Researchers at Rockefeller University found that fruit flies do not simply fly upwind and sweep side to side when they lose a scent, as the long-standing “surge and cast” model suggests. Instead, experiments indicate that they track the edges of odour plumes, repeatedly crossing into the scent, looping through clean air and returning to the boundary, a strategy that may help them locate food or mates in turbulent conditions.

The team tethered flies above a ball acting as a miniature treadmill in darkness, while a steerable airflow delivered controlled pulses of apple cider vinegar. In a virtual 50-millimetre-wide scent corridor, flies spent most of their time outside the plume but made most progress towards its source during brief entries into it; they also followed edges rather than the centre of the corridor. The setup let researchers precisely simulate shifting plumes and scent gradients, offering a clearer view of how small insect brains process unreliable chemical signals.