Many animals bear patterns and markings that may deceive the viewer – for example moths have patterns that create the impression of 3D form to avoid predation. Some of our current work investigates how illusions may be incorporated into animal signals to manipulate the viewer.
Masters student James Firkins is currently testing whether the ocelli on the tail feathers of male great argus pheasants create the illusion of 3D form for viewing females. In The Descent of Man (1871), Darwin said “The ocelli on the wing-feathers are wonderful objects; for they are so shaded that…they stand out like balls lying loosely within sockets. These feathers have been shown to several artists, and all have expressed their admiration at the perfect shading. It may well be asked, could such artistically shaded ornaments have been formed by means of sexual selection?”