Triangulation and tracking of agent bees. Sample images (left camera) illustrate the triangulation and tracking challenges; (a) and (b) show the frames f 102 and f 182, respectively; (c) and (d) show details from f 177 and f 184, respectively. In a-b and c-d, luminance values have been inverted for better contrasting of the abdomens. Agent bees identified and triangulated into real-world coordinates were colour-coded regarding their z-positions and assigned unique numbers. The z-values and their differentials (Δz/Δf; fps = 60 Hz) were categorized in 2 × 14 steps of strength (see inset), towards the comb (blue shadings), and away from the comb (red shadings). Agent 58 is indicated by an orange circle in a, and by yellow circles in b-d. (e,f) Time courses of the z-deflection of agent 58 in mm (e) and its differential in mm/frame (f); the experiment was started at time zero; therefore the z-position of agent 58 prior to wave w1 (in e) was not affected by any preceding wave process; vertical bars refer to the time points of the samples (a-d) and have the same colours as the labels of agent 58 used above.