Figure 2
Examples of images used during the demonstration in the various experiments. Here we present only one example per type of treatment, but every treatment included a mixture of top and lateral views of the copulating pairs. (a) Unmodified photo where only the background was removed and the colours were made brighter; (b) a "dots" demonstration, i.e. pink or green area (or dot) on the back of the males; (c) a "painted" demonstration, i.e., the whole male and whole couple were coloured in pink or green; (d) dots but in which males eyes were removed; (e) dots in which female eyes were removed; (f) dots in which we removed the eyes of all flies; (g) dots in which we removed the wings of all flies; (h) photo in which we removed the eyes of males; (i) photo in which we removed the eyes of the female; (j) photo in which we removed the wings of males; (k) photo in which we removed the wings of females.
