English: In this episode two successive waves were generated by a dummy wasp that was moved from left to right (in the image). The episode started at f 1, but the playback session refers only to ff 550–650 (corresponding to 1,700 ms). The dummy wasp was moved 20 cm in front of the nest (shown at the left bottom corner of the image). The part of the nest displayed in the film corresponded to the area marked by the four yellow spots in Fig. 1A and comprised about 1,250 bees of the surface layer; the thorax of the focus bee selected for this film was marked in red. Left panel: black-and-white images, inverted to enhance the contrast of the abdomens; right panel: the same view but displayed as differential image with the motion strength in pseudo colours (with relative motion strength scaled from blue = 0.0 to red = 1.0; see rainbow scale on the right bottom side). Original recording speed: fps = 60 Hz; playback speed: fps = 60 Hz.