response to an irritating stimulus, changing its behavior when one strategy fails, researchers report online December 5 in Current Biology. The study suggests that single cells, rather than being preprogrammed to react in a certain way, are capable of “changing their minds” based on experience. “This fascinating experiment reminds us that primitive organisms can do complicated things,” says Sindy Tang, a cellular engineer at Stanford University who wasn’t involved in the study. S. roeseli rose to prominence in 1906, when the American zoologist Herbert Spencer Jennings described some of the most complex behaviors ever reported for a single-celled organism. The millimeter-long freshwater protist spends much of its life fastened to drifting algae, using hairlike cilia on its body to sweep food into its mouth. Jennings messed with S. roeseli,...