Direction of vector flights.

<p>The direction is defined by the intersection of the vector flight with a 200° bins. The x-axes give the angels in degrees clockwise from north. The median angle is marked in red for each group. Significant differences in the direction are indicated by different letters under the group names. Clothianidin treated and both imidacloprid treated groups differ significant from the control group but not from each other. The thiacloprid treated group did not differ significantly from all other group (p<0.05, Watson -Williams F-test). The direction of the learned route from the feeder to the hive is 294°, and the direct route from the release site to the hive would be 343°. Note that the x-axis is interrupted for the imidacloprid 0.6 µM group as there was one bee flying north-east with a 10.9° angle from north.