Fig. 3. Experiment 1. Effect of pattern motion on flight speed. The graph shows mean axial flight speed (V_x) when the pattern on the walls was static (0 pattern velocity), moved in the direction of flight (positive pattern velocity values) or against the direction of flight (negative pattern velocity values). The open circles represent V_x values for various pattern speeds. N denotes the number of bees, n denotes the number of flights. The horizontal lines on the error bars denote standard error of the mean; the uncapped bars denote the standard deviation. The dashed line represents a model of the flight speed data for large negative pattern velocities; the slope of this line is slightly smaller than 1. The solid line represents a model of the flight speed data for the positive and negative pattern velocities near zero; the slope of this line is not significantly different from zero. The dotted line represents a model of the flight speed data for large positive pattern velocities; the slope of the regression line was slightly greater than 1. The equations for each regression are shown. Note: only five bees participated in the data shown for negative pattern velocities, due to difficulties in getting them to enter the tunnel under these conditions.