bees were trained to receive a reward after they had flown past a specified number of landmarks. During training, the landmarks were strips of evenly
spaced yellow paper (upper). Spacing interval was randomly varied every 5 min, to ensure the bees could not learn the reward location by measuring flight distance. Different experimental groups were tested on the same landmarks as in training; in tunnels where the stripes were replaced by yellow disks, presenting a smaller cumulative yellow surface; or in tunnels where landmarks were arranged as baffles, so that only one could be seen at a time. (b) Results of an experiment where bees were trained on landmark 3, then tested with landmarks spaced regularly every 40 cm (upper panel)
or irregularly spaced (lower panel). From Skorupski P, MaBouDi HD, Galpayage Dona HS, Chittka L. 2017 Counting insects. Phil. Trans. R. Soc. B 373: 20160513.