Butterfly wings have been described as “billboards” advertising the species and properties of the owner. Butterfly wings have an overall color motif, but also smaller patches of color. These color spots can signal male or female as in the cabbage white butterfly, Pieris rapae. Males possess a single black spot on the dorsal surface of each forewing. Females possess two spots> Can butterflies “see” these smaller patterns and respond to the information they provide?
A group of scientists* created a butterfly model that would flutter its wings. They measured the attraction of male and female cabbage white butterflies to male and female pinned specimens and moving models. They created a two-spot model by adding a spot to a male butterfly wing with a marker. Models consisted of male wings, female wings and a male wing with a spot added. In both cage and field experiments, males showed more interest in the females and two spot models. Females were less interested in conspecifics than males, but females showed a preference for the one spot males over the females and two spot models. This suggests that butterflies can see spot patterns in wings and may use the spots in mate selection.
*Andrew M. Stoehr, Kaitlin Hayes & Erin M. Wojan. Assessing the Role of Wing Spots in Intraspecific Communication in the Cabbage White Butterfly (Pieris rapae L.) Using a Simple Device to Increase Butterfly Responses. Journal of Insect Behavior
pp 1-13. First online: 04 May 2016.