Fig. 7. Frequency distributions of running speed (A) and continuous running distance (B) in the respirometric chamber. (A) Histograms of running speeds measured in all 46 ants at the five different inclines: -60° (purple data points), -30° (green), 0° (black), 30° (red), 60° (blue). Speeds from 0 to ±5 mm s^-1 were disregarded to avoid disruption of curves by resting periods. Positive and negative running speeds indicate locomotion against and with the direction of airflow, respectively. Speed distributions were approximated by Gaussian fits (curves with respective colours). Peak locations and standard deviations (0.85 times half width) of the Gaussian curves are (in mm s^-1) 0.7, 78 (-60°); 1.1, 101 (-30°); 2.0, 87 (0°); -0.6, 94 (30°); -0.1, 78 (60°). None of the values are significantly different from each other (P>0.05). (B) Histograms of walking distances covered in continuous bouts by ants in the respirometric chamber (time segments >0.4 s during which the ant maintained running speeds >5 mm s^-1; N=42, n=4038 running segments). Level walking, black; ±30° incline, red; ±60° incline, green. Length of respirometric chamber was 500 mm (vertical dotted line).