Figure 1. Exploring chemotaxis in flies in the presence of air currents.

Álvarez-Salvado et al. performed experiments in which they tracked the movement of flies in small-scale wind tunnels when pulses of an odor (apple cider vinegar) were released from a point source (not shown) and were carried by the wind through the tunnel: in the figure the wind is blowing from top to bottom. Left: tracks of three genetically blinded flies before (black), during (magenta) and after (cyan) a 10 second odor pulse. At the onset of the pulse the flies turn rapidly toward the source of the odor and increase their upwind velocity. When the pulse ends the flies start to change direction in an effort to locate the odor. Right: based on these findings Álvarez-Salvado et al. built a model to simulate the movement of flies in the wind tunnels. The model does a good job of capturing the responses of the flies to various odor pulses.