Butterfly and moth wings do seem to reflect the motto inspiring beauty pageants: 'beauty with a purpose'. The attractively coloured and designed wings make these cold blooded creatures not just beautiful but warm too.
Chitin, the material constituting butterfly scales acts as a thermoregulatory mechanism. The air gaps present in between are responsible for absorbing and reflecting sunlight. The thickness of the scales is also responsible for thermoregulation.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/beauty-purpose
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/down-earth
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/insects
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/environmental-science