Cabbage White Butterflies will fly until late in autumn and may begin flight during late winter in Indiana. This May, cabbage butterflies are active in spite of cool to cold temperatures. To fly efficiently, butterflies need to warm their thorax to a minimum temperature, which they do by collecting heat from the sun.
A study in the journal, Nature Science Reports, finds that the cabbage white butterfly wings are excellent reflectors of sunlight.* Detached cabbage white butterfly wings held at a 17 degree angle to a solar power cell increased the power by 43 percent. When scales removed from the wing were attached to tape and held in similar fashion to reflect light onto the photo cell, most of the increase in power was preserved. The cabbage white butterfly scales reflect sunlight to more rapidly heat the thorax and may serve as a model for biomimetic, light-weight, light reflective surfaces.
Shanks, K. et al. White butterflies as solar photovoltaic concentrators. Sci. Rep.
doi: 10.1038/srep12267 (2015)