But male study subjects paid scant attention to male wings similarly mounted. The next phase of the experiment showed that color was responsible for this choice. I prepared a card with two sets of male wings. A quartz slide that transmits both visible and ultraviolet light covered one set of wings, and a filter that blocks ultraviolet wavelengths overlaid the other. This species displays a sexual difference in ultraviolet reflectance similar to that in the Little Yellow, and after a male's ultraviolet reflectance is obliterated other males treat him like a female.
Color also can influence mate recognition by females.
My research group at Arizona State University took advantage of a dense population of a species known as the Checkered White , Pontia protodice , in a rural area near Phoenix to study this phenomenon. We captured Checkered Whites of both sexes and tethered them by tying one end of a thread around the waist between the thorax and abdomen and the other end to a length of stiff wire. We then used this wire like a fishing pole to display the captive butterflies in sight of females in the field. These free females often took off after the tethered butterflies. Their chases after tethered females halted quickly, whereas they showed far greater perseverance toward the males.